Transcript for:
Understanding Infectious Disease Diagnostics

LEC 59[a]: INTRO TO INFECTIOUS DISEASE Why do we perform diagnostic testing? * Disease presence or absence * Gauge severity * Monitor response to therapy (e.g localize disease in body) * Inform prognosis * Note: must look at the whole picture & understand pathogenesis of organisms Selection of the best diagnostic test * Helps to reach a diagnosis swiftly * Allows therapy initiation sooner * Decreases medical costs * Helps prevent diagnostic errors * Many diagnostic errors are due to ordering the wrong test or submitting the wrong sample All Tests Are Not Created Equal * No test is perfect! * Tests are compared to a reference standard (sensitivity & specificity) * (“Reference standard” is the newer terminology for “gold standard”) * Necropsy is the gold standard for most infectious diseases * Predictive values vary with disease prevalence 2 x 2 Tables Sensitivity = TP / (TP + FN) * The proportion of disease positive patients that test positive * Example: 100 dogs have an infection and 90 test positive. What is the sensitivity? → 90/100 = 90% * Highly sensitive test: many FPs → negative test rules out disease * Example: antibodies for Lyme disease Specificity = TN / (TN + FP) * The proportion of disease negative patients that test negative * Example: 100 dogs are NOT infected, 95 of those test negative. What is the specificity? → 95/100 = 95% * Highly specific test: many FNs → positive test rules in disease * Example: Cryptococcus fungal culture of CSF Ideal Test: highly sensitive & highly specific * Few false negatives & few false positive * Almost no diagnostic tests are like this Predictive Values * More helpful to inform clinical decision than just sensitivity & specificity Positive Predictive Value = TP / All positives * Proportion of test positives that have the disease Negative Predictive Value = TN / All negatives * Proportion of test negatives that have the disease Example: You have discovered a new virus that can turn cats into zombies. The virus affects 10 of every 1000 cats. You also designed a diagnostic test for this virus that has 90% sensitivity and 90% specificity. * If a cat tests positive, what are the chances that the cat actually has the disease? * 90% sensitivity = 9/10 of the cats will test positive * 90% specificity = 90% of cats without disease will test negative * PPV = 9/108 = 8.3% * Thus, even if the cat tests positive, it likely is not disease positive because the disease is low prevalence * This is why shelters do not test for FIV or FeLV anymore * Need to perform another diagnostic test to confirm * This test is most valuable when the result is negative: you are very confident that this cat does not have disease * NPV = 891/892 = 99.9% Infectious Disease Tests Organism Detection Antibody Detection * Assess for direct evidence that an infectious organism is present in your patient * Assesses for whole organisms, antigen, or nucleic acid (DNA or RNA) * Advantages: * Positive implies presence of organism * Can localize the disease process (e.g. histoplasmosis in bone marrow explains pancytopenia) * Sensitive in the immunocompromised (e.g. on chemotherapy or immunosuppressants) * Quantification of organism numbers may be possible * Disadvantages: * False positives possible * Positive test doesn’t always imply disease (may be part of normal flora) * No sense of chronology (contrast to: antibody tests) * Low sensitivity for some infections (often when the organism load is low) * Assess response to an infection * * Upon exposure to new antigen: IgM is the first antibody made → peaks at 1-2 weeks → wanes → isotype switching from IgM to IgG * Paired acute & convalescent antibody titers: required to document infection for acute diseases (e.g. leptospirosis, anaplasmosis) * Acute sample: low antibodies * Convalescent sample: 4x ↑ antibody titer is indirect evidence that an infection is present * Single antibody titers: can be accurate for some chronic, persistent infections (e.g. Lyme, FIV) * Single time point: high levels of IgG * Disadvantages * Antibodies must be present to be detected! * Negative early for acute diseases * Before a good Ab response * Negative with localized disease (e.g. URIs) * When you don’t get a good systemic response * Negative in immunocompromised patients * When they can’t mount a good Ab response * False positives are common: * Previous exposure or infection * Cross-reactivity * After vaccination (except DIVA assays) * **DIVA = Discrimination of Infected and Vaccinated Animals**: detects antibodies that should not be made as a response to a vaccine (e.g. some Lyme tests) * Poor indicators of treatment success (because antibodies stick around after infection resolves) Cytology & Histopathology: performed on impression smears, aspirates, bodily fluids, or tissue samples (histology) * Special stains (e.g. IFA) can be applied * Can identify organisms directly * Can be very insensitive Culture * Majority performed with cell-free culture * Allows for organism identification & antimicrobial susceptibility testing * Organism Detection Identification Techniques * Morphology * Biochemical testing * Matrix Absorption Laser: Desorption/Ionization-Time of Flight Mass Spectrometry (MALDI-TOF): isolate bacteria from culture → shoot with lasers to break up organism → each organism has its own “fingerprint” * Pitfalls * False negatives with: low specimen sizes, inadequate incubation times, or after ABX admin * Some organisms un-culturable (e.g. Bartonella, Mycoplasma), fastidious, or need special labs * Loss of viability with storage & transport * False positives from contamination by commensals or saprophytes * Can be expensive Immunoassays Detecting Antigen * Detect organism proteins * Test has antibodies → add patient sample: organism protein in patient sample binds to antibody → add second antibody which binds to organism protein & acts as an indicator * Methods: * Enzyme-linked immunosorbent assay (ELISA) * Lateral flow assay (LFA) * Direct fluorescent antibody (DFA or direct IFA) * Latex agglutination (LA) * Enzyme immunoassay (EIA) * Common Examples: * FeLV SNAP test * Parvovirus fecal antigen SNAP test * Giardia fecal antigen DFA * Dirofilaria immitis (Heartworm) test * Cryptococcus latex agglutination test (LCAT) * Pitfalls * False negatives with low antigen levels * False positives from cross-reaction with other organisms (esp. fungal assays: histo & blasto) * Variable sensitivity & specificity depending on assay Nucleic Acid Assays - PCR * Detects organism DNA or RNA * Need organism specific primers + polymerase enzymes * Warming & cooling mixture → exponential replication of nucleic acid * Pretty specific in most situations * Can be detected in two ways * Endpoint (qualitative): indicates whether or not nucleic acid is present * Real-time (quantitative): indicates amount of nucleic acid present * Indicated when: * When it is difficult or dangerous to culture * When you need very rapid results (e.g. FIP) * Prior to robust antibody production (acute disease) * In animals that won’t mount a strong antibody response – immunocompromised * Pitfalls: * False negatives if *insufficient sample* type/size (e.g. Leptospirosis: undetectable in urine until 7 days post-infection) * False negative if there is strain variation – DNA primers must match! * Inhibition of enzymes from some bodily fluids: feces, urine * False negative from degradation of nucleic acid – esp. RNA * False positives from contamination – endpoint PCR more likely contaminated * Can detect inactivated organisms if nucleic acid still present Immunoassays Detecting Antibody * Test has piece of organism → add patient sample: antibody in patient sample binds to piece of organism → add second antibody which binds to first antibody & acts as an indicator * Method: * ELISA * Lateral flow assays (LFA) * Indirect fluorescent antibody (DFA or indirect IFA) * Agglutination tests * Western Blot * Gel immunodiffusion * Examples: * FIV test * Tick borne disease on 4DX * Ehrlichia, Anaplasma, Lyme * NOT heartworm (which is an antigen test) * Leptospirosis MAT * Babesia, Anaplasma ELISAs * Coccidioides AGID How do you choose? How do you choose? * Organism Test * Acute disease * Immunocompromised host * Antibody Test * Chronic, persistent infection * Organisms undetectable * Sensitive Test * For screening purposes * To rule OUT disease * Specific Test * To confirm a diagnosis * To rule IN a disease LEC 60: FEVER Fever * Non-specific adaptive immune response * Helpful for immune response until a certain body temp & duration * Usually a combo of both generating heat & retaining heat * Exogenous (eg. LPS) or endogenous pyrogens stimulate macrophages to release endogenous pyrogens: Il-1, Il-6 & TNF-α * Alter hypothalamic set point * High body temps can fluctuate & usually do not persist at very high temps * Localizing the problem: can be difficult & expensive * If can’t find specific differential, look at statistics (e.g. immune disease for older/middle-aged large breed dog) Differs from: Hyperthermia * Normal set point retained (hypothalamus does not play a role) * Non-specific adaptive response usually to external factors * Body overheats due to undesirable heat retention or over-production of heat (e.g. heat stroke, excitement, seizures, tetanus, adverse drug reactions, strenuous exercise) * Athletic dog body temps routinely reach 106-108℉ but rapidly drops back down * Unlike fever: * Not responsive to anti-pyretics (because not driven by inflammation) * Can be severe & rapidly fatal (if persists at 106-108℉) Humoral Mechanism of Fever Induction * Endogenous pyrogens (e.g. Il-1, Il-6 & TNF-α) activate the arachidonic acid pathway in microglial cells to produce PGE2 * Entry across BBB via circumventricular organs around the hypothalamus * ↑ PGE2 raises the set point in the hypothalamus * Active generation & retention of heat occurs as a sympathetic response: * Vasoconstriction, shivering, non-shivering thermogenesis, brown adipose metabolism Neuronal Hypothesis of Fever Induction * Complement C5a stimulates PGE2 production by the liver → liver signals hypothalamus via neuronal pathway involving the vagus nerve → same consequences as humoral mechanism “Drug Fever” (misnomer) * Not actually a fever: alters hypothalamic setpoint BUT due to exogenous products (not PGE, IL1, IL6, etc.) * ↑ body temp due to drug-induced alterations in muscle activity OR sensitivity of hypothalamic neurons to changes in body temp * Hypothalamic neurons influenced by norepinephrine, dopamine, serotonin, acetylcholine, prostaglandin, & neuropeptides * Causes: * Malignant Hyperthermia Syndrome (classic example but not common) * Autosomal dominant mutation of ryanodine (RYR1) receptor in dogs * Excessive intracellular release of calcium within myocytes in the presence of anesthetic agents → rhythmic contractions & heat production * Serotonin Syndrome * Medications affecting serotonin levels * Many commonly used drugs implicated: tramadol, antidepressants, antinausea * Neuromuscular & hypothalamic effects * *Opioids in cats* (most common): used for anesthesia & sedation but causes unpredictable hyperthermia * Almost all opioids: morphine, oxymorphone, hydromorphone, fentanyl, buprenorphine * EXCEPT: Tramadol (synthetic mu analog) NOT associated with ↑ temperature * NOT dose-dependent * Mechanism appears to be interference with hypothalamus → excitement, excessive sedation, staring, hyperthermia (>107°F or 41.7°C) Factors that Modify Fever * Extremes of age (neonates & old): ↓ body temp (e.g. neonate: no fat stores, slow metabolism, high surface area) * Renal failure (most common): fever ≥ 101ºF * Uremic toxins are endogenous cryogens or antipyretics, or alter basal metabolic rate (i.e. ↓ core body temp) * Appropriate body temp ≈ 97-98℉ * If normothermic, may actually be febrile due to something infectious of inflammatory (e.g. pyelonephritis, lepto) * Immunosuppression * Anti-inflammatory drugs (e.g. glucocorticoids, NSAIDs) Fever Classifications Type * Persistent = above normal throughout day, does not vary more than 2 ºF * Remittent (fluctuating) = above normal throughout day, varies more than 2 ºF (e.g. endocarditis, bacterial shedding) * Intermittent or Relapsing (e.g. Borrelia, cyclic neutropenia, immune-mediated disease) * Can reach pretty high temps * Helpful to narrow down ddx Magnitude * Low grade (<104ºF): chronic (usually atypical infections: do not develop robust immune response & can be undetected for years) * Fungal infections (classic) (except candidiasis) * Bartonellosis * Lyme disease * Mycobacterial infections * Mycoplasma infections * High grade (≥104ºF) (or may be low grade) * Viral infections * Gram- & some Gram+ bacterial infections * Salmon poisoning disease * Rocky Mountain Spotted Fever * Plague & tularemia * Cytauxzoonosis in cats * Hyperpyrexia (>106.7ºF) Underlying Problem * Febrile neutropenia * Central fever (e.g. brain hemorrhage) * Fever of unknown origin (FUO) Fever of Unknown Origin (FUO): becoming less relevant of a term & less diagnosed as vet med advances * No standardized definition in vet med but may be defined as an animal with a fever lasting: * 3 outpatient visits (diagnostic tests & labs but still no known cause of fever) * 3 days in the hospital without elucidation of a cause * 1 week of “intelligent & invasive” ambulatory (outpatient) investigation Older Study (1998): adult dogs (n = 101) with FUO diagnosed by pDVM & referred to specialty * ~50% either immune-mediated (esp. IMPA) or bone marrow disease (esp. neoplasia, myelodysplasia) * 20% FUO * Others: infectious, misc. inflammatory, non-marrow neoplasia Recent Study: juvenile dogs (n = 140) with fever * Most (79%): non-infectious inflammatory * 48% steroid responsive meningitis/arteritis (SRMA) * 13% IMPA * 18% other * Some (17%): infectious disease * 3% congenital immunodeficiency Study: cats (n = 105) with fever * Almost always (39%): infectious * 20% FIP * 18% non-infectious inflammatory: pancreatitis/peritonitis * 12% neoplasia * Very uncommon (6%): immune-mediated * 10% miscellaneous inflammatory disorders * 15% FUO Causes of Fevers Infectious[b] Routine Bacterial * Discospondylitis: painful, proprioceptive deficits * Meningitis: low head carriage * Soft tissue cellulitis (CATS) * Visceral abscess (“When you see a febrile cat, the first thing you do: look for an abscess”) * Peritonitis, pyometra (common in intact female dogs), pyothorax, pneumonia, pyelonephritis, pyoderma, prostatitis * Septic arthritis * Osteomyelitis * Endocarditis: heart murmur * Secondary to FB (common) * Salmonellosis: esp. raw diet (caution: zoonotic) Atypical Bacterial (e.g. tick-borne diseases) * Mycobacteriosis * Lyme borreliosis * Ehrlichiosis/ Anaplasmosis * RMSF * Salmon poisoning disease * Bartonellosis * Leptospirosis * Hemoplasmosis Fungal: tend to be chronic, low-grade fevers (keep in mind geographic distributions) * Blastomycosis * Histoplasmosis * Coccidioidomycosis * Cryptococcosis * Molds (e.g. Aspergillus) * Pythiosis Viral * FeLV, FIV, FIP, FHV-1, FCV, FPV * CPV, CDV, rabies Protozoal: may be chronic, low-grade fevers * Babesiosis * Leishmaniasis * Toxoplasmosis * Neosporosis * Hepatozoonosis Immune-Mediated Neoplasia Inflammatory Common in dogs, NOT in cats * Polyarthritis (IMPA) (common) * Meningitis * Systemic lupus erythematosus (SLE) * Immune-mediated hemolytic anemia/thrombocytopenia: don’t tend to have fever but can * Sterile nodular panniculitis * Drug reactions Any * Most likely round cell neoplasia: * Leukemia * Lymphoma * Multiple myeloma * Carcinoma * Sarcoma * Pancreatitis * Phlebitis * Cholangitis LOCALIZE Steps are in order, but not all steps are required for each animal (dictated by clinical suspicion) * Start non-specific (e.g. PE) then get more targeted starting with cheaper & less invasive (e.g. rads, AUS) (1) PE: very important for infectious diseases (also travel hx) * Eyes: ocular & fundic exam * Look for: flare (anterior uveitis) * Skin * Look for: petechiae, ectoparasites, draining lesions, scabs * Rectal exam (ALWAYS in dogs, only anesthetized cats) * Musculoskeletal exam (esp. important for IMPA) * Joints palpation & range of motion * Long bone & spinal cord palpation (2) Laboratory Work * CBC * Chemistry profile * Urine * Urinalysis * +/- aerobic urine culture & sensitivity (e.g. bacterial infections) (3) Imaging * TXR & AXR * AUS (esp. abdominal visceral disease) (e.g. if you palpate something abnormal, back pain) * Keep in mind: very expensive (e.g. TXR $450, AUS $700) * Make sure to provide radiologist with all the case info for best interpretation results (4) Repeat the exam!! * Yourself or ask a colleague to do a PE (5) * Arthrocentesis: IMPA is a common cause of FUO * Joints may look & feel normal * May have crouched posture * Erosive vs. non-erosive * LN aspirates * Blood cultures (more relevant for specialty than GP): * When: patient is febrile, before ABX given * Virtually all patients with persistent fever * How: using aseptic technique * Never through an IVC (unless brand new because biofilms develop quickly) * How Many: at least 3 within 12 hr period * Sensitivity is not great → more samples increase the likelihood of a positive result * ANA (antinuclear antibodies): for SLE (uncommon but has multiple immune-mediated manifestations) * Serology: always remember limitations of these tests * Tick-borne diseases (esp. if thrombocytopenic) * Anaplasma phagocytophilum * Ehrlichia canis * Rickettsia rickettsii * Borrelia burgdorferi * Leptospirosis * Toxoplasma & Neospora * Fungal panel * Antibody: Coccidioides * Antigen: Cryptococcus, Aspergillus, Histoplasma, Blastomyces (6) What else? * CSF tap * Bone marrow aspirate & core biopsy * Repeat PE * Repeat blood work * Repeat spinal radiographs * Repeat titers Take-Home Points * Never underestimate the power of a PE (most powerful tool) * Fever does not imply infection (nor does an inflammatory leukogram) * But it is the most common cause in cats * Localize, localize, localize * Fever work ups can be expensive * Tell client clear expectations CBL 6: FEVER CASE 1: Fannie – 2 y FS Pitbull terrier * Presenting complaint: fever, inappetence, lethargy * Pertinent Hx: 2-3 month cycles of recurring episodes * Episodes last ~1 week, take 2-3 weeks to fully recover * 6 episodes over the last year * Last visit to pDVM was 3 days prior to presentation * Previous evaluation & work up * Peripheral lymphadenopathy * Leukocytosis characterized by mature neutrophilia * Chemistry panels WNL * Previous therapy (no convincing response) * Doxycycline * Enrofloxacin * Cefovecin * Meloxicam * SC fluids Physical Examination * QARH, T 105.9, P 110, R30, BW 24.1 kg * INTEG: Full clean haircoat; no ectoparasites; erythematous papular crusted rash along caudal ventrum. Erythematous & mildly alopecic interdigital epidermis. * EENT: Eyes clear OU, no ocular discharge OU. No nasal discharge. Ears clean AU. Throat: mild gingivitis, mandibular prognathism. Pink MM, CRT < 1 sec. * MS: BCS 6/9. Ambulatory x 4. Symmetrical muscling. Reluctant to flex neck laterally and ventrally. * CV: No murmurs or arrhythmias ausculted. Femoral pulses synchronous bilaterally, no deficits. * RESP: Eupneic. No crackles, wheezes, or increased lung sounds noted. * GI/GU: Abdomen tense, grunts when palpate it. No organomegaly or abdominal masses palpated. Rectal smooth, symmetrical, no masses. Small amount of frank blood. Anal glands feel full. * NS: Mentation appropriate. Menace, palpebral and PLR present. * LN: Subtle submandibular lymph node asymmetry (right>left) Problem List * Fever * Neck pain? * Hx neutrophilia * Hx peripheral LN enlargement CBC * HCT 35.4% (40 - 55) * MCV 62.5 fl (65 - 75) * MCHC 36.7 g/dL (33 - 36) * Retics 40,900/uL (7,000-65,000) * WBC 42,820/uL (6,000-13,000) * Bands 428/uL (rare) * Neut 37,682/uL (3,000-10,500) * Lymph 3,426/uL (1,000-4,000) * Mono 1,285/uL (0-1,500) * TPP 6.6 g/dL (6.0 – 8.0) * Platelets 128,000/uL (150,000-400,000) Chemistry * Total protein 6.2 g/dL (5.4-6.9) * Albumin 1.9 g/dL (3.4-4.3) * Globulin 4.3 g/dL (1.7-3.1) * Creat 0.6 mg/dL (0.8-1.4) * BUN 21 mg/dL (11-33) * Glu 92 mg/dL (86-118) * Chol 160 mg/dL (139-353) UA * SGr 1.018 * Well hydrated * 25 mg/dL protein * pH 7 * 3 mg/dL bilirubin * 5-10 RBC/HPF * 5-10 WBC/HPF * UPC 2.0 * Common finding in febrile dogs * Urine culture negative Skin: unremarkable Eyes: ocular & fundic exam WNL Rectal Exam: unremarkable Musculoskeletal Exam: * Joints feel normal – no pain, warmth or swelling * Repeatable cervical spinal pain? AUS * Mild mesenteric lymphadenopathy * Remaining abdominal organs unremarkable Radiographs normal * Vertebral Column Radiographs (allows collimation & bone technique): look for * Discospondylitis * Multiple myeloma (fracture of dorsal spinous processes) How about another PE? → more thorough neuro exam * General Observations: Quiet, alert, responsive. Mentally appropriate. * Gait: Ambulatory with no lameness or ataxia noted. Low head carriage. * Cranial Nerves: No abnormalities found. * Conscious proprioception: Intact. * Segmental reflexes: Intact. * Palpation: No pain found on palpation. Resists lateral flexion with no overt pain elicited. Appears to move head and neck freely when not manipulated. * Neuroanatomic localization: no overt neurologic abnormalities * Low head carriage & quiet mentation may be due to fever or other aspects of her systemic disease. Recommend pursuing possible causes of fever, including immune-mediated joint disease & discospondylitis. Meningitis cannot be ruled out as a cause of her clinical signs & an MRI & CSF tap would be recommended if other causes are excluded Updated Problems: all non-specific, just markers of inflammation * (Intermittent) fever ? * Neck pain * Mild microcytic nonregenerative anemia * Moderate neutrophilic leukocytosis * Mild thrombocytopenia * Moderate hyperglobulinemia * Proteinuria Differentials Fever * Meningitis * Steroid responsive meningitis arteritis - classic signalment (young large breed dog) * Infectious * Immune mediated polyarthritis * Can explain the neck pain * Multiple myeloma * Bacteremia - source? (somewhere that evades immune system, e.g. endocarditis, nephritis) * Less likely due to hx of many ABX Microcytic nonregenerative anemia * Anemia of inflammatory disease: typically mild * Iron deficiency (esp. with microcytosis) * Typically loss through the GIT (usually do not have melena unless severe) * Liver insufficiency (portosystemic shunts - often microcytic) * Preregenerative * Endocrine: Hypothyroid, Addison’s, Kidney disease * Bone marrow disease Neutrophilia * Infectious (degenerative left shift = indicator) * Inflammatory * Immune * Neoplasia Thrombocytopenia * ↓ production * Destruction * Sequestration * Consumption Additional Tests - Results * Arthrocentesis (perform before CSF tap because less risky) * Gross findings: small volume, relatively normal in appearance * Cytology: ↑ (18-42%) non degenerate neutrophils but relatively normal cellularity → inconsistent with IMPA * Normal cell type: macrophages (“anywhere there’s fluid there should be macrophages”) * Aerobic & anaerobic blood cultures: negative * Ideally when dog is febrile * CSF Tap: hypercellular with majority neutrophils → suggestive of meningitis * Normal: * Low cellularity (<5 cells) * Low protein (<25 mg/dL) * Diagnosis: steroid responsive meningitis & arteritis * Treatment: immunosuppressive glucocorticoid therapy (very long course: months to years) CASE 2: Dash 1.5 y MI Greyhound * PC: fever/difficulty walking * 2-3 day history of progressive cough, hyporexia & shifting lameness * Owner took temperature – 103ºF * From kennel of dogs in Coalinga (Central Valley) with Babesia & other vector borne disease PE * GEN: T: 103.6ºF, P: 96, R: 20, QAR, mm: pink, CRT 1 sec, BCS: 4/9, Wt: 34kg * Prefers to be laterally recumbent, must be helped into standing position, stiff gait when prompted * Pain on flexion/extension of multiple joints * Both carpi, tarsi, elbows, shoulders * Remainder WNL CBC * Hct 34% * 15,000 retics * WBC 21,910 * 19,062 neuts with 219 bands (toxic) * Platelets clumped Chemistry * Albumin 2.7 * ↑ loss (GI, renal, blood loss, cavitary effusion) * ↓ production (liver insufficiency) * Malnutrition (esp. abused or feral animals) * Globulin 3.6 * Inflammation * Neoplasia: multiple myeloma, lymphoma, plasma cell tumors * Infection * Immune-mediated disease * Hilar lymphadenopathy Arthrocentesis: 4 joints sampled → indicative of IMPA * 10,000-15,000 cells/uL * Normal: 1,000 cells/uL * 57-87% non degenerate neutrophils Infectious Disease Testing * 4Dx Snap Plus (Ehrlichia, Anaplasma, Lyme, Heartworm): negative * Vector-borne PCR panel (Anaplasma spp., Bartonella spp., Borrelia burgdorferi, Ehrlichia canis, Rickettsia spp., Babesia spp. & Mycoplasma spp.): negative * Coccidioidomycosis titer - IgM positive IgG negative (often comes later) → Valley Fever * IgM indicates recent infection Problem List: * FEVER * Polyarthritis * Cough with hilar lymphadenopathy * Hyporexia * Neutrophilic leukocytosis with a left shift * NNN anemia * Hypoalbuminemia * Hyperglobulinemia * Raw food diet Differentials * Primary IMPA * Secondary IMPA * Infectious * Vector borne disease? (Tick-borne) * Coccidioidomycosis (other systemic mycoses?) * Neoplasia * Histiocytic sarcoma * Lymphoma * Medications * Sulfa drugs IMPA = type 3 hypersensitivity (chronic immune-complex deposition) → think about: * Fungal disease * Routine bacterial infections in atypical places/immune privileged areas (e.g. eyes, joints, prostate, brain, kidney, endplates) * Diagnosis: Secondary IMPA due to Valley Fever * Treatment: * Fluconazole 5 mg/kg PO BID x 4-8 weeks * Effective against Valley Fever * Prednisone 0.5 mg/kg PO q24h for 5 days * Glucocorticoid for comfort to start eating CASE 3: Mocha – 8-year MC Ocicat * Presents for bilateral ureteral obstruction * Bilateral stents placed at VMTH * Esophagostomy tube placed under same anesthesia * Placed because animals often do not feel well after surgery & are reluctant to eat * Fever developed 4 days after surgery (103.3) & e-tube site warm * E–tube culture may not be necessary because normal flora will be present * More important if animal has been on ABX & develops hospital acquired infection in the face of ABX * Show Staph. pseudintermedius infection * Serratia is not a big deal, likely environmental * Often NOT treated systemically → instead remove the E-tube & clean site/topicals * If doesn’t resolve: use ABX * Chloramphenicol: not tolerated by cats * Doxycycline: OK but stricture formation * Gentamicin: avoid because nephrotoxic Differentials (febrile cat in hospital who recently had anesthesia) * Inflammatory * Pancreatitis (poor perfusion under anesthesia & pancreas is sensitive) * Phlebitis** (important differential for hospitalized patients with IVCs) * Infectious * Aspiration pneumonia * Septic peritoneum: due to surgical procedure/E-tube placement * E-tube abscess/cellulitis * Immune-mediated (uncommon in cats) * Neoplastic * Opioid use What’s next? * Evaluate use of opioids * Check IV catheter (for phlebitis) → pull if no longer needed/no other findings * Investigate e-tube site * AUS (for pancreatitis) * Consider spec fPl * TXR (for aspiration pneumonia) Treatment * Minimize opioid use if possible * Replace IV catheter * Remove e-tube * Topical therapy for e-tube * +/- initiate antimicrobial topical therapy (better to just do warm compress & nursing care) LEC 61: ATYPICAL BACTERIA – ACTINOMYCOSIS, NOCARDIOSIS, MYCOBACTERIOSIS Atypical Bacteria * Wikipedia: “bacteria that do not get colored by gram-staining but rather remain colorless (neither gram + nor gram -)” * Does NOT apply to actinomyces & nocardia (both gram+) * Causes of atypical pneumonia in humans → organisms that do not cause ‘typical’ lobar pneumonia * Mycoplasma, Chlamydophila pneumoniae, Coxiella (Q-fever) Clinical Questions: Nocardia & Actinomyces * How common are Nocardia & Actinomyces infections in CA? * Actinomyces is very common, Nocardia is rare * (Mycobacteria are uncommon) * How do Nocardia & Actinomyces differ in their transmission? * Look the same but very different pathogeneses * What is the typical signalment of a dog with these infections? * How do dogs with these infections typically present? Cats? How is the diagnosis ultimately made? * What treatment is recommended for these infections? Actinomyces & Nocardia * Filamentous, **branching, Gram+** bacteria * Light microscopy: may look like fungi but much narrower & Gram+ * Opportunists: usually do not cause disease in immunocompetent hosts * Chronic pyogranulomatous inflammatory lesions * Sulfur granule (‘gritty mineralized chunks’): large colonies that form & are visible macroscopically * More common in Actinomyces * Sporadic disease * Not transmitted between animals CASE: ‘Jack’ 3yo M GSHP * Hunting dog * Ran into fence ~6 months ago * Last month: less active, eating less, now losing weight, difficulty breathing * Chronic * PE: T=103F, RR=80, ↓ breath sounds (which implies pleural effusion), muffled heart sounds Actinomyces Clinical Findings * Skin: firm to fluctuant swellings, +/- draining tracts * Serosanguinous to purulent fluid (“tomato soup-like exudate”) * Sometimes “sulfur granules”: more common in Actinomyces * Other Sites: * Fever, anorexia, weight loss * Lungs: pleural effusion & pyogranulomatous pneumonia * Bronchointerstitial patterns, **hilar lymphadenopathy**, extrapulmonary masses, pleural effusion → major ddx: fungal infection * Pericardial involvement * * Abdomen: abdominal distension, mass lesions, organomegaly * Retroperitoneal space: spinal pain, sometimes PL paralysis/paresis * Possible spondylitis ventral to vertebrae due to abscessation * CNS: neuro signs (hyperesthesia, tetraparesis) Nocardia Etiologic Agent * Facultative or obligate anaerobe * Normal oropharyngeal & GI inhabitant * NOT in environment * Associated bacteria important in disease: utilizes O2 → allows actinomyces to proliferate Etiologic Agent * Aerobe * Found in environment – ubiquitous soil saprophyte: house dust, beach sand, garden soil, swimming pools * Usually NOT associated with other bacteria Risk Factors * Common * Young adult to middle-aged large breed dogs * Immune competent animals are affected * Immune defense is breached due to penetrating material Risk Factors * Uncommon to rare * Cats or Young adult purebred dogs * Genetic immune deficiency * ¼ to ⅓ of dogs (& humans) are immunosuppressed Pathogenesis * Penetrating material (e.g. grass awns/foxtails in CA) contaminated in oropharynx, migrates from airways or GIT → thoracic & abdominal cavities * Diagnosis may be delayed months to years * Bite wound inoculation * Cervicofacial actinomycosis: slowly grows as abscesses/pyogranulomatous masses (may be mistaken for tumor) * Limb or subcutaneous tissue infections * CNS actinomycosis: hematogenous spread or extension from head/neck (basilar meningitis: swallows plant awn → migrates to base of spine → ascending CNS infection) Pathogenesis * Inhalation from environment → systemic spread * Bite, scratch, surgical, or foreign body wounds → subcutaneous nocardiosis * Example: cats with feeding tube * Hematogenous dissemination to other organs: * CNS * Eyes * Joints * Bones * Kidney * Heart Diagnosis * Gram stain: thin Gram+ beaded branching filaments * Indistinguishable by Gram staining * Culture: multiple specimens, biopsy if possible (need high yield, NOT just a swab) * Slow growing, susceptible to overgrowth → alert lab to incubate 2-4 weeks * Smooth & moist or wrinkly, velvety colonies (“molar tooth”) * Histopath: use methenamine silver & Gram stain (does not stain well on H&E or PAS) * Central necrosis surrounded by neutrophils, macrophages, lymphocytes, & plasma cells * Fibrosis * Tissue granules & other bacteria suggest Actinomyces Diagnosis – Culture: * Fastidious * Some tolerate aerobic conditions * NOT acid-fast Diagnosis – Culture: * Grows on simple media * Variably acid-fast * May be contaminant from a non-sterile site Treatment * **Penicillin** derivatives * Tend to be very susceptible to penicillin * Prognosis: good – cure rate: ~90% * Sometimes euthanized if severe (e.g. severe pyothorax, many plant awns) Treatment * Prolonged treatment with high doses of antimicrobials to prevent relapse * Cutaneous infections: 1-3 months * Pulmonary infections: 6 months * Systemic infections: 12 months * *Sometimes shorter duration if the foreign material can be removed * Drain abscesses or pyothorax (not penetrated by ABX): chest tube for 4-10 days * Bronchoscopy +/- exploratory surgery may be required Treatment * **TMS** * Susceptibility testing is not great at predicting susceptibility of Nocardia * Prognosis: guarded (due to underlying immunosuppression) CASE: ‘Belly’ 6 yo MC DSH * Evaluated for renal transplant * FeLV/FIV, urine culture negative * Blood transfusions * Interstitial & glomerular fibrosis * Gastrostomy tube placed * No complications * Treated with immunosuppressive drugs (cyclosporine & prednisone) to prevent graft rejection * 2 years later * 2-week history lethargy, inappetence * Today depressed, dyspneic * PE: * T 100.8F, P 240, R 55, BCS 7/9, Obtunded, Fair pulses, pink MM, CRT 1 sec * Normal temp because immunosuppressive drugs * Shallow breathing, decreased lung sounds * Anisocoria, intact PLRs, CP deficits, absent menace, Chorioretinitis * Treatment * Broad spectrum ABX: Enrofloxacin & Ampicillin * Oxygen + Fluid therapy * Day 2: respiratory & cardiac arrest * Gram stain: Gram+ branching filamentous * * Necropsy: Nocardia isolated from lung & liver * Necrotizing pyogranulomatous inflammation with intralesional filamentous bacteria * Lung, liver, myocardium, diaphragm, spleen, allograft, adrenal, stomach, brain, meninges * Pyogranulomatous choroiditis Lab findings: * HCT 30%, 22860 WBC → anemia & marked leukocytosis * 19660 neutrophils, 2286 toxic bands (left shift: suggests bacterial infection), 457 lymphs, (may be due to immunosuppressive drugs) 229 monos, 229 eos, adeq plts * Na 136, K 3.5, Cl 98, albumin 1.4, globulin 3.4, Tbili 1.5, creatinine 0.8, BUN 48 * UA: SGr 1.054, 3+ bili (always abnormal for a cat), 1+ blood, 0-2 WBC * Urine culture negative * Cyclosporine trough level: 1100 ng/mL → indicates opportunistic infection * AUS: WNL * Rads: marked pleural effusion, mass lesion in caudodorsal lung?, ↓ abdominal detail * Mycobacterium Etiologic Agent * Do NOT confuse with mycoplasmas (no cell wall: don’t survive well in environment) * Gram+, aerobic, nonmotile * Cell wall rich in mycolic acid (lipid): RESILIENT * Resistant to phagocytosis (proliferate inside of macrophages) * Acid-fast: retain carbol fuchsin after heating & acid exposure ^AFB = acid-fast bacteria Classification: 2 Groups Mycobacterium TB Complex (MTBC) Mycobacteria Non-Tuberculous Mycobacteria (NTM) Most pathogenic & most feared zoonotically * Facultatively or obligately intracellular * Differentiation difficult (even with genetic sequencing – 99% DNA homology): can use liquid chromatography or mass spectrometry * Maintained by infection of reservoir mammalian hosts * Survives 1-2 weeks in the environment * Reverse zoonosis (i.e. contact with people with TB) * Saprophytic, survive >2 years in the environment * 3 Types * Slow-growing * Rapidly growing (RGM) * Fastidious/lepromatous (differentiated into 3rd group in human med) M. tuberculosis * Pulmonary predilection * Humans = reservoir host * Dogs & cats infected after prolonged exposure (usually years) to human respiratory secretions * Esp. pets living with immunocompromised people * Esp. Atlantic coast, SE US, & CA * Dogs most susceptible (rare) * Most dogs subclinically infected * Potentially zoonotic M. bovis: rare in US * Cattle = reservoir hosts in the US * Also other wildlife species (e.g. white tailed deer) * Ingestion of unpasteurised milk or uncooked meat or offal, predation * Raw food diets * GIT in cats vs. respiratory tract in dogs Slowing-Growing NTM: M. avium complex (MAC) * Acid soils high in organic matter * Lesions resemble TB lesions * NO spread from animals to people * Dogs & cats are quite resistant to infection except: * Mini schnauzers, Basset hounds, & FIV-infected cats * More common in inbred animals Fastidious Mycobacteria (rare): Lepromatous mycobacteria (M. leprae, M. lepraemurium) * Localized cutaneous nodules: may ulcerate, sometimes disseminate * Difficult or impossible to culture → DO NOT culture * Only detectable via molecular tests: many organisms on cytology or histopath → detect with PCR * Clinical signs: canine leproid granuloma syndrome (CA, Australia) * Short-coated breeds; usually head, pinnae * Histopathology * Tuberculous granulomas: focal necrosis surrounded by plasma cells, macrophages, & a fibrous tissue capsule * Giant cells uncommon in dogs and cats * Calcification may be present * NTM: pyogranulomatous inflammation * Isolation * Multiple deep tissue biopsies * Requires egg-enriched media (e.g. L-J media) * Tuberculosis mycobacteria: may take 4-6 weeks to grow on solid media, faster in liquid media * RGM: 3-5 days * PCR Rapidly-Growing Mycobacteria (RGM): M. smegmatis & M. fortuitum (most common) (other: M. thermoresistible) * Inoculated into skin via trauma * Enhanced pathogenicity in adipose * Most animals immune competent * Cats most susceptible: esp. females, age 3-11 years * Younger dogs * Clinical Signs: cutaneous & subcutaneous granulomas (mycobacterial panniculitis), esp. inguinal area * No systemic signs * Resemble cat fight abscesses, later ulcerate, drain * Do NOT treat like regular abscess (will spread & difficult to manage if sx performed) * Resistant in environment * Resists many disinfectants * Inactivated by direct sunlight & dilute household bleach * LOW zoonotic concern * Public health risk only for MTBC * NTMs have no zoonotic concern * Not directly transmissible from animals to people Pathogenesis * Multiply intracellularly at inoculation site & local LN * MAC infections tend to be disseminated * Localized cutaneous infections also been reported * Defective cell-mediated immunity (CMI) → persistence or dissemination * Granuloma reflects inability to clear the organism Clinical Signs (MTBC & MAC) * Respiratory: fever, weight loss, cough, anorexia * GI: weight loss, anorexia, V/D, anemia, enlarged mesenteric LNs * Disseminated: lymphadenopathy, anorexia, fever, weight loss, organomegaly, effusions, neuro signs, ocular disease, osteomyelitis, non healing skin lesions Diagnosis: * Presentation + acid fast stained cytology * Organisms are elongated & often beaded * Absence of organisms does NOT rule out * Lots of organisms often with MAC & leproid granuloma syndrome Treatment MTBC * Combination medical therapy * * Consider E-tube * Monitoring: liver enzymes 0, 14 days, then monthly (rifampicin) * Treat minimum 3 months, 2 months beyond resolution of signs * 70-80% recover with proper treatment * Rarely surgery NTM * Triple therapy as for MTBC * MAC often resistant to enro-, marbofloxacin * Various combinations pradofloxacin, macrolides/azalides, rifampin, +/- doxycycline * Susceptibility if poor response * Remove immunosuppression if possible * Rarely surgery (refractory osteomyelitis) RGM * Skin lesions * High doses fluoroquinolone or doxycycline, then surgical excision * 3-6 months of doxycycline of a FQ * Rarely, lifelong treatment LEC 62-63: DISEASES FOR WHICH WE VACCINATE Immuoprophylaxis – Why do we vaccinate? * To improve the specific immune response in an animal * Provides protection against an infectious disease (or toxin exposure) * Lowers the risk of developing signs of illness when naturally exposed or reduces the clinical signs associated with infection if contracted * Not 100% preventative * Less morbidity (animal & client suffering) * Less mortality * Lower cost of pet care (illness $$$ > vaccine $) Vaccination Protocols: confine for 1 week after the last vaccine (Rabies 1 month) * Core Vaccines: 6-8 weeks → then every 3-4 weeks until at least 16 weeks (consider extending to 20w) * FVRCP (aka HCP) (Feline Herpes (Viral Rhinotracheitis), Calici, and Panleukopenia): revaccinate at 6 months of age → then every 3 years * At 4 months, some cats still have maternal antibody blocking full response to vaccine * DAP (Distemper, Adenovirus, Parvo): revaccinate within 1 year (recommendation may change to 6 months) → then every 3 years * Can consider serological testing for CPV & CDV after initial series or instead of revaccinating to confirm adequate protection * Consideration: Rabies at the last booster? * Rabies: minimum 3 months → then within 1 year later → then every 1 or 3 years per manufacturer’s recommendation * If dog >2 years of age & no known vaccination hx: give 1 vaccine → repeat within 1 year → repeat every 3 years * If cat >2 years of age & no known vaccination hx: give 1 vaccine → revaccinate every 1 or 3 years depending on vaccine used * Leptospira & Borrelia (bacterins – immunity does not last long): revaccinate yearly * Bordetella: revaccinate yearly * FHV1 & FCV in high-risk situations (e.g. shelter, cattery, hoarder): revaccinate yearly CANINE DISTEMPER VIRUS INFECTION CASE: ‘Lucy’ ~2 year old Catahoula Mix * Pulled from shelter by rescue and brought to you with her litter of 5 day old puppies * Received DAP & RV on admission to shelter ~2 weeks ago * Presents for “severe kennel cough” & diarrhea * PE: dull, BCS 3/9, T 103.6, CRT<2, bilateral conjunctivitis, moist cough, tachypnea, mucopurulent nasal discharge * Puppies all have serous to mucopurulent nasal discharge. One has tremors * Diagnosis: Distemper – likely infected with DAP before receiving vaccine on admission * All puppies had to be euthanized * Lucy had a full recovery, but developed seizures later in life * What signs would a dog with distemper virus infection exhibit? * How would you confirm a dx of distemper? * If a dog has distemper, should it be treated, and how? What is the prognosis? * How likely are in-contact animals to be infected? * How do I disinfect the environment? * Are vaccines for distemper effective? How many DAP vaccine doses should you give a dog that is >2 years of age and has no known vaccination history? * 2 vaccines spaced 3-4 weeks apart → repeat within 1 year → repeat every 3 years * Ideally would have that booster 3-4 weeks later but not required Etiologic Agent * Enveloped RNA virus → readily inactivated in the environment * Disease in dogs, raccoons, ferrets, exotic felids * Strain virulence & neurotropism varies Exposure/Infection * Shed in respiratory secretions, feces, & urine (all body secretions) for up to 3 months after infection * Spread by direct contact, aerosol, or respiratory droplet exposure * Raccoons may be a source * Many infections subclinical * Infections often occur when maternal antibody wanes Pathogenesis * Stage 1: lymphoid tissue * Virus inhaled & contacts URT epithelium→ replication in local macrophages (lymphatic spread)→ tonsils & bronchial nodes → systemic lymphoid tissue (day 2-6) → fever, lymphopenia/ lymphocytolysis → immunosuppression (often present with bacterial opportunistic infection) * Stage 2: epithelial & nervous tissue * Clinical Signs: **GI, Respiratory, Neuro Signs** * Early signs: * Lethargy, inappetence, fever * Conjunctivitis, cough, serous ocular & nasal discharge * (Serous discharge is expected from a virus) * Progression to: * Obtundation, anorexia, vomiting, diarrhea * Mucopurulent ocular & nasal discharge * (Mucopurulent discharge from a bacteria) * Moist cough, tachypnea * Neurologic signs: development unpredictable; may be delayed up to 12 weeks * Hyperesthesia * Ataxia, circling, head tilt, tremors * Paralysis * Myoclonus (very typical) * Partial or generalized seizures * Other Clinical Signs * Nasal & footpad hyperkeratosis (‘hardpad’): esp. in puppies * Optic neuritis & chorioretinitis (‘gold medallion lesions’) * Enamel hypoplasia (not in acute disease) Diagnosis * Clinical signs suggestive * Severe respiratory disease * CBC: * Lymphopenia * Distemper virus inclusions * Quantitative PCR +/- paired with serology * Respiratory secretions, CSF, feces, urine * False positive possible within 1-3 weeks of vaccination * False negative also possible * Negative PCR + adequate antibodies = unlikely to be infected * Conjunctival scrapings for inclusions * Fluorescent antibody * False positives & false negatives (more false neg) * Can also be applied to other tissues: urine sediment, transtracheal wash & CSF (with neurological signs) Treatment * Supportive care * Isolation * IV fluids (because dehydrated, not wanting to eat, vomiting, diarrhea) * Parenteral antimicrobial drugs (because immunocompromised) * Oxygen supplementation (if progressed to pneumonia) * Neurologic signs usually permanent – warn owners if not yet present * May or may not be compatible with life (e.g. status epilepticus) Prevention * Vaccinate: very effective * Proper vaccine storage imperative – fragile: use within 1h of reconstitution * Vaccinate ASAP before shelter entry * Isolation: infected dogs shed for ~1 month but up to 3 month Post-vaccinal CDV (rare) * More common in exotic carnivores * Ferrets: use recombinant vaccines * Encephalitis 7-14 days after vaccination In shelter outbreaks, consider serological testing * Separate & vaccinate seronegative animals * Foster incoming seronegative animals until they seroconvert * 1:16 (or per WSAVA any positive) titer is considered protective Summary * Highly infectious * GI, respiratory, and neurologic signs * Important differential in young dogs with respiratory disease * Some dogs with distemper only have respiratory signs * Vaccination has reduced incidence * Still occurs sporadically, esp. in shelters * Can be spread by raccoons FELINE HERPESVIRUS CASE: ‘Sassy’ 10 month old FS DSH * Acquired from shelter 7 days ago * Current on vaccines per shelter paperwork * Hiding/shy since adoption, now presents for squinting & sneezing * PE: QARH, BCS 4/9, T 102.3F, CRT<2s * Unilateral blepharospasm, chemosis, epiphora & sneezing (clear nasal discharge), bilateral airflow + * How do cats get herpes? * Is there a treatment? * Why bother vaccinating if a cat already has herpes? * Is feline herpes serious? * How common is feline herpesvirus? * ~97% of cats are exposed in their lifetime * Lifelong infection in up to 80% of exposed cats * Up to 45% of infected cats periodically shed the virus, usually when stressed * Can show signs when stressed How many FVRCP (MLV) vaccine doses to give a cat that is >2 yo & has no known vaccination hx? * 1 (parenteral/attenuated live) OR 2 (parenteral/inactivated) dose, 3-4 weeks apart → repeat every 3 years * 2 (intranasal/attenuated live) doses, 3-4 weeks apart → repeat yearly Exposure/Infection * Direct contact with oronasal & conjunctival secretions (e.g. grooming) * Droplets can be sneezed far (~1.3 m) * Kitten contact with queen (NOT transplacentally) * Fomites (don’t last long in environment): typically only a problem in catteries +/- shelters Pathogenesis * Lifelong latency in neurons → shedding during stressful periods * Clinical Signs: upper respiratory & ocular signs common * Serous discharge from the eyes and/or nose * Mucopurulent discharge if secondary bacterial infection present (>day 5-7) * Sneezing * Hyperemic conjunctivitis * Lethargy * Anorexia (sometimes because can’t smell food properly due to congestion) * Rarely, trouble breathing * Corneal ulcers may occur (keratitis) * Fever * Clinical signs typically resolve in healthy animal (within 10-14 days) * Infrequently: oral & skin ulcers, dermatitis & neurological signs (cytolytic disease) * In severe infections: erosion of epithelium & nasal turbinates → chronic rhinitis Diagnosis * Clinical signs (most important) * Dendritic ulcerative keratitis (pathognomonic) * PCR (not sensitive): may indicate low level viral shedding NOT causing clinical signs * Virus isolation tests (less sensitive than PCR): detect by culturing the virus from clinical samples * IFA on conjunctival or corneal smears or biopsies * Serology: does NOT differentiate between infection & vaccination * Don't use unless 100% sure the animal has not been vaccinated before Treatment * Supportive care: support feeding (↓ sense of smell), clean nose, lubricating eye drops, saline nebulization (if not too stressful) * Corneal ulcers, severe UR signs: consider antiviral drugs * Idoxuridine (used more commonly) * Others less commonly used: Ganciclovir, Interferon alpha * Stress reduction * Note that giving medications is stressful * Multicat housing, surgery/vet visits, household changes, steroid use (immunosuppressive dose) * Systemic ABX if secondary bacterial infections occur Prevention * Vaccination: may not prevent infection in all cats * Reduces severity of clinical signs * Reduces viral shedding * Separation of affected cats * Appropriate hygiene * Susceptible to most disinfectants INFECTIOUS CANINE HEPATITIS (ICH) * What causes ICH? * What clinical signs should make me suspect ICH? * How common is the disease? * How would I diagnose ICH? * Caused by canine adenovirus-1 (CAV-1) * Related to CAV-2 (respiratory disease) * Systemic viral infection of dogs * Usually young puppies * Also coyotes, foxes, bears, raccoons * Targets endothelial cells & hepatocytes * Virtually extinct in the USA * Uncommon even prior to vaccination * Re-emerged in Europe Clinical Signs * Most infections subclinical * Peracute form * Circulatory collapse * Death in 24-48 hours * Acute form * Puppies aged 6-10 weeks * Fever, anorexia, lethargy, tonsillitis (look in mouth) * Cough, tachypnea * Hepatomegaly, abdominal pain, edema, ascites * Vomiting, diarrhea * Hemorrhages * CNS signs (hepatic encephalopathy, direct damage) * Fever common in early phase * Corneal edema (‘blue eye’ = hallmark lesion) & anterior uveitis → sign of inflammation * Type III (immune complex) hypersensitivity * May be the only sign * Painful Transmission * Oronasal exposure: animal-to-animal contact or exposure to fomites * Shed in feces, urine, & saliva * Shedding in urine can last for 6-9 months Diagnosis * Clinical signs & signalment (most important) * Bloodwork: * CBC: lymphopenia, neutropenia (signs of severe infection) * Chemistry: ↑ liver enzymes, hypoglycemia (signs of liver damage) * UA: bilirubinuria, proteinuria * Organism detection * PCR (e.g., on blood, respiratory secretions, urine) * Histopathology at necropsy: intranuclear inclusions in Kupffer cells, hepatocytes, glomeruli, blood vessels (meninges, renal tubular vascular endothelium) Prevention * Vaccines contain CAV-2: protects against CAV-2 & CAV-1 * Why use CAV-2 if we are targeting CAV-1? * CAV-1 vaccines caused ‘blue eye’ & subclinical nephritis in 0.4% of vaccinates * Do NOT use mucosal CAV-2 vaccines to protect against CAV-1 * Injectable product is needed to protect against CAV-1 * CAV-2 is a causative agent of CIRD CANINE AND FELINE PARVOVIRAL INFECTIONS CASE: ‘Bert’ 3 month old MC Rottweiler * Acquired from breeder 3 days ago – vaccinated at least once by the breeder * Bright the first day, then has been lethargic and inappetent. Vomited frothy fluid three times today. * PE: lethargic, T 104F, prolonged CRT, 10% dehydrated, tense abdomen, hematochezia on thermometer * How do dogs & cats acquire these infections? * How do these viruses cause disease & what are the clinical signs? * If an owner’s new puppy has parvovirosis, can you predict when & where it was infected? * How is a diagnosis made? Could false positive & false negative test results occur? * What treatment is recommended? What is the prognosis? * How effective is the vaccine? * Highly contagious, often fatal if untreated * Feline panleukopenia/parvo (FPV): less common than canine Parvo * FPV does not infect dogs * Canine parvovirus: one of the world’s most common canine infectious diseases * Emerged late 1970s, worldwide pandemic * Caused by CPV-2, mutated to CPV-2a, CPV-2b & CPV-2c * May have arisen from feline panleukopenia virus (FPV) * CPV-2a, CPV-2b, & CPV-2c infect cats (similar signs to FPV, cats shed the virus for up to 6 weeks) * Tiny, non-enveloped viruses * Require rapidly dividing cells to replicate * Shed for max. 4 wks after infection (rarely > 2 wks) * Isolate infected animals for at least 1 month * Resist disinfection & survive > 1 year on fomites * Bleach:detergent 1:32 * Accelerated hydrogen peroxide 1:16 * Potassium peroxymonosulfate (Trifectant) * 10 min contact time * Transmission by contact with feces, vomit, fomites Epidemiology * Widespread subclinical infection * Puppies & kittens 6 weeks to 6 months * Declining maternal antibody * Rapidly dividing cells * Immunosuppression → concurrent severe viral, bacterial, & parasitic infections * Less common in the winter – less breeding/young puppies? Pathogenesis: Oronasal exposure spreads via viremia to GI epithelium, lymphoid tissue, & bone marrow → marrow destruction & intestinal crypt destruction * If infected in utero or <2 weeks * Dam subclinical * Myocarditis & CHF in puppies (rare due to maternal antibody) * Cerebellar hypoplasia in kittens (& rarely dogs) * Also optic nerve atrophy, retinopathies * Reproductive failure or fading puppies/kittens Feline Panleukopenia Virus – Cerebellar Hypoplasia * Due to infection in utero or at < ~9 days * Ataxia, intention tremors, incoordination, broad-based stance * Clinical signs appear at 2-3 weeks * Mental status normal, acceptable pets * Learn to adapt to signs * Other signs less common * Seizures * Behavioral changes * Retinal degeneration, folding * Optic nerve hypoplasia Clinical Signs: severe enteritis & leukopenia in dogs & cats * Somewhat unpredictable: can look terrible but respond well to tx or look good but decline rapidly → treat every patient like high risk * Incubation period: (if recent adoption, can not definitively determine if infected before or after adoption from breeder) * 3-14 days CPV-2 vs. 2-10 days FPV * Lethargy, fever, then inappetence, vomiting, & diarrhea * Usually bile-stained vomit in cats * Yellow-gray, blood-streaked, or dark red malodorous diarrhea * Abdominal pain, dehydration * Leukopenia (not always, esp. in the acute phase) * Peracute form: death in 1-2 days * Secondary to Gram- bacterial sepsis, DIC Diagnosis * History, clinical signs * CBC: leukopenia (not always present, not specific) * Chemistry * Hypoglycemia * Prerenal azotemia & electrolyte abnormalities (due to fluid loss) * Fecal antigen ELISA: marketed for CPV but also detects FPV * ~50% sensitive (a negative may not really be negative!) * May get false positive post recent (10 days) vaccine - modified live virus (MLV) * Fecal PCR (“not a great test, not something I would rely on”) * Significance? Subclinical shedding? * Positive after vaccination * Serology: tests for protective antibody titers, not for infection * Do NOT use to diagnose * Histopathology * Intestinal crypt necrosis * Intranuclear inclusion bodies * Immunohistochemistry Treatment * Isolation (highly contagious) * Inpatient (ideal) * Aggressive IV fluid therapy * Antiemetics * As early as possible enteral feeding via NE tube * Central parenteral nutrition * Plasma for hypoalbuminemia * Immune plasma? – best after infection but before clinical signs * Need large doses parenterally (6.6-11 mL/kg)? * IV dextrose (for glucose support) * Broad-spectrum IV antimicrobials: Cefazolin, Enrofloxacin/Ampicillin * Prevent secondary bacterial infection * Treat parasites * Gradual reintroduction of water then food – start with 1/3 caloric needs * Highly digestible, low fat, low fiber (i.e. nutritionally dense) every few hours * Outpatient protocol: SC fluids, maropitant (antiemetic) & cefovecin (ABX), Karo syrup, Tumil-K (for K+), Buprenorphine (for pain), feed A/D * Not optimal but cheaper & better than nothing Prevention * Vaccination * Attenuated live vaccines * Avoid use in pregnancy, kittens & puppies < 4 weeks * Concern of cerebellar hypoplasia or abortion * Possible exception in shelter outbreaks * Vaccinate to 16-20 weeks * Consider checking titers after pediatric series (>3 weeks) * Not routinely done but possible for high risk patient * Hygiene & appropriate disinfection LEPTOSPIROSIS CASE: “Sammy” 8yo MN Lab X * 5 day history inappetence, lethargy, vomited 3 times * Initially PU/PD, now not drinking * PE: T 102.7F, P 98, R 16, 7-8% dehydrated * Tense abdomen * Mild peripheral lymphadenomegaly * Initial Chem panel: azotemia, slightly elevated liver enzymes * What signs should raise suspicion for a diagnosis of leptospirosis? * How would a diagnosis of leptospirosis be made? * How do dogs get leptospirosis? * Can leptospirosis be effectively prevented? * Is there an effective treatment for leptospirosis? What is the prognosis? Are there any long-term complications? Etiology & Epidemiology: Leptospira interrogans * >200 antigenically-related serovars, grouped into serogroups * >10 cause canine disease * Wild & domestic animal reservoir hosts (rodents) * Shed in urine → widespread subclinical exposure * Serovars/genotypes are adapted to different reservoir hosts * Young, lepto-unvaccinated adult dogs * VERY rare in cats (possible but not concerning) * Survives in stagnant or slow-moving, warmer water & moist environments, wet soil * Temps: 32-68F (0 to 25C) * Increased rainfall/flooding is a risk factor but NOT required * Disease seen in small-breed dogs from urban areas * Transmission is by: * Direct contact with contaminated urine, bite wounds or ingestion of infected tissues * Indirect contact with urine-contaminated food, water, soil, bedding * Organisms penetrate intact mucous membranes or abraded skin * Weeks 1-2: bacteremia with spread to liver & kidney + other tissues (e.g. pancreas, lung, meninges, genital tract, eye) * Antibody response limits organism to renal tubular epithelial cells * Shed in urine for days to weeks * **Newer guidance: “ALL dogs are at risk of leptospirosis, regardless of signalment, geographic location, lifestyle, and the time of year” * NOT just hunting & rural dogs Clinical Signs * Extent of disease depends on strain virulence & host susceptibility * AKI +/- hepatic insufficiency (NOT failure) +/- hemorrhagic disease (esp. lungs) * Characteristic clinical picture * Fever, inappetence, vomiting, dehydration * Reluctance to move (ddx: IMPA) * PU/PD or anuria/oliguria * Abdominal pain * Mild peripheral lymphadenomegaly (firm prominent LNs) * Icterus (e.g. eye color change: blue eyes turn green) * +/- uveitis (yellow or red cast on eye) * +/- tachypnea due to pulmonary hemorrhage Laboratory Finding * CBC: leukocytosis, anemia, thrombocytopenia (mild to moderate: 50-60%) * Chemistry: * Azotemia (kidney injury) * +/- ↑ liver enzymes (ALP>ALT) * Normal liver function tests: normal cholesterol * Hypoalbuminemia (due to renal loss) * High CK (due to myositis) * Normo- or hypokalemia * UA: casts, glucosuria, organisms not seen * Significant proteinuria NOT a feature (interstitial nephritis) * Differential diagnosis: other causes of AKI Imaging Findings * TXR: normal OR mild interstitial to patchy or diffuse alveolar pattern * AUS: changes to kidneys * Hyperechoic renal cortices * +/- perirenal fluid * Renomegaly Diagnosis * History, clinical signs, laboratory findings (start treatment before tests come back) * Antibody-detection tests * Microscopic agglutination test (MAT), paired titers (interval 2-4 weeks) * Initial titers often negative * Positive titers from subclinical exposure & vaccination (up to 1:6400) * Fourfold rise in titer required over >2 weeks * Positive titers to multiple serovars due to cross-reactivity * Highest titer is NOT predictably the infecting serovar * Species differences can make it so that a lower serovar is the one causing the disease * SNAP® Lepto (IDEXX) * Positive or negative blue dot (not a quantitative result) * Same problems as MAT (can be negative early on) * WITNESS® Lepto (Zoetis) * IgM-based, may have higher sensitivity (98%) & specificity (93.5%) than MAT * Not worth running * Dark Field microscopy of urine: insensitive * Culture: special media, 4-6 weeks, not done * PCR: blood AND urine * Not sensitive * False negatives after ABX * Kidney biopsy: low organism numbers, low yield, higher risk to the patient Treatment * Ampicillin or penicillin for vomiting dogs * Doxycycline for 2 weeks after vomiting stops (d/c penicillin) * Aggressive IV fluid therapy (for kidney injury) * Diuretics * Antiemetics * Hemodialysis: the sooner the better if rehydrated & oliguric * Expensive Prognosis * 85% survival rate with aggressive therapy (costly) * Chronic kidney disease may be a sequela Prevention * Treat co-exposed household dogs * Restriction of access to wildlife/rodents * Vaccination: 4 serovar vaccine (not the 2 serovar form): Grippotyphosa, Pomona, Canicola, Icterohaemorrhagiae * Annual vaccination * Shift to ‘core’ vaccine * Adverse reaction rate low (<1%) but 2x that of DAP vaccines * Antibody titers do not correlate with protection * Recurrence of disease not reported after natural infection * Continue to vaccinate to prevent infection with other serovars Zoonotic Potential * No need to place in isolation → just limit contacts: * Signage * Gloves, impermeable gown * Gurney outside * No pregnant or immunosuppressed employees * Take outdoors to area away from other dogs * Lift after 72h of appropriate antimicrobials * Subclinically infected reservoir hosts may represent greater risk LEC 64: FELINE INFECTIOUS PERITONITIS CASE: Moso – 1 y MI DSH * PC: 3 week history of fever * No C/S/V, some soft stool * Picky appetite, no PU/PD * Not vaccinated * No current medications * Socialized from feral mother 6 months ago with 3 littermates * Always a timid cat, bullied by littermates * Presented to rDVM 1 month ago: T 104.3, P 260, R 40 * CBC WNL, Globulins 5.6 (2.8-5.1) → hyperglobulinemic * FeLV/FIV negative * Clavamox prescribed for 14 days → not responsive * Re-presented to rDVM: T 103, P 240, R 90 * Hct 30% * Urine culture negative * Globulins 7.8 (3.0-5.9) → progressive hyperglobulinemia (marked) * USG 1.069 * PE at UCD: T 104.1, P 200, R 50, Wt 3.6kg, BCS 6/9 * MM pale pink & moist * Otherwise WNL * Initial problem list * Fever * Hyperglobulinemia * Initial diagnostics CBC * Hct 18% (severe) * NNN * WBC 14,820 → leukocytosis * 13,338 neuts → neutrophilia * 148 bands → mild left shift * 741 lymphs → lymphopenia (common in viral disease in cats) * 105,000 platelets → mild thrombocytopenia * MPV 21.3 Chemistry panel * T prot 10.8 (6.6-8.4) * Glob 8.4 (2.8-5.4) * Alb 2.4 (2.2-4.6): liver function parameter * Chol 88 (89-258): liver function parameter * T bili <0.2 (<0.2) * BUN 16 (18-33) * Glu 113 (63-118) Serum Protein Electrophoresis * Performed to investigate hyperglobulinemia * How do we interpret this result? (pay attention to gamma globulins) * Broad polyclonal band → most consistent with chronic immune stimulation/ infection * Not a single population of lymphocytes (e.g. lymphoma) Radiographic Findings * When suspect FIP, look for cavitary effusion * NOT present in Moso AUS * Large hypoechoic LN * Large spleen (but normal texture) * Diffuse intestinal thickening Cytology of liver mass: concerning for lymphoma * Monomorphic population of mature intermediate sized lymphocytes * Nuclei ~1.5-2 RBC in diameter, with clumped chromatin & inapparent nucleoli * N:C ratios are high * Scattered typical small mature lymphocytes, large lymphocytes, histiocytes, non-degenerate neutrophils, & plasma cells FeLV antigen & FIV antibody: * Negative Refined Problem List * Fever * Hyperglobulinemia * Anemia * Thrombocytopenia * Neutrophilia with left shift * Hypocholesterolemia * Lymphadenopathy Differentials for fever with hyperglobulinemia? * Infectious: viral (FIP), bacterial/atypical bacteria (Bartonella), protozoal (Toxoplasma), fungal (Histoplasma), parasitic * Does Moso fit the signalment of a cat with FIP? * ‘Young cat disease’: 3 months to 3 years, occasionally geriatric (10-13 yo) * Purebred cats * But not effusive * Inflammatory (less likely in young cats): chronic skin or dental disease * Neoplasia: lymphoma, multiple myeloma * Immune disease (rare in cats): IMPA How might Moso have acquired FIP? * Fecal-oral spread of feline enteric (avirulent) coronavirus (FECV) * Acquired from another cat or introduced by Moso * Mutation to virulent FIPV (‘internal mutation hypothesis’) → multiplies in macrophages * Strains vary in virulence * Genetic susceptibility * FIP is generally considered non-transmissible - FECV mutates within the animal ‘Avirulent’ (FECV) vs. ‘Virulent’ (FIP) FCoVs * FCoV seropositivity is high (for FECV) * Single cat vs. multicat household * Cycle of infection, shedding, & recovery * Persistently-infected cats (certain cats due to genetic susceptibility → try to identify these cats) * DISEASE IS SPORADIC * Uncommon (1/5000) in single cat households * Significantly higher (up to 5%) in multicat households * Overcrowded, stress → ↓ immune defenses * Virulent FCoVs do not replicate in the GIT FIP: a viral host cell switch * Feline enteric coronavirus (FECV) infects enterocytes to cause mild to inapparent enteritis (affects the villus tip in the intestines) → spike gene mutates → tropism change: feline infectious peritonitis virus (FIP) infects macrophages to cause fulminant disease * Spike virus: docking mechanism that allows the virus to get into cells * This mutation happens in every infected cats (‘de novo mutation’) PE findings Lab Findings Effusion Depends on site of infection & effusive vs. non-effusive (more of a continuum than a binary) * Tachypnea * Muffled heart sounds (often indicates pleural effusion) * Sometimes respiratory distress * Icterus (classic) * Hepatomegaly * Splenomegaly * Irregular renomegaly * Abdominal masses * Anterior uveitis (classic) * Retinal detachment, hemorrhage * Neurologic signs Can spread to many different organ systems * Classic (>50% of cats but non-specific) * NNN anemia * Neutrophilia * Lymphopenia * Thrombocytopenia * Azotemia * ↑ liver enzymes * Hyperbilirubinemia * Hypoalbuminemia * Hyperglobulinemia * >70% non-effusive * >50% effusive * Effusive disease is easier to diagnose (& more common) * “Not many other ddx for young cat with fever & abdominal effusion” * Effusion: abdominal more common than thoracic/pleural * Does not fit into typical categories for effusion – exudate? modified transudate? * Relatively low cellularity & relatively high protein * Straw/yellow colored & viscous * Specific finding for FIP Moso * Developed peritoneal effusion * Abdominal exploratory performed * Abdominal fluid analysis: characteristic for FIP * Very high TP * Midline nucleated cells count Feline Coronavirus Serology * Positive serology = exposure to any coronavirus (CCV, TGEV, FCoV) * Does NOT predict FIP (just a general coronavirus serology): just indicates more or less likely to be FIP * Titers >1:1600 may be suggestive * 98% specific, 67% sensitive in cats with compatible clinical signs * High titers useful for cats from households with 1 or 2 cats * Ensure go to endpoint * Titer results VARY between labs * Some cats with end-stage FIP lack antibodies * Does not predict shedding * Does not indicate immunity to FIP * Paired titers are NOT helpful for diagnosis (because chronic disease) * Moso – FCoV serology: positive at 1:25,600 * Remarkably high → suggestive of FIP (but does NOT confirm) Gold Standard Diagnosis: Lesion (biopsy/cytology) + Associated Virus (immuno- or molecular technique) * Not always practical → sometimes diagnosis is just based on clinical presentation Biopsy & Cytology * Immunocytochemistry on effusion: 60% sensitive, specificity? * Biopsy Associated Virus * Immunohistochemistry (IHC): uses antibody to shows presence of antigen * Lymphadenitis with presence of antigen * Molecular Diagnostics: RT-PCR for FECV or some FIP mutations * No specific mutation distinguishes virulent from nonvirulent strains * Some genes important (eg. 3c, 7b, spike protein genes) * IDEXX FIP RealPCR detects mutations in spike protein gene associated with virulence * False negatives with degradation, strain variability * Avirulent coronavirus strains can be found at any site in healthy & sick cats * Testing tissues & effusion not helpful alone * Effusion PCR positive + clinical signs match ⇒ diagnostic for FIP * FECV should not be in other tissues in conjunction with characteristic inflammation Treatment * Supportive care (fluids, nutrition, fluid removal) * Novel antiviral medications * Drug legally available * Oral GS-441524: commercially available for prescription use & office use in most states * Daily dose 15-20 mg/kg (ideally split in 2 doses) - 84 days * Neuro & ocular disease requires a higher dose, potentially longer duration * For very sick cats, need to start this ASAP (but legally can’t stock compounding drugs) * Stokes pharmacy in US has a license from BOVA, compounding pharmacy in the UK that worked with Gilliad for the legalization/patenting of the drug * FDA is letting this happen * Injectable GC376: not currently commercially available, licensed to Anivive * Remdesivir & Molnupiravir: variable access & cost * Painful injections, less effective? (remdesivir) * Other groups (FIP Warriors) supply drugs illegally (used to be supported when it was the only option) CASE: Tabitha 9 month-old FS DSH * Diagnosed with FIP * Treatment: injectable GS-441524 (2.0 mg/kg SQ q24h) * Stings on admin * 12-week course * Monthly recheck exams & labs * Gray = globulins * Yellow = albumin * A:G ratio rapidly normalized within ~1 month * 6 month recheck: 12 weeks off GS * Eating well, regained weight * Good activity Prognosis for FIP * Without treatment: days to > 1 year (most 5-7 weeks) * With treatment: good to excellent * Negative prognostic factors * CNS involvement * Prognosis dismal for cats that fail to respond beyond 3 days Prevention * Single cat households * Inform the breeder & choose from a different genetic pool! * Wait 2 months before the introduction of a new cat? * Multi-cat households * Test (fecal PCR) & removal programs not usually effective * Attention to hygiene & stress reduction * 3 or fewer cats per room, enough litter boxes * Minimize prolonged stays in shelters * Maintain high adult:juvenile cat ratio * Don’t breed cats (esp. male) that produce kittens with FIP FIP Summary * No molecular diagnostic test accurately differentiates FIPV infection from FECV infection (regardless of specimen type) * IDEXX assay (FIP Virus RealPCR) detects 2 mutations in spike protein gene associated with increased virulence * IHC may be the most useful noninvasive antemortem diagnostic assay * Virulent FIPV may not replicate in enterocytes well * Some cats can be infected for years * Rapid treatment initiation important to improve cats outcome * Approved treatment remains to prednisone +/- novel antivirals * Selective breeding programs may be the solution LECS 65-66: FELINE RETROVIRAL DISEASE Screening = testing a healthy population for disease Feline Leukemia Virus (FeLV) CASE: Shadow 2 yo FS DSH * Indoor/outdoor * UTD on core vx * One other cat in the household * Last 2 weeks became lethargic, anorexic * PE: mucosal pallor, recumbency, tachycardia, slightly ↑ RR * BW: anemia, leukopenia * “Flat white cat” → FeLV infection = main differential Clinical Questions: * How common is FeLV? * What sort of diseases does FeLV cause? * How do cats become infected by FeLV & what is the typical signalment of a cat with FeLV? How does that compare with FIV? * How do you diagnose FeLV infection? What are you trying to detect? How good are the tests? * What should you tell an owner whose healthy cat tests positive for FeLV? Are other cats in the household likely to become infected? * Can you treat FeLV infection? * Is vaccination for FeLV effective? FeLV = leading cause of feline mortality * Immunosuppression (& opportunistic infections) * Bone marrow disorders (e.g. leukemia) * Hematopoietic neoplasia (esp. lymphoma) Factors Affecting Outcome * Challenge dose * Viral strain/subgroup * Immune status * Age Etiologic Agent * Enveloped RNA virus * Oncornavirus subfamily (Retroviridae) * Subgroups A, B, C, & T * B & C only found in cats infected by A * FeLV A integrates into genome & recombines with endogenous retroviruses present in all healthy cats → B & C subgroups form * Vaccine is protective against all different subgroups * Related to gp70 envelope glycoprotein variation * T associated with immunosuppression * C associated with aplastic anemia * Many different strains with varying pathogenicity * Susceptible to desiccation, heat & disinfectants * Don’t worry about transmission in hospital (requires prolonged close contact) Epidemiology * Transmission: * Shed in saliva * Viremic cats live months to years * Subclinical shedding * Transmission via blood transfusion (screen all blood donors!) * Prevalence: has declined due to testing & vaccination * Up to 30% of cattery cats * <3% in suburban & shelter cats * Regressive vs. Progressive Infection * Regressive: proviral DNA integrates into the genome & is non-productive (i.e. no replication/production of the virus) → NOT shed in the saliva * Cat mounts a strong immune response → can live normal lives * Latency: can reactivate disease if immunosuppressed (e.g. after renal transplant on cyclosporine & prednisone) * Concern for neoplastic risk factor due to disruption of oncogene during proviral DNA integration (but no evidence) * Progressive (persistent viremia): infects bone marrow & is continuously shed in saliva * Age-related resistance: FeLV occurs in * 70-100% of neonates without maternal antibody * 30-50% of 8-12 week old kittens * <10-20% of adult cats after prolonged exposure * Uncommon to see FeLV viremia in cats >10 years * Age-related resistance abolished by immune suppression * May be due to genetics, overcrowding, stress, poor nutrition, immunosuppressive drugs * Most persistently viremic cats die in 4 years due to FeLV-related disease * Younger or more immunosuppressed more likely to die sooner * Multicat households: 50% in 2 years, 80% in 3 years * Less for single cat households * Malignant transformation results from proviral integration into the genome near cellular oncogene * Multiple tests available: antigen tests & PCR tests * NOT the first choice ever for FeLV infection * Week 3: critical time point of bone marrow infection → determines whether cat develops progressive (~⅓) or regressive infection (~⅔) * IFA: negative because not sensitive, requires a lot of antigen * All PCR tests includes * Proviral PCR (viral DNA integrated into cat’s genome) * RT-PCR (viral RNA from replicating virus) * Results may fluctuate over time: can initially fluctuate between regressive & progressive Diagnosis * Antigen-detection ELISA & IFA: detect p27 core * ELISA (POCT): #1 choice for screening & diagnosis * Cheaper & more sensitive than IFA * Sensitivity & specificity 98% * 50% chance of false positive when used for screening (due to low incidence) * Retest using diagnostic lab or another test kit to confirm true positive * IFA: not sensitive, only positive if progressive * Bone marrow aspirate (more sensitive because more cells) or blood smear * PCR (NEVER the first choice for FeLV) * Proviral DNA (IDEXX) * (RNA tests only available in Europe) * Blood donors: test with both PCR & ELISA * ELISA can miss if regressively infected * If true positive → verify progressive infection * Retest ELISA positive cats 3 months later OR * If no other cats in household * If negative = regressive infection * Do an IFA test (less common) OR * Indicates if bone marrow is infected * Do a quantitative PCR assay (better than IFA) * High proviral load = progressive * Low proviral load = regressive * Possibly serial testing (progressive disease has low proviral loads early on) * IDEXX is the best PCR lab FeLV-Associated Diseases Lymphoma * Young to middle aged cats * Esp. mediastinal lymphoma (classic: 80% are FeLV+) * Pleural effusion containing lymphoblasts * Dyspnea, regurgitation (due to esophageal compression), Horner's Syndrome, ↓ chest compressibility * Multicentric lymphoma * Multiple site involvement * Renal lymphoma * GI lymphoma (most common form of lymphoma in cats): NOT associated with FeLV * Usually FeLV- * Older cats (average 8 years) Leukemia * Acute granulocytic, erythroid, lymphoid, or megakaryocytic * Pancytopenia with lethargy, bacteria infections, sepsis, hemorrhage Bone Marrow Conditions * Myelodysplasia (=disordered maturation of bone marrow cells) * Cytopenias * Maturation abnormalities, ↑ blasts * Myelofibrosis (=scarring of bone marrow) * End stage marrow failure * Need core biopsies to detect (not bone marrow aspirate) Anemia (common): through multiple mechanisms * Impaired erythrocyte production * Nonregenerative anemia * Isolated & severe anemia = pure red cell aplasia * With leuko- and/or thrombocytopenia = aplastic anemia (pancytopenia) * Bone marrow releases macrocytes (premature RBCs) → macrocytic anemia without regeneration (“a red flag for FeLV) * Immune-mediated destruction * Anemia of inflammatory disease Immunosuppression (not a major outcome – not as severe as FIV) * Mechanism poorly understood * Impaired T-cell & neutrophil function * Predisposes to: * Bacterial infections (e.g. stomatitis) * Viral infections (e.g. FIP, URTD) * Protozoal infections * Fungal infections (e.g. cryptococcus) Immune complex disease (less common in cats compared to dogs) * Glomerulonephritis & polyarthritis Reproductive diseases * Infertility, resorption/abortion, endometritis * Fading kitten syndrome Peripheral lymphadenopathy * Subclinical or with fever & inappetence Enteritis: crypt cell infection * Can lead to chronic GI illness or be more severe (like FPV) Neurologic disease (common) * Unilateral mydriasis → anisocoria * Myelopathy & urinary incontinence * Urinary incontinent cats: top differential is FeLV! Other weird outcomes (rare) * Multiple cartilaginous exostoses * Olfactory neuroblastoma * Keratin horns What to tell owners with healthy viremic cats? * Retest first * Some (⅔) may develop regressive infection * Other cats in the household may be infected or immune * House all cats indoors/catio * Vaccinate FeLV+ cat as necessary * FVRCP as normal Treatment * Chemotherapy for lymphoma * Blood transfusions, erythropoietin/darbepoetin * Glucocorticoids for immune-mediated disease * In selected cases & with monitoring * Can ↑ shedding of virus * Antimicrobials for secondary infections * Antiviral: not available yet * Antivirals (AZT, raltegravir) have shown some clinical activity but have significant drawbacks → not used Prevention: Vaccines * Vaccines are effective against progressive infection & disease * Whole inactivated (killed) vaccines * Non Adjuvanted recombinant canarypox vaccine (BI) * Vaccine recommendation * 2 doses SQ, from 9 weeks of age then every 1 year (recombinant) or every 3 years * Core in kittens, then based on risk (outdoor, multicat households, shelters) * Left pelvic limb (LPL) admin to monitor for vaccine associated sarcomas * Test first → vaccinate only FeLV negative cats (just to know status of cat before vaccination; vaccinating an FeLV positive cat doesn’t do anything) * Vaccination does not interfere with testing (because recombinant or inactivated) Feline Immunodeficiency Virus (FIV) * First isolated in 1986 * Worldwide distribution * Chronic infection → immunodeficiency * Not infectious to humans Clinical Questions * How common is FIV infection? Can owners catch it from their cats? * What sort of disease does FIV cause? * How do cats become infected with FIV and what is the typical signalment of a cat with FIV infection? * How do you diagnose FIV? What are you trying to detect? How good are the tests? * What should you tell an owner who’s healthy cat tests positive for FIV? Are other cats in the household likely to become infected? * Can you treat FIV infection? * Can you vaccinate for FIV infection? No Epidemiology * Prevalence in sick cats ~13-15% * Low prevalence in healthy cats ~2-3% * Prevalence 2-3x greater in males * More profound than for FeLV * Free-roaming & feral cats * Mean age 6-8 years * 80% of cats are >2 years * Disease mostly in adult/geriatric cats Etiologic Agent * Enveloped, single-stranded RNA virus * Lentivirus subfamily (retroviridae) * Infection is for life (NEVER eliminated) * Antibody positivity = current infection Transmission * Saliva by biting (aggressive interaction) * Must be inoculated under the skin * Transplacental transmission depends on: strain & degree of maternal viremia * Most kittens probably infected via saliva or milk * Indoor housing decreases transmission Pathogenesis: **FIV infection is for life (unlike FeLV)** * Targets: * T helper (CD4+) lymphocytes[c] * Later CD8+ cells & B cells * Tissue macrophages * For some strains, other cells such as astrocytes * Results in: * Gradual destruction of the immune system * Larger ↓ CD4 count (& ↓ CD4:CD8 ratio) than the normal decline with just aging * Promotion of neoplastic disease (less than FeLV) * Due to integration into genome & immunosuppression * Neurologic disease (affects astrocytes) * Degrees of viremia during the acute phase may predict speed of progression * Usually not determined clinically * Some cats never develop terminal disease (because very slowly progressive) * NOT associated with a ↓ lifespan (unlike FeLV) Clinical Findings Transient Primary Illness (acute phase) * 3-6 months, often unrecognized * Tests negative on antibody tests in the first 2 months * Transient lymphadenopathy, pyrexia, depression, anorexia * Transient neutropenia & lymphopenia * Sometimes opportunistic infections: * URTD * Enteritis * Stomatitis * Occasionally neurologic signs * Behavior changes * Partial or generalized seizures, paresis, anisocoria, motor abnormalities Subclinical Phase: progressive decline in immune function * Hyperglobulinemia: common finding, not treated for Terminal Phase: FAIDS (feline AIDS) = clinical disease associated with infection * Usually geriatric cats * Variable Signs (hard to determine if signs are due to FIV or just because geriatric) * Secondary infections * Stomatitis (most common clinical sign in FAIDS), recurrent URTD * Diarrhea, weight loss * Chronic skin disease: dermatophytosis, mites, bacterial infections * Other opportunistic infections (e.g. cryptococcus, toxoplasmosis, mycobacteriosis) * Hyperglobulinemia * Ocular disease: anterior uveitis, conjunctivitis, glaucoma * Eventually neuro signs: opportunistic infections, neoplasia, direct damage * Chronic muscle wasting * Azotemia due to interstitial nephritis * Wasting, neurologic disease, & tumors are the most common reasons for euthanasia Diagnosis: Antibody testing with ELISA assays most common (POCT) * Virus levels are LOW except terminally * Usually proviral PCR negative during subclinical phase Interpreting ELISA+ Results * Maternal antibodies up to & including 6 months of age * Retest after 6 months old (to ensure positive is not due to maternal antibodies) * Antibody from previous FIV vaccination (no longer available but can last up to 7 years) * Retest adult SNAP ELISA+ cats * Low risk populations * Western blotting * DIVA test (differentiate between virus & vaccination): Antigen assay or Witness Test * IDEXX is NOT a DIVA * Positive test results may be irrelevant to the clinical problem Interpreting ELISA- Results * Negative may occur in: * Cats in the acute stage (rarely recognized) * Retest suspect cats 2+ months later for FIV & FeLV * Cats with FAIDs (due to lack of Ab production) * Test with PCR (never as sensitive as antibody tests) Prevention * Inactivated vaccine used to be available * Heterologous protection is difficult, perhaps only 50% efficacious or less * Interfered with testing using IDEXX SNAP (not Witness or Antigen assays) Treatment: * No good antivirals * Keep cats indoors * Identify & treat opportunistic infections * Manage stomatitis * Vaccinate for other pathogens (FVRCP) CASE 1 CASE 1: ‘Pumpkin’ 7 yo FS DLH * Sick last 3 days * Diarrhea * Greenish, mucoid * Anorexia, lethargy, fever 105.1°F (101-103) * Vomited 3 times in last 24h * No response to SC fluids * Plays with elastic bands * No toxin exposure * Indoor, 3 other indoor-only cats, caged birds * All cats FeLV+ * Likely on an antigen test * Diagnosed with FeLV infection 18 months ago * PE: QARH, pink MM, CRT 1s, P 220, R 36, T 104.4F, BCS 7/9 * Unkempt haircoat * Resents cranial abdominal palpation * Cannot palpate right kidney * Greenish fecal material staining perineum * Fundic exam WNL * Problem List * Fever * Vomiting * Diarrhea * Inappetence, lethargy * Possible abdominal pain * Historical FeLV+ status * What is the typical signalment for a cat with FeLV infection? * Younger cats, rare in cats > 10 years * How was FeLV transmitted through this household? * Transmission in saliva, close contact (biting, fecal shedding) * Why is Pumpkin still alive 18 months later? * Regressive infection: current problem unrelated to FeLV infection * Progressive infection: current problem could/could not be related to FeLV infection * False positive (less likely because of positive housemates) * Might Pumpkin not be FeLV+ after all? * What diagnostic tests are currently available to detect FeLV infection? * Another ELISA test * Proviral IFA * What test was used on Pumpkin? * Likely ELISA [d] * What test(s) could you use to confirm the diagnosis of progressive FeLV infection? * Repeat an ELISA assay later (now!) * IFA on peripheral blood * Less sensitive than ELISA * Beware false positives * Quantitative PCR for viral DNA (proviral) or RNA * How long can cats live? * Most persistently viremic cats die in 4 years * Average: 3.1 years, Range: 0.6 to 6.5 years * Depends on dose, immune status of host, strain * THREAT vs. THREATENED * Threat: how MEAN & how MUCH * Threatened: age & immune status * Assuming Pumpkin is FeLV+ again, would you recommend euthanasia? * No, other FeLV-unrelated disease may be present & FeLV-related disease can be treated * What do you want to do for Pumpkin? * Ddx for vomiting, diarrhea, fever * GI signs: primary vs. secondary GI * Fever: infectious, immune, inflammatory, neoplasia * Confirm FeLV status via FeLV/FIV ELISA * CBC, chemistry panel, UA * Fecal flotation, enteric panel (Salmonella)? * Abdominal radiographs * AUS * Lab work: * FeLV+, FIV- * CBC: HCT 25% (30-50), 7800 retics, 10438 neuts (2000-9000), 459 toxic bands (left shift), 344 lymphs (1000-7000), clumped platelets * Chemistry normal * UA: 1.020, 1+ protein, 2+ hemoprotein, few WBC, rare rods * Urine culture: negative * O gave cat ABX prior to visit → may explain the negative culture results despite bacterial rods on UA * Hemoplasma PCR negative * Imaging: * Radiographs: gas & fluid-filled small intestines, right kidney? * Ultrasound: absent right kidney (likely congenital deformity) * Problems * NR anemia * Neutrophilia with left shift & toxicity * Probable UTI * Fever * Vomiting, diarrhea, inappetence, lethargy * Possible abdominal pain * Persistent FeLV infection * Presumptive diagnosis: * Pyelonephritis * Treated with ABX * Recheck at 1 year!! * CBC, chemistry, UA normal * One sibling died with non-regenerative anemia * Phone call at 4 years later!! * Pumpkin is ‘alive & kicking’ * Bloodwork, urine cultures WNL * Still FeLV+ * Death 2 years after that * 7.5 years after initial diagnosis (FeLV cats usually don’t live this long) CASE 2 CASE 2: ‘Oreo’ 6 mo M DSH * FeLV+ at local DVM * Doing great, excellent appetite * PE normal * Confirm positive result with another test → then determine if regressive or progressive * CBC: * HCT 34%, MCV 54 (35-45) * Macrocytosis with the absence of regeneration → indicates progressive infection/FeLV associated disease * Giant Howell-Jolly bodies * Three months later HCT 15% FeLV infection: testing recommendations * Screen with ELISA * Consider testing positive cats with quantitative proviral PCR for prognostication * All cats, at least once * Except TNR: focus resources on sterilizing as many cats ASAP * Any sick cat * Before FeLV vaccination * Before introduction * After potential exposure * If negative, retest at least 60 days later (with FIV) * Blood donors: Antigen & PCR * Serial testing may be required to determine true status: consider those with discordant results infectious FeLV infection: Prevention * Indoor housing whenever possible * Do not use infected queens for breeding * Multiple cat households: isolate new acquisitions, test and retest 60 days later * Adopt FeLV+ cats into single cat households (or with other FeLV+?) * Vaccination * Recommended for all kittens * Every 2-3 years thereafter for cats 2 years or older that are considered at risk * Annually for cats at high risk * Unvaccinated cats with bite wounds 7.5x more likely to be infected than vaccinated cats with bite wounds * May not prevent regressive infection * Administer as distally as possible in the LPL CASE 3 CASE 3: ‘Freddy’ 11yo MC DSH * Lethargy, inappetence 1 week * Indoor/outdoor cat, catches mice & birds * Lives alone * FIV+ FeLV- 3 years ago * CBC WNL * Chem: glob 5 g/dL * At local vet: * CBC: HCT 25%, 9900 WBC * Chem: albumin 2.4 g/dL, glob 5.5 g/dL * Orbifloxacin 7 mg/kg PO q12h * Minimal improvement * HCT stable * WBC: progressive decline * Neutropenia * Platelets were normal then clumped * PE at UC Davis: * QAR, pale MM, T 103.9F * BCS 2/9, generalized muscle atrophy * Unkempt hair coat, broken teeth * Fundic exam WNL * CBC: HCT 23%, 7400 retic, 1100 WBC, 99 bands, 704 toxic neuts, 220 lymphs, 77 monos, 32K plts * Chem, UA: WNL * Problems: fever, inappetence, pancytopenia, historical FIV+, and hyperglobulinemia Does Freddy have FIV? * Could have been a false positive, but unlikely due to consistent signs Why is he still alive 5 years later? * Lifelong disease How might Freddy have contracted FIV? * From a cat bite * Being born to a FIV+ queen (uncommon) * Does the test result indicate disease due to FIV or development of disease? * Neither * PCR? * Positive results = infection * Can sometimes get negatives with different subtypes * Sensitivity may vary regionally * Se/Sp 92% & 99% in one Australian study (Westman et al, 2015) * SNAP FeLV/FIV negative * Bone marrow aspirate: marked myeloid hyperplasia, marked erythroid & megakaryocytic hypoplasia * Blood cultures negative How do you explain the negative FIV test result? Might it have been a false negative? * Immune system is so depleted that it is not producing antibodies What to do next? * PCR → strongly positive FIV infection: when to test * Screen with antibody ELISA, consider retesting positive cats * All cats (not TNR), at least once * Any sick cat (including cats with bite/fight wounds) * Prior to introduction * If positive when first tested at < 6 months * At least 60 days after potential exposure * Periodically if high risk * Consider PCR Prevention: indoor housing, neutering, blood donor testing, breeding practices DIS 15: CARDIOVASCULAR INFECTIONS https://drkrystlereagan.com/ Terminology: different organisms infect different areas * Blood/RBCs → bacteremia = viable or cultivable bacteria in the bloodstream*** * Transient bacteremia = clinically insignificant bacteremia that follows medical or surgical procedures * Rapidly cleared (in immunocompetent patients) * Fungemia = fungi in the bloodstream (most commonly with yeast, e.g. Candida) * Differs from sepsis = host’s systemic inflammatory response IN RESPONSE to infection * A bacteremic patient may or may not be septic * Heart valves/endocardium → endocarditis * Myocardium → myocarditis * Pericardium → pericarditis Portals of Bacterial Entry * Urinary tract → pyelonephritis * Respiratory tract → pyothorax, pneumonia * Skin → grass awns, pyoderma, bite wound * Genital tract → pyometra * GIT→ foreign bodies, neoplasia * Normal flora translocates into portal vasculature into systemic circulation (esp. animals with compromised mucosal lining of GIT from inflammation, ulceration, NSAIDs, corticosteroids) * Orthopedic infections → implant-associated osteomyelitis * Catheter-related infections Infective Endocarditis (IE) Infective Endocarditis (IE) = bacterial (or fungal) infection of one or more endocardial surfaces of the heart * Way more common in dogs than cats * Almost always involves a cardiac valve – most common (dog): mitral valve & aortic valve * Pathogenesis: turbulent flow → change in valve surface (e.g. systemically ill, underlying damage to valve) → non-bacterial thrombotic endocarditis: platelets, fibrin, fibronectin accumulate on endothelial lining (this also occurs during DIC & vasculitis) → heart valve colonized by bacteria → layers of fibrin & platelets due to tissue factor & cytokines * Every time the heart beats, pieces of the fibrin/platelet clot breaks off & disseminates throughout the body ⇒ septic emboli throughout the body → areas of acute infarct throughout the body Etiologic Agents * Top 3 Offenders of IE = Streptococcus, Bartonella, & Staphylococcus [e] Diagnosis * Modified Duke Criteria * Gold standard = necropsy (valve biopsy) Blood Cultures * Indications: bacterial infections that we cannot access ‘with a needle’ (e.g. suspected endocarditis, suspected bacteremia, discospondylitis) * Aerobic & anaerobic * Recommend 3 sets * Collect aseptically over (ideally) 12 hours * Shorter in grave patients (0 min, 10 min, 1 hour) * ↑ sensitivity prior to ABX * May be negative in IE due to: * Bartonella is very difficult to culture * ABX started before blood culture collection IE Diagnostic Criteria: Modified Duke Criteria * Definitive diagnosis: ≥ 2 major OR 1 major + 2 minor * Possible diagnosis: 1 major + 1 minor OR 3 minor * Treatment is the same regardless because IE is a serious disease & you should be proactive Major Criteria * Endocardiogram consistent with IE * Vegetative lesions * Erosive lesion * Abscess * New valvular insufficiency * Positive blood cultures * ≥ 2 bottles with typical organism * ≥ 3 bottles with common skin contaminant * Persistent positive cultures for any microorganism when samples are ≥ 12 hours apart Minor Criteria * Rectal temp >102.2F (39C) * New or worsening heart murmur * Predisposing cardiac disease (subaortic stenosis) * Evidence of thromboembolic disease * Evidence of immune-mediated disease (polyarthritis, glomerulonephritis) * Microbiologic findings not meeting major criteria * Positive Bartonella serology * Blood cultures not meeting major criteria CASE 1 CASE: Dude 8 yo MC Black Lab * 1 day hx of lethargy, collapse, anorexia, reluctant to walk * History of “some knee problem” but not on any medications for this currently * No V/D/C/S * From Oroville area * On regular flea, tick, & heartworm prevention * Intake PE: * T = 103.2, P: 130, R: Panting * Quiet mentation, reluctant to stand, won’t ambulate * Grade III/VI left apical systolic heart murmur with a regular rhythm * Harsh lung sounds bilaterally * Initial Diagnostics * CBC: * Mild to moderate NNN anemia of 32% * Moderate neutrophilia of 29,000 with 3,500 bands (left shift) & slight toxicity * Low normal platelets of 150,000 * Chemistry panel: * Mild hypoalbuminemia of 3.2 (systemic inflammation) * Mild hyperglobulinemia of 3.4 (systemic inflammation) * Very mild mixed hepatopathy * Normal BUN & creatinine * UA: USG 1.032, remainder unremarkable * No history of a heart murmur so ordered a cardiology consult * Revealed large freely moving vegetative lesion consistent with endocarditis * * What are 3 key history questions you would like to ask the owner? * Elaborate on his past medical history * Dude has some joint disease and had a TPLO performed on his left stifle about 3 months ago * He did have a few days of limping on that leg prior to this episode * Current/recent medications * He has not been on any ABX or any other medications than those listed above in the past month * Travel/tick/toxin history * No travel outside of the immediate area and Tahoe area for some hiking * He does have foxtail exposure, but not recently * Other pets in the household? (if cats, worry about Bartonella) * No other pets in the household * What are 3 more diagnostics you would like to perform and why? * Thoracic Radiographs * Evidence of mild cardiomegaly * Diffuse bronchointerstitial pattern * No evidence of congestive heart failure * AUS: to look for nidus of infection (e.g. abscess in abdomen) & evidence of thromboembolic disease * Evidence of acute splenic thrombus formation * Mildly enlarged mesenteric lymph nodes * Remaining examination unremarkable * Aerobic Blood Cultures * 3 aerobic bottles all positive for Staphylococcus pseudintermedius * Will help determine treatment options * Urine Culture * No growth * Radiographs of Left Stifle (radiograph all implants in dogs with IE because possible nidus of infection) * Evidence of osteomyelitis surrounding TPLO bone plate * Bartonella Serology * Negative for Bartonella antibodies * Using Duke’s criteria, does Dude have IE? * Yes - 2 major, 3 minor * What major and minor criteria does he fulfill? * Major: vegetative lesion, 3 positive blood culture bottles * Minor: fever, new heart murmur, evidence of thromboembolic disease * What is Dude’s prognosis? What is the MST for mitral valve IE? What are negative prognostic factors? * Overall prognosis: guarded (differs with co-morbidities or consequences of IE) * Survival Time: 44-50% (recent studies) * MST = 136 days (range: 0.04-1,028 days) * Negative Prognostic Factors: thromboembolic events, AKI, or CHF had higher risk of mortality * Congestive heart failure, due to the development of valvular insufficiency, is the most common cause of death in dogs with IE * Valve replacement surgery not common in dogs (CSU does it but very risky) * Thromboembolic disease (80%) of dogs with IE – can manifest in renal (infarcts in both kidneys → AKI), myocardium, brain, etc. * Cardiac arrhythmias * Immune-complex mediated disease: common in dogs with IE (polyarthritis- 75%, glomerulonephritis -36%) * Positive Prognostic Factor: admin of antithrombotics associated with prolonged survival time * What treatment would you institute? * Antimicrobial therapy should be instituted if IE is suspected or confirmed * Ideally, conduct cultures before initiation of antimicrobial therapy * Broad-spectrum ABX are recommended (e.g. potentiated β-lactam + fluoroquinolone OR ampicillin + aminoglycoside), while awaiting culture results * Antimicrobials can then be adjusted as needed * Antithrombotic (e.g. clopidogrel) for prophylaxis * Medications to treat congestive heart failure if present * Antiarrhythmic drugs if an arrhythmia is noted * IF the nidus of infection/portal of entry of bacteria into the bloodstream is identified & can be removed, this should also be considered! * Remember that Dude had a TPLO and radiographs showed osteomyelitis. That bone plate needs to go! Hemoplasma Hemoplasma * Epicellular hemotropic mycoplasmas * Cause a bacteremia * Very difficult to culture * Can be respiratory, commensal, attach to RBC * Lack cell walls → ABX that target cell walls don’t work (e.g. penicillin, amoxicillin) Etiologic Agents Cats (more common clinically affected) * Mycoplasma haemofelis (most common) * Candidatus Mycoplasma haemominutum * Candidatus Mycoplasma turicensis Dogs * Mycoplasma haemocanis * *Splenectomy can predispose dogs because spleen is responsible for filtering out infected RBCs* Pathogenesis Anemia: ranges from mild/not present to severe * Mechanisms: * Splenic sequestration * Immune mediated destruction Pre-Bacteremic Phase (1-3 wks) * Likely transmitted via saliva or vectors (infected mouth parts) * Subclinical Acute Phase (at least 1 month) * Start to show clinical signs * Cyclical fluctuations in organism # & HCT * Mycoplasma sits on RBC & induces lysis of RBC Recovery Phase * Occurs in ⅔ of cats (mounts immune response to clear organism) Chronic Phase * Occurs in ⅓ of cats * Only mild anemia * Transmit to other cats CASE 2 CASE: Freddie 6 yo MC DSH * Presented for extreme lethargy & anorexia * Indoor/outdoor cat with ~10 other cats living on the same property outside of Sacramento * Has been previously healthy, no current meds * Initial Intake PE * T: 102.7, P: 240, R: 80 with slight effort * Quiet mentation, laterally recumbent * Pale MM * No murmur noted * Flea dirt present Initial diagnostics * PCV/TP: 12%/7.6 * CBC: * Severe macrocytic hypochromic (very) regenerative anemia * Slightly inflammatory leukogram * Normal platelets * Chemistry: slight hyperbilirubinemia of 1.2 * What other PE findings might you expect to see in Freddie? * No clinical signs ranging to severe clinical signs * Weak or bounding pulses * Heart murmur from severe anemia * Splenomegaly * Mild icterus → indicative of hemolysis * “All the things that would make you want to reach for a blood transfusion” * Hypothermic * Tachypnea * Mentally dull * Besides hemoplasma, what are 3 other differentials for Freddie’s anemia? * Differentials for Anemia: * The first step is to define the type of anemia present. In this case there is a moderate, macrocytic, normochromic, strongly!! regenerative anemia. * What is the definition of regeneration? How do those nucleated RBCs come into play? * Could you think of a scenario when a cat with a hemotropic mycoplasma may have a non-regenerative anemia? * When I am confronted with a regenerative anemia, here is the flow chart I go through in my mind to find the most likely differentials * Name & describe two diagnostic tests for hemoplasma. Cytology of blood smears: use fresh blood (organisms can detach from RBCs due to EDTA, making them harder to identify) * Identify organisms on RBCs * Low sensitivity (~50%) * Stain precipitate can be easily confused with organisms & be interpreted as a false positive, but generally this is a very high specificity test → positive rules in disease PCR: send a purple top (EDTA) with whole blood because organisms are found on RBCs * Detect bacterial DNA in blood * Many commercially available * Very high sensitivity & usually specific * Real-time PCR assays are typically species specific, therefore multiple tests must be ordered to test for all of the common mycoplasma species that infect cats * What is your treatment plan both in the acute setting and for prevention moving forward? * Acute Treatment * Stabilize: in patients with severe anemia, blood transfusion may be indicated to stabilize the patient * PE parameters: * CBC findings indicating anemia * MM color * Antimicrobials: usually 2 weeks of therapy with either * Doxycycline: inhibits protein synthesis * Can cause severe esophagitis & esophageal strictures in cats → always follow the med with water * Other adverse effects: hepatopathies & GI upset * Fluoroquinolone (enrofloxacin) * Associated with retinal degeneration leading to blindness in cats (mostly with higher doses) * Other adverse effects: GI upset, neurologic signs, hepatopathy, & damage to the cartilage in young, rapidly growing animals * Does not occur with pradofloxacin * Administration of corticosteroids is controversial, with no clear evidence of a benefit * Monitoring * Overall demeanor & PCV/HCT * Recheck real-time PCR can also be used to monitor for resolution of infection * Prevention * Proper flea prevention since likely transmitted by fleas * Stable indoor household with proper vector control * Outdoor access is a risk factor * All cats that donate blood for transfusions should be tested for hemoplasma to ensure nosocomial transmission is prevented LEC 67-68[f][g][h]: DEEP MYCOSES CASE: Sable 3yo FS Black Lab * 3 day hx inappetance, lethargy, intermittent cough * O also noted slight LTL lameness * PE: T= 102.6, RR=40, thin BCS, ↑ breath sounds bilaterally, uveitis OD, retinal detachment OS, draining skin lesions in left humerus * Classic for a systemic mycoses → skin lesions, thin body condition, chronic clinical signs, respiratory signs (where these pathogens often start) Major Fungal Infections Molds * Aspergillus (D > C): most important for systemic infections * Hyalohyphomycosis (D > C) (uncommon): non-pigmented molds * Penicillium, Paecilomyces * Phaeohyphomycosis (uncommon): pigmented molds * Exophiala, Cladophialophora, Alternaria, etc. * Zygomycosis (rare): very drug resistant molds; more common in humans * Rhizopus, Mucor, etc. * Dermatophytosis (C > D) * Cats are generally more resistant * Immunosuppressed at higher risk (e.g. dogs on immunosuppressant drugs) Yeasts * Dimorphic: spore-forming molds in soil & yeasts in tissues * Cryptococcus (C > D): common in CA * Sporothrix (C > D): seen in CA, zoonotic * Histoplasma (C > D): seen in CA * Blastomyces (D > C): not common in CA, more in midwest * Coccidioides (D > C): valley fever; increasing problem in CA * Spores = infectious particle * Infection not transmitted directly from animals to humans (or animal to animal) * Exception: Sporothrix * Commensal: invade opportunistically * Candida (D > C) & Malassezia (D > C) When to Suspect Deep Fungus * History of travel to endemic areas or soil disturbance * * Immunosuppressed animals with any new illness * Cyclosporine, azathioprine, leflunomide, combinations * Esp. susceptible to molds or Candida * Signalment * More common in young adults * Purebred dogs (potentially due to genetic immunodeficiency) * Aspergillosis → GSD & Vizsla * Ubiquitous in environment but unable to eliminate due to genetic immunodeficiency * Present at 1-2 years old because slow growing * Cats: Siamese, Abyssinian * History & PE findings * Pulmonary signs: cough, signs of respiratory difficulty * Suggestive extrapulmonary signs: * Osteomyelitis (lesions can be osteoproliferative or osteolytic) or discospondylitis (for mold infections) * * Draining or nodular skin lesions * Claw bed lesions (masses or swelling) * Parenchymal organ involvement (esp. Histoplasma) * Liver, spleen, GIT, bone marrow * Ocular lesions (esp. chorioretinitis, also uveitis) * Meningoencephalitis * Anything can go anywhere with immunosuppression (e.g. thyroid gland, adrenal gland) * Suggestive lesions on TXR * Hilar (tracheobronchial) lymphadenomegaly * Ddx: nocardiosis, actinomycosis, mycobacteriosis * * ^classic fungal disease (e.g. blasto, cocci, histo) * Other ddx: neoplasia * Miliary or nodular interstitial patterns * * Lobar consolidation * Pleural effusion (uncommon), pyothorax * * Cavitary lung lesions (rare in dogs compared to humans) * * Suggestive CBC & Chemistry Findings * Often nothing (e.g. not much inflammation, neutrophilia, mild anemia) * Hypercalcemia * Azotemia (molds: aspergillus in the renal pelvis) * Hyperglobulinemia & hypoalbuminemia due to chronic immune stimulation * Failure to respond to antibacterial drugs * Clinical signs worsen after initial improvement with glucocorticoids * (e.g. suspect bacterial infection but not responsive to ABX → started on steroids because suspect immune-mediated → initially improve due to ↓ inflammation → clinical signs worsen due to immunosuppression) Pathogenesis * Inhalation of spores from the environment * Incubation a couple of weeks or longer (sometimes years) * Clinical signs develop at the end of the incubation period * Pulmonary infection may resolve before lesions appear elsewhere * Sometimes pulmonary signs will be resolved by the time other signs appear and diagnostics are conducted * Rarely inoculation (=local skin lesion in area of inoculation) * Disease severity depends on: * Dose of organism * Host immune competence * Strain virulence Diagnosis * Cytology, histopathology * Know structures → can know which organism it is based on appearance * Histopathology aided by special stains * PAS: stains fungi pink * GMS (silver stain): stains fungi black * Specific serologic tests * Know antibody vs. antigen tests Treatment = Azole antifungals +/- Amphotericin B * Usually months to years of treatment (sometimes even lifelong!) * No emergency anti-fungal treatment exists → use symptomatic care * May be costly (esp. due to the length of treatment) * Signs can worsen for 2-3 days before they get better → killing the fungi initiates an inflammatory response (don’t euthanize yet!) → can take 5-10 days to ‘turn the corner’ * May require supportive care with O2, anti-seizure meds, anti-inflammatory drugs * Amputation may be required for refractory bone lesions (e.g. severe osteomyelitis) * Enucleation may be required for severe ocular involvement * CNS involvement generally has a poor prognosis (esp. for Blastomycosis) Azole Antifungals * Itraconazole or fluconazole * (also very commonly prescribed for superficial mycoses: dermatophytosis & Malassezia) * Do NOT use compounded formulations (powder inside of capsules instead of beads): low bioavailability & ineffective; sold outside of US * DO NOT USE ketoconazole due to adverse effects (there are better antifungals) * Voriconazole or posaconazole for severe mold infections or refractory disease * Very expensive for severe disease * Oral triazole derivatives (IV forms available) * MOA: inhibit fungal sterol synthesis * Takes some time to take effect since fungi replicate slowly * PK: * Itraconazole: preferred because more active * Better for bone involvement * Penetrates the CNS, eye, & urine poorly * Can still help with CNS infections due to anti-inflammatory effects * Fluconazole: NOT active against molds → NEVER use to treat systemic Aspergillosis (or other mold) infections * Penetrates urine & brain * Can be used for cryptomycosis that tends to go to those site * Admin * Solution: best absorbed on empty stomach (give without food), lower dose * Itrafungol = oral itraconazole solution labeled for cats for dermatophytosis * ELDU for deep fungal infection (higher doses) * Capsules: best absorbed with food (give with food) * Can be costly * Adverse effects * ↑ liver enzymes (ketoconazole > itraconazole > fluconazole) * Expected → monitor monthly * If ALT > 400 U/L or inappetence/vomiting/diarrhea develops (i.e. clinical signs of HEPATOTOXICITY), discontinue immediately * Remind owners to keep an eye on their pet’s appetite and vomiting and when to stop the medication * Ulcerative dermatopathy (itraconazole) * More common on higher doses (↓ dose OR stop & restart at lower dose) * <5% of dogs on 5 mg/kg/day * Can look like ulcerative lesions secondary to fungal disease (don’t ↑ dose) * Diarrhea (high doses of fluconazole) Amphotericin B (‘Amphi-terrible’): unlikely to be given in GP, common in SA IM rotation * Polyene antimicrobial from Steptomyces nodusus * MOA: binds fungal sterols, with ↑ membrane permeability * Ergosterol over mammalian cholesterol * Electrolytes leak out of fungal cell wall * NEPHROTOXICITY * Given parenterally (IV), M-W-F basis in D5W for a month (and then in pulse treatments once a month) or until azotemia develops * Kidney panels monitored before each infusion * Formultions * Deoxycholate: lyophilized, most nephrotoxic * Given with NaCl diuresis over 4-6 hours (longer time) * Lipid-complexed: more expensive but less nephrotoxic (& more effective) * 3 different forms: liposomal, colloidal dispersion with a disk particle shape, lipid complex with a ribbon shape * Given IV over 2 hours (more convenient) * Does not require fluid diuresis * Engulfed by macrophages, reduced toxicity, so higher dose can be used Public Health Aspects * Transmission of some deep mycoses from dogs to humans * Biting * Needle-stick injury * Necropsy: conversion to mycelia can occur in 72 hr on exposure to air * Laboratory-acquired infections * Culture for diagnosis only if necessary & warn lab of suspicion * Safe for cryptococcus, candidiasis, most organisms that form molds in tissues * Contaminated bandaged around skin lesions harboring mycelia? (insignificant) Coccidioidomycosis Coccidioides spp. * Soil-borne dimorphic fungus * Thick-walled, barrel-shaped, multinucleate arthroconidia in environment * Arthrospores dispersed in air & inhaled * Young, adult, often purebred dogs * Feline disease rare (more common in AZ) Epidemiology * Sandy, alkaline soil * High temperatures * Low elevation * Southwestern USA, Mexico, Central & South America * In the US: Arizona, SW Texas, CA * Also New Mexico, Utah, Nevada, eastern WA * San Joaquin Valley (“Valley fever”) * Phoenix & Tucson hyperendemic * Spreading across western US Pathogenesis * Incubation period 1-3 weeks or longer (years) * Wind, soil disruption, etc. stirs up arthrospores * Arthrospores inhaled → form a *spherule* that partitions into hundreds of endospores (looks like ‘pomegranate’) * Macrophages surround spherule that enlarges to 20-200 um in diameter → spherule ruptures → released endospores attract neutrophils (pyogranulomatous inflammation) & form new spherules * Arthrospores enter pulmonary tissue: bronchioles, alveoli, peribronchiolar, & subpleural tissue * With immunosuppression: dissemination to hilar LNs & other organs over 3-4 months * Esp. skin, bones, pericardium, CNS, eyes, testicles, liver, kidney * Course of disease months to years long (often years) * Reactivation of subclinical infection with immunosuppression Clinical Signs * Humans * Mostly subclinical (60%) or mild respiratory signs * Most humans recover & are immune * 2% develop disseminated disease * 3-4% develop persistent pulmonary infections * Cough (hilar lymphadenopathy or pulmonary involvement) * Systemic signs * Lameness, lymphadenomegaly, skin lesions, ocular lesions, right-sided CHF (secondary to pericarditis) * Skin lesions begin as SQ masses or nodules, may ulcerate “Grow & Blow Phenomenon” * After rain during extended periods of drought, many arthrospores disseminated * Outbreaks after dust/soil disturbance: * Dust storms, earthquakes, heavy rains * Digging behavior is a risk factor in dogs * Incidence increasing & geographic range spreading Diagnosis * Similar to other fungal diseases * Lab Work usually normal * Hyperglobulinemia * Hypoalbuminemia * Proteinuria (glomerulonephritis) * TXR * Can be normal * Hilar lymphadenopathy * Patchy alveolar infiltrates * Miliary to nodular patterns uncommon * Pericardial or pleural effusion * Organism Detection: low sensitivity → often negative results * Cytology * Spherules can be seen with Wright’s stain * Often surrounded by inflammatory cells * Aspirates, respiratory lavages * Histopathology * Spherules * Pyogranulomatous inflammation * Culture only if necessary (contagious to lab personnel) * Antibody detection: positive result is diagnostic * Very sensitive, rare false negatives * Agar gel immunodiffusion (Gel ID), IgG, IgM * Titer correlate with disease severity, and fall with effective treatment * 1:128 is a high titer (1:32 or higher) * Low-level positives (1:8 or less) in hyperendemic areas do not correlate with disease due to subclinical exposure Treatment * Antifungal drugs: often >1 year or lifelong in dogs with dissemination * Itraconazole most effective (esp. with bone lesions) but fluconazole OK * Amphotericin B for disseminated disease initially, then azoles * Monitor titers every 1-3 months during treatment * Rising titers suggest poor drug efficacy or absorption Blastomycosis Blastomyces spp. * Dimorphic fungus * Large (5-20 um in diameter) * Thick, refractile, double cell wall * Broad-based budding with thick wall * “Blasto = broad-based budding” * “Crypto = narrow-based budding” Epidemiology * Dogs & humans, rarely cats * Multiple dogs in a household may be infected * Dogs sentinels for human infection (dogs 10x more susceptible) * Subclinical infections common in humans * Water sources & acid, sandy soil * Upper midwest: 95% of dogs are <400m from water * Soil disturbance: rain & construction work facilitate spore release * Mainly North America: OH, MS, & MO river valleys, mid-Atlantic states * Quebec, Manitoba, & Ontario * Only 2 cases ever at VMTH (short incubation period, so not many travel-related cases) * Occasional cases elsewhere (Africa, Central America) Pathogenesis * Spores inhaled, convert yeast in lungs * Dissemination to skin & SQ tissues, bone, CNS, eye, prostate, testes, sometimes elsewhere Clinical Signs (typical: thin young adult outdoor hunting dog) * Non-specific signs * Poor body condition * Nodular or draining skin lesions * Lymphadenopathy * Signs of pulmonary involvement * Ocular involvement common (uveitis, retinal detachment, panophthalmitis) * Lameness * CNS signs Diagnosis * Organism detection * Cytology & histopathology: usually positive * Very sensitive, but false negatives possible * Aspirate skin nodule (or other infected tissue) * Pyogranulomatous to suppurative inflammation & budding yeasts * GMS * Culture only if necessary (infectious to lab personnel) * Antigen testing * Best with urine! * Urinary antigen tests >90% sensitive * Cross-reactivity with histoplasma antigen (use geography to raise clinical suspicion) * Same treatment but worse prognosis * Can be used to monitor therapy * Currently available antibody tests lack sensitivity & specificity TXR: miliary nodular interstitial pattern Treatment (for Blasto & Histo) * Azoles, amphotericin B * Minimum 6 months of treatment * Less commonly lifelong compared to coccidioidomycosis Histoplasmosis Histoplasma capsulatum * Soil-born dimorphic fungus * Disseminated in bat guano * Prefers moist, humid conditions & N-rich organic matter * Indoor animals can acquire infection from houseplant soil & dirt on shoes Epidemiology * Temperate & subtropical regions worldwide * Most US cases in OH, MS, & MO river valleys (southernmost parts) * Also in parts of NorCal & SoCal * Many infections subclinical * Cats as susceptible as dogs * Most animals < 4 years of age Pathogenesis * Mycelia produce microconidia & macroconidia, which are inhaled * Incubation period at least 12-16 days * Microconidia become yeasts in tissues * Bud intracellularly within MACROPHAGES & extracellularly * Disseminate by blood & lymph * Latent subclinical infection can occur with reactivation Clinical Signs * Goes to parenchymal organs (e.g. spleen, liver, GIT, bone marrow) * Dogs can get colitis with large bowel diarrhea signs → scrape rectal wall to find yeast Cats * Most have disseminated disease * Pulmonary involvement * TXR: mixed alveolar interstitial pattern * Organomegaly (e.g. hepatomegaly) & lymphadenomegaly * Conjunctivitis, chorioretinitis, retinal detachment, optic neuritis * Bone involvement, rarely skin Dogs * Nonspecific signs common * Pulmonary involvement with hilar lymphadenomegaly * Most in North America have GI involvement * Protein losing enteropathy * Pyogranulomatous colitis with hematochezia * Liver & spleen * Bone marrow * Ocular & skin involvement uncommon Diagnosis – Organism detection * Cytology & histopathology * Sensitive * Rectal scrapings * Aspirates, biopsies * Culture if needed * Antigen test * Best with urine! * Urinary antigen tests >90% sensitive * False negatives with localized disease (e.g. ocular disease) * Cross-reactivity with blastomyces antigen (use geography to raise clinical suspicion) * Same treatment but better prognosis Cryptococcus * C. neoformans (dogs) & C. gattii (dogs & cats) * Cause different clinical signs * Dimorphic fungus * Narrow-based budding * Thick polysaccharide capsule virulence factor (glucuronoxylomannan) * Antiphagocytic * Immunosuppressive * Grows as a yeast in culture (NOT infectious to people) * Mycelial (mold) form likely in the environment * Grows in culture if V8 juice is added * Important cause of meningitis in AIDS patients * C. neoformans Epidemiology * C. neoformans: likes pigeon guano * C. gattii (VGI - VGIV) * Australia (VGI) associated with Eucalyptus * Western USA (VGII & VGIII): variety of tree species (e.g Douglas fir in Pacific NW), also in air & water * Subclinical carriage (uncommon) in nasal passage or around 1 in 10 dogs & cats * Cats more susceptible than dogs * Breed predispositions * American Cocker Spaniels in US * Siamese cats Pathogenesis * Initial site of infection: deposited in nasal cavity, with nasal granulomas/cryptococcomas * NOT the lungs (unlike in many other fungi) due to thick capsule preventing inhalation deep into lungs → not much pulmonary involvement * Local extension or hematogenous dissemination * Meninges * Eye * Other: LNs, skin, sometimes bone & kidneys * Anywhere in dogs infected with C. neoformans * Predisposing immunosuppressive illness rarely identified in dogs & cats Clinical Signs Cats – C. gattii * Usually upper respiratory, CNS, ocular, or skin * Chronic nasal discharge/URI signs * Nasal cavity signs: * Discharge, masses, ulceration * Swellings over the nasal planum/bridge (CLASSIC) * Ddx: SCC, eosinophilic granuloma, sporothrix → wear gloves in case sporothrix * Mandibular lymphadenopathy * Turbinate destruction & facial distortion * Stertor * Pulmonary involvement uncommon * Mediastinal masses (uncommon) Dogs * C. neoformans (more common in dogs) * Young adult purebreds (likely immunodeficient) * CNS & ocular involvement common * Widespread dissemination to all sites (GIT, LNs, pancreas, myocardium, kidneys, liver) * C. gattii (more common in cats than dogs) * Localized nasal cavity cryptococcomas * Localized cutaneous masses CASE: Tuthra 8 yo MC DSH * 5 week history of reluctance to jump (‘clenching’ the furniture), intermittent head shaking & sneezing * Treated by rDVM with clavamox, enrofloxacin, then metronidazole and prednisone 10 mg q 24 hours * ABX (no response) → steroids (initial improvement) * Tuthra began panting, crying, twitching * Treatment changed to clindamycin after 3 weeks (suspected toxoplasmosis?) → did not improve → referred At the VMTH: * Bilateral mydriasis, icterus, focal tremors, obtunded * CBC: mild NR anemia (27%), lymphopenia (828, normal >1000) * Chem, UA: NSF * FeLV/FIV: negative * TXR: WNL * MRI: high T2, low T1 = characteristic for crypto * * CSF tap: fungus on the brain → isolated VGIIa * ← no capsule because type of stain * LCAT 1:32,000 (very high) * Deoxycholate amphotericin B * Fluconazole 50 mg q12 hours * Prednisolone 0.75 mg/kg q 24 hours (for inflammation secondary to dying organisms) * E-tube feeding Diagnosis - Organism Detection * Cytology & histopathology: usually positive * Sensitive: usually diagnosis is cytological * Skin lesions, aspirates (e.g. LNs), CSF, urine sediment * Most stains work well * Culture * Antigen test: very sensitive (very rare false negatives) – more in cats than dogs * Serum or CSF * Types: * Latex Cryptococcus agglutination test (LCAT) * POC test: quick (10 min) but false positives common → need to verify with LCAT * >95% sensitive in cats, >85% sensitive in dogs * Low level false positives 1:200 or less in cats → confirm with cytology or culture * Treat until titers fall to zero Sporotrichosis Sporothrix spp * Dimorphic fungus, worldwide, esp. subtropical regions * Round, oval, or cigar shaped yeast in tissues * Species in Brazil is very transmissible from cats to people (concern for animal imports) Epidemiology * Soils rich in decaying organic matter * Pricking fingers: rose growers, hay bale handlers, sphagnum moss, Christmas tree farmers * Hunting dogs with wood splinters * Male cats that roam outdoors & fight * Contaminated claws * Cats can transmit infection to humans (skin to skin) Clinical Signs * Three forms * Cutaneous (most common) * Single or multiple nodules, localized * Can resemble cryptococcosis * Cutaneolymphatic * Follows lymphatics on distal limbs * Disseminated * Rare Diagnosis * Cytology & histopathology * Many organisms in cats, rare in dogs * Pleomorphic yeasts intracellularly & extracellularly * Culture if necessary Treatment * Itraconazole * Prognosis good * Wear gloves when handling cats suspected to have sporotrichosis, wash with chlorhexidine * Direct transmission possible, without break in the skin Aspergillosis * Saprophytic fungi, everywhere in the environment * Branch dichotomously at 45 degree angles; septate, nonpigmented (hyaline) molds * Common mucosal contaminants * Sinonasal & disseminated disease in dogs * Rare sinonasal & sino-orbital disease in cats Disseminated Aspergillosis * Usually A. terreus & A. deflectus, rarely others * Esp. Australia & western USA * Often no overt immunocompromise * Female GSD (& Vizslas) * Likely genetic predisposition * Immunosuppressive drug therapy * NOT transmissible between animals * Nasal cavity usually spared * Spores inhaled then disseminate hematogenously, often ot kidneys (renal pelvis), intervertebral disks, then eyes Clinical Signs * Common manifestations: discospondylitis, fungal pyelonephritis, pulmonary lesions * Non-specific signs: anorexia, weight loss, cachexia, pyrexia, weakness, lethargy * Signs of specific organ involvement: paraparesis, lameness, ocular disease, tachypnea, renal failure Diagnosis * Cytology & histopathology * Urine sediment exam * Culture from a normally sterile site * Aspergillus galactomannan antigen testing (serum or urine) * Cross-reactivity with other molds & fungi unpredictable * False positives with Plasmalyte treatment * Antibody testing is insensitive, not recommended Treatment * Voriconazole or posaconazole monotherapy * Aggressive antifungal therapy: * Amphotericin B followed by an azole (NOT fluconazole because mold) * Caspofungin (IV only) * Long-term treatment (for life) * Guarded prognosis * Die weeks to ~1 year after diagnosis with treatment Canine Sinonasal Aspergillosis * A. fumigatus (different species than disseminated) * Chronic nasal discharge & sneezing * Dolichocephalic dogs predisposed * May accompany foreign bodies * Normal to ↑ nasal airflow on PE * Occasionally bony defects on palpation * Early diagnosis & treatment is critical Diagnosis * No single test conclusive, false negatives common * Aspergillus AGID antibody test: positive suggest likely, but insensitive * Antigen testing not useful * Nasal radiography (insensitive): loss of turbinate detail * CT scan: loss of turbinates, evaluation of cribriform plate * Rhinoscopy: fungal plaques, cytology, histopathology, culture of biopsies * Surgical trephination (frontal sinus) Treatment * Debridement & intranasal clotrimazole * Most need 2-3 treatments 1 month apart * Sometimes with oral azole therapy * Prognosis is guarded due to recurrent bacterial infections Pythiosis * Cutaneous, GI, or disseminated disease * Pythium insidisum * Oomycete (not a fungus; lacks ergosterol) * Morile, flagellate zoospores Epidemiology and pathogenesis * Dogs, rarely cats, people * Wet, tropical and subtropical climates * Gulf of Mexico, Florida * Northern CA (rice fields) * Zoospores released in stagnant water in warm weather * Attracted to damaged tissues * Large breed, immunocompetent dogs Clinical Signs * Cutaneous lesions: extremities and perineum * Spongy proliferative, with ulcerative and draining tracts * GI tract (most common) * Cases from CA * Esophagus - regurgitation from hypersalivation * Intestinal tract * Palpable mass, vomiting, diarrhea, weight loss * Infiltrative granulomatous enteritis, sometimes with perforation Diagnosis * Cytology & histopathology * Wide, poorly septate, branching irregular hyphae * Stain best with GMS * Fungal culture * Experienced laboratories * ELISA antibody serology * Sensitive and specific * Auburn University Treatment * Surgical resection of cutaneous and focal GI lesions if possible * Limb amputation may be necessary * Combination of itraconazole, terbinafine, and prednisone LECS 69-70: TICK-BORNE DISEASE Vector-Borne Disease Principles * Diseases (infections) transmitted by blood-feeding arthropods * Mosquitos (e.g. Dirofilaria) * Ticks * Fleas (e.g. Bartonella, tapeworm) * Sandflies or other biting flies * Kissing bugs (e.g. Chagas disease from protozoa Trypanosoma cruzi) * Viral, bacterial, protozoal, parasitic * Most bacterial vector-borne diseases are responsive to Doxycycline * New infection occurs from the environment or is introduced by a carrier (e.g. from shelter) * Infection leads to disease OR subclinical seroconversion, with or without PERSISTENCE in tissues/bloodstream * Many subclinical infections occur & very few actually develop disease * Vector introduction * History of vector exposure may not be present (e.g. can just be dog from shelter who was brought home) * Geographic distribution is that of the vector (& sometimes specific reservoir hosts) * Coinfections: multiple pathogens infecting one vector → coinfections in the host * Pets are sentinels for human disease * Zoonotic potential * Needle-stick injuries * Aggressive interactions (bite wounds) * Vector exposure * SNAP 4Dx Plus ELISA: used to screen for heartworm & for antibodies against Anaplasma, Ehrlichia, & Lyme * NOT a great test for Anaplasma or Ehrlichia because often early on in disease & no antibodies have been made yet + subclinical exposure is common * Majority of vector-borne agents cause chronic, persistent infections * Chronic infections allow pathogens to promote transmissibility by allowing organism to adapt to host * Some organisms (e.g. Francisella tularemia) can cause acute severe disease or chronic persistent disease Major Tick-Borne Diseases * Bacteria: very important! * Typical * Atypical (Rickettsiae) * Protozoa: very important! * Viruses: not dogs & cats in the US (TBEV Europe) * Fungi & Parasites: not common Rickettsiae: Ehrlichia, Anaplasma, Rickettsia, Neorickettsia * Arthropod-transmitted * Gram-negative pleomorphic BACTERIA * Coccobacilli * Obligately intracellular, may form morulae * ‘Doxycycline-deficiency diseases’ * Susceptible to tetracyclines (no documented resistance) Ehrlichia & Anaplasma * Monocytes: E. canis, E. chaffeensis * Granulocytes (neutrophils): E. ewingii & A. phagocytophilum (identical on cytology) * Platelets: A. platys * Can cross host species barriers 4 Major Tick Vectors in the US Ixodes Species * Ixodes scapularis (Blacklegged/deer tick) * East coast/upper Midwest * Ixodes pacificus (Western Blacklegged tick): less common vector because prefers to feed on lizards which destroys it * West coast * Transmits: * Lyme disease: #1 vector-borne disease in humans * Granulocytic anaplasmosis * Logs & trunks in forested areas, leaf litter * Adults: large mammals (deer) * Larvae & nymphs: small mammals, birds, lizards (I. pacificus) * Peak activity early spring Rhipicephalus (Brown Dog Tick) Species: Rhipicephalus sanguineus * Nationwide: uncommon in CA, seen here due to travel * Endemic regions: mostly in South US (humid), may be close to the border in SoCal * But can be anywhere because entire life cycle can be completed indoors * & Canada & Hawaii & worldwide * Transmits: * Canine monocytic ehrlichiosis * RMSF (Rickettsia rickettsii) * Babesia vogeli * Cyclic thrombocytopenia (Anaplasma platys) * Disease transmission increasingly recognized * Esp. warmer climates * Dogs preferred for all life stages * Feeds on other mammals, humans Dermacentor Species * American Dog Tick (Dermacentor variabilis) * Eastern half of US + CA * Pacific Coast Tick (Dermacentor occidentalis) * CA * Rocky Mountain Wood Tick (Dermacentor andersoni) * Transmit: * RMSF * Tularemia (Francisella tularensis) * Colorado Tick Fever (humans) Amblyomma Species * Amblyomma americana (Lone Star Tick) * Eastern half of US * Amblyomma maculatum (Gulf Coast Tick) * Gulf coast + Southern Atlantic coast ish * Transmits * Human monocytic ehrlichiosis (E. chaffeensis) * Canine granulocytic ehrlichiosis (E. ewingii) * Rickettsia spp. * Feline cytauxzoonosis * Canine American hepatozoonosis * Aggressive tick: feeds aggressively; distribution is moving northwards; less sensitive to parasiticides ^Lone Star Tick: characteristic appearance Canine Monocytic Ehrlichiosis (CME) * One of the most common canine infectious diseases worldwide, esp. warmer climates * Very rarely found in cats, humans (South America) * Mainly SE & SW states * Transmitted by Rhipicephalus sanguineus (Brown Dog Tick) * Caused by Ehrlichia canis * Unique acute, subclinical, chronic phases * Acute & chronic can be difficult to differentiate * Only some dogs reach the chronic phase – we don’t know why * ANY travel history is relevant (because subclinical phase) Transmission & Pathogenesis * Incubation period (short: 8-20 days) * Acute phase (first 2-4 weeks): more common in places where Brown Dog Ticks are endemic (NOT in CA) * Multiplies in MONOCYTES with splenomegaly, lymphadenopathy, (sometimes hepatomegaly) * Infected cells adhere to endothelium in lungs (vasculitis), meninges, & kidneys * Thrombocytopenia, +/- mild leukopenia, anemia * All dogs seen in CA with CME have chronic phase due to travel Clinical Signs * Acute Phase * Fever, organomegaly (lymphadenopathy, splenomegaly) * Anorexia, depression, weight loss, oculonasal discharge * Peripheral edema * Neurologic signs * (e.g. hyperesthesia, muscle twitching, cranial nerve deficits) * Diagnostics: PCR+, seronegative * Subclinical Phase: from 6-9 weeks PI, lasts years * No signs, +/- thrombocytopenia * Chronic Phase: small % affected dogs * Impaired marrow function & pancytopenia * Lymphadenopathy, splenomegaly * Pallor, bleeding tendencies (thrombocytopathia) * Weight loss, debilitation * Anterior uveitis, retinal hemorrhage * +/- Neurologic signs * Secondary infections * Diagnostics: positive on 4Dx, positive titer on IFA (more sensitive), PCR+ (less sensitive) Diagnosis * Variable anemia, pancytopenia, lymphocytosis, thrombocytopenia * Morulae (mostly only acute) in peripheral blood * Hyperplastic (acute/chronic) or hypoplastic (chronic) marrow * Polyclonal or rarely monoclonal gammopathy (“the 1 disease that can cause monoclonal gammopathy that’s not neoplasia”) * Can look like multiple myeloma/lymphoma: monoclonal gammopathy, lymphocytes & plasma cells on bone marrow aspirates * +/- protein-losing nephropathy as a result of immune stimulation in chronic phase * Organism Detection Tests: morulae on blood smear, PCR panels * Best for acute phase → not useful here * Not sensitive: tend to have low organism numbers * Not good for the chronic phase * Antibody Detection Tests: lack sensitivity early → always do a titer * Cross-reactivity among Ehrlichia species * Widespread subclinical exposure problematic * Rare false negatives in chronically infected dogs * Types of tests * SNAP 4Dx Plus ELISA (Ehrlichia spot – not specific for E. canis) or Accuplex (Antech) → if positive & consistent signs: perform titer to confirm * Quantitative serology (IFA): high titers in dogs with chronic disease * Acute & convalescent * Titers can remain high for months with treatment * Watch for improvement in platelets, globulin Treatment * Persistent infection = prolonged treatment * Doxycycline 5 mg/kg PO q12h 6-8 weeks * Prognosis: * Good for acute ehrlichiosis * Poorer for chronic ehrlichiosis * Recombinant EPO & G-CSF for impaired bone marrow function * Prednisolone for suspected immune-mediated consequences [i] Ehrlichia chaffeensis * Human monocytic ehrlichiosis * Dogs exposed and infected * Febrile illness experimentally * Clinical significance unclear Canine Granulocytic Anaplasmosis * Caused by Anaplasma phagocytophilum * Upper Midwest, northeast, CA, OR (also Europe) * Ixodes pacificus in NorCal * Ixodes scapularis in the midwest * Same vectors as Borrelia burgdorferi, often co-transmitted Clinical signs * ‘ADR of dogs’: non-specific signs, often just fever & lethargy * Widespread subclinical infection * Fever, lethargy, vomiting, lymphadenopathy, splenomegaly, scleral injection * Lameness (neutrophilic polyarthritis?) * Neurologic signs? * Other signs? * Thrombocytopenia, mild anemia, neutropenia/neutrophilia, lymphopenia, hypoalbuminemia, slightly ↑ ALP Diagnosis: * Organism detection tests: better because acute disease * Blood smear evaluation: morulae within GRANULOCYTES (look like Ehrlichia ewingii but different geographic distribution) * PCR: best test (most sensitive) * Antibody detection tests: not really useful because no antibodies when dogs first get sick (more useful for epidemiology to look for exposure to Anaplasma) * IDEXX SNAP 4Dx Plus (Anaplasma spot – not specific A. phagocytophilum), Accuplex * Acute & convalescent phase serology (no one ever does this) * Response to treatment: feel better within 48 hours (VERY responsive) * Doxycycline 5 mg/kg PO q12h for 2 weeks Very similar to Ehrlichia ewingii * Similar clinical signs * Both are human diseases * Main difference: Ehrlichia ewingii can persist in bloodstream (1 year) but Anaplasma phagocytophilum goes away Rocky Mountain Spotted Fever (RMSF) * RMSF is seen in SoCal but NOT NorCal * Increasing incidence due to climate change * Most cases March-October * Rickettsia rickettsii * Vector: Dermacentor spp., Rh. sanguineus (Arizona, Mexico) * Similar syndromes caused by other subclinical non-pathogenic spotted fever group rickettsia species * Including those transmitted by Amblyomma spp. * Can cross-react with Rickettsia rickettsii on diagnostic testing * Ticks attach for 5-20h * Rickettsiae infect ENDOTHELIAL CELLS of small blood vessels * Vasculitis, necrosis, ↑ vascular permeability * Edema, hemorrhage, hypotension, shock, sloughing off of tissues Clinical Signs * Incubation period 2-14 days * Signs related to vasculitis * Fever, anorexia, depression * Edema, hyperemia & necrosis of extremities * Mucopurulent ocular discharge * Vomiting, diarrhea * Neurologic signs (e.g. neck pain due to meningitis) * Respiratory signs * Joint pain & swelling, muscle pain * Cardiac arrhythmias * Bleeding/thrombosis * Ocular lesions * Permanent cardiovascular, renal and neurologic damage possible * Humans: FEVER, RASH, Headache, death in 4% Laboratory abnormalities * Leukopenia/leukocytosis, anemia, thrombocytopenia**, rarely DIC * Hypoalbuminemia, ↑ liver enzymes Diagnosis * Indistinguishable from acute ehrlichiosis but SHORT course * Dead or better in 2 weeks (if sick for longer, NOT RMSF) * +/- tick infestation, season, travel history * Acute & convalescent phase titers – IFA (eg. Protatek) but no POC tests * Cross-reactivity with other SFG rickettsiae * Organism detection tests? * Biopsy from a skin lesion & conducting PCR is more likely to detect an organism than a blood sample (because organisms are within endothelial cells) Treatment & Prevention * Doxycycline - 5 mg/kg q12h 2 weeks * Improvement in 24-48 h * Use fluids with caution * Lifelong immunity following natural infection * Effective vaccination not available * Tick prevention * Dogs a sentinel for human disease * ‘Rapid & steep ↑ in the # of free-roaming dogs & host-seeking Rh sanguineus in impoverished communities’ * Median time onset to evaluation 2 days, 13% correct dx * Patients who do not receive doxycycline by day 5 are at 2.5-3.5x ↑ risk of death, 4x by day 6 Salmon Poisoning Disease Etiologic Agent * Neorickettsia helminthoeca * Elokomin Fluke Fever (EFF) agent (related, causes similar clinical signs) * Transmitted through ingestion of a fish containing fluke metacercariae of the trematode Nanophyetus salmincola (infects snails only found in Pacific NW which are brought to other areas, e.g. SoCal) * Salmon → Trematode/Fluke (Nanophyetus salmincola) → Neorickettsia helminthoeca * Disease of canidae (dogs & coyotes), NOT cats Pathogenesis: most cases are dogs that have eaten fish but not always, maybe have eaten snails or swimming in areas with cercaria * Mature flukes in intestine release rickettsiae into intestinal epithelial cells * Spread to rest of body via lymphatics * Ulcerohemorrhagic enteritis → often severe diarrhea with melena * Lymphoid tissue invasion by macrophages & plasma cells * Trematode eggs are in feces 5-8 days after fish ingested; shed for 60-250 days Epidemiology * Common in NorCal * Geographically limited by the trematode’s first intermediate host, Oxytrema silicula (snail) * Dogs are often sporting breeds of any age & sex * Often young male sporting breed → due to lifestyle, not predisposition Clinical Signs (“any time you see a dog with acute severe diarrhea with generalized lymphadenopathy, you’ve got to be thinking about Salmon Poisoning Disease”) * Incubation period 5-8 d (up to 33 d) * Usually have fluke eggs in feces when start to show clinical signs * SEVERE signs (some may be more mild depending on challenge dose) * Fever, anorexia, vomiting, diarrhea, profound weight loss, lymphadenopathy (mesenteric & peripheral), splenomegaly * DEATH in 7-10 days if untreated Diagnosis * History of fish exposure in 50% of cases * Nugget fish too! * Snails? * CBC: lymphopenia, thrombocytopenia (90%) * SCP: hypoalbuminemia & ↑ ALP * Trematode eggs best identified by combining flotation & sedimentation (clinical signs + eggs = diagnostic) * > 80% of cases * Inclusions in macrophages in LN aspirates * PCR on feces or LN aspirates ^sedimentation * Poorly organized morulae within histiocytes Treatment * Tetracyclines for 2 weeks * Doxycycline * Parenteral oxytetracycline if vomiting * Praziquantel for the fluke infestation * IV fluids +/- blood products (e.g. colloids for hypoalbuminemia) * Dogs should not eat raw fish! Lyme borreliosis * Most common vector-borne disease of humans * CDC: ~476,000 cases diagnosed & treated/year in the USA (but only 30,000-40,000 reported) * Caused by Borrelia burgdorferi (spirochete – closely related to Leptospira) * Many other species of Borrelia * Persistent, low-level infection of connective tissue (NOT bloodstream like other pathogens) * Disease reflects the host immune response Epidemiology * 90% of cases in the USA in the NE * Ixodes scapularis is all throughout east coast but northern clade causes Lyme * Widespread subclinical exposure * Most remaining: upper midwest * Not common in CA (but # of cases increasing), issue in travel dogs * Ixodes pacificus can feed on western gray squirrel (reservoir host) Life Cycle (~2 years) * Ixodes scapularis ticks (northern clade) are usually infected after feeding on the white-footed mouse (Peromyscus leucopus) = main reservoir host (extremely high burdens, subclinically infected) * Spring/summer: eggs hatch into larvae (uninfective – NO transovarial transmission) * Larvae become infected after feeding on small rodents (e.g. white-footed mice) * Over winter: infected larvae burrows & become nymphs → nymphs feed on dogs & humans * Nymphs most likely to transmit infection * Small (often unnoticed) * Engorge quickly * Most prevalent in spring, summer * Nymphs become adults → adults feed on deer * Tick Feeding & Transmission * Transmit after 24h * Prevent transmission by pulling tick off within 24 hours * (contrast to Ehrlichia canis: transmit after 2h → repellent products are important for prevention) * Tick saliva is complex, > 100 molecules * Saliva-assisted transmission (SAT) * Inhibits CD4+ cell activation, proinflammatory cytokine production * Eg. Salp15 binds to & protects OspC from immune recognition * Outer surface protein (Osp) * Most important is OspA: attaches to TROSPA receptor on tick midgut → as tick starts to feed, Borrelia migrates into salivary gland & downregulates OspA expression (& upregulates expression of OspC, then VlsE, then OspF) → Borrelia enters dog/human & OspA downregulation continues until Borrelia no longer expresses OspA → antibody response to OspC (sometimes to OspA) Clinical Signs Humans * Early disseminated Lyme: * Multiple erythema migrans = target-shaped rash that humans get upon initial infection * 70-90% of infected humans (does NOT occur in dogs) * 3-30 days after a tick bite (usually 7-14 days) * Reaction to tick saliva & migrating spirochetes * Spirochetes migrate at up to 0.5 inch/hr → outer edge of rash (=inflammatory reaction to spirochetes migration) up to 35 cm diameter * Break down connective tissue * Inhibition of T cell function * With or without central clearing * May be pruritic/painful * May be accompanied by headache, malaise * Cranial nerve palsies, meningitis, myocarditis * Late Lyme: Arthritis * Chronic, ABX treatment resistant arthritis is rare, associated with certain HLA types Dogs * No clinical signs: 95% of infected dogs * In endemic areas, 90% of dogs are positive on 4Dx * Neutrophilic polyarthritis (most common manifestation) (also caused by Anaplasma phagocytophilum (which is transmitted by Ixodes) & Ehrlichia ewingii) * Thrombocytopenia, arthritis * 2-5 months after infection * Protein-losing nephropathy (Lyme nephritis): often the cause of death * Retriever breeds * Thrombocytopenia * Likely a sterile immune-complex disease Diagnosis * Consistent clinical signs * Polyarthritis: neutrophilic (can be caused by granulocytic anaplasmosis too) * Dog with neutrophilic polyarthritis that tested positive for Borrelia could actually have A. phagocytophilum polyarthritis but still be negative for A. phagocytophilum on 4Dx (because Anaplasma is an acute disease) → retest 2 weeks later on 4Dx: can be positive for Anaplasma (& polyarthritis is actually due to Anaplasma, not Borrelia) * Protein-losing nephropathy * Especially with thrombocytopenia (often mild) * Organism detection tests: not really useful → PCR not useful * Not found in blood * Can be positive on synovial fluid but not sensitive * Skin biopsies? * Serology for C6 peptide: only expressed during natural infection * VlsE has C6 peptide → C6 peptide is recognized by 4Dx & Acuplex (NO false positives in dogs vaccinated for Borrelia) * Always antibody positive for C6 when showing clinical signs Serologic diagnosis of Borrelia exposure * C6 peptide * SNAP 4Dx® Plus, IDEXX * Antech Accuplex * Quant C6® ELISA, IDEXX (no clinical relevance) * Multi-target antibody assays * Cornell bead: OspA, OspC, & OspF * Western blotting * Zoetis VETSCANTM: VlsE, OspC, flagellin (single line) * Canine Flex4 Rapid (includes Anaplasma, Ehrlichia, HW Ag) * Lyme Rapid “False” negatives: acute disease * Incubation period 2-5 months * IgM/IgG not useful * Antibody negative Lyme rare in dogs “False” positives * Previous exposure (all assays) * Vaccination: assays with non-C6 targets * Reactions to OspA occur in some naturally infected dogs Treatment & Monitoring * Doxycycline: 4 weeks for sick dogs (only see chronic Lyme disease in dogs so long disease course) * Amoxicillin * Cefovecin 8 mg/kg SC, 2 doses, 14 days apart → not recommended * Organism elimination? * Monitoring with quantC6? * Reinfections may occur * Immunosuppressive drugs (Mycophenolate) for Lyme nephropathy * Guarded prognosis but sometimes some response to treatment * Healthy seropositive dogs: do NOT treat with ABX * Emphasize ectoparasite control * Dogs act as sentinels * Consider vaccination Prevention * Vaccination: OspA is the MOST critical vaccine antigen * ALL vaccines stimulate antibody production to OspA → the vaccines work inside the TICK: antibodies are ingested by the tick & act on OspA in tick midgut * 4 vaccine types available in dogs: * rOspA non adjuvanted (lipidated) vaccine (BI): high titers to OspA (critical target because important surface protein) * OspA+ & OspC+ bacterins (mixed cell lysates, 2 strains) (Merck, Elanco) * Subunit chimeric vaccine containing rOspA (non lipidated), 7 OspC types (crLyme, Zoetis) * Human vaccine currently underdevelopment * Vector control * Early tick removal? * Year-round parasiticides * Parasiticides: judicious use * Most products approved from 8 weeks * Seek products that: * Repel ticks & fleas and target juvenile flea stages (growth regulators) * Work rapidly (< 24h); other co-pathogens are transmitted more rapidly that B. burgdorferi * Pyrethroids, isoxazolines CASE: ‘Thumper’ 13yo MC Terrier Mix * Routine geriatric exam, rabies booster * From Davis, CA; travel to San Diego 3 years ago, Palm Springs a year ago * Otherwise healthy, normal PE * SNAP 4Dx Plus: positive for Ehrlichia antibody * CBC: HCT 48%, 6560 WBC, 83000 plts * Chemistry: ALT 81, ALP 220, globulin 4.4 * Normal 1 year before * UA: SGr 1.027, 2+ protein * UPC 1.6 * Ultrasound: hyperechoic liver nodules * IFA antibody titer ≥ 3200 * Recheck post 2 months doxycycline * Normal PE * CBC: HCT 48%, 9440 WBC, 257000 plts * Chemistry: ALT 99, ALP 265, globulin 3.2 * UPC 0.5 CASE: ‘Oscar’ MC Rottweiler cross * Rescue dog from Arizona, Adopted 5 days ago * Ravenous appetite, tapeworms in feces * Presented by student for evaluation of malnourishment * PE: BAR, P 90, R 18, BCS 1/9 * Ambulatory * Clear lung sounds * Patchy generalized alopecia with scaling, crusting, hyperpigmentation, lichenification, ulceration * CBC: NNN anemia (32%), 5900 neutrophils, 1900 lymphocytes, 750 monocytes, 1700 eosinophils, 322000 platelets * Chemistry: Albumin 2.9, globulin 4.8 * UA SGr 1.048, benign sediment * IDEXX 4Dx Plus SNAP test * Ehrlichia canis/ewingii antibody + * Negative for Borrelia burgdorferi, Anaplasma phagocytophilum, and Heartworm * Fecal flotation * Giardia cysts (1/40x) * Sarcoptes mites (1-10/10x) * Skin scraping: Sarcoptes mites * Tick-borne disease serology * Rickettsia rickettsii 1:40960 * Ehrlichia canis 1:655360 * Negative for Babesia vogeli & Anaplasma phagocytophilum * Treatment: * Doxycycline 5 mg/kg PO q12h 8 wks * Selamectin 3 times, q2 wks * Praziquantel twice, q3 wks * Fenbendazole 50 mg/kg q24h 3 days * Cephalexin 22 mg/kg q12h 4 wks * Oatmeal shampoo * Recheck 3 weeks... * Recheck at 6 weeks * All oral lesions resolved! * Neutered * Exam 3 months later (dentistry) * Periocular & muzzle alopecia * On cephalexin & selamectin * Skin scraping: Demodex mites * Treatment: ivermectin 0.6 mg/kg q24h * Recheck 1 month * Ivermectin toxicity diagnosed 2 weeks later * Drug discontinued CASE: ‘CJ’ 6 yo M Golden Retriever * From Groveland, CA * 4 day history anorexia, lethargy, depression, soft cough * Often had ticks removed * PE: depressed, hydrated, normothermic, mild lymphadenopathy and scleral injection * CBC: HCT 38%, 9580 WBC, 8143 PMNs, 479 bands, 287 lymphs, 671 monos, platelets clumped, many morulae * Chem: mild hypoalbuminemia * Unremarkable AUS * Isolated A. phagocytophilum in HL-60s * Aph IFA titer 1:1280, other tick titers negative * Responded to doxycycline in 3 hours!!! LECS 71-72: SYSTEMIC PROTOZOAL DISEASE * Protozoa have a sexual & asexual reproductive cycle * Sexual reproductive cycle: in definitive host * Asexual reproductive cycle: in intermediate host * Almost all protozoal infections remain lifelong (use caution when interpreting serology) * Goal in treatment: get animal in remission Summary * Systemic protozoal disease result in multisystemic disease, as with other vector borne diseases * Hematologic, musculoskeletal, and endothelial injury common * Geographical exposure critical to determining risk for disease * Protozoal organisms are difficult to clear – remission does not always indicate eradication of organism * Animals might be prone to relapse (e.g. following splenectomy, immunosuppression, chemotherapy) Canine Babesiosis Epidemiology * RBC parasites: lyses RBCs → immune-mediated disease → sexual reproduction in ticks * ‘Large’: Babesia canis, B. vogeli, B.rossi * Large piriform organisms * Singly or paired in RBCs * ‘Small’: B. gibsoni, B. conradae, B. vulpes * Feline babesiosis NOT documented in US (large cats in Africa) * Transmission * Tick-borne (mostly) * Blood transfusions * Transplacental transmission (B. gibsoni) * Direct transmission (e.g. bite wound: one of the main mechanisms) Large B. vogeli Vector: Rhipicephalus sanguineus (Cosmopolitan = worldwide) * Present in the US * Least pathogenic of ‘large’ Babesia * Seroprevalence 4-60%, higher in: * Kenneled dogs * Adults * Greyhounds (race in hot & humid areas where ticks are present) * Consider testing if you’re going to immunosuppress B. canis Vector: Dermacentor spp (Europe, Africa, Asia) * Previously classified all large babesia as subtypes of B. canis, now differentiated into B. rossi & B. vogeli B. rossi Vector: Haemaphysalis leachi (South Africa) Pathogenesis/Clinical Signs – less pathogenic * Incubation period 10-21 days * Chronic carriers: often subclinical until immunosuppressed (e.g. steroids, chemotherapy (esp. OSA in Greyhounds), & **splenectomies** (e.g. prophylactic for GDV)) * Anemia, fever, hypotensive shock in peracute/acute cases * Sometimes icterus, splenomegaly & immune-mediated thrombocytopenia Small B. gibsoni MOST COMMON Vector: Haemaphysalis spp. (endemic to SE Asia) * Small pleomorphic organism * Found singly in RBCs * Distributed across the world via fighting dogs, including US Problem of Fighting Dogs: many subclinical * In the US most cases are in Pitbull & Staffordshire bull terriers * 55% of Pitbulls in AL (common dog fighting area) * Transplacental: can go multiple generations * Some coinfected with Babesia vulpes B. conradae Tick vector not identified * CA (mostly Central Valley) & other southern states * Medium-sized organism * Initially misidentified as B. gibsoni * Fighting? Epidemiology * 4.7% overall prevalence * 32% of coyotes from Fresno * Coyotes * Unclear about clinical disease * Unclear if definitive or incidental hosts? B. vulpes * Not common Pathogenesis & Clinical Signs – more pathogenic but can also be subclinical * Incubation period 1-2 weeks * Fever, anorexia, weakness * Anemia, thrombocytopenia * Splenomegaly, lymphadenopathy * Icterus rare * Surprisingly usually not hyperbilirubinemia even though this is a hemolytic event Diagnosis * Bloodwork * Pancytopenia * Thrombocytopenia, ↑ MPV (moderate - no bleeding tendencies) * Ddx: other vector-borne diseases * (Hemolytic) anemia (+/-) regeneration * Leukopenia * Hypoalbuminemia, hyperglobulinemia * Detection of organisms on blood smears * Degree of parasitemia varies * Low loads in chronically infected animals → hard to identify * Higher loads in hemolytic crisis * PCR – current test of choice * Species-specific → not all assays detect all species * Serology: does not differentiate where organisms are causing disease * Indirect IFA or ELISA * Titers > 1:80 positive * False negatives common * Cross-reactions occur unreliably Treatment * Blood transfusions (depends on how anemic) * Fluids * Antibabesial drugs: depends on species * Imidocarb dipropionate * Clears large species * Atovaquone & azithromycin * For B. gibsoni & B. conradae * Steroids used with care!! * Babesia mimics IMHA (which is treated with steroids) * Immunosuppression → more severe disease Prevention * Tick control * Avoid splenectomy & immunosuppression in chronically infected dogs * Screen blood donors serologically CASE: Outlaw – 2 y M Greyhound X * 2 month hx fever, inappetance, weight loss * Kennel in Central Valley * Working sighthounds * Decade history of unexplained deaths: fever, AKI, cytopenias Testing * Jan 2011: HWD (Ag), Brucella, Borrelia, Ehrlichia, Leishmania, Babesia serology (Hansen Lab) * 6 dogs positive for Babesia & 5 dogs positive for Leishmania * All of those dogs were treated but did not improve * Mar 2011: Leishmania PCR (Iowa State University) * All dogs negative 1. Does Outlaw’s history fit the typical picture of babesiosis? * Chronic non-specific signs * Hx of exposure * Pancytopenia 2. How would you confirm this diagnosis? * Confirm with PCR 3. What about treatment? * Atovaquone & azithromycin [j] VMTH - June 2011 PE: unremarkable * T 101.4°F * P 90 * R 24 * Abd palpation WNL * No lymphadenopathy CBC * Hct 36.2% (strongly regenerative) * Retics 296,700/uL * WBC 5,200/uL (mild) * Neuts 2,964/uL (mild) * Plt 83,000/uL (MPV 23.3 fL) Chemistry * Alb 3.2 g/dL (low normal) * Glob 5.0 g/dL UA * USG - 1.043 * No proteinuria Problem List: Regenerative anemia, Leukopenia, Thrombocytopenia, Hyperglobulinemia Pancytopenia → ddx: * Myeloid neoplasia * Myelophthisis (=space occupying lesion of bone marrow) (e.g. round cell tumor, fungal disease) * Myelotoxicity (e.g. chemo, estrogen drugs) * E. canis infection * Parvovirus * Babesiosis * Leishmaniasis Feline Cytauxzoonosis Introduction & Etiology (analogous to Babesia for cats) * Usually (not always!) fatal, tick-borne disease of cats * Higher risk in outdoor cats (more tick exposure) * April to September (more common when animals go outside) * Cytauxzoon felis * Vector: Amblyomma americanum * Southern & SE US (NOT in CA) – also now mid-Atlantic states * Missouri, Arkansas, Oklahoma, Texas, Mississippi, Louisiana, Florida * Uncommon to see here because very peracute * Bobcat reservoir/definitive host Pathogenesis (2 stages unlike Babesia) Schizogenous Phase * Enormous infected mononuclear phagocytes obstruct veins in spleen, liver, lung, lymph nodes * Rupture & release organisms → massive multisystemic signs: DIC, shock Intraerythrocytic Phase * 1-3 days after schizonts appear * Ring-shaped organisms in RBCs * Released organisms infect RBCs → hemolytic anemia, high fever Clinical Signs * Develops very quickly after inoculation * Usually rapidly fatal within 5 days * Anorexia, lethargy * High fever * Dark urine, dehydration, icterus, pallor, prolonged CRT, hypothermia * Attenuated strains have been found * Mild or no signs Diagnosis * Bloodwork * CBC: pancytopenia = nonregenerative anemia, leukopenia, thrombocytopenia * Chemistry: hyperbilirubinemia, ↑ ALT, hyperglycemia, hypoalbuminemia * Prolonged coagulation times * Organism detection * Blood smear * PCR: gold standard Treatment * High mortality despite treatment * Apart from recent isolates * Atovaquone & azithromycin * Supportive care, heparin? * Some cats have survived without treatment Leishmaniasis (less common but zoonotic) Etiologic Agent & Epidemiology – uncommon but has been seen in dogs in CA (can lay latent for years after travel) * Many Leishmania spp. cause disease in dogs (~30 species) * Important human disease: >10 million infected, >350 million at risk * Dogs & rodents (cats?) reservoirs for human infection * Sandfly vector * Old World: Mediterranean basin & Portugal * New World: South & Central America; foci in Ohio, Oklahoma, Texas, Maryland * Foxhounds in the USA * Cutaneous, mucocutaneous, & visceral forms * L. donovani causes both in dogs, VL only in humans Pathogenesis * Flagellated promastigotes (infectious) injected into vertebrate host, engulfed by macrophages * Transform into amastigotes, which replicate & infect new cells → pyogranulomatous inflammation * (“When you think pyogranulomatous inflammation, think atypical infections: Nocardia, Actinomyces, Mycobacterium, FIP, fungal, protozoal) * Sandfly ingests amastigotes Clinical Signs Cutaneous * Forms in 90% of infected dogs 1 month - 7 years post infection * Hyperkeratosis & intradermal nodules Visceral (most concerning) * Splenomegaly, lymphadenopathy (classic for vector-borne diseases) * Immune-complexes because chronic → Polyarthritis, Glomerulonephritis, Uveitis * Rhinitis * Icterus * Thrombocytopenia * Poly- & monoclonal gammopathies (classic) * Ddx: neoplasia (lymphoma) Diagnosis * Visualization of amastigotes in biopsies or aspirates (of spleen) * PCR (blood or infected organ): more sensitive * Serology Treatment * Treatment of dogs in the US controversial * Competent sandfly vector exists in SE US * Goal = remission BUT still will be risk factor for human disease, can relapse, very expensive → consider euthanasia * Treatment: Meglumine antimoniate (go-to but not available in US) * Others (don’t work as well): miltefosine, sodium stibogluconate, amphotericin B, allopurinol * Prognosis variable, most recur Canine Hepatozoonosis (less common) Epidemiology – not seen in CA * Hepatozoon canis infects dogs & cats in Africa, southern US, southern Europe & Asia * Vector: Rhipicephalus sanguineus * Hepatozoon americanum infects dogs & coyotes in southern US * Vector: Amblyomma maculatum (Gulf coast tick) Pathogenesis: the only tick borne disease (that we’ll discuss) where the dog ingests the tick * Dog eats tick → merozoites penetrate GI epithelium & disseminate via neutrophils → merozoites released → release pyogranulomatous inflammation Diagnosis * Bloodwork * Marked leukocytosis (esp. neutrophilia) * Nonregenerative anemia (due to anemia of inflammatory disease) * Hypoglycemia, ↑ ALP * Hypoalbuminemia * Skeletal rads: periosteal reaction nearby organisms * Blood smear: clear ovoid gamonts in PMNs * Uncommon: only in 0.1% of cells * Muscle biopsy (gold standard, sensitive): detect cysts (‘onion skin cells’) or pyogranulomas * ELISA for H. americanum antibodies * 93% sensitive & 96% specific * Tests for H. canis are not useful (no cross-reactivity) Clinical Signs * Incubation period 1 month – chronic * WASTING DISEASE (encysts in muscle) * Fever, mucopurulent ocular discharge * Pain (generalized), gait abnormalities * Glomerulonephritis (due to immune complex formation), amyloidosis Treatment * Transient remission: TMS, clindamycin, pyrimethamine * Long-term admin of decoquinate has achieved prolonged remission * NSAIDS (for pain/mobility issues) * Spontaneous remission in 20% Toxoplasmosis CASE: Autumn’ 7 year old FS DSH * 5/1: CKD diagnosed → screened to see if appropriate candidate for kidney transplant: * 5/8: E. coli isolated from urine → treated, culture-negative * Cyclosporine challenge: to test if she can handle immunosuppression to tolerate a transplant * 8/31: Renal transplant (glomerulosclerosis, medullary amyloidosis of diseased kidney) → Creatinine dropped from 3.8 to 1.2 mg/dL * Cyclosporine & prednisone therapy instituted Started having URT signs on Day 2: stertor & Day 5: sneezing Days 26-27: febrile (103.4), depressed Day 24 (return to VMTH): inappetence & URT signs * PE: * T 101.4F, R 40 * Stertor * Referred upper airway noises * Nasal planum & lingual ulcerations * Bilateral mucoid nasal discharge * Moderate to severe dental disease * Laboratory findings: * CBC: * HCT 29.6% * 7,870 WBC (7,272 neutrophils, 488 lymphs (mild) 102 monos, 0 eos, 8 basophils) * 568,000 plts (normal) * Chemistry: Albumin 2.3 (low normal), Creatinine 1.6 (static), BUN 29 → tolerating kidney well * Normal chest radiographs * Cyclosporine trough level: 850 ng/mL → above target indicating she was adequately immunocompromised * Aim: 500 ng/mL then 250-350 ng/mL * Treatment (for presumed infection) * Enrofloxacin * Cyproheptadine (appetite stimulant) * Cyclosporine dosage reduction (worry about toxicity) * Supportive care * Nebulization * E-tube placement Day 28: febrile, depressed, tachypneic * Interstitial pattern in caudodorsal lung field (worse on left) & large heart * Congestive heart failure * Infiltrative disease? * Treatment: Clindamycin & Butorphanol Day 29: tachypneic, vomited brown fluid & was intubated, Cardiac arrest Cytology from ETT: * Macrophages * Neutrophils * Protozoal organisms (tachyzoites characteristic for Toxoplasma) Necropsy: Transplanted kidney was infected with Toxoplasma gondii H&E & IHC for Toxoplasma * Necrotizing inflammation with tachyzoites (lung, liver, pancreas, peritoneum, myocardium) * Necrotizing tubular nephropathy with tachyzoites (allograft) * Necrotizing ureteritis & cystitis with tachyzoites * Glomerulosclerosis & amyloidosis (native kidney) Etiology: Toxoplasma gondii * Obligate intracellular coccidian parasite * Definitive host Felidae (all cats) * Intermediate hosts cats & other animals ← bradyzoites Routes of Infection * Transplacental/congenital: particularly important in humans * Naïve animals/humans infected DURING or just prior to pregnancy → placentitis & spread of tachyzoites to the fetus * Infection in utero causes the most severe form of disease * Note: PREGNANCY is NOT associated with bradyzoite cyst reactivation (contrast to: Neospora) * Bradyzoite cyst ingestion * Oocyst-contaminated food, water, or soil ingestion * Other less common: Blood product transfusion, Organ transplantation, Ingestion of infected goat milk Enteroepithelial Cycle (Sexual Cycle): ONLY cats → few clinical signs * Occurs in GIT: * Cat ingests bradyzoite cyst in muscle of prey species (e.g. rodents) * Oocysts produced by 97% of naïve cats * Prepatent period 3-10 days * 100 million oocysts shed/day for 7-10 days in feces (NOT shedding lifelong) * Sporocysts are not immediately infective, take time to dessicate & sporulate * Sporulation: takes 1-21 days depending on environmental conditions * Important to clean litter box! * Can persist for a really long time in environment * Less likely: cat ingests tachyzoite/oocyst from themselves or littermates * Oocysts produced by 20% of naïve cats * Prepatent period is >18 days * Fewer oocysts shed for several weeks * In immune cats, the sexual cycle is ARRESTED & oocysts are not shed anymore * Immunity may last for several years * Reactivation (& more shedding): only lasts a short period of time * May occur due to: * High doses of steroids (significant immunosuppression) * Infection with new strain of Toxo * Coinfection with Cystoisospora Extraintestinal Cycle (Asexual Cycle): all warm-blooded animals (including cats) * Sporulated oocysts or bradyzoites in other hosts are consumed * Bradyzoite in tissue cysts (e.g. raw meat) * Sporulated oocysts/tachyzoite (e.g. litter box, contaminated water/food) * Starts with GI signs → spread via macrophages to the rest of the body → dissemination & multisystemic signs * Tachyzoites in body fluids (e.g. CSF, aqueous, blood) → forms & persists as bradyzoites tissue cyst * Bradyzoite cysts may reactivate as tachyzoites (any host with extraintestinal disease) * May occur due to: * Severe immune suppression * High dose steroids * HIV infection * Chemotherapy * Anti-rejection drugs * Quiescent disease becomes really bad disease Diagnosis: * Clinical Pathology * +/- nonregenerative anemia, leukocytosis * +/- hypoalbuminemia, hypoproteinemia * Chronic infections may show hyperglobulinemia * +/- ↑ CK, Tbili, ALP, ALT, lipase * Cytology: rarely seen * CSF tap: normal or ↑ protein & WCC * Tachyzoites rarely seen in body fluids * Radiology: * Thoracic: Diffuse interstitial to alveolar pattern, Pleural effusion * Abdominal: Intestinal masses/mesenteric lymphadenopathy, Hepatomegaly, Peritoneal effusion * Fecal Exam (Sheather’s centrifugal sugar flotation) usually NOT performed because: * Examine FRESH feces to determine human health risk * Diseased cats rarely shed oocysts & shedding period is short * Can’t differentiate from other coccidia that don’t cause disease: H. hammondii & B. darling * Serology: * * Tentative antemortem diagnosis based on: * Clinical signs * ID of organism OR titers * IgM titers > 64 OR 4x or greater increasing or decreasing IgG or other antibody titers * Exclusion of other causes * Response to anti-toxoplasma agents * Organism Detection * Histopath: tachyzoites (NOT bradyzoite cysts), aided by IHC * Requires biopsy * PCR for fluid (peritoneal, pleural, CSF taps) Clinical Signs * General * Most infections subclinical (like most protozoal parasites) * Young animals often most susceptible * Age, sex, host susceptibility/species, parasite strain, & # of organisms may also be important but not completely understood * Cats: * Enteroepithelial (sexual) cycle: usually subclinical, possibly self-resolving diarrhea * Extraintestinal cycle: depends on where the tachyzoites go * Stillbirth, neonatal death * Anorexia, lymphadenopathy, fever * Respiratory signs: dyspnea, coughing * CNS signs * Uveitis (common), chorioretinitis * Vomiting, diarrhea, icterus (liver signs) abdominal effusion, pancreatitis, splenomegaly, myositis * Dogs: similar to cats * Ocular disease less common * Chronic neuromuscular disease * Humans: * Immunocompetent: mild, flu-like illness * AIDS & transplant patients: encephalitis, chorioretinitis, occasional pneumonia * > 95% of cases due to bradyzoite cyst reactivation * Transplacental infections * Often asymptomatic at birth: later show chorioretinitis & mental retardation * Spread to fetus less common in early pregnancy but disease more severe * <20% of women show signs Treatment * Supportive therapy * Specific therapy * Requires help from the immune system * Response may be reduced in immunosuppressed patients * Drug of choice: Clindamycin * Given for 4-8 weeks * Anterior uveitis: topical or systemic glucocorticoids Risk of Cat Ownership * 30% of dogs & cats seropositive in the US * Pet cats of little risk * Short shedding period * Immunity to re-shedding * Uncommon reactivation * Meticulous groomers: cats clean themselves (e.g. from diarrhea) before the oocyst can sporulate * Seronegative cats greatest risk to seronegative women * If the cat becomes infected, they will start shedding → human is at risk of infection * Seropositive hosts tend to not get reinfected * Reduction of Oocyst Levels – pregnant women should take precautions * Avoid contact with soil & cat feces * Feed cats commercial diets only or cook meat thoroughly Epidemiology - Humans * 500 million people worldwide have been exposed, esp. in warm, moist, tropical climates * 25-50% of people in the US are seropositive (as common or more common compared to cats) * Prevalence increases with age * Esp. in populations that eat rare meat * In the US, cysts present in: * 10-20% of lamb products * 25-35% of pork products * Incidence in beef is much lower * Poultry & horse meat * Game meat such as elk, deer, moose; 80% seroprevalence in Pennsylvania black bears * Reduction of Bradyzoite Cyst Levels in Food * Cysts killed by * Salting, curing, heating processed meats * Freezing several days * Microwaving is ineffective Neosporosis Etiology – many shared features with Toxoplasma but less common (& less important) * Neospora caninum * Life cycle resembles Toxoplasma, but definitive host = dog * Bradyzoite cysts (up to 100 μm in diameter): infective form * CNS, PNS, retina, muscle * Transplacental transmission following ingestion of tissue cysts by carnivores or oocysts by herbivores * Example: cows infected → abortion → dogs eat aborted material → dogs infected * Intermediate hosts: dogs (esp. farm dogs), cattle, sheep, horses, goats, deer * NOT cats or humans Epidemiology * Purebred dogs * Chronically infected bitches REACTIVATE during gestation with transplacental infection * Successive litters affected * Most pups in the litter * Female should NOT be bred * Congenital subclinical infection may be followed by reactivation late in life following immunosuppression * Postnatal infection probably uncommon Clinical Signs * Herbivores: abortion * Dogs: neuromuscular abnormalities (sometimes dermatologic, pulmonary, hepatic, & myocardial disease) * Ascending paralysis & muscle atrophy and stiffness (PL extensor rigidity) in dogs <6 months of age Diagnosis * Serology (IFA) * Serum and/or CSF * Cross-reactions with T. gondii insignificant * PCR Treatment: goal is remission * Clindamycin: can lead to decent QOL * Prednisone Prevention: limit access of dogs to raw meat & placental materials on farms LECS 73-74: IMMUNOSUPPRESSIVE THERAPY Immune-mediated disorders in dogs (rare in cats): similar work ups as infectious diseases * Immune-mediated hemolytic anemia (IMHA) * Immune-mediated thrombocytopenia (IMTP) * Immune-mediated polyarthritis (IMPA) * Glomerulonephritis * Myasthenia gravis (MG) * Perianal fistula * Pemphigus complex disorders * Granulomatous meningoencephalitis (GME) * Systemic lupus erythematosus (SLE) * Inflammatory hepatopathies * Immune-mediated endocrinopathies Immunosuppressive Drugs[k]: many available * Glucocorticoids * Azathioprine * Chlorambucil * Vincristine * Cyclosporine (ciclosporin) * Leflunomide * Mycophenolate mofetil * Gold salts * Tetracycline/niacinamide * Danazol * Splenectomy * IV Ig * Liposomal immunotherapy * Therapeutic plasma exchange... Clinical Approach Step #1: Confirm that you are truly dealing with an immune-mediated disease * Determine if: * Primary Idiopathic (⅔ cases) * Secondary (⅓ cases) = immune stimulus in body → negative effects in other sites in body * Due to: * Chronic persistent infections * Neoplasia: round cell lymphoma often associated * Medication Reaction: Sulfa Drugs (TMS, zonisamide, penicillin) * Comprehensive rule out: $4-5k at VMTH * Do everything possible to ensure it really is immune-mediated disease: * CBC, chemistry, UA, urine culture (to r/o urinary infection) * Blood cultures (to r/o bacteremia) * TXR & AUS (to look for masses) * Echocardiogram (to look for endocarditis, esp. if new murmur) * Biopsies (or at least FNAs): any abnormal mass * Infectious disease testing as indicated (e.g. 4Dx): depends on location Step #2: Education & communication with clients * Establish open lines of communication with client * Explain to the owner why each diagnostic is necessary * Most are to rule things out so it can be confusing to owners why we are doing so many tests that come back negative * Warn that infection or neoplasia can go undetected despite your best efforts to uncover it * Due to misdiagnosis or secondary to immunosuppressive therapy Step #3: Rational application of immunosuppressive drugs * Minimize excessive immunosuppression → degree of immunosuppression relates to: * Drug & # of drugs used, frequency, dose, chronicity * Never use more than 2 drugs at a time – “administering 3 is asking for a disaster” (e.g. Cyclosporine-Pred-Aza) * Evaluate dosing of current drugs, is the owner administering them properly, reevaluate diagnosis? * Pre-existing immune defects/concurrent disease * Including age & breed * Target is “pulse” immunosuppression Step #4: Active monitoring Continue to monitor & adjust medications * Tapering medication * Use objective measure to assess remission * Aim for <6 months of therapy (to get into remission & then tapering off drugs) * Remission (for at least 1 month) → rechecks every 2-4 weeks * Taper by ~25% at each check in * Balance adverse effects – start tapering the drug causing the most side effects first * Success (most) = * Remission of disease with gradual taper of medication over 3 months * Minimal adverse effects * Relapses possible (biggest risk of relapse occurs when tapering) * Failures (some require a lot of trial & error to find the right medication protocol) = * Inadequate response to treatment * Multiple relapses * Drug adverse reactions (can be profound) * Opportunistic infections Immunosuppressive Drugs Glucocorticoids “The heavy lifter” First line drug (used in almost all immune-mediated disease) * Prednisone, prednisolone, dexamethasone, betamethasone spray, etc. * Note the difference in potency * [l] * VERY effective → PROFOUND adverse effects (absolutely will occur) * Can be dosed at different levels * Physiologic: low (baseline to survive, e.g. tx for Addison’s) < anti-inflammatory: medium (0.1 mg/kg) < immunosuppressive: VERY high (2 mg/kg) MOA Broad Immunosuppressant * Inhibit phospholipase A2 → inhibits the arachidonic acid pathway → ↓ prostaglandins (critical for mucosal health), leukotrienes * Multiple MOAs: * Suppress cytokine production * ↓ antibody response * ↓ T cell activation * ↓ phagocytosis * ↓ inflammatory cell influx * ↓ Fc receptor expression by macrophages * Lymphopenia, eosinopenia * Use alone or in combination * Affordable * Prednisone & prednisolone = most commonly used * Starting dose: 1 mg/kg PO q12 hrs * Up to max dose of 60 (to 80) mg total per day * Chemotherapy drug for lymphoma at this dose → dosed based on body surface area (overdosed at mg/kg for large dogs) * Never admin with NSAIDs!! * Inhibits prostaglandins to the degree of mucosal GI ulceration & perforation Adverse Effects: esp. large breed dogs * PU/PD, polyphagia (D) * Panting (D) * Muscle wasting, weakness (D) * ‘Pot belly’ * ‘Pred Head’ * Hepatomegaly (D) * Calcinosis cutis (D) * Hypercoagulability (D) * GI ulceration with anemia (D) * Alopecia, thin skin, impaired hair regrowth (D, C) * Lethargy, behavioral changes (D, C) * Opportunistic infections (esp. bacterial) (D, C) * Sodium retention (D, C): can ↑ blood volume → heart failure * Early growth plate closure (D, C) * Diabetes mellitus (C) “High dose steroids turn your pet into a monster” * Push down toddlers for food, get into the trash, eat food off of tables * Panting in your ear all night * Have to get up multiple times during the night to go pee * Female dogs will be incontinent * Lose all their muscles * Pitbulls blow their cruciates * Calcinosis cutis CASE: Jack 5yo MC Lab * Diagnosed with severe immune-mediated vasculopathy * Treated with prednisone 1 mg/kg PO q12h * Vasculitis resolved * The owner did not return for follow up * Skin wounds developed with poor healing * Developed GI perforation → septic abdomen → death Cyclosporine A (cyclosporin) “The runner up drug” (second most commonly used) * MOA: calcineurin inhibitor * Interacts with cyclophilins in lymphocytes → block transcription factors for IL2 (which is necessary for T-cells) → downregulation of T-cell proliferation & activation * Expensive Product * Atopica® (preferred): vet product, FDA approved formulation * Well established research but expensive * Cyclavance®: generic vet formulation (sometimes available) → bioequivalence with Atopica * Human products * Neoral®: modified formulation but NOT equivalent to Atopica * Sandimmune®: unmodified formulation → NOT recommended, not bioequivalent or well absorbed * Drug absorption varies between individuals, so drug monitoring may need to be performed periodically Dosing * For immune suppression: 3-5 mg/kg q12 hrs initially (Plumbs will say SID but better to do BID) * Monitoring: * Clinical response * IL-2 expression assay (peak concentration) - at a specific lab * Trough concentrations (Aim 300-500 ng/mL) * Labeled for atopic dermatitis: 5 mg/kg q 24 hrs until clinical improvements (~1-2 months) * Taper to q48hr then q72hrs Adverse Effect (freeze the medication to limit the side effects) * GI signs (most common): V/D, NOT ulceration * Gingival hyperplasia (usually minor) * Less common signs: * Verrucous/papillomatous dermatopathy * Hirsutism * Hepatotoxicity or Nephrotoxicity * Lameness * Neoplasia (lymphoma, up to 10% chance) * Opportunistic infections Drug Interactions (many) * p450 enzyme substrate * Other drugs metabolized by cytochrome p450 will increase in concentration * Concentration increased by: * Azole antifungals * Metoclopramide? * Macrolides * Fluoroquinolones → possible opportunistic infections * Omeprazole * May inhibit MDR1 transporter * May predispose to ivermectin toxicity CASE: Spar 12 yo MC Border Terrier * Diagnosed with severe IMHA – suspected primary disease * Double immunosuppressed with * 1 mg/kg PO q12 prednisone & 7 mg/kg PO q12 cyclosporine * Also on ... 1.2 mg/kg omeprazole q12 (for GI bleeding due to steroids) * Likely a mistake considering already high cyclosporine doses * IMHA → went into remission * Tail lesion noted by owners → opportunistic fungal infection * Cutaneous mold infection due to aggressive cyclosporine dose Azathioprine Less commonly used due to many adverse effects * MOA: thiopurine competes with adenine (purine analog) → impaired nucleic acid synthesis → faulty transcription * Targets rapidly dividing cells: * T & B cells * Intestinal epithelium (mucosa) * Usually used in combination with glucocorticoids for a severe disease * Cons: * Delayed onset of action → takes awhile to work! * Dosing: 1-2 mg/kg q24h PO for 10-14 days * Then DECREASE to q48h (otherwise would wipe out bone marrow) * Inexpensive but monitoring costs $$$$$ due to potential side effects Adverse Effects * Dogs: many * GI upset (most common) * Impaired hair growth * Bone marrow suppression: monitor CBC q2 weeks for first 3 months then q2-3 months * Hepatotoxicity: monitor liver enzymes q2-4 weeks * Pancreatitis * Profound muscle weakness & tetraparesis * Cats: DO NOT USE IN CATS!! * Severe adverse effects in cats, esp. marrow suppression Chlorambucil 2nd line for immunosuppression in cats * Alkylating agent (Leukeran) * Used most often in cats: 2 mg every other to every 3rd day (immunosuppressive dose) * Usually not given every day because chemotherapy agent (can cause bone marrow suppression) * Also used for IBD, lymphoma, immune disease * Low potency * Adverse effects (uncommon): GI effects & bone marrow suppression Other treatments: many other options available if failed other medications * Cytosine arabinoside (cytarabine, Cytosar) * GME in dogs * Interferes with DNA synthesis * Given by IV infusion * Doxycycline-niacinamide * Human IVIg – for ITP * Splenectomy * Therapeutic plasma exchange: used for severe life-threatening immune diseases (e.g. IMHA) * Take out plasma (which has self-reactive antibodies & inflammatory cytokines) and return donor plasma Mycophenolate Mofetil (cellcept) * MOA: inhibits purine synthesis → targets rapidly dividing cells (e.g. lymphocytes) * First line for glomerulonephritis * Also used for refractory IMHA, IMPA * Adverse events: GI toxicity (can be profound) Leflunomide * MOA: inhibits pyrimidine synthesis → targets rapidly dividing cells (e.g. lymphocytes) * Utilized for IMPA or other refractory disease (that has not responded to prednisone & cyclosporin) * Adverse events: GI toxicity & bone marrow suppression/anemia CASE: Finny 4 yo FS Chesapeake * Presented for lethargy * PE: 101.2, P 180, R 30, pallor, Wt 29kg * Splenomegaly, remainder WNL * Diagnosed with strongly regenerative anemia at rDVM * Hct 27% * 120,000 reticulocytes * Differentials for regenerative anemia * Loss: external vs. internal * Hemolysis: immune-mediated vs. non immune-mediated (e.g. pennies with zinc, onion toxicity, acetaminophen) IMHA * Hallmarks of IMHA * Regenerative Anemia * Agglutination * Spherocytosis * Hemolysis (e.g. hemolyzed serum, hyperbilirubinemia) * Positive Coombs Test * Type 2 hypersensitivity: * Antibody-mediated * Prognosis: only 50% of animals that come to the hospital with IMHA leave alive * Negative prognostic factors * Intravascular hemolysis * Absence of regeneration * Auto-agglutination * Thrombocytopenia * Hyperbilirubinemia (higher = worse prognosis) * Increasing # of transfusions needed (sometimes due to cost to owner) Treatment * Immunosuppressed with prednisone (high dose → tapered): responded well * 30 mg PO q12h 2 weeks (HCT incr to 39%) * 30 mg AM, 20 mg PM 10 days * 30 mg AM, 10 mg PM 10 days (HCT 40%) * 30 mg q24h 20 days (HCT 39%) * 30 mg q48h 10 days * 20 mg q48h 10 days * 10 mg q48h 10 days (HCT 41%) * 5 mg q48h 10 days * Thromboprophylaxis: Clopidogrel or Rivaroxiban * Thromboembolic disease is a major complication for IMHA * 3 months of treatment (generally pretty good, sometimes can be much longer): concurrent immunosuppressants & thromboprophylaxis * 6 recheck visits * Total cost = $4500 (probably more expensive today) Diagnostics → presumptive primary IMHA * CBC * Spherocytes (look like RBCs with no central pallor) * Agglutination * Hemolysis * Leukocytosis with left shift * Coomb’s Test: to look for autoantibodies on surface of RBCs to test for IMHA → positive * Biochem Panel: hyperbilirubinemia * UA * Urine Culture * TXR & AUS CASE: Coco 5yo FS Golden * Presenting complaint: kidney issues * 10-day history of progressive lethargy & hyporexia * 4 days of refractory azotemia & developing fluid overload at rDVM rDVM work up * CBC: Hct 38.5% (40-55) * Chemistry: Alb 1.7g/dL (3-4.5), BUN 73 mg/dl (10-28), Crea 2.7 mg/dL (0.8-1.4) * Lepto PCR – negative * 4DX - Negative * Urine Protein:creatinine ratio: 19 (should be <0.5) * Urine culture: negative * Tx: supportive care & ABX * IV fluids * Ampicillin * Doxycycline * Enrofloxacin * Cerenia VMTH * PE: * QARH, T: 100.5 P: 90 R: 36, MM pink, CRT 1s * MS: BCS: 5/9. Ambulatory x4, but reluctant to walk. Pitting edema noted in distal extremities * LN: generalized lymphadenopathy * Problem List * Renal Azotemia * Profound Proteinuria * Differentials * Renal azotemia * CKD vs. AKI → differentiated via renal biopsy * Proteinuria * Glomerulonephritis * Amyloidosis * Diagnostics: renal biopsy with anti-IgG stain → revealed antibody-antigen complexes in glomerular capillaries (which causes protein leakage) * Diagnosis: immune-mediated glomerulonephritis * Treatment options * Single plasma exchange treatment (to remove antibodies from body) * Also hemodialysis (because fluid overloaded & azotemic) * Anti-inflammatory dose of corticosteroids (fast onset to limit ongoing inflammation) → combined with mycophenolate CASE: Callie 4yo FS Lab History * 1 month history of waxing & waning fever * Owners notice she seems reluctant to walk * Empirically treated with Clavamox & Baytril with no improvement in clinical signs * Lives outside Sacramento, CA with 2 other healthy dogs PE: * GEN: BARH T: 105.3, P: 120, R: 30, Weight: 37.5kg. * CV: mm: pink, crt: 1.5 sec, No murmurs or arrhythmias ausculted. Femoral pulses strong, synchronous, symmetrical. RESP: Clear but mildly increased lung sounds in all fields. No crackles, wheezes, stridor, stertor. * MS: Reluctant to ambulate, generalized pain. BCS 5/9. No overt joint or long-bone pain. No pain on flexion/extension of any joints. * LN: Mandibular, superficial cervical and popliteal lymph nodes are soft, symmetrical and approximately 1 cm in size. * NEURO: Appropriate mentation. No pain on neck or spine palpation or flex/extension. * Additional tests: Normal fundic, Normal neurologic examination, Abnormal, stiff gait, Very mild joint effusion Diagnostics: signs of systemic inflammation * CBC: mild anemia, mild neutrophilia with left shift * Chem: mild hyperglobulinemia, mild hypoalbuminemia * UA & culture: mild proteinuria, no bacterial growth * TXR & AUS: unremarkable Joint Tap * Collect fluid from 3+ stifle joints (carpus, tarsus, stifle) to be able to diagnosis IMPA * IMPA: multiple joints with non-degenerate, neutrophilic inflammation * Normal fluid: low cellularity, primarily mononuclear cells, & high viscosity * Callies Results: ↑ cellularity with 80-90% non-degenerative neutrophils → diagnosis: IMPA IMPA Pathophysiology * Type III hypersensitivity reaction * Antigen-Ab complexes accumulate in the joint space * Activates complement resulting in local inflammation * In some cases, antibody is directed against collagen → more destructive or erosive disease * More common in chondrodystrophies (e.g. dachshund, corgis) * May have joint laxity * Types * Primary/Idiopathic: ~⅔ of cases * Secondary/reactive * Infectious/inflammatory: ~⅓ of cases * GI disease: <5% of cases * Neoplasia: <5% of cases Treatment: Primary IMPA * Glucocorticoids are the cornerstone of therapy * Immunosuppressive doses of prednisone (~2 mg/kg/day) * Back up option: cyclosporine (takes time) + NSAIDs (for pain relief before cyclosporine takes effect) * Treat until there is clinical and/or cytologic evidence of remission * Clinical evidence = clinical signs resolve + biomarker (C reactive proteins) * Cytologic evidence = serial arthrocentesis * Then taper the dose by ~25% every 2-3 weeks over 4-6 months Monitoring * Recheck at 2 & 4 weeks: assess gait, joint effusion, range of motion, systemic signs * Serial Arthrocentesis (gold standard): * After one month of therapy * ↓ in total cell count & % neutrophils is consistent with recovery * C reactive protein: may be a good biomarker for inflammatory disease (normalizes in remission) * Acute phase protein produced by the liver * NOT specific! * Use to avoid re-tapping the patient to assess remission Polyarthritis Syndromes Polyarthritis/Polymyositis: joints + muscles * Spaniel breeds * Widespread muscle atrophy * Rare Polyarthritis/Meningitis: joints + CNS * Several breeds (e.g. Bernese Mountain Dog, Weimaraner) * Neck pain +/- CNS signs * Rare Erosive Polyarthritides: immune-mediated destruction of bones in joints with IMPA * Less common/rare, but more severe * Can provide treatment but some destruction to bones cause lifelong effects * Rheumatoid arthritis * Usually adult, middle-aged dogs * Greyhounds & related breeds CASE: Sally 5 yo FS Mixed Breed * Presenting complaint: 1 week lethargy * Hx: food allergies * PE: BAR, T= 99.5, P = 96, RR = 30/sniffing, Wt = 13.6kg * Multifocal petechiae/ecchymosis on the ventral abdomen * Diagnostics * CBC: Platelets 7,000 (no clumps seen) * Chemistry: WNL * UA: WNL (free-catch! do NOT cysto dogs with thrombocytopenia!) * 4Dx negative * TXR & AUS: unremarkable * Immune mediated thrombocytopenia * Rx: 15mg prednisone PO BID * Recheck in 3 days: 186,000 platelets * Recheck in 1 week: 254,000 platelets CASE: Captain Jack Sparrow 4yo MC Lhasa Apso * Diagnosed with primary IMPA 6 months prior to presentation * Treated with * 1.2 mg/kg PO BID prednisone & 6 mg/kg PO BID cyclosporine * 1.5 week history of lameness & lethargy * PE: multifocal lameness, multiple firm subcutaneous masses throughout the body, peripheral lymphadenopathy * Diagnostics * CBC: severe neutrophilia with left shift * Chem: hyperglobulinemia, hyperbilirubinemia * Biopsy of skin lesions: severe neutrophilic & histiocytic inflammation with intralesional Nocardia * AUS: abdominal mass → biopsied lesions * Blood cultures – Nocardia Spp = opportunistic infection * Treatment * Tapered immunosuppressive medication * Start antimicrobials: TMS (concern: induces immune-mediated disease) DIS 16: ANTIMICROBIAL SELECTION How to Choose the Best Prescription Patient and Bacterial Factors * General health (e.g. vomiting) * Signalment (e.g. enrofloxacin in cats → retinal degeneration & blindness; tetracyclines in young dogs → enamel hypoplasia) * Renal & hepatic function (consider drug excretory/metabolic routes) * Infection location (e.g. β-lactams don’t cross blood-prostate barrier) * Bacterial species & susceptibility Antimicrobial Factors * Penetration to site of infection * Route of administration * Cost (esp. large dogs) * Side effects * Action against infecting bacteria * Bacteria intrinsic resistance * Antibiograms (regional/site specific): shows what species of bacteria are susceptible to which drugs based on culture results at that location * Culture & susceptibility Culture & Susceptibility * Interpreting culture results * MIC = minimum inhibitory concentration * Lowest concentration of antimicrobial that inhibits growth of an organism * Measured as μg/mL * Lower MIC → more active the antimicrobial * ONLY compare MIC to published breakpoint (NOT other MICs of other antimicrobials) * Moving from MIC to susceptibility pattern * Breakpoint = the cut off MIC for which an organism is likely to be susceptible or resistant in vivo * MIC < breakpoint = susceptible against organism * Gray zone: may be intermediate * MIC > breakpoint = resistant against organism * Organisms with MICs > breakpoint cannot be inhibited with normal dosing protocols * Vary with bug/drug combo * Streptococci & doxycycline breakpoint is ≤ 2, but it is ≤ 4 for other bacteria * No published breakpoints → no interpretative criteria (“No Int P”) Which of the following statements is true? C&D 1. The lowest MIC on a susceptibility panel indicates the best choice 2. The highest MIC on a susceptibility panel indicated the best choice 3. MICs cannot be compared between antimicrobials 4. The MIC level is pretty meaningless without susceptibility interpretation (i.e. a breakpoint) CASE 1 Annabelle 4 month-old F Beagle (7 kg) * Presented to primary veterinarian for cough 5 days after adoption * Littermate (adopted by another family) also coughing * Initially prescribed hydrocodone (for presumptive CIRD) * No S/V/D Physical Exam: * GEN: BARH, T: 100.3F, P: 100 bpm, R: 30, MM: pink and moist, CRT: 1 sec, BCS 5/9, Wt: 7kg. Friendly demeanor. * EENT: [EYES] Adequate tear film. Normal retropulsion. Isocoric. Cornea, anterior chamber, lens clear OU. No conjunctival hyperemia or ocular discharge OU. Visual OU. [EARS] No discharge AU, mild erythema, non-odorous, non-painful canals AU. No alopecia or erythema on pinnae AU. [NOSE] Moist nasal planum, mild mucoid discharge, bilateral nasal airflow. [MOUTH] No dental calculus or gingivitis. Deciduous canines and adult incisors present. No masses or ulcers noted. [THROAT] Cough elicited on tracheal palpation. * CV: No murmurs auscultated. Regular underlying rhythm. Femoral pulses bilaterally strong, symmetrical, and synchronous. No jugular pulses. Normothermic extremities. * RESP: Eupneic. Normal bronchovesicular sounds present in all lung fields. No crackles, wheezes, stridor, or stertor. * GI: Abdomen soft with no overt pain on palpation. Bowel loops smooth and non-painful. No masses or organomegaly palpated. 1. What are your differentials for Annabelle’s cough? * Kennel Cough (CIRDC): start tx with supportive care & cough suppressant → if persists or develop progressive clinical signs, tx with ABX * Bordetella * Canine parainfluenza * Canine adenovirus * Mycoplasma * Pneumonia * Distemper 2. Which antimicrobial drug would you choose? What dose, route and duration would be appropriate for treatment? * Clavamox: reasonable but not effective against mycoplasmas * Enrofloxacin: poor antimicrobial stewardship * TMS * Doxycycline: Bordetella more susceptible to doxy than clavamox (in Davis) * Dose (Plumbs): 5-10 mg/kg PO q12-24 hours * Tend to do: 5mg/kg BID or 10mg/kg SID * Available in: capsules (50mg & 100mg) or suspension (5 mg/mL) * 50 mg PO q12 hours * Antimicrobials tend to round doses up based on capsule/tablet sizing * Amikacin 3. Can you locate a reference to back up your choice? – ISCAID guidelines CASE 2 Sandy 9-year FS mixed breed dog * Presented to rDVM 1 week ago for a 2 cm dermal mass on the lateral aspect of the right metatarsal region * Surgical removal & biopsy returned as a benign mass * Sandy has been licking at the wound & started limping on the RPL yesterday Physical Examination * GEN: BAR, Hydration: euhydrated, T:101.1, P:82, R: panting; Wt: 27.2 kg. * INTEG: Adequate skin turgor. Smooth, clean coat. No masses, no ectoparasites. Distal RH swollen, erythema. 2 cm open incision with purulent draining material * EENT: EYES- cornea, anterior chamber, lens clear OU. EARS- otic epithelium smooth and non-erythematous, NOSE- No discharge. MOUTH- mild dental calculus, mild gingivitis. * CV: MM: pink / moist, CRT: <2cm. No murmurs or arrhythmias ausculted. Femoral pulses strong, synchronous, symmetrical. * RESP: Clear lung sounds in all fields. No crackles, wheezes, stridor, stertor. * ABD: Soft and non-painful abdomen. No masses/organomegaly. * GU: Vulva clean No palpable mammary masses. * MS: BCS 5/9. No overt joint or long-bone pain. Toe touching on RH when standing, when walking non-weight bearing RH. * LN: Mandibular, superficial cervical and popliteal lymph nodes are soft, symmetrical and approximately 1 cm in size. Right popliteal firm and enlarged. Upon intake: Culture * Sterile swab was utilized to collect purulent material from the surface of this wound and it was submitted to the microbiology laboratory for culture * Mixed growth noted including Staphylococcus pseudintermedius, Pseudomonas aeruginosa, E. coli, Enterobacter spp, many anaerobes * Shows contamination from mouth & normal skin flora → nearly impossible to interpret to determine actual cause of infection & what needs to be treated After: the wound was cleaned & debrided (purulent material was flushed away, necrotic tissue was removed) * A culture was collected from a deep tissue biopsy from Sandy * 1. Are systemic antimicrobials indicated for this patient? Why or why not? * Yes, infection (edematous, erythematous) has spread beyond the site of the wound 2. Create a detailed antimicrobial plan & write a prescription that has the dose to admin & discharge instructions for owners with instructions for admin * Clindamycin: good option * Good tissue involvement, good bone penetration * Susceptible * GI side effects (pretty safe) * 10 mg/kg PO q 12 hours * TMS: another good option * Good tissue penetration & cheap * Generally well tolerated (but may cause KCS, IMPA in black&tan dogs) * Chloramphenicol: good tissue penetration * BUT long term admin has risk to humans (aplastic anemia) * GI side effects long term * Erythromycin: not practically accessible * Never choose vancomycin (very important drug in humans) DIS 17: AI IN DIAGNOSTICS Introductory Video * AI in human medicine used for: * Early detection/prediction * Diagnostic/prognostic tools * Image classification * Drug Discovery * Chatbots: triage patients * Medication Management: prevent errors * Trend in ↑ use in human med as well as vet med * Antech’s Renaltech → provide early prediction of development of kidney disease in cats * Image classification in radiology & pathology * AI/ Machine Learning * Data inputs (sensors, bloodwork, images, signalment) → AI/ Machine learning algorithm (mathematical algorithms search for patterns in data) → tasks performed by ML (trained algorithm can use what it has learned from the data to make decisions about new data) * Supervised machine learning * Takes a dataset → real person labels data → creates an algorithm based on human labeling → trained algorithm that can apply that to new data * Unsupervised machine learning * Dataset → machine learning process clusters the data into groups that makes sense to the machine → creates an algorithm and refines it as it receives more data * Looks for pattern in the data and cannot inuit new data it has not been trained on * AI in Vet Med * Early disease detection * Diagnostic Aid * Can pick up on subtleties that are hard for veterinarians to pick up on in one consultation * Comb through patient data to point to certain differential diagnosis * Outcome prediction & prognosis evaluation Machine Learning: based on pattern recognition * Makes thousands of decision trees from data set → compares decision trees (majority voting/averaging) → final result * Important things to consider * What question is the AI answering? * How was it trained? * Were there any biases in the population? * How was it tested? * How did the model perform? AI model (LEAP) Hurdles in AI Clinical Decision Making * Bias in data * Poor quality data * Rigorous clinical trials * Implementation in the clinic How do I interpret the results? * Ask for peer reviewed literature * Know the performance statistics * Identify the correct target population * Apply sensitivity & specificity and interpret in light of your patient CASE: Clyde 5 yo MC Mix Breed * Presented: Laterally recumbent, weak pulses, pale gums * Immediate treatment: Supplemental O2 * History: 4 day progressive history of lethargy, anorexia, and vomiting * Severe electrolyte and kidney abnormalities, mild liver abnormalities, low cholesterol * Differentials? – Kidney Differentials * Pyelonephritis * Toxin (grapes, ethylene glycol) * Leptospirosis * Obstruction * Hypotension * Nephrotoxic drugs (NSAIDs) * Addison’s disease * Glomerulonephritis * Juvenile nephropathy * Pancreatitis * Uroabdomen * Sepsis Data Performance for Detecting Addison’s Breed Neither sensitive or specific Electrolytes Neither sensitive or specific White Blood Cells Low specificity Low cholesterol Low specificity Review the Leptospirosis chapter in Canine and Feline Infectious Diseases textbook, focusing on clinical features and the laboratory abnormalities Case Example: Canine Leptospirosis * Infection can result in severe kidney & hepatic injury * Diagnosis is often retrospective (i.e. not solidified until after the patient needs care) * Present with AKI → need dialysis TODAY (VERY $$$$) * Excellent prognosis for dialysis for AKI caused by lepto * Prognosis for dialysis for AKI caused other diseases (e.g. NSAID toxicity) can be very poor * Can not definitely determine if dog has lepto today * Nearly all cases of lepto before presenting to UCD were treated with ABX * ABX makes it nearly impossible to detect Leptospira in blood or urine (very low PCR activity) → use antibody titers but must wait 10-14 days to seroconvert * * Leptospirosis * Breed & Signalment: large-breed, outdoor, intact male dog * Vaccine history: very low risk of getting severely ill if UTD on vaccine * CBC/chem * Azotemia * Cholestatic hepatopathy * Mild thrombocytopenia * Hyperkalemia, hyponatremia (associated with anuria) * Inflammatory leukogram * Glucosuria (acute stages) (impairs glucose reabsorption in nephron because affects proximal renal tubular epithelium) * CASE 1 Josie 9-year FS Bloodhound * 5-day history of severe, progressive lethargy * ↓ appetite to anorexia for the past 3 days. 1 episode of vomiting. * Was on Rimadyl for 4 weeks for lameness of her right limb → switched to carprofen (generic) before becoming sick. Unknown vaccine history. * Current medications: Carprofen unknown dose PE: * GEN: Quiet, Hydration: very elastic skin, overloaded?, T:99.6, P:136, R:56, Wt: est 50kg. * INTEG: Extra skin turgor. Smooth, clean coat, periocular hyperkeratosis and hyperpigmentation lateral canthi. No masses, no ectoparasites. Multiple shaved areas, 7Fr 60cm triple lumen catheter medial left saphenous with bandage. Pedunculated mass on the left hind paw * EENT: EYES- cornea, anterior chamber, lens all hazy OU. Profound ectropion OU Mild conjunctival hyperemia. Some ocular discharge. EARS- otic epithelium smooth and non-erythematous, no discharge, non-painful canals. NOSE- No discharge. MOUTH- moderate dental calculus, mild gingivitis. No masses or ulcers. Hypersalivation. * CV: mm: pink, crt:1s, No murmurs or arrhythmias ausculted. Femoral pulses good, synchronous, and symmetrical. * RESP: Loud lung sounds in all fields. No crackles, wheezes, stridor, stertor. Increased rate and effort. * ABD: Soft and non-painful abdomen. No masses/organomegaly. Bowel loops smooth and non- painful. Unable to palpate urinary bladder. * GU: Vulva- 8Fr foley urinary catheter in place, slightly erythematous labia. Some mucoid fecal staining to perineum, on catheter, and external genitalia. No palpable mammary masses. * MS: BCS 7/9. No overt joint or long-bone pain. Sternally recumbent. Left distal toes beyond bandage slightly swollen. * LN: Mandibular, superficial cervical and popliteal lymph nodes are soft, symmetrical and approximately 1.5x1.5 cm in size. * NEURO: Dull but oriented. more anxious when nauseated and preparing to vomit. * Rectal: not completed * Erythropenia * Leukocytosis * Neutropenia * Proteinuria * Glucosuria * High anion gap metabolic acidosis * Mild Hyponatremia * Moderate hyperkalemia * Moderate hypochloremia * Low bicarbonate * Hyperphosphatemia * Hypercalcemia * Azotemia * Hypoalbuminemia * Hyperglobulinemia * Elevated CK * Elevated ALP * Hypermagnesemia Clinical Signs, Diagnostic results, History consistent with lepto & LEAP positive for lepto * Worry false positive: performed dialysis but prognosis is poor CASE 2 Braxlee 13 yo FS Cavalier King Charles spaniel * 3-day history of lethargy, and a 2 week history of hyporexia * Decreased water intake for 2 days * She has a history of cardiac disease that has been stable for many years * Vaccines are “up-to-date” * Current medications: Pimobendan 2.5mg PO BID, Furosemide 18.75mg(?) PO BID, Enalapril 5mg PO BID Physical Examination: * GEN: QAR, Hydration: 5% dehydration, T:99.5, P:120, R:48, Wt: 10.72kg. * INTEG: Adequate skin turgor. Smooth, clean coat. Spot of dried blood over left shoulder. No ectoparasites. No scaling, no crusting. 0.5cm growth on right forehead. * EENT: EYES- cornea, anterior chamber OU. Opaque lens OU. No conjunctival hyperemia. No ocular discharge. EARS- otic epithelium smooth and non-erythematous, yellow crusted debris AU, non-painful canals. NOSE- Nasal planum dry, serous nasal discharge. MOUTH- mild dental calculus, mild gingivitis. No masses. Ulcers on maxilla buccal mucous membranes bilateral. Halitosis. Missing teeth. * CV: mm:pink, tacky, crt:1s, Grade V/VI left apical systolic murmur. No gallops or arrhythmias ausculted. Femoral pulses strong, synchronous, symmetrical. * RESP: Clear lung sounds in all fields. No crackles, wheezes, stridor, stertor. No cough in exam room. * ABD: Tense, painful abdomen. No masses/organomegaly. Bowel loops smooth. * MS: BCS 7/9. No overt joint or long-bone pain. * LN: Mandibular, superficial cervical and popliteal lymph nodes are soft, symmetrical and approximately 0.5 cm in size. * Rectal: Firm, left anal sac mass, non-expressible, 1.0cm in size. Right anal sac empty. * High anion gap metabolic acidosis * Moderate hyperkalemia * Moderate hypochloremia * Low bicarbonate * Hyperphosphatemia * Hypercalcemia * Hyperglycemia * Azotemia * Elevated CK * Elevated ALP/ ALT * Hypermagnesemia LEAP negative for lepto, signs not consistent with lepto DIS 18: ZOONOSIS CASE 1 Nesta 2 yo FS GSD * Acquired as puppy * Multifocal episodes of pain, esp. after activity * Hypersensitivity to touch * Somewhat responsive to NSAIDs, not gabapentin or tramadol * UTD on vaccines (be specific about what vaccines that includes) * Normal appetite Physical examination * Normal TPR (temp 100.7) * Very painful on palpation * BCS 7/9 * Somewhat stiff gait, occasional low head carriage * No specific neurologic deficits Problems * Multifocal pain (chronic) Work-up * CBC: mild eosinophilia & lymphocytosis * Chemistry: WNL * UA: mild pyuria (10-15 WBC/HPF) * Urine culture negative * Spinal Rads: discospondylitis → ddx: aspergillus, brucella (ZOONOTIC), staph, strep, actinomyces Diagnostics: all positive for Brucella * Disk Aspirate culture: Brucella canis * Aerobic/anaerobic blood cultures; Brucella canis (3/3 bottles) * Brucella canis serology (RSAT) positive Brucellosis * Venereally-transmitter * Problem in breeding kennels; may infect non-breeding dogs * Occurs worldwide * Subclinical infections, infertility, abortions, stillbirths, epididymitis, scrotal enlargement, scrotal dermatitis, discospondylitis, uveitis * Shed in all secretions: reproductive, urinary, saliva, respiratory secretions * Penetrates intact MMs or abrasions, occasionally inhalation * Treatment difficult (long term ABX) Humans * Flu-like illness in humans * Incubation 5 to 30 days * Fever, chills, malaise, splenomegaly, lymphadenopathy * Bacteremia, peritonitis, endocarditis * Young children with puppy contact, HIV/AIDS, dog breeders, laboratory personnel, vets * Diagnosis Challenging * Non-specific signs * Intermittent, low-grade bacteremia * Serologic tests detect only antibodies to smooth Brucella (not B. canis) * Humans relatively resistant to B. canis (more often B. melitensis) Prevention * Neutering * Hygiene practices around aborting bitches * Avoidance of contact by high risk individuals Classic for Brucella * Just PAIN with no neuro deficits or systemic signs of illness * Young (neutered or intact) dogs (likely infected in utero) CASE 2 Shasta older adult FS Golden Retriever * Cough, lethargy, hyporexia, intermittent vomiting 2 months * Historical UTIs (E. coli & Proteus), treated with fluoroquinolones * UTD on vaccinations * No current medications * At local veterinary clinic: * Routine CBC & biochemistry normal * TXR: consolidation R cranial lung lobe, hilar lymphadenomegaly (think: atypical bacteria, fungal, neoplasia) * Amoxicillin prescribed, no improvement (no response to ABX → think fungal) * Referred * Obtained from a rescue program * Indoor/outdoor dog * Goldfish, 29 parakeets * No report of tick or toxin exposure * No travel outside CA since being obtained * UCD: Normothermic, HR 110 (70 – 120), panting * Alert, responsive, hydrated * BCS 8/9, ambulatory * No murmurs or arrhythmias, moderate pulses * Increased bronchovesicular sounds * Remainder of exam WNL Diagnostics: * Shows renal failure → suggests pyelonephritis * CBC normal * Creatinine 3.2 (0.5-1.6 mg/dL), BUN 74 (8-31 mg/dL), globulin 4.9 (2.3-4.4 g/dL), K 3.6 (4.1-5.3 mmol/L) * UA: USG 1.011 (isosthenuric), protein 1+, 60-80 WBC/hpf, many rods * Urine culture: Klebsiella pneumoniae, susceptible to fluoroquinolones & TMS * TXR: hilar lymphadenopathy & alveolar pattern (air bronchograms, consolidated cranial lung lobe) * * AUS: normal * Coccidioides serology negative (antibody test: usually positive by the time of clinical signs) → r/o Coccidioides * Lung lobe aspirates: foamy macrophages + cholesterol crystal * Owner declined further diagnostics * Clavulanic acid-amoxicillin (for UTI) * Enrofloxacin * Piroxicam (for possible pulmonary neoplasia) * Partial improvement, signs returned when meds discontinued * 18 months later (thus likely not neoplasia): returned for further work-up * CT of lung: consolidated R cranial lung lobe, enlarged LNs with mineralization, stellate opacities * Lung biopsy impression smears * Low numbers of neutrophils * Rare acid-fast bacilli (think mycobacteria: esp. Mycobacteria avium is most common to cause disseminated disease in a (immunosuppressed) dog) * Aerobic, anaerobic, fungal, mycoplasma cultures negative * Histopath: tubercles with acid-fast staining bacteria in the center → think Mycobacteria bovis or tuberculosis * M. avium complex (MAC) PCR negative * MAC/Mtb complex (MTBC) PCR positive * National Jewish Laboratories (specialty lab): * rRNA PCR positive for MTBC * Culture positive for MTBC * M. tuberculosis * Susceptible to isoniazid, rifampin, ethambutol, ethionamide, streptomycin, capreomycin, janamycin, amikacin, cycloserine, p-aminosalicylic acid * Spoligotyping, MIRU-VNTR: Beijing spoligotype (Type 1) Treated with anti-mycobacterial drugs: isoniazid, rifampin, clarithromycin, tramadol, TMS * Seizures (due to isoniazid toxicity) followed by euthanasia * ID tuberculin tests on owners negative * Public health department notified * All hospital students & staff that had contact with the dog during hospitalization were TB tested Mycobacterium tuberculosis complex (MTBC): VERY RARE * In humans: most cases in CA & southern states * MTBC organisms difficult to differentiate * Mammalian reservoir hosts * M. tuberculosis reverse zoonosis CASE 3 ‘Gus’ 5-year-old MN DSH * 3-day history of inappetence & lethargy * rDVM: T = 105°F, icterus, left cervical mass * CBC: 13000 PMNs, toxic neutrophils, lymphopenia * Na 133, Cl 99, K 3.4, Tbili 3.7 * NSAIDs & broad-spectrum ABX: Ketoprofen, enrofloxacin, clavulanic acid-amoxicillin → no response * Referred VMTH * PE: Lethargic, T = 105.9°F, R = 60, P = 176, CRT < 2 sec * High fever + marked left shift → think infectious: esp. bacterial in cats * Fever & icterus → septic? * No ectoparasites seen * 2x2x6 cm firm SQ mass in region of left retropharyngeal nodes * Left mandibular node enlarged (2 cm) Lab work: * HCT 20%, 19000 PMNs, 3700 bands, 231 lymphs, 102K plts * Tbili 2.1 mg/dL, all other values WNL * Hyperbilirubinemia * 1+ bilirubinuria (never normal in a cat) * TXR & AUS: WNL * Cervical ultrasound: lymphadenomegaly * Transferred to isolation! * Hot, icteric cat with lymphadenomegaly → think: tularemia or plague Yersinia pestis (plague): * Western half (ish) of US * Fleas/rodents → cats * Human risk: inhalation from cats with pulmonary involvement * Also transmissible with * Cat bites * Scratches Lymph node aspirates: * Many degenerate neutrophils * Aerobic & anaerobic culture negative (had been treated with abx at rDVM) * Francisella tularemia PCR negative * Francisella tularemia: generally distributed across US (Eastern US types more virulent) * Dermacentor ticks; exposure to infected rabbit * Treated (for presumptive plague/tularemia) with ampicillin & gentamicin * T = 107°F the following day, diarrhea (common with ABX tx to horrible bacterial infections) * Right cervical lymph nodes also enlarged (due to dying organisms) * Complete recovery Public Health Department notified * Cat was from Lake Tahoe region * Lived with 3 cats, 3 dogs, 2 rabbits * Owner adopted a wild mouse several weeks before onset of illness CASE 5 CASE 6 Ellie 7yo FS Lab * May 2011 – 5 day Hx hemoptysis, hematemesis, fever, inappetence * Search & rescue dog: VERY friendly * Left cranial lung lobe consolidation * Lung lobectomy → Yersinia pseudotuberculosis (zoonotic) cultured at surgery * Outbreak investigation Gigi’ 3 yo F British shorthair * Presented for dystocia: 1 kitten stillborn * C-section performed * Mouth-nose resuscitation to kittens * Kittens revived by vigorous rubbing with dry towels * Covered in yellow-green placental material, slow to revive * Began suckling when queen recovered from anesthesia * 2 weeks after surgery 50-yo female veterinarian and 23-yo female veterinary technician develop fever, severe headache, neck pain, chills, night sweats, myalgia, stiffness * Technician hospitalized for 3 weeks with vomiting, pneumonia * Treated for suspected psittacosis (Chlamydia, usually from birds) with doxycycline CASE 7 Nani’ 2 yo FS Bengal from Vallejo, CA * Ulcerative skin lesions on face (think Cryptococcus or Sporothrix), tail, right hind paw * Treated with a long-acting injectable cephalosporin 3 weeks ago, no response * CBC (not exciting): HCT 45%, neutrophils 4175, lymphs 3859, monos 298, eos 421, plts clumped * Chemistry: normal, UA: normal, FeLV/FIV negative * Impression smear: pleomorphic yeast (no capsule) → Sporothrix Q Fever (Coxiella Burnetii) * Obligately intracellular Gram- bacterium * Extremely resistant in environment * Worldwide * Traditional reservoirs domestic ruminants * Periparturient cats (no clinical signs) * Aerosol transmission 40% human infections symptomatic, serious acute & chronic infections, death * Endocarditis, hepatitis, bacteremia, chronic fatigue (similar to Coxiella) CASE 8 ‘Bubba’ 2 yo MC DSH * Sporotrichosis * Apparently non-responsive to months of itraconazole & terbinafine * No improvement because compounded itraconazole * Tx with AMB & itraconazole: * After 1 month: still new lesions with Sporothrix appear * After 6 months: very improved 1 month of AMB 6 more months LAB 3: BONE MARROW & LN ASPIRATES, JOINT TAPS, & BLOOD CULTURES LN Aspirate * A sterile 20- to 22-gauge (for large dogs) or 22- to 23-gauge (for small dogs and cats) needle is used * Skin should be gently cleaned with ethanol or isopropyl alcohol * Skin should be surgically prepared, if one is to biopsy an internal lymph node * Dog often in standing position * While grasping the superficial node with one hand with the thumb and forefinger or with the ultrasound guide, the needle is held by the thumb and forefinger of the other hand * Insert needle → pulled back to the cortex without withdrawing → redirected again deeper into the gland in a slightly different direction (5 redirections) → remove needle * Cells and fluid will collect within the needle lumen by capillary action * Always insert the needle away from the fingers grasping the LN * Remove needle from syringe → fill syringe with air → gently push the plunger to expel material onto a slide * One should avoid ejecting a “jet” of material from the syringe * Coverslip smear preparation * Second clean coverslip is placed on top of the first → material will spread * The tip of each coverslip should be held separately and pulled apart horizontally just as the spreading sample material reaches the ends of each coverslip Using this technique, fragile juvenile lymphocytes can be well preserved if 60% horizontal and 40% vertical motions are applied when separating the coverslips * The coverslips should be immediately air-dried or heat can be gently applied while holding the coverslip. * Smears * 2nd slide placed at right angle over the sample: The sample is expelled gently on the first slide one-third of the distance from the top * The sample material will spread with the weight of the top slide and the top slide is then gently pulled away from the bottom * The smear on the bottom slide usually is best for evaluation * The slide should be immediately air-dried. * “In-house” evaluation: fixed with fresh methanol for 2 to 5 minutes and stained with Wright-Giemsa stain. * Diff-Quik type quick stain may be used for initial evaluation, but the final diagnosis should be made on the properly prepared Romanowsky-type stains such as Wright-Giemsa or May-Grünwald-Giemsa. * Submitting to reference veterinary laboratory: air-dried, unfixed samples can be mailed * Mandibular LN aspirates often have the lowest diagnostic yield because of increased risk of background ‘noise’ (i.e. inflammatory cells) * Due to prevalence of periodontal disease in small animals * Reactive LN: response to local inflammation → normal maturation of large, immature lymphoblast through to small, mature lymphocytes * Plasma cells are often evident in these samples as the immune system begins to produce antibodies * When lymphoblasts are seen in percentages greater than 50%, lymphoma is a definite concern * Neutrophilic inflammation is characteristic of lymphadenitis as can be seen with certain immune-mediated and infectious diseases. Joint Aspiration / Arthrocentesis Video * Using a syringe to collect synovial fluid from a joint capsule * Indications: joints may not be obviously abnormal in patients with shifting leg lameness, systemic illness, fever, suspected immune-mediated polyarthritis, past orthopedic surgical site, unexplained lameness * Aspirating multiple joints can provide higher diagnostic yield Patient Preparation and Positioning * Adequate analgesia, sedation (dogs) or anesthesia (cats) * Positioned in lateral recumbency * Clipped and prepped aseptically alternating chlorhexidine scrub w/ alcohol (3 passes) * Sterile gloves, needles and syringes should be used. Draping is not necessary * First manipulate the joint to find the degree of flexion that allows the largest “window” into the synovial space * Either have a technician manipulate or doctor will have to have 1 sterile (dominant) and 1 non sterile(non dominant) hand * Small (22-25 gauge), short needles attached to a small (typically 3 cc) syringe, break “the seal” in the syringe to allow for smooth movement of the plunger * Insert needle slowly perpendicular to the skin * The carpal joint is shallow, while the elbow, stifle and tarsus joints may require insertion of the entire needle to retrieve fluid * If bone or cartilage is encountered or no joint fluid aspirated, the needle should be withdrawn slightly and redirected * Gentle and intermittent negative pressure should be applied with the plunger once the needle has passed through the skin and into joint space * Only a small amount of fluid is required for analysis, sometimes as much as 0.5-1 mL can be easily aspirated from abnormal joints (sometimes only 0.2 mL can be withdrawn from a healthy joint) * Avoid excessive negative pressure which may lead to hemorrhage, reducing the value of most samples * Negative pressure should be completely released prior to withdrawing the needle from the patient to avoid blood contamination from the skin or SC tissues. Discard any needle and syringe with blood contamination Anatomic Landmarks * Carpus joint: sampled at the proximal radiocarpal joint either along its medial or dorsal aspect * Typically patient in lateral and carpus on ‘down’ limb from medial approach * Dorsal approach provides a bigger window into the joint → always the preferred method - on the down leg or up leg * When using the dorsal approach, care should be taken to avoid the cephalic vein which courses across the joint surface * Peripheral smaller joints are often used for suspect IMPA * Tibiotarsal joint is accessed from the lateral aspect along the talus; again, care should be taken to avoid the superficial blood vessels in the area * Lateral aspect of the ‘up’ limb * The needle should be advanced parallel to the axis of the metatarsals, perpendicular to the tibia * Towards the toe, with the syringe up against the gastrocnemius * Stifle: either medial or lateral approach (clip and prep both sides) * Lateral aspect of the ‘up’ limb * A longer needle (often 1 1⁄2 inch) is generally required as the synovial fluid tends to accumulate caudal to the patellar fat pad * Point the needle towards the popliteal LN * Most often diagnosed with septic arthritis in small animals. * 1) this is a large joint and more susceptible to trauma or penetrating wounds, often opened at surgery due to cranial cruciate disease which could result in either * 2) direct contamination of the joint or * 3) permanent prosthesis which can serve as a nidus of infection should the dog ever be bacteremic Fluid Handling * EDTA-containing tube and/or as prepared slides * Red top tubes for large amount of fluid for fluid analysis * Slides: dropping a small amount of joint fluid onto a glass slide near the frosted edge and slowly spreading the sample across the slide using a second slide * Evaluated by a clinical pathologist for color, turbidity, cellularity, differential cell count and cytologic inspection for infectious organisms or exfoliate neoplastic cells * Crude test of synovial fluid viscosity can be performed by stringing the sample between the thumb and index finger * Normal joint fluid should string 3-5 cm * Abnormal: shorter * Submitted for microbial culture and susceptibility testing in a sterile tube or culturette tube * Basic fluid analysis can be performed by assessing the total solids, color, turbidity, and microscopic appearance * Nucleated cell count can be roughly estimated by multiplying the number of nucleated cells per high power field by 1000 * In normal joints, the fluid is highly proteinaceous and contains hyaluronic acid with relatively low total nucleated cell counts (generally small numbers of large mononuclear cells – macrophages). Neutrophils are the marker of active inflammation and can be seen in dogs with both immune-mediated joint disease or septic arthritis. Lymphocytes can be seen in dogs with chronic joint disease (i.e. osteoarthritis). Erythrocytes might indicate contamination during arthrocentesis though could also indicate a condition called hemarthrosis – a condition associated with coagulopathies Bone Marrow Aspiration Video Indications: abnormal CBC, searching for organisms that cause systemic infections such as Leishmania, Cytauxzoon, and Histoplasma species, or looking for occult neoplasia when abnormalities are found on physical examination, diagnostic imaging, or a serum biochemistry profile (multiple myeloma, lymphoma, and histiocytic sarcoma) Contraindications: few, risk of bleeding from this procedure is very low * Severe coagulopathy involving deficiency or impairment of coagulation factors is a concern and marrow aspiration should be delayed until it is controlled * Causing a bone fracture is low but it can occur if an inappropriately sized needle is used for a patient or if the bone is already compromised by disease. Decision of whether to do an aspiration versus a biopsy, or both, can depend on the clinician’s differential list and what exactly is being searched for * Individual cell morphology is best evaluated with cytopathologic examination of marrow aspirate smears that can highlight few or very small organisms or subtle cell features that can aid in identification of cell lineages * Bone marrow core biopsies give information on the architecture of the marrow, overall cellularity, and the presence of myelofibrosis, necrosis, and mass lesions within the marrow space Materials and Equipment * Size of the needle should be appropriate to the patient and the site being aspirated * Bone marrow aspirate: Rosenthal needle or Illinois sternal iliac needle * Illinois sternal iliac needle: removable plastic cap and needle guard and can be re-sterilized for additional use, but the tip usually becomes dull quickly and one-time use is recommended * Bone marrow biopsy: Jamshidi biopsy needle * No needle guard, can be resterilized * Dulls w/ repeated use * Dogs: 15-gauge Illinois sternal iliac needle, Cats, Small dogs: 18-gauge needle is available for cats and small dogs. * All needles must be sterile, and all consist of two pieces— the hollow stainless-steel needle and a solid stylet * Battery-powered drill (OnControl Bone Marrow [OBM] Biopsy System, Vidacare) has been used for bone marrow aspiration and biopsy in humans and in healthy cats * Required equipment: microscope slides, 12-mL syringe, sterile anticoagulant (4% disodium- or dipotassium-EDTA), Petri dish or weigh boat, and forceps or pipette. Patient Preparation * General anesthesia or heavy sedation with analgesia is recommended * Common sites: greater tubercle of the proximal humerus, the iliac crest of the pelvis, and the trochanteric fossa of the proximal femur * Site should be shaved and surgically prepared, and a local anesthetic block performed, starting with the periosteum, subcutaneous tissues, and then the skin with 1% to 2% lidocaine * NSAID * Sterile procedure - sterile gloves, drape, instruments * Ensure the stylet is properly aligned with the needle and attachments are snug Procedure * Sampling the iliac crest → lateral recumbency * Small incision over iliac wing at the flattest aspect * Pull up 0.1-0.2 mL EDTA solution into the syringe to prevent clotting * Assistant holds the pelvic limb while the aspirate needle is driven through the stab incision and into the iliac crest with firm pressure and a rotatory movement * Hold the handle in the palm and use the index finger to stabilize the needle * Use second hand to stabilize the needle * Do not wiggle the needle back and forth - Use a twisting and pushing movement * Can often feel when the needle reaches the marrow because it gets a bit easier to advance the needle → remove the stylet → attach the 12mL syringe w/ EDTA → repetitive firm pulls back on the plunger to obtain marrow * Can reinsert the stylet and adjust back or forward if no sample is initially obtained * Biopsies can be obtained from the same sites * Remove the inner style as soon as the needle is set within the bone (~1 cm) * The needle is inserted in until set to an appropriate depth for the patient size * Rotate 360 in both directions aggressively once the needle is firmly set into the bone to break the piece away from the rest of the bone → remove core needle in one swift movement * Use included needle to remove the core biopsy from the stylet → by pushing needle down the style to push the biopsy out the bottom * Biopsy can be placed on a slide or directly into zinc formalin * Sampling the proximal humerus → lateral recumbency, easiest to sample the patient’s humerus that is the same as the clinician’s dominant hand * Right-handed clinician stands ventral to the patient and uses the left hand to grasp the patient’s right forelimb distal to the elbow, slightly rotating it externally to stabilize it * Or you can have your assistant rotate and stabilize the forelimb * Lateral aspect of the greater tubercle is the target site for aspiration: a flattened, roughened area of bone where muscle and fat coverage are minimal and the needle is least likely to slip off the bone. * Sampling the proximal femur → lateral recumbency * Trochanteric fossa is located by palpation of the greater trochanter. * Fossa is located just medial to the trochanter * Limb should be adducted and rotated medially to minimize the risk of sciatic nerve damage * Beedle is directed so it is parallel to the shaft to the femur, to allow placement within the marrow cavity * Small stab incision is made in the skin with a #11 scalpel blade → Needle placed through the stab incision and aligned along the long axis of the bone → Firm pressure is applied, with repetitive, back-and-forth twisting motions to advance the needle through the cortex → Once the needle is firmly seated, the cap and stylet are removed, 12 mL syringe is attached to the end of the needle → rapidly pulls back the plunger until the smallest flash of blood is seen, and then stops suctioning (Ongoing suction causes hemodilution, reducing sample quality) * The entire needle is removed (with the syringe attached) from the bone, and the contents of the syringe and needle are placed onto glass slides or into a collection dish Sample Preparation * Prepare slides quickly to avoid clotting * Slides should be laid out at an angle prior to collection → place a drop of sample at the top of each slide → assistant follows behind placing a second clean slide perpendicular to the first slide and gently spreading the marrow spicules across the slides → rapidly air-drying * Marrow and blood remaining in the container can be transferred to an EDTA vial in case additional slides need to be prepared. * Clinician should stain and examine one slide to look for evidence of cellularity * Reveal densely stained marrow particles populated by mixed hematopoietic cells with variable amounts of fat and hemorrhage * If cellularity is low or uncertain, a second attempt should be made to collect an adequately cellular sample * Some pathologic conditions like myelofibrosis or aplastic anemia, cellularity will be poor regardless of the best technique and in those cases a bone marrow biopsy should be collected * Slides should be submitted along with a recent CBC * Small bony particles (spicules) seen grossly within a sample placed into a petri dish generally indicate that the sample was taken from the medullary cavity of the bone Blood Culture Video * Positive blood cultures are essential for establishing a diagnosis of IE and for selecting appropriate antimicrobial treatment * Unfortunately, 60-70% of obtained blood cultures in dogs with IE have been reported to be negative * High proportion of dogs receiving antimicrobial therapy prior to the time of sampling presumably contributes to the lack of bacterial growth. * Chronic “encapsulated” infections * Non-infectious IE (only platelets and fibrin in vegetation) * Failure to grow organisms from samples. * Should not be regarded as definitely negative until they have been cultured for 10 days (Bartonella requires culture for up to 4 weeks). * PCR methodology may be used to amplify and identify bacterial nucleic acid in blood, and thereby potentially increase the likelihood of detecting bacteremia * Not more sensitive * Microorganisms known to cause IE in dogs are Staphylococcus spp. (S. aureus, S. intermedius, coagulase-positive and coagulase-negative), Streptococcus spp. (S. canis, S. bovis, and beta- hemolytic), Bartonella spp., Escherichia coli, Pseudomonas aeruginosa, Corynebacterium spp., and Erysipelothrix rhusiopathiae * Bartonella vinsonii and related proteobacteria (B. henselae, B. clarridgeiae, B. washoensis) have been recognized as potential causes for endocarditis in dogs. * Bartonella spp. were the cause for IE in 28% of the cases, and in 45% of the IE cases with negative blood cultures * ticks and fleas may be vectors * Both enteric organisms and gram-positive skin flora are all isolated in relatively equal proportions and Bartonella is associated with a particularly pathogenic form of endocarditis (generally on the aortic valve). Enterococcus is not often cultured from the blood Obtaining Blood Cultures * The reference laboratory should ideally be contacted concerning the preferred type of vials before obtaining a sample * To avoid contamination, strict aseptic sampling should be observed (sterile prep, sterile gloves) * 3-4 samples of approximately 5-10 mL each (the likelihood for a positive blood culture increases with increasing blood volume) from different puncture sites at least 30 minutes to 1 hour apart. * At VMTH, initial samples are taken (sometimes through an IV catheter being placed at admissions), then a sample is taken 10 minutes later. A third sample is usually acquired 1-12 hours later to coincide with trough concentrations of antimicrobials * Typically use a butterfly needle, can also use a straight needle * If gravely ill, samples can be collected within 1 hr period * Best if collections can coincide with spikes in fever * Pop off tops of blood culture bottles → disinfect the rubber stopper w/ alcohol → replace sterile needle on syringe → puncture the rubber stopper on the bottle to transfer the blood → gently invert the bottle * If already on abx, pull samples immediately prior to administration of antimicrobials * Samples should be submitted for aerobic and anaerobic culture * Sterile blood culture bottles w/ different media depending on aerobic or anaerobic * Pediatric & adult sizes * Lysis centrifugation tubes may increase diagnostic yield * Sampling through indwelling catheters should be avoided but may be used as a last option * For culture of Bartonella spp., 2 mL EDTA blood collected aseptically is frozen at −70°C until cultured → samples are cultured on a special culture medium for Bartonella for up to 4 weeks [a]reagan hinted poll everywhere questions might be on the exam [b]less emphasis, more of a reference [c]main cell type that you need to know [d]just to show high sensitivity and specificity [e]just need to know top 3 [f]for treatment & PE findings: just know general patterns for fungi, not for each specific species [g]don't need to know specific clinical signs for each species, just know clinical signs of fungus in general [h]won't ask exam questions on species that aren't covered in class [i]don't memorize, just know there's a spectrum of diff Ehrlichia species [j]? [k]focus on the ones that are common and discussed in class for the exam [l]don't memorize, just to show that they differ in potency