Lecture: Phases of HIV Infection

Introduction

• Presenter: Dr. O
• Topic: Three phases of HIV infection

Overview of HIV Infection Phases

1. Phase 1: Asymptomatic or Minor Symptoms

   • Possible symptoms: Chronic swollen lymph nodes (chronic lymphadenopathy)
   • Acute HIV syndrome:
     • Initial drop in CD4 T-cell count
     • High viral load
   • Seroconversion: Process taking up to 3 months for full antibody response
   • Post-seroconversion:
     • Viral load decreases
     • CD4 T-cell count increases as body clones more CD4 positive T cells

2. Phase 2: Persistent Decline in Health

   • Weaker immune system
   • No specific infections but increased susceptibility
   • Constitutional symptoms:
     • Affect entire body: fever, night sweats, chills, weight loss

3. Phase 3: Progression to AIDS

   • Definition of AIDS:
     • CD4 T-cell count drops below 200
     • Less than 14% of normal
   • Onset of opportunistic diseases:
     • Diseases that affect immunocompromised individuals

Opportunistic Diseases

• Toxoplasma gondii:
  • Common in immunocompromised; leads to encephalitis
• Cytomegalovirus (CMV):
  • Causes encephalitis, blindness, or death
• Tuberculosis (Mycobacterium tuberculosis):
  • Worse in HIV/AIDS patients
  • Contributes to drug-resistant strains
• Pneumocystis: Mentioned in history of HIV
• Yeast infections: Common in AIDS
• Kaposi's sarcoma: Cancer of skin and blood vessels

Impact on Immune System

• Final stages: Complete eradication of CD4 T-cell population
• Death caused by inability to fight infections

Diagnosis of HIV

1. Initial Test: ELISA
   • Detects HIV antibodies
   • Takes a few months for antibodies to appear
2. Confirmatory Tests:
   • Western Blot
   • AB TEM (RNA test)
   • Look for actual virus (HIV is an RNA virus)

Conclusion

• Summary of HIV phases and diagnostic tests
• Encouragement and well-wishes from Dr. O

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Remember, these notes provide a summary and should be supplemented with additional study materials for comprehensive understanding.