the lecture for chapter 12 the eukaryotes this is a diagram of a generalized eukaryotic cell and in chapter four i went through the basic structure and all the organelles of eukaryotic cells and remember this is a combination of a plant cell and an animal cell so make sure you know which structures are found in plant cells compared to animal cells all the organisms that are discussed in this chapter are eukaryotic microbes so this is their basic cell structure in this lecture i'm going to go through the different types of eukaryotic microbes and i've already mentioned them before so you have the fungi with the molds and the yeast then you have the protozoa and then the algae with the unicellular and the multi cellular and the helmets now as i go through this lecture it's going to be very important for you to pay attention to the differences between the different types of eukaryotic microbes and again the point of this is to be able to identify the different types of microbes for when they infect humans so again we're looking for a selectively toxic medication that would be able to kill off the eukaryotic microbes that are causing disease in the humans and not harm the human cells so that's one thing you want to pay attention to are the differences between the different types of eukaryotic microbes the first group of eukaryotic microbes that i want to go through are the fungi and the fungi are found mainly in the soil that's where almost all the species are found and they're in the soil because their main role is to act as decomposers so they are the organisms that break down the dead structures dead bodies of plants and animals so they serve a very important function in the cycling of the elements in breaking down other living structures to return carbon to the air in the form of carbon dioxide so because they do this they are heterotrophic remember heterotrophic other feeder so in order to get energy and to get carbon they have to ingest other living things in terms of their structure they can be unicellular or multicellular remember the unicellular are the yeast and the multicellular are the molds also they can reproduce asexually and sexually so asexual reproduction is where you get two identical daughter cells from one parent cell sexual reproduction is where there are gametes from two individual parents that form into one offspring examples of fungi are the mushrooms yeast and molds and in this class we are going to focus mainly on the yeast and the molds because of course this is microbiology and most of you are going to be going into healthcare you're more interested in the pathogenic microbes so again yeast or unicellular molds are multicellular so they have these long filaments and again the vast majority of fungi are living in the soil they're decomposers so they have no negative effect on humans in reality only 0.2 percent of fungi are pathogenic so they're very very few fungi that actually cause disease in humans as i've mentioned before yeast are unicellular fungi so that means an individual yeast organism is composed of one cell and there are many different types of yeast many different species of yeast but when you look at them under the microscope they all look the same so if you need to identify different species of yeast you need to use biochemical reactions and biochemical reactions what i mean by that is that you have to perform different biochemical tests on them to determine what enzymes they have so what you're doing to identify individual yeast is you're looking at their enzyme profile so what enzymes they have what biochemical reactions they can catalyze and different yeast species have different profiles different enzyme profiles so that's how you identify different yeast species molds are multicellular fungi and because they are multicellular you can see them with the naked eye and i'm sure you have seen molds before mold will grow on bread that is left out it will grow in cheese that'll that's left out actually grow on pretty much any type of food item and also in lab mold can be cultured on agar so these are all different mold colonies now one of the things you can notice on the bread and on the petri dish is that different types of mold have different morphologies so they look different so because the molds are macroscopic macro means big you can see them with the naked eye and they have different morphologies you can actually identify them by differences in their structure even when you look at the molds under the microscope they have different structures where you can identify them by those structures so this is an aspergillus this is the cereal cystis this is a candida albicans and so under the microscope even they look different so if you need to identify a different type of mold you can do that physically that's different compared to the yeast where the yeast they all look the same even under the microscope so you have to use biochemical tests you have to develop an enzyme profile because the molds are multicellular they actually have a little bit of anatomy that you need to know so molds are made of long filaments called hyphae and those filaments can come in two different types of structure they can be septate hyphae and septate comes from septum which means a division so these hyphae have divisions between all the cells and those are called the septa the other type of hyphae are coincidic hyphae or non-septate hyphae and these do not have any divisions between cells so when you look at those hyphy they look like one long unbroken strand when molds reproduce they produce a spore and when that spore lands on a substance that contains nutrients like a piece of bread or other food item then that spore will start to grow hyphy and the hyphae will extend out from the spore and develop into a mold a multicellular mold in terms of function there are two types of hyphae there's ariel hyphae and vegetative hyphae and the vegetative hyphae is the hyphae that grows into the substr substance and absorbs nutrients from that the ariel hyphae are known as reproductive hyphae and the reproductive hypha these are the hyphae that produce the reproductive spores so for instance if you have a piece of bread that you leave out exposed to the air there will be some mold spores in the air so little mold spores in the air that are floating around and one of those mold spores will land on the bread when it lands on the bread then right away it's going to start producing vegetative hyphae that are going to grow into the bread and these vegetative hyphae are dissolving the nutrients in the bread and absorbing them to help the mold grow once the mold is established then it's going to start producing aerial hyphae or reproductive hyphae and the ariel hyphae are going to grow up into the air away from the substance and they are going to form structures on the top that will be filled with reproductive spores when the structure matures it will rupture releasing those reproductive spores into the air so that they can land on another substance and repeat the process and often those ariel hyphy have a particular color and that's what you see here so when you see the mold when you see sort of the white fuzzy hyphy those are usually vegetative hyphy and when the mold has a particular color to it those are usually the reproductive or ariel hyphae so those are the structures that contain the spores and again when they release then they spread and start a new mold organism in the general description of fungi i mentioned that they can reproduce sexually and asexually and this is just an example of that type of reproduction and how they relate to each other you do not have to memorize this graph but you should just know that they can reproduce sexually and asexually and again sexual reproduction involves gametes that fertilize and form an individual asexual reproduction involves mitosis so where all the resulting organisms daughter organisms are genetically identical to the parent so again you don't have to memorize this graph but you do need to know that fungi can reproduce both sexually and asexually because most students who take microbiology are interested in a career in health care we spend a lot of time talking about pathogenic microbes so the different diseases caused by various microbes but i just want to remind you that the vast majority of microbes are beneficial or harmless to us so like i talked about in chapter one there are lots of different benefits we get from the microbes and very very few are actually pathogenic so a disease caused by a fungus is called a mycosis myco means fungus and cis means inflammation so when we're infected with a fungus and it causes inflammation that's causing a disease so a mycosis is a fungal disease and in reality only 0.2 percent of fungi are actually pathogenic and within those that are pathogenic the mo the majority of those are opportunistic pathogens and remember an opportunistic pathogen is a microbe that under normal circumstances is beneficial or harmless but if it gains access to a part of the body where it should not be or it's allowed to overgrow then it causes a disease so mycoses plural mycoses are usually caused by opportunistic pathogens but there are a few that are obligate pathogens and remember an obligate pathogen obligate means that the microbe must infect an individual and in doing so is going to cause damage to that individual cause a disease and the reason they must infect the individual is that's the only way they can get nutrients or replicate so there are a few fungi that are obligate pathogens but it's really an extremely small percentage most mycoses are chronic so chronic means that they last for a long time like a period of months to years and part of the reason for that is that fungi are very slow growing so they're very slow growing so it's more difficult to kill something if it is growing very slowly the last thing about pathogenic fungi in general is that they tend to be dimorphic dye means two morph means form and so these pathogenic microbes tend to be found in both yeast and mold form and often they are found in mold form the multicellular form when they're in the environment and usually they grow in mold form at about 25 degrees celsius or less but when they infect a human so when they gain access to the human's body then they are exposed to body temperature which is 37 degrees celsius and at that temperature they then grow in yeast form so that's a dimorphic fungi when out in the environment at lower temperatures like 25 degrees celsius they grow in mole form but when they colonize the human body then at 37 degrees celsius then they're growing in yeast form now i want to go through and talk about several different types of mycoses and all of these are listed on your microbes to memorize list so you may want to get that list out and as i go through the lecture it may help you to remember them if you know a little bit more about the disease so the first one i'm going to talk about is an opportunistic fungus and again most of the fungi pathogenic fungi are opportunistic but this first one is named pneumocystis jurobisi and pneumocystis jurobisi as far as they can tell is a unicellular fungus so it is in yeast form and it is normally as much as they can tell in the respiratory system of humans that's the normal environment and when that overgrows it can cause pcp which is pneumocystis pneumonia and basically this microbe is found originally in the respiratory system and in people with a normal immune system it doesn't seem to cause any problem but if the person is immunocompromised where their immune system is depressed for some reason that allows the pneumocystis to migrate to the lungs and cause pneumonia inflammation in the lungs now this pcp is pretty much characteristic of immunocompromised people especially hiv positive people so again if you have a normal functioning immune system you're probably not going to develop pcp the second mycosis i'm going to talk about is also opportunistic and this one is caused by candida albicans and candida albicans is also a yeast and it is also found on the human body as its natural habitat and albicans means white because when you grow it on agar it creates a white colony and candida albicans is actually responsible for two different types of mycosis the first is thrush and thrush is often found inside the mouth of babies usually children and you can see a white growth of the fungus of the yeast on the tongue or on the gums or inside the mouth and this is often found in babies because babies have not developed their immune system sufficiently enough to fight off the fungus you can also find thrush in adults if they're immunocompromised and again hiv aids patients often they will come down with rush another example of a microsis caused by candida albicans are is the yeast infection so yeast infection this is in the vagina and candida albicans is normally found it's norm it's part of the normal flora of the vagina and so what happens for this disorder to develop is that the candida albicans overgrows so it starts replicating more than it should and that is what causes the disease the disorder the next type of mycosis i want to talk about is caused by an opportunistic fungus which is found in the environment and these fungi cause systemic mycoses and a systemic microsis means that the fungus is inhaled by the person into the lungs and then that fungus spreads from the lungs to the rest of the body and the first example of this is histoplasma capsulatum and histoplasma capsulatum is found in bird and bat feces so it's found in the bird and bat feces and when that gets airborne and a person inhales it then the fungus goes to the lungs and spreads out to the rest of the body from there so this is an opportunistic fungus because it's normal habitat is in the soil in the bodies of other animals birds and bats and usually people who develop this either they're immunocompromised or they spend a lot of time around bird and bat feces one type of person who comes in contact with a lot of bat feces are spelunkers and if you don't know what spelunking is it's cave exploring so this has happened a couple of times where people have gone into caves exploring caves there is a lot of bat feces on the ground and it's kicked up in the air as they walk by they inhale a high amount of that fungus and then they develop the disease the systemic microsis another one that can cause systemic microsis is cryptococcus neopormans and this is very similar except this is found mainly uh in bird guano and again same idea where the individual inhales the spores the of the fungus the spores go to the lungs and then it can spread to the rest of the body the next type of mycosis is also caused by an opportunistic fungus and this type of mycosis is a subcutaneous mycosis and the example of this is caused by the fungus sporotherix chaneky and sporo3 is found in the environment and specifically it is on the stems of plants so its normal environment is out on plants and specifically sporothrix is found on roses so it's covering the whole outer surface of the rose and the disease that is caused by this is called sporotrichosis and this is also known as rose handlers disease so rose handler's disease and how do you think the person gets this is they're out gardening interacting with the roses the thorns prick the skin and because the thorn is covered with the fungus the fungus gets injected below the skin hence subcutaneous below the skin so the fungus is injected below the skin and then you get these nodules of infection growing in the skin and while it looks really bad this is tends to be a chronic disease but localized it doesn't spread to the rest of the body does not enter the bloodstream so it's not life-threatening another type of mycosis that i want to talk about actually causes nosocomial infections and nosocomial infections are infections that are acquired by patients when they're in a medical setting so by patients who are in the hospital or in a nursing home this is an infection they get while they're under that care and this is a new type of fungus that was discovered about 10 years ago or so and is called candida auris and candida oris is related to candida albicans but it is a different species and candida auris is worldwide but it started in japan and in japan they noticed that it was causing ear infections and that's what aorus relates to ear so that's how it got its name and what they noticed is it was causing ear infections and then it was spreading and causing nosocomial infections and in the united states it has spread to the united states and i want you to notice that illinois has one of the higher number of cases of candida oris and there is a death rate associated with this because candida auris is highly resistant to all different types of antimicrobials so it's incredibly difficult to treat and if the patient is immunocompromised enough it can cause death and these are just the cases i just want to show you the increase in cases recently this goes to 2018 but incidences of candida oris infections in hospitals has been increasing and again it's very difficult to treat so this may be something you will come in contact with with patients in the hospitals but again usually it's the patient who gets the nosocomial infection because they're immunocompromised their immune system is not functioning normally they think candida albic aureus is actually part of most people's flora so again this would be an opportunistic pathogen the last type of mycosis i want to talk about is actually caused by an obligate pathogen so again this is a rare type of fungus that is an obligate pathogen and these cause cutaneous mycoses cutaneous refers to the skin and that is because these fungi secrete keratinase keratin ace ace means it's an enzyme keratin it digests keratin and you should know that keratin is found in skin and nails and hair two examples of this are microsporum and trichophyton and these cause tinea pettis pettis that should remind you of feet so this is the cause of athlete's foot so this is a fungus that lives on the surface of the skin and digests the keratin and causes inflammation then there is tinea corporis corporis means body and this is ringworm so ringworm and ringworm it's called ringworm but it is a fungal disease and it's called ringworm because it starts in one spot and then grows out in a ring so that's what it does and all of these microsporum trichophyton they are contagious so very likely to get these and you can see i actually like this picture because i don't know which started first but when his arm touched his body here it was transferred almost exactly to the corresponding spot that's tiny corpus and then last one is tunia and guyium and that is the nail fungus so that's the funguses found specifically in the nails and it can be in the toenails or in the fingernails and of course this is not deadly mycoses are deadly when they enter into the bloodstream so a systemic mycosis uh one that enters into the bloodstream somehow pneumonia those can be deadly but the vast majority of mycoses are not deadly the next group of eukaryotic microbes that i want to talk about are the algae and for general characteristics algae are found in the water are very close to the water like on rocks near the water they are all autotrophic so self-feeders that means they perform photosynthesis so they do not ingest other living things they are not heterotrophic also they can be unicellular or multicellular and they can reproduce asexually or sexually unicellular algae are referred to as a type of plankton of phytoplankton and so those are all unicellular and the multicellular form of algae are referred to as seaweed again as a reminder they can reproduce sexually or asexually and this is a diagram showing the difference and again remember sexual reproduction involves gamete formation and fertilization whereas asexual reproduction involves mitosis and again you don't have to know this graph you just have to realize that algae can reproduce sexually and asexually because algae are autotrophic that means they perform photosynthesis they do not cause disease in humans so they would not directly colonize our bodies because they can't get nutrients from our tissues but algae can indirectly cause disease in humans by forming an algae bloom algae blooms are usually caused by red algae and algae can come in different colors usually somewhere between green and red and when the red algae overgrows in the water it can cause a red tide and this red algae can produce a toxin but the way it usually affects the humans is when the humans eat shellfish so shellfish use algae as a source of food and when the shellfish eat a lot of the algae the toxin that the algae produces builds up in the shellfish and then when the human eats them the human is affected by that toxin so algae can indirectly cause disease in humans but it never directly causes disease another group of microbes that i want to mention are the lichens and you may not have heard that word before but i'm sure you have seen lichens in many places and especially on the trunks of trees and a lichen is this greenish grayish growth that you see on trees it can be in rocks it can even be on buildings and a lichen is a symbiotic relationship between algae and fungi so symbiosis is when two species live in close contact and here you have the fungi which form the major structure for the lichen and inside that associated with the fungi are algae algal cells and the way this function is that the algae performs photosynthesis and the end product of photosynthesis is glucose and that glucose is then used by the fungus so that's the main nutrient source for the fungus so lichens actually are photosynthetic so it may look like the tree is diseased but the lichen is just living on the outside of the tree it's not taking nutrients from the tree it's not causing damage to the tree and lichens are kind of interesting some deer can eat lichens especially up in northern countries in the northern hemisphere like finland but recently they've been looking at lichens as a source of potential drugs and medication to treat human disease the next big group of eukaryotic microbes i want to go through are the protozoa and remember protozoa proto first animal zoa means animal and the main habitat for the protozoa is water and soil so that's where you find most of the protozoa and the protozoa can be heterotrophic or autotrophic so they can eat others or they can be self feeders perform photosynthesis one thing about the protozoa is that all of them are unicellular so all protozoa are unicellular and depending on the type of protozoa they can reproduce sexually or asexually and protozoa can have two forms the first type of form is called a trophozoite and a trophozoite this is the active form so this is the active form where the protozoa is moving around it's feeding and reproducing the other form is called a cyst and the cyst is the protective form so it's a protective form and it's kind of like hibernation so this is the form the protozoa takes when it wants to protect itself from a harsh environment now i'm going to describe the different types of protozoa and these different types of protozoa are loosely grouped by their modes of locomotion and the first one i want to talk about are the excavata and sometimes they're called the archaeozoa but excavata that kind of reminds me of excavate and that's what archaeologists do archaeozoa so this relates to a very ancient form of protozoa and they think this might have been the first type of eukaryotic cell to evolve because they do not have mitochondria so these are the cells that evolve before endosymbiosis took place so those are the excavata and they move using flagella so their mode of locomotion involves flagella and one example is giardia lamblia and giardia lamblia this is what it looks like in the trophozoite form and in the trophozoite form you can almost see these flagella here it has quite a few flagella but the tropozoid almost looks like a face it looks like it has two eyes and a mouth but that's guardia lamblia and it's normally found in the large intestines of wild mammals and when it leaves with the feces the large intestines it leaves in the form of a cyst so this is a guardia lamblius cyst and again the trophozoite form is the active modal feeding modal feeding form and the cyst is the protective form so when the giardia lamb lamblia leaves the large intestines of the animal it needs to be protected from the harsh environment and giardia lamblia causes giardiasis which is when a person ingests a cyst or a few cysts and the guardian goes to the large intestines of the human it forms into its trophozoite form and then it causes a diarrheal disease and that's geordasis another protozoan that belongs to the group excavata or archaeozoa and again excavate archaeologists ancient form so they don't have the mitochondria and they use flagella to locomote but another example is trichomonas vaginalis so trichomonas vaginalis where do you think you find it in the vagina and this is a protozoan that causes an std and one of the reasons this causes an std is because the trichomonas vaginalis only has trophozoite form so it cannot form a cyst no cyst form and remember a cyst protects the back the protozoan from the environment so if this cannot form a cyst it doesn't have any way to be protected from the environment so in order to go from host to host it needs that intimate contact because it cannot survive outside of the host so trichomonas vaginalis because it cannot form a cyst it can't protect itself out in the environment it's an std on the other hand giardia lamblia can form a cyst it can survive outside the host so it does not need that intimate contact to be transmitted the next group of protozoa are the euglena zoa and the eugleno also use flagella so they also use flagella but they are different than the excavator because they do have mitochondria and most of the euglena zoa have chloroplasts so they are autotrophs they perform photosynthesis so of course the vast majority of the euglenozoa are not pathogenic because they are autotrophs but there is an exception and those are the hemoflagellates so hemo refers to blood flagellates cells that have a flagella so these are examples of hemoflagellates they're a type of euglenozoa and they are specialized these are parasitic uh obligate pathogens and they infect mammals because they get nutrients from the red blood cells so these are the hemoflagellates and on your microbes to memorize list there are two you should know tripansoma brucey and trypansoma cruisy hemoflagellates are transmitted to a host by an insect bite so they require an insect vector to infect a host and tripensomabrucy is transmitted by the titsy fly and the titsy fly is found in africa and that helps to give the name of the disease caused by tripansoma brucey this is african sleeping sickness and the life cycle is depicted here so what happens is that an infected titsy fly will take a blood meal and as it is doing so it's going to inject the tripansoma into the bloodstream of the human and while in the bloodstream the tripansona brucey is going to take nutrients from the blood the lymph and the spinal fluid and that causes anemia and severe exhaustion then when another titsy fly bites that person and acquires tripansoma then that infects another titsy fly and the salivary glands become infected and then that tc fly infects another person so that's the life cycle of triphensoma brucey trypanosoma cruzi causes chaga's disease and it has a very similar life cycle to tripansoma brucey in this case it's a different insect and this is transmitted by the kissing bug which is also found in africa and this shows the life cycle which is very similar but slightly different so in this case the infected kissing bug bites the individual and takes a blood meal but while the bug is taking the blood meal it's also going to defecate it's also going to poop on the skin of the person and the tripansoma is in the feces so that's the difference for triphensumabrucy the triphensoma is in the salivary glands for the triphensomacruzi it's in the feces and then the triphensoma is able to infect the person either by going in through the bite wound that the kissing bug made or going into the mucous membranes so if the kissing bug defecated near the eye or the nose or the mouth and the person rubs the feces into those mucous membranes it can enter that way or it can enter through the bite wound and then the tripansoma goes into the blood where then it is taking nutrients from the individual and causing similar symptoms and again when another kissing bug bites the infected person then that kissing bug becomes infected and the cycle continues the next group of protozoa i want to talk about are the amoeba or the amoeba zoa and these basically are the amoebas and for locomotion the amoebas use pseudopods to locomote an example of a protozoan that belongs to amiibe is entamoeba histolytica which causes amoebic dysentery so that is a diarrheal disease and the entamoeba histolytica has a trophozoite form so this is the trophazoid form and it also has a cyst form and basically this is a traveler's diarrhea so when you go to a country that does not have good sanitation and you're told to not drink the water but you do drink contaminated water or food that was washed in that water then the cyst goes into the digestive system so the cyst goes to the digestive system and then it forms into a trophozoite taking nutrients and possibly transferring or traveling to other parts of the body but then as it multiplies it will form cysts and then cysts will be released into the stool and contaminate the water again this is common in areas that do not have good water sanitation a cellular slime mold is an organism that is related to amoebas and the interesting thing about cellular slime molds is that for a period of time the individual amoebas come together and act as a multi-cellular organism so basically in this life cycle you can start with individual amoebas and the individual amoebas they can live a unicellular life so they can live a regular unicellular life or they can get a signal and they're not sure exactly what the signal is often it's when they don't have food so they are nutritionally depleted but all these individual amoebas will gather together and they will form what they call a slug and it is a multi-cellular organism and it's macroscopic you can actually see it and so they can come together for a period of time forming a much larger organism and they can either hunt for food to eat or ingest organisms that are larger than individual amoebas and or they can be involved in reproduction so they can be involved in reproduction and then after they've acquired nutrients after they have reproduced then all the individual cells disassociate and you go back to individual amoebas so it's very interesting because it's an example of where individual cells come together and for a short period of time they act as a multicellular organism the next group i want to talk about are the appy complexa and appy means apex like a point and complexa means complex so when you look at these cells they have sort of a pointed end and it has a complex structure and the other thing about the api complexa is they do not have a mode of locomotion and there are two examples of the epicomplexa that i'm going to talk about first is plasmodium so plasmodium is the causative agent of malaria and the second one is toxoplasma gondii which is the causative agent of toxoplasmosis and so both of them have an apex so they both have an apex and it is relatively complex plasmodium again causes malaria and plasmodium requires an insect vector so it requires a mosquito and the life cycle of plasmodium is kind of complex there it involves sexual reproduction and asexual reproduction it goes through many stages but what i want to point out to you is that it requires two hosts it requires a mosquito as the definitive host and that is where you have the sexual reproduction but it also requires infecting a human and here is the human and the human is the intermediate host so in the intermediate host you get the asexual reproduction but it's a fairly complex life cycle and you don't have to know all the details in this cycle toxoplasma gondii is part of the normal pleura of cats and so the normal life cycle of toxoplasma gondii is that it infects the cats it's in the large intestines of the cats and the toxoplasma gondii the cysts are released in the feces so it's released in the feces and then the life cycle is that rodents would become infected with the toxoplasma and then when the next cat eats an infected rodent then the next cat would acquire the infection and that's the normal life cycle now with humans what can happen is that if a human takes in some of the cysts some of the osis then the human becomes infected and this usually happens when the human is coming in contact with cat feces like cleaning the litter box and then the toxoplasma can colonize different parts of the human can go to the brain and cause a different neurological effects it can go to the heart it can go to the eye and it can colonize the cornea and cause cloudy vision but also in a pregnant woman it can interact with the fetus and cause birth defects and so this is the reason why pregnant women are not supposed to clean the cat box because you want to prevent this infection with toxoplasma gondii which could affect the fetus the last group of protozoa that i want to talk about are the ciliates and the ciliates use cilia as their mode of locomotion and a typical example is the paramecium so this is often seen in pond water samples and even though they are heterotrophs virtually no ciliates cause disease there's really only one type of ciliate that causes disease and that's balantidium coli but it's very very unusual and it's not seen in the united states so this is not on your list of microbes to memorize but for all intents and purposes the ciliates are non-pathogenic the last group of eukaryotic microbes i want to talk about are the helmets and helmets technically are animals so many of their characteristics are the same as human characteristics helmets are found mainly in the water that's where you find the vast majority of the different species of helmets and they are all multicellular and they are multicellular to the point where they have body systems so they have circulatory systems digestive systems nervous systems and so on and all helmets are heterotrophs all animals are heterotrophs so they have to ingest other living things or nutrients from other living things in order to survive and they reproduce sexually so helmets are producing gametes those gametes fuse together to form a new individual with helmets they have a little bit unusual replication they can be monoisius and mono means one means one issues means house and then that means that in one individual organism you have female reproductive organs and male reproductive organs so monoisius means they're hermaphrodites they have both reproductive organs in one individual the other type of helminth can be dioecious dye means two issues means house that means you have individual females and individual males so that's dioecious dioecious you have males and females monoisis every worm is a hermaphrodite now most of the worms the helmets are free living worms and they are marine worms they live in the ocean they live in the sea and they are free living and they move around the ocean bottom they hunt they sense the environment they reproduce just like an animal very very few of the helmets are actually parasitic when we use the term parasite we're referring to an obligate pathogen and remember obligate pathogen must infect a host in order to get nutrients and to replicate so there are parasitic helmets but compared to the free living helmets it's a very small percentage there are three groups of helmets and the first group are called the trematodes and the trematodes are also known as the flukes and the flukes are named for the uh often named for the organ that they infect so there's liver flukes lung flukes blood flukes and so on and the flukes are all monoisis so here's one individual and it has ovaries and testes so the individual flukes are monoisius and also flukes compared to the other helmets they're relatively short and thick an example of a fluke tramatode is schistosoma and schistosoma is the blood fluke and this starts the life cycle starts with eggs that are shed from an infected human by feces and it gets into the water and then the schistosoma has to infect a snail as part of the life cycle once it infects the snail then a larva larval form will move into the water and then when it comes in contact with human skin it can directly penetrate human skin and then it enters into the human goes through its life cycle forms cysts for eggs i'm sorry eggs which are released into the water and these usually trematode infections are found in other areas not north america so you don't really see a lot of these infections that are generated here sustones sustodes are commonly known as tapeworms and with the sestoed you should know the basic anatomy for the cestos so the cestode has two basic parts it has a head called the scolex and the head is where the tapeworm attaches to the intestines so it often has suckers and hooks on it and then extending out from the scolex are the proglottids so the proglottids are these segments that are extended out from the scolex and as they move away from the scolex they mature and each proglottid has testes and an ovary so they are monoicious sestoeds are monoesius and so as they grow away from the scolex the eggs are fertilized and the proglottids become sacs of mature eggs and as the proglottids mature they break off from the tapeworm and they are released with the feces tina saginata is the beef tapeworm and the life cycle for the beef tapeworm is similar to all tapeworms so this is a diagram showing the life cycle of the beef tapeworm and one of the things that's important for tapeworms or sestoeds is during the life cycle you need two organisms and one organism needs to be a carnivore the other organism needs to be a herbivore so going through the life cycle i'll start with the carnivore so the carnivore is infected with the tapeworm and so in this person's intestines you have a mature tapeworm that has a scolex and proglottids and remember as the proglottids mature and are filled with eggs then they are released in the feces so they are released in the feces out into the environment in a place where you have poor sanitation so now the eggs are released into the the environment the vegetation and when the herbivore comes along the herbivore while they're eating the grass they will ingest the eggs once the tapeworm goes into the herbivore then it is going to form a larval form and this larva is going to go into the muscles of the herbivore so it's not going into the large intestines it's going into the muscle tissue and in the muscle tissue it will form these cysts so these are like a larval form of a tapeworm so in the carnivore it's your prototypical tapeworm but in the herbivore it's going to be in the muscle tissue in this larval form and then to complete the life cycle when the carnivore eats the muscle tissue when the carnivore eats the muscle tissue then these larval forms will then travel to the carnivore's large intestines and develop into your prototypical tapeworm so forte worms whether they're beef tapeworm pork tape worm other types of tapeworms you need to cycle between a carnivore and a herbivore the last group of helmets are the nematodes and the nematodes are otherwise known as the round worms and nematodes are dioecious so they're dioecious so you have individual females and males so that's different than the monoishes with the tramatos and the cestos nematodes are dioecious and one example of a nematode is enterovirus vermicularis otherwise known as the pinworm and pinworm infections are very very common in the united states and very common in winnebago county and pinworm usually infects children so it usually infects children and the life cycle is very very simple so basically what happens is that an individual a child usually ingests pinworm eggs and the pinworm eggs travel down to the large intestines travel down to the large intestines where they form into individual females and males in the large intestines the males and females mate and then when the child goes to sleep at night when their body temperature goes down level of activity goes down the female travels to the anus and she exits the body at the anus and then she lays her eggs on the tissues surrounding the anus and these eggs are held on to the skin by a substance that is an irritant so when the child wakes up and has an irritated anus the child usually scratches the anus picks up the eggs on the child's fingers and then the child either reinfects themselves by ingesting food that is contaminated with the eggs or infects siblings in the house so if one child in the house has pinworms probably everyone in the all the children in the house have pinworms and it's a common childhood infection uh usually it doesn't infect adults because adults immune systems are competent to eliminate the worms but children under the age of seven their immune systems are not fully developed and so they are susceptible to the infection so this is a very common infection in the rockford area enterobioscrimicularis pinworm is a very common infection in the united states including rockford and if you have children or you're working with children it's very possible you will come in contact with a child that has an active pinworm infection and to determine if your child has a pinworm infection there's a test that can be done they kind of call it the tape test and this is where you take a piece of scotch tape you put it on the skin around the anus and what you're trying to do is pick up eggs or pick up worms that are there and then you can tape it to a petri dish or to a slide and look at it under the microscope to determine if there are worms or eggs and this is the example of a positive test this is the piece of tape and it obviously picked up two female worms that had exited the body via the anus if you don't have a microscope and you can't use this type of test you can just use the old-fashioned flashlight test and for this if you suspect your child has pinworms you wait till they go to sleep after they've been asleep for a while you take a flashlight and you just look at the skin around the anus and here is an individual who has a lot of pinworms that have exited the anus and are laying eggs around the anus and you also will be able to see proof that this is a common infection in this area because if you go to walgreens or walmart you can buy over-the-counter pinworm medication so again this is a very common helmet infection that you see in this area nectator americanus is another nematode and this causes hookworm and this was very common in the southern united states and it is also found in africa but again this is a nematode so their individual males and females so it's dioecious and the life cycle is as follows so life cycle you have a human who is infected with a hook worm with nectator americanus and they mate and then the eggs are released in the feces then once those eggs are released they developed into a larva form and if the larva form comes in contact with naked human skin it will burrow through the skin where it enters the circulatory system and once it enters the circulatory system then it will travel to the lungs where it leaves the circulatory system moves up through the trachea and then is swallowed so it travels down to the large intestines and the life cycle starts over again so nectator americanus is usually only common in areas that have poor sanitation where the eggs that are in the feces can make it out to the ground and come in contact with bare skin with bare feet and this is a picture of a person who was infected with hookworms so the hookworm entered here and then caused inflammation as it was moving into the circulatory system now the last thing i want to talk about is the hygiene hypothesis and this actually directly relates to the helmets and if you haven't heard about the hygiene hypothesis it is basically a hypothesis to explain why over time in developed countries we have seen increases in immune disorders so immune disorders can be things like autoimmune disease and also allergy and asthma type diseases so over time the rates of allergy and asthma and autoimmune disease have been increasing and the hygiene hypothesis idea is that we are too clean that we are keeping our children too clean and so their immune systems are not getting an adequate workout they are not responding to normal pathogens like they should and so they overreact and cause asthma allergy and autoimmune disorders and so the cure for this or the treatment would be to be less hygienic and have children especially really interact with environmental microbes and in doing so the immune system will start attacking normal potential pathogens and leave the body alone one of the things that has come out of the hygiene hypothesis is the idea of helminthic therapy and helminthic therapy is basically using helminth infections to treat some types of autoimmunity or allergy and i just want to show you that a lot of research is being done on this currently so this is nothing that you have to memorize or read or anything but i just want to show you that a lot of recent publications so these are just a few of the publications in 2020 that have to do with helmetic therapy and even they're thinking about helmetic co-infection and coronavirus so covid19 but here just goes through a few with the effect of trichonella spiralysis on colitis and here's hookworm treatment for multiple sclerosis and actually hoof worm i don't think that's a very good idea because it's possible for a hookworm instead of going to the lungs instead of using the circulation and going to the lungs to get to the digestive system sometimes the hookworm makes a mistake and it goes to the liver or goes to the brain and can cause death that way so i'm not sure hookworm is exactly the best helmet to use but in some of them this one helminthic extracellular vesicles this uses secretions from the helmets to stimulate the immune system so anyway it's a very interesting and new area of science that relates helmets to the immune system to curing disease