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91 Cards in this Set
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- Back
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What are the two geographical influences on parasitic infections?
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Local ecology
Local socioeconomic conditions |
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That are the types of alveolates?
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Dinoflagellates
Apicomplexa Ciliates |
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What are the properties of alveolates?
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Submembrane
Cytoskeleton has a fixed shape |
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What is the bug that causes an invasive intestinal protozoal infection?
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Entamoeba hystolytica
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What is the bug that causes amoebic dysentary?
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Entamoeba histolytica
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What disease does entamoeba histolytica cause?
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Amoebic dysentary
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What are the kinds of bugs that cause a non-invasive intestinal protozoal disease?
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Giardia lamblia
Cryptosporidia Cyclospora microsporidia |
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Giardia lamblia belongs to what class of parasite?
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Diflagella
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Cryptosporidia and cyclospora are members of what classes of parasites?
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Apicomplexa
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What are the characteristic symptoms of non-invasive intestinal protozoal infections?
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Watery diarrhea
Weight loss |
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What is the general life cycle of an intestinal protozoa?
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1. Ingestion of a cyst
2. Cyst--gastric acid--> Trophozoite 3. Trophozoite forms inside the intestine 4. Near end of GI tract trophozoites-->cysts 5. Excretion in the feces |
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What is the mechanism of division for trophozoites?
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Binary fission
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What are the two life forms of E. histolytica?
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Trophozoite (1 nuclei)
Cyst (4 nuclei) |
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What type of cell is commonly ingested by E. hystolytica? What form ingests the cells?
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RBCs
Trophozoites |
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What is the reservoir for E. histolytica?
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Humans
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What are the key virulence factors of E. histolytica?
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Amebic lectin
Amoebapores Cystine protease |
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What is the function of amebic lectin in this parasite?
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E. hystolytica
Binds to galactose-containing sugars on host cells Adherence |
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What is the function of amoebapores in this parasite?
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E. histolytica
Performs cytolysis on adhered cells |
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What is the function of the cystine protease in this paracite?
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E. hystolytica
Cleavage of preIL-1B -->Il-!b Results in the mounting of a host inflammatory response |
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Histologically, what does mucosa infected by E. hystolytica resemble?
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An iceberg: the area of damage under the surface is larger than the damage above
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With E. hystolytica, what does the stool appear like
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Low volume
Bloody |
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What are the intestinal syndromes of an infection by E. hystolytica?
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Anywhere inbetween:
Asymptomatic Chronic diarrhea Amebic dysentery (similar to shigella) |
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What are the extraintestinal clinical syndromes of an infection by E. histolytica?
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Amebic liver abscesses
Metastatic foci to the brain |
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How does one diagnose an infection by E. histolytica?
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Stool sample: ID of trophozoites/cysts
Stool antigen tests Serology |
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What are the two types of Entomoeba?
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histolytica: disease causing, invasive
dispar: non-pathogenic; shouldn't be treated |
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What is the treatment for E. histolytica
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Metronidazole
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Where does the excystation of G. lamblia occur?
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Upper small intestine
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Histologically, what does G. lamblia cause? What is the overall effect of this change?
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Killing off of the villi in the duodenum-->hypersensitivity
Malabsorption of fats |
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What are the clinical features of giardia?
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Chronid diarrhea
Malabsorption Steatorrhea Weight loss |
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What is the most effective way to diagnose an infection with G. lamblia?
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Antigen testing from stool.
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What antibiotics are used to treat Giardia?
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Metronidazole
Tinidazole |
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How is Giardiasis prevented?
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Filtering the water
Heading the water to 50C 2% iodine x 30 min |
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What two protozoa stain with the acid fast stain?
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Cryptosporidium
Cyclospora |
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Where do cryptosporidium, cyclospora, and microsporidia grow?
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Inside intestinal mucosal cells
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What diseases is Cryptosporidium parvum associated with?
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Travelers diarrhea
Chronic diarrhea in immunocompromised patients |
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Where is a place that a person would normally acquire Cryptosporidium parvum? Why there?
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Pools, drinking water
They're Cl resistant |
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What is the treatment for cryptosporidosis?
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Supportive!
No real treatment |
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What is the difference between cyclospora and cryptosporidium?
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Cyclospora is much smaller.
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What is the treatment for cyclospora? Would the treatment change in an immunocompromised individual?
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Bactram for 7 days.
Yes; you need to give them antivirals in order for treatment to be effective. |
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What are some of the apicomplexa tht cause a systemic protozoal infection?
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Plasmodium
Babesiosis Toxoplasmosis |
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What are the dinoflagellates that cause a systemic protozoal infection?
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Leishmania
Trypanosomes |
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What is the disease that Plasmodium species cause?
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Malaria
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What disease is caused by T. gondii?
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Toxoplasmosis
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What symptoms are common to malaria and babesiosis?
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RBC infection
Fever |
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What is common about the method of infection by toxoplasmosis and leishmani?
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The bugs are intracellular
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How do bugs in the apicomplexa move?
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LIKE A TANK!
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How does apicomplexa enter the cell?
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Through a little ring of its own making
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What is unique about an apicomplexa/parasitophorous vacuole?
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No host proteins
No acidification No endosomal/phagosomal fusion It's invisible |
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What is typical animal associated with a toxoplasma infection?
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Cats and kitty litter
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What is a place that a toxoplasma infection will first localize too?
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Intestinal cells --> mesenteric nodes
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How long can a toxoplasmosis cyst persist?
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Decades - they're periodically released.
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What are some serious clinical syndromes associated with toxoplasmosis?
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Acute acquired toxoplasmosis
Congenital toxoplasmosis: what does this appear like? Ocular toxoplasmosis Cerebral toxoplasmosis (in AIDS - the worst kind) |
Blueberry muffin lesions
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What type of patient are we most concerned about for toxoplasmosis?
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Pregnant women - the parasite can go into newborns.
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What tests are useful for a diagnosis of toxoplasmosis?
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Serology:
+IgG: prior infection Single high IgM/IgG: recent in fection PCR: useful only if + |
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If a woman has toxoplasmosis earlier in pregnancy does the baby have a greater or lesser chance of infection? Is it more/less serious?
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Lesser chance of infection
BUT Much more serious for the baby |
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Where is the first place of localization for malaria?
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Liver
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What is the type of plasmodium that are injected into the blood by mosquitos?
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Sporozoites
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What kind of plasmodium are released from the liver to infect the blood?
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Merozoites
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What is the kind of plasmodium that is found within a RBC?
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Trophozoites
This is what is picked up by the mosquitos |
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What kinds of plasmodium are released by a lysis of RbCs
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merozoites
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Where does sexual reproduction of plasmodium take place?
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Inside the gut of a mosquito.
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How long after infection by plasmodium do symptoms start to show?
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10 days - 1 month
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What is a large aggregation of merozoites called? Where are thy found?
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Schizont
Inside hepatocytes, RBCs |
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What is the main RBC receptor for Plasmodium falciparum?
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Glycophorin
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What is the RBC receptor for Plasmodium vivax? What group does not have this on their RBCs?
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Duffy blood group
People from Africa; resist malaria from thei bug |
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What is the energy source for Plamodium? What problem does this cause for the organism?
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Consumption of hemglobin within RBC's
Heme toxicity. It needs to export the heme, which is a process that is targeted by the cloroquinones. |
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What toxic byproduct is put in these aggregates by plasmodium?
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Heme
Hemozoin - brownish pigment deposits |
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What histologic feature is diagnostic of a merozoite?
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Ring form within RBC
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What is the most serious kind of plasmodium? Why?
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Falciparum.
Because it is able to attack all types of red cells, not just young/old like the others. |
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What is the difference between stable and unstable malaria?
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Stable: endemic. Kids die of it; adults have immunity. Splenomegaly common.
Unstable: not endemic; all ages die. |
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What are the clinical features of malaria?
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Synchronous fevers caused by the RBC's releasing merozoites:
5 hrs.: fever, myalgia, headache, GI problems. 2 hrs: sweating, exhaustion |
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What are the immunologically-mediated hematologic clinical changes in plasmodium?
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Anemia
Thrombocytopenia Leukopenia |
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What are secondary problems to infection by plasmodium falciparum?
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Attachment of infected RBCs to venular endothelial cells via ICAM, etc. -->> reduced flow; hemorrhage
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What genetic disease provides protection from malaria?
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Sickle cell anemia
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What tests are most effective in the diagnosis of malaria?
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Microscopy
Rapid antigen detetion |
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What histologic features are diagnostic of p. falciparum?
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Ring forms
Multiple bugs/cell Banana shaped gametocytes |
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What is the treatment for malaria?
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Chloroquinones (blocks heme polymerization; falciparum is resistant)
Quinine + doxy Primaquine: vivax and ovale |
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What is the mechanism of chloroquinone?
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Changes the pH inside of the malrial vacule, preventing the polymerization of heme Toxicity.
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What is the mechanism of resistance to chloroquinone by this bug?
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P. falciparum
Efflux of chloroquinone by an amino acid transporter. |
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What are the current malaria prevention strategies?
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Mosquito control: insecticides, habitat removal
Mosquito protection: nets, screens Mass tx: get rid of carriers. |
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What is the vector for babesois?
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Ticks
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What is the pathology of babeosis?
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RBC lysis in asplenic/elderly
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What is the geographic local of babeiosis?
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Same as lyme disease - transmitted by ticks.
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What is the vector for leishmaniasis?
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Sand flies
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What are the symptoms of infection by leishmania?
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Skin ulcers - if bug grows at colder tempreatures
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Where do leishmania live inside the body?
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Phagolysosmes inside of macrophages
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What kinds of leishmania grow inside the body?
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L. donovani
L. infantum/chagasi |
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What internal organs do the intracellular leishmania parasites target?
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Think of the filtration of the body:
Liver Spllen Lymph nodes |
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What are the symptoms of a systemic leichmania infection?
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Fever
Malaise Weight loss Abdominal pain Pancytopenia, increased LFTs |
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Why is an infection by P. falciprum more serious than the others?
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Merozoites enter RBCs of any age
Parasitemias reach very high levels Infected RBCs (containing trophozoites and schizonts )stick to the sides of vascular endothelium, causing microinfarcts and hemorrhage |
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What are the symptoms of acute toxoplasmosis?
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Myalgia
Swollen Lymph noodes Symptoms may last for a long time - over a month. |
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