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28 Cards in this Set
- Front
- Back
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Name the 3 common trypanosomes.
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1. African trypanosomes
2. American trypanosomes 3. Leishmaniasis |
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Name 3 features common to all trypanosomes.
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1. Asexual reproduction
2. Single flagella and kinetoplast 3. Can live in water |
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Name the 4 life cycle stages of trypanosomes. Where is each found - in the mammal host or vector?
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1. Amastigote - mammal host
2. Promastigote - insect vector 3. Epimastigote - insect vector 4. Trypomastigote - mammal host |
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Describe the flagella of the amastigote and trypomastigote.
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*amastigote is aflagellar
*trypomastigote has a flagella that stretches the length of the organism |
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Where in the parasite is the kinetoplast located? How much of the organism's total DNA is contained here?
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*mitochondria
*20% |
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What is unique about the DNA contained in the kinetoplast?
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The RNA transcribed from it does not code for protein.
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How many minicircles of DNA are contained in the kinetoplast? Describe its function.
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*5,000-10,000
*code for guide RNA that binds DNA produced by maxicircles and inserts uracil residues |
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How many maxicircles of DNA are contained in the kinetoplast? Describe their function.
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*20-30
*code for mRNA that is edited and then yields proteins |
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What is the vector for African trypanosomiasis? What feature of its reproduction makes it difficult to control with insecticide?
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*tsetse fly
*eggs hatch in uterus and fed with milk glands *larva are deposited in soil and develop into pupae |
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What are two differences between the East African and West African forms of African trypanosomiasis?
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1. West has a human reservoir; East has an animal reservoir
2. West associated with chronic disease; East associated with acute disease |
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Describe the 3 stages of disease in African trypanosomiasis.
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1. Primary: swollen lymph nodes
2. Secondary: fever, wasting, systemic infection 3. Advanced: CNS penetration with lethargy, mental status changes, coma, death |
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What is the periodicity of African trypanosomiasis? What causes this?
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*1-2 weeks
*complete antigenic turnover of parasites with renewed immune response |
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How many new cases of African trypanosomiasis are seen each year?
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100,000
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What is the causative agent of Chaga's disease?
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T. cruzi
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What cells does the amastigote form of T. cruzi inhabit? How is it able to live here?
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*macrophages (or muscle cells)
*escape the phagolysosome to reproduce in the cytoplasm |
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What forms does T. cruzi adopt in human and animal reservoirs? In its vector?
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*Reservoir: amastigote, trypomastigote
*Vector: epimastigote, metacyclic, trypomastigote |
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What is the vector of T. cruzi? How is the parasite transferred from its vector to a human host?
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*Reduviid beetle (a triatome)
*the beetle takes a blood meal and defecates at the site of penetration |
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Describe the acute form of Chaga's disease. What are the symptoms of the chronic form?
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*acute: facial and eyelid swelling, parasitemia, fever
*chronic: occurs years after acquisition, chronic cardiomyopathy, megacolon, mega esophagus |
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How is Chaga's disease currently diagnosed?
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Serology and immunological tests.
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What is the vector of Leishmaniasis?
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Sand fly
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What form does the Leishmaniasis parasite take in the human host? In in the insect vector?
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*host: amastigote
*vector: promastigote |
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Describe the pathogenesis of the leishmaniasis parasite in the human host.
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The parasite is taken up by macrophages and remain in the phagolysosome to reproduce until the cell eventually ruptures.
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How many people are infected by the cutaneous/mucocutaneous form of leishmaniasis each year? What are the symptoms of this form? Where is this form endemic?
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*1-1.5 million/year
*painless ulcer that heals into a hypopigmented scar *South America and the Middle East |
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How many people contract the visceral form of Leishmaniasis each year? What are the symptoms of this form?
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*500,000/year
*spread through the RES causes splenomegaly, hepatomegaly, and bone marrow depression with associated cytopenia |
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What are the two forms of visceral leishmaniasis? Which has an animal reservoir?
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*endemic: animal reservoir
*epidemic: no animal reservoir |
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Name two patient populations that are particularly susceptible to severe disease with leishmaniasis infection.
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*malnourished peds
*HIV/AIDS |
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Name the two strains of leishmaniasis. Is each strain specific for one disease form vs. the other?
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*dermatrophic and viscerotrophic
*each can cause either disease form |
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Name 3 means of diagnosing leishmaniasis.
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1. culture
2. serology 3. skin test |
