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61 Cards in this Set
- Front
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These are the hemoflagellates
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African trypanosomes (African sleeping sickness)
Leishmania Trypanosoma cruzi (Chaga's disease) |
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These are shared features of hemoflagellates
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Insect hosts at some point in their life cycles
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Amastigote
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Obligate intracellular stage of hemoflagellates in their vertebrate hosts (African trypanosome does /not/ have an amastigote stage since it is always extracellular)
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Kinetoplast
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Mitochondrion of hemoflagellates that produces the flagellum. Rich in tiny circular DNA. Used in the identification of hemoflagellates
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Transmission of Leishmania
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By blood-sucking insects (as is true for all hemoflagellates)
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This is how we distinguish between the various extracellular forms of hemoflagellates
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By the location of the kinetoplast and flagellum
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These hemoflagellates are always extracellular in the vertebrate host
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African trypanosome (sleeping sickness)
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Diagnostic stage of trypanosomiasis (sleeping sickness)
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Flagellated parasite in blood, LN bx, or CSF
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This parasite multiplies in the blood, lymph, CSF and tissue of humans
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African trypanosome (sleeping sickness)
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A bite by this fly can cause an ulcerating cutaneous lesion
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Tse tse fly. African trypanosome parasite multiplies locally, producing the lesion.
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Definitie host of African trypanosome
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Tse tse fly
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This disease is caused by two subspecies of the same parasite
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Sleeping sickness (Trypanosomiasis)
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Winterbottom's sign
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Lymphadenopathy (esp POSTERIOR CERVICAL LYMPH NODES) seen in sleeping sickness (Trypanosomiasis)
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Signs and symptoms of sleeping sickness (trypanosomiasis)
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Fever, LAD, parasitemia; lethargy, coma, death with invasion of the CSF
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Unlike malaria, it is impossible to develop immunity to this disease
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Sleeping sickness (Trypanosomiasis). The parasite changes its major surface glycoprotein to evade immune system
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This disease is characterized by waves of parasitemia and fever
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Sleeping sickness (Trypanosomiasis). The parasite changes its major surface glycoprotein to evade immune system, so different glycoproteins are favored at different times, resulting in waves
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This parasite undergoes antigenic shift to evade the immune system of its host
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African trypanosome (sleeping sickness)
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Treatment of African trypanosomiasis (sleeping sickness)
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Highly toxic drugs
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This parasite exists in humans as amastigotes (intracellular parasites) in the reticuloendothelial system
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Leishmania
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Diagnostic stage of Leishmaniasis
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Amastigote in cells
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Vector of Leishmaniasis
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Sandfly (Phlebotomus)
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The flagellated form of this parasite enters monos, loses its flagellum and multiplies as an intracellular amastigote
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Leishmania spp.
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The fly vector of this parasite ingests infected macrophages from the human host to propagate the parasite's life cycle
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Leishmania spp.
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How long before the sandfly can transmit Leishmania after it has ingested parasites?
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1-2 weeks. During this time the ingested amastigotes transform into extracellular, flagellated forms
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DTH skin test can be used to test for current or prior infection by this parasite
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Leishmania spp.
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Cause of visceral leishmaniasis (Kala-azar)
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Leishmania donovani
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What three diseases do Leishmania species cause?
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Visceral, cutaneous, mucocutaneous
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T/F: Leishmania is easily treated
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False. Treatment is difficult because many of the availabe drugs are toxic.
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Kala-azar
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Another name for visceral leishmaniasis (caused by L. donovani)
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Geographic distribution of Kala-azar
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(Visceral leishmaniasis) Asia, Africa, Mediterranean basin, South America
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Incubation of Kala-azar
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2-6 months or longer
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Signs and symptoms of Kala-azar (visceral leishmaniasis)
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Insidious onset fever (twice daily), splenomegaly, LAD, hypergammaglobulinemia
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This parasite infection causes hypergammaglobulinemia
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Kala-azar (visceral leishmaniasis)
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Diagnosis of Kala-azar (visceral Leishmaniasis)
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Marrow bx.
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This hemoflagellate infection is notably common in AIDS patients in endemic areas
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Kala-azar (visceral leishmaniasis)
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Humans are the main reservoir for this leishmaniasis
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Kala-azar (visceral leishmaniasis). Caused by L. donovani
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Domestic dogs, rodents and other mammals are the main reservoir for this leishmaniasis
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Cutaneous and mucocutaneous leishmaniasis
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"Oriental sore"
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Lesion found in cutaneous leishmaniasis, often on arm, leg, face (Asia, India, Mediterranean, West Africa)
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"Chiclero ulcer"
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Lesion found in cutaneous leishmaniasis, often on head (Central and South America)
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Signs and symptoms of cutaneous leishmaniasis
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Papules that ulcerate, lasting for months to years
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Incubation of cutaneous leishmaniasis
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2-8 weeks
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Papule that ulcerates at site of bite seen in this disease
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Cutaneous leishmaniasis
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Diagnosis of cutaneous leishmaniasis
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Bx of lesion
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This is a horribly disfuguring disease of leishmania
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Mucocutaneous leishmaniasis
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This disease is characterized by massive necrotizing lesions at mucocutaneous junctions of mouth or nose
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Mucocutaneous leishmaniasis
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Diagnosis of mucocutaneous leishmaniasis
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PCR. Bx of lesion often fails to dx
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Reduviid bug
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Host of T. cruzi
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This parasite enters the human host not via the salivary glands, but via the feces of the vector
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Chaga's disease (Trypanosoma cruzi)
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This parasite enters skeletal and cardiac muscle cells, in addition to reticuloendothelial cells, where it takes on amastigote form
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Trypanosoma cruzi
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Infectious stage of T. cruzi
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Flagellated forms in bug feces
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Diagnostic stage of T. cruzi
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C-shaped extracellular flagellated forms in the blood (only in acute disease). Dx is difficult
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Signs and symptoms of Chaga's disease
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Initial infection mild or subclinical. Heart failure, meningitis in acute phase can kill. Chronically, we see myositis (enlarged heart, CHF); and mega-colon and mega-esophagus due to destrection of autonomic ganglia (probably an autoimmune phenomenon).
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Romana's sign
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Painless swollen lesion near eye, caused by bite of Reduviid bug
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T/F: Chaga's disease can be transmitted transplacentally
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True. 3% of chronic infections in pregnancy will transmit to fetus
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This is the most reliable diagnostic test for Chaga's disease
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Xenodiagnosis. Feed uninfected reduviid bugs patient blood and check bug rectum for fecal parasites 1-2 months later. This will be replaced by PCR.
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C-fixation test
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Used to detect prior infection of T. cruzi (Chaga's disease)
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Diagnosis of this disease is often difficult
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Chaga's disease. Smear, then culture, then inject mice, then feed bug (xenodiagnosis).
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The vector of this disease lives in substandard housing
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Chaga's disease
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This disease is found only in South and Central America and in Mexico
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Chaga's disease
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This disease is transmitted by blood transfusion in South America
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Chaga's disease
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This bug-transmitted disease has been eliminated in these countries.
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Chaga's disease has been elminated from Brazil, Argentina, Chile, and Uruguay.
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