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38 Cards in this Set
- Front
- Back
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What is the morphology of a giardia trophozoite?
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Teardrop shaped, bi-lobed ventral adhesive disc, flagella, and 2 nuclei.
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What is the morphology of a giardia cyst?
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Oval shaped, hyaline wall, 4 nuclei (when mature).
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Which morphology is characteristic of the infective stage of giardia lamblia?
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cyst (Oval shaped, hyaline wall, 4 nuclei).
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What are the clinical manifestations of giardiasis?
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Intestinal pain, diarrhea, steatorrhea, flatulence, malabsorption, anorexia, and B12 deficiency
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What happens in the intestine if it is colonized by giardia lamblia?
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Giardia lamblia adheres tightly to the intestinal mucosa, causes inflammation, and alters epithelial function (absorption).
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Where do you get giardia?
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From water contaminated with human or animal feces. In the USA, beavers contaminate streams and lakes.
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What is the treatment of choice for giardia lamblia infection?
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Metronidazole
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Compare the morphological features of the trophozoite and the cyst in Entamoeba histolytica.
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Troph: Amoeboid with 1 nucleus. Cyst: Round to oval shaped with 4 nuclei.
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Where in the body does the giardia trophozoite colonize?
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The duodenum
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Where in the body does the Amoeba trophozoite colonize?
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The large intestine
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What are the clinical manifestations of Ameobiasis?
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Diverse manifestations from dysentery to extra-intestinal abscesses. Can cause ulcerations leading to peritonitis.
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Does Ameobiasis cause fever?
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Yep
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What virulence factors are involved in hepatic abscess from an amoeba?
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Tissue invasion virulence factors: Lectin, cysteine, proteinases, phospholipases, amoebapore
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How do you diagnose amoebiasis?
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Must demonstrate hematophagous trophozoites or cysts in feces. ELISA for antigen of E. histolytica.
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Explain the morphology of Cryptosporidium spp.
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Oocyst: (4 sporozoites but no sporocyst)
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Where do the cryptosporidium spp colonize?
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Brush border of small intestine.
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What is the typical course of infection of cryptosporidium in an immunocompetent person?
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Infection is short lived ~2 weeks
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How is cryptosporidium transmitted?
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Animal to person and Person to person. Day care settings, homosexual men. Also through waterborne and zoonotic infections.
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Why can you get cryptosporidium from a public swimming pool?
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oocyst is resistant to chlorine, and therefore viable in the pool.
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What viral disease is cryptosporidium often associated with?
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AIDS
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What is the treatment of choice for cryptosporidium?
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Nitazoxamide
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What is the morphology is cyclospora cayetanensis
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autoflorescent oocyst that is considerably larger than the oocyst of cryptosporidium.
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What is the clinical presentation of cyclospora cayetanensis?
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Fever, chills, abd cramps, nausea, vomiting, explosive nonbloody diarrhea, flatulence, anorexia, rapid weight loss, profound fatigue.
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Does cyclospora cayetanensis often relapse?
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Yep
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What is the host for cyclospora cayetanensis? Transmission?
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Humans are the host. Fecal-oral route of transmission.
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Can food contaminated with really fresh stools give you cyclosporiasis?
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Nope. Oocysts require days to weeks outside the host to sporulate and become infectious.
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What 2 protozoans have oocysts that are resistant to chlorine?
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Cryptosporidium and cyclospora
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Describe the staining of cyclospora cayetanensis.
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Acid-fast positive
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Drug of choice for cyclospora cayetanensis?
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Trimethoprim-sulfamethoxazole (7-day course)
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What do you need to know about cytoisosporiasis?
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Causes diarrhea and stuff. More common in HIV and immunocompromised. Treat with trimethoprim-sulfamethoxazole.
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What is the morphology of blastocystis hominis?
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Polymorphic protozoan. Sometimes characterized with a large central vacuole and multiple nuclei distributed around the rim of the cytoplasm. CANNOT DIFFERENTIATE FROM OTHER BLASTOCYSTIS SPP BASED ON MICROSCOPY ALONE.
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What is the morphology of Balantidum coli?
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Ciliated large protozoan characterized by a troph and a smaller cyst. Prominent macronucleus and smaller micronucleus. Peristome leads to cytosome (mouth).
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Where does Balantidum coli like to colonize?
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Trophs reside in the colon and caecum.
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Is balantidum coli infection usually asymptomatic in humans and pigs?
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Yep
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What virulence factors are found in balantidum coli?
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Proteolytic enzymes -----> perforation of the colon in acute infections.
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Geographic prevalence of Balantidum coli?
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Rare in USA. More prevalent in the Phillippines.
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What is the therapy for Balantidum coli infection?
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tetracycline or metronidazole
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How do you control of prevent infection of Balantidum coli?
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Don't drink water polluted with swine feces... =/
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