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16 Cards in this Set
- Front
- Back
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How does one get Giardia?
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Ingestion of 10-25 cysts
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What happens to Giardia cysts when they are ingested
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Gastric acid stimulates excystation with release of throphozoites in the duodenum and jejunum, where the bacteria multipies by Binary Fission
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What 3 things does Giardia do in the intestines?
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Trophozoitres attach to the intestinal wall by a ventral sucking disk.
This causes: decreased vilii inflammation of the mucosa hyperplasia of the lymphoid follicles TISSUE NECROSIS DOES NOT OCCUR |
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What is the clinical presentation of Giardia?
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within 1-4 weeks of ingestion (average 10 days) mild diarrhea to severe malabsorption can occur
Sudden onset of severe, foul smelling, wattery diarrhea. Abdominal cramps, flatuance, and STEATORRHEA no blood in stool bc no tissue descruction |
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What is the treatment of Giardia?
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rehydration with sponaneous recovery in 10-14 days.
Drug of choice is Metronidazole, which prevents DNA synthesis in protozoa |
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What are the 4 stages of Cryptosporidium life cycle in a host?
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1) Mature oocyst with sporozoites are ingested
2) Sporozoites attach to surface of intestinal epithelium and mature (Schizogony) 3) Sexual forms develop (gametagony) and produce fertilized oocyst 4) mature oocyst in feces is diagnosed |
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After Cryptosporidum oocysts are ingested, what happens?
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Excystation occurs in teh upper part of the small intestine after contact with gastric acid and proteolytic enzymes. 4 cresentic sporozoites are released per oocyst.
Via gliding motility, sporozoites penetrate the brush border membrane of the enterocyte and rearrange host actin to reside in a destinctive intracellular but exocytoplasmic position |
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In cryptosporidium, what is a schizont?
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the multinucleated cell stage during the asexual reproductive phase in the life cycle of a sporozoon
Sporozoites develop into trophozoites intracellularly and divide asexually to form a schizont with 4 -8 meroxoites, which are released by rupture of the enterocyte |
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What type of cells are at risk for infection with Cryptosporidium?
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all cells of the intestine lined with polarized epithelial cells, especially in the small intestine
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What morphological changes are seen in cells infected with Cryptosporidium?
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Structural damage with villous atrophy, decreased brush border enzymes, crypt hyperplasia paracellular permeability
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What is the clinical presentation of Cryptosporidium?
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self-limiting enterocolitis characterized by wattery diarrhea without blood
If you have AIDS-- 50 stools/day |
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Treatment of Cryptosporidium?
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Fluid replacement
Drug: nitazoxanide |
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Pathogenesis of Entameoba Hystolitica
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cysts are ingested
in the Stomach, gastric acid stimulates the release of the pathogenic trophozoite in the Duodenum. trophozoites divide and produce extensive local necrosis via a cytotoxin |
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How does EH cause cell damage?
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Galactose Ibhibitable Adherance Protein mediates attachment and the altreration of membrane permeability of colonic epithelial cells and WBCs results in irreversible [Ca]i
Lysis of these cells brings in more neutrophils which will die a simailar death |
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Clinical presentation of EH?
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Numerous bloddy stools per day
localized tissue destruction of the LARGE INTESTINE --> abdominal pain cramping Colitis w/ diarrhea |
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Treatment of EH?
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Metronidazole
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