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11 Cards in this Set

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What are protozoa?
They are free living, single celled, eukaryotic cells with a cytoplasmic membrane and organelles including 1 or 2 nuclei.
Size varies from 5um to 2mm, with an endoplasm and ectoplasm.
It ingests through a mouth called a cytostome.
How do protozoa reproduce?
They reproduce asexually, undergoing DNA replication followed by division into 2 cells. They also produce sexually by the fusion of two cells followed by DNA exchange.
protozoa can secrete a protective coat and shrink into a round armoured form called a cyst. TRUE/FALSE
There are 5 intestinal protozoa that cause diarrhea. What are they?
1. Entamoeba histolytica- causes bloody diarrhea
2. Giardia lamblia and 3.Cyclospora cayetanensis- cause a non bloody diarrhea
4. Cryptosporidium, and 5. Isospora belli cause severe diarrhea in immunocompromised individuals.
About 10% of the world population and 1-5% of the US population are infected with E. histolytica. TRUE/FALSE
TRUE. Most of these are asymptomatic. These carriers pass the infective form, the cyst to other individuals via the fecal oral route.
What is a trophozoite?
It is the motile feeding form of the amoeba. It cruises along the intestinal wall, eating bacteria, intestinal and RBCs.
It can convert to a precyst form with 2 nuclei, that matures into a tetranucleated cyst as it travels down and out of the colon.
What is a chromotoid body.
It is a precyst that contains aggregates of ribosomes. It is the cyst that is eaten, infecting others.
Sometimes the trophozoites invade the intestinal mucosa causing erosions. THis results in loose stool with flecks of blood. TRUE/FALSE
Can the presence of trophozoites cause death.
Yes. They may penetrate the portal blood circulation, forming abscesses in the liver, the lung and diaphram. Pulmonary abscesses can result in death.
How are the protozoa diagnosed?
Stool is examined for the presence of cysts or trophozoites. Trophozoites with RBCs in the cytoplasm suggest active disease, and those without suggest asymptomatic carriage.
How are protozoa treated?