test 3 coccidian Flashcards
Describe the apicomplexans.
Unicellular protists. have a unique organelle called the apical complex, which helps them burrow into cells.
Name the diseases caused by apicomplexan organisms.
Babesiosis, Malaria, cryptosporidiosis, and coccidian diseases including: Cyclosporiasis, toxoplasmosis
What are the structures in the apical complex called that secrete enzymes that allow the parasite to enter a cell?
Rhoptries and micronemes.
Where in the body do coccida infect?
cells in the intestinal tract. They are obligate intracellular parasites.
What is the general lifecycles of coccidians?
Starts with a sporulated oocyst, which contains 4 sporocysts. It is swallowed and and oocyst releases the sporocysts. Out of the sporocysts come 2 sporozoites which invade the cells in the gut. In the gut cell they form a trophozoite, which becomes a schizont. Merozoites are released from the schizont. The merozoites can reinfect a cell or go on to become male or female gametes. Male and female fuse to form the oocyst.
Where does the cryptosporidium parasites infect?
In the intestines in the brush border.
Where do Cryptosporidium oocysts sporulate?
inside the host.
How many sporozoites are in one cryptosporidium oocyst?
4
Differentiate the two different types of cryptosporidium (C. hominis and C. parvum).
C. hominis is almost exclusively a parasite of humans and is very aggressive. C. parvum infects a wider range of hosts including humans.
How many oocysts are produced by calves every year?
65 quadrillion
What does intracellular extracytoplasmic mean?
the trophozoite hangs on the outside of the cell so its inside but not surrounded by the cytosol.
Describe cryptosporidiosis.
Explosive onset of watery diarrhea, weight loss, abdominal cramps.
Resolves spontaneously.
Second infection is very mild in immunocompetent people.
Describe cryptosporidiosis in an immunocomprised person.
abdominal pain, weight loss, high mortality.
Small percent have no symptoms, 30% have transient diarrhea, 60% have chronic diarrhea, small percent have severe cholera like symptoms (can excrete 2 liters of fluid per day).
What goes into a diagnosis of cryptosporidiosis?
biopsy of jejunem or rectum, examination of stool sample.
What drug is recommended for treatment?
Nitazoxanide
Where is Isospora belli found?
Has a world wide distribution but mainly found in Tropical areas, 3rd world countries (poor sanitation).
Diagnosis of I belli?
Ovoid oocysts in the stool.
How many sporocysts does the oocyst contain? Sporozoites?
each oocyst contains 2 sporocysts, each sporocyst contains 4 sporozoites.
Where does sporulation take place for I. belli.
Outside the host.
Compare I. belli and cryptosporidium oocysts.
Cryptosporidium are tiny and spherical while I. belli are large and oval shaped.
What is the parasite related to raspberries?
Cyclospora cayetanensis
compare the sizes of the of the oocysts of the coccidian parasites.
Cryptosporidium are the smallest (4 mics), cyclospora are medium (mics), isopora are the largest (30X15 mics)
What are two parasites commonly found in our area? How are the transmitted?
Cryptosporidium parvum and Giardia intestinalis. Fecal oral route.
How much diarrhea can a person infected with C. parvum pass each day?
around 3 liters.
How do you purify a water source?
Because coccidians are resisntant to chemicals a filter is the best way.
