Exam3Lec5ProtozoanInfectionsoftheGItract

Question 1

What is the mode of transmission for all protozoan infections?

Answer 1

Fecal-oral

Question 2

What are the protozoan parasites of the GI tract? Mention the disease, parasite, and mode of transmission

Answer 2

1. Amebiasis (Entamoeba histolytica; fecal-oral infection)
2. Cryptosporidium (Cryptosporidium parvum; fecal-oral infection)
3. Giardiasis (Giardia lamblia; fecal-oral infection)

Question 3

What is the pharmacological challenge of protozoa?

Answer 3

Biochemistry and cell biology of protozoan parasites (and fungi) similar to that of other eukaryotic cells, including human cells.
Resulting in high toxicity of many drugs against protozoan parasites and fungi (i.e., similar eukaryotic drug targets that also affect human cells)

They are eukarytoic cells

Question 4

What is the parasite and mode of transmission for amebiasis?

Answer 4

Parasite: Entamoeba histolytica
Tranmission: fecal-oral (contaminated water)

Question 5

What is the life cycle of Entamoeba histolytica?

Answer 5

1. Cysts and tophozoites passed in feces
2. Mature cysts are ingested
3. infection

mature cysts cause disease

cysts and trophozoites of E. histolytica are seen in stool of pt ( eggs in stool survive longer)

Question 6

What is the disease (pathology) of amebiasis?

Answer 6

Initial sx: amebic dysentery including
* diarrhea w/ cramping (blood and mucus in stool)
* lower abdominal pain
* Low-grade fever

Progresses to:
* amebic LESIONS in the intestine
* amebic ABSCESSES in the liver

Question 7

What is the parasite and mode of transmission of cryptosporidiosis?

Answer 7

Parasite: Cryptosporidium parvum
Transmission: fecal-oral (contaminated water)

Question 8

What is the life cycle of Cryptosporidium parvum?

Answer 8

1. Thick-walled oocyst (sporulated) exits host
2. Contamination of water with oocysts
3. Thick walled oocyst ingested by host

find oocyst of Cryptosporidium in stool of pt

Question 9

What is the disease/pathology of Cryptosporidium parvum?

Answer 9

Inital sx: usually self-limiting (~15 days)
* profuse watery diarrhea
* epigastric cramping pain
* nausea

AIDS patients
Prolonged profuse water diarrhea (3-6 liters/day for months/years)

Question 10

What is the parasite and transmission of Giardiasis?

Answer 10

Parasite: Giardia lamblia
Transmission: fecal-oral (contaminated water, clear mountain creeks; ‘beaver fever’)

Question 11

What is the life cycle of Giardia lamblia?

Answer 11

1. Cyst passed in feces (trophozoites are also passed in stool but they dont survive in the environment)
2. Contamination of water, food, or hands/fomites with infective cysts.

trophozoites and cysts of Giardia lamblia in stool of pt can be found

Question 12

What is the disease/pathology of giardiasis?

Answer 12

Pathology:** trophozoites** in the intestine (dorsal sucking disk leaves mucosal scars; inflammation)

Sx:
* VERY foul smelling watery diarrhea
* abscence of blood/mucus in diarrhea
* epigastric pain
* low-grade fever
* nausea