Lab session 3

Protozoa Eukaryotic Unicellular Two stages Trophozoite Metabolically active Motile In most cases found inside the host

Cyst stage Dormant stage Most cases found outside the host

Entamoeba histolytica Cysts are released in the feces Transmitted in contaminated food or water When the cysts are ingested, they reach intestinal tract Become trophozoites They feed on cells lining the intestinal tract Red blood cells Dysentery

Cyst

Trophozoite

Trichomonas vaginalis Transmitted by sexual contact Itching in the area Single nucleus Bunch of flagella on one end of the cell

Giardia lamblia Cysts are released in the feces Contaminated food and water Cysts transform into trophozoites. Attach themselves to the intestinal wall and absorb nutrients. Diarrhea, weight loss

Cyst

Trophozoite

Trypanosoma gambiense African sleeping sickness Transmitted by tsetse fly Injected into the bloodstream Toxins – damage certain parts of the nervous system. Confusion, drowsiness, coma, death

Trypanosoma cruzi Chagas disease Kissing bug Mexico, South America Injected into the bloodstream Toxins damage certain parts of the nervous system Mega colon, mega esophagus

Balantidium coli Cysts are released in the feces Contaminated water or food Become trophozoites in the intestinal tract Dysentery

Plasmodium falciparum Malaria Mosquito Forms a ring stage in the red blood cell Diagnosis is based on the presence of the ring stage