protozoa

Question 1

what does protozoa mean

Answer 1

• unicellular eukaryotes
• have nuclei
• heterotrophic and motile stages

Question 2

what is a parasite

Answer 2

an organism that lives in or another organism to the determent of that host

Question 3

what are the 3 species of human entamoeba

Answer 3

• entamoeba histolytica - pathogenic
• entamoeba dispar - not pathogenic
• entamoeba moshkivskii- not known

Question 4

how does amebiasis cause disease

Answer 4

1) cysts and trophozoites passed in faces
2) mature cyst is ingested
3) occurs in the small intestine and trophozoites image are released, which migrate to the large intestine. Trophozoites may remain confined to the intestinal lumen.
4) trophozoites reproduce by binary fission producing cyst
5) passed through faces

Question 5

how does balantidium coli cause disease

Answer 5

1) cysts shed informed stools
2)cyst in infectious stage acquired by ingestion of contaminated food or water
3) The trophozoites reside in the lumen of the large intestine and appendix of humans and animals, where they replicate by binary fission, during which conjugation may occur
4) Trophozoites undergo encystation to produce infective cysts

Question 6

how does Giardia cause disease

Answer 6

1) trophozoites passed in stool but don’t survive in environment but cyst does
2) infectious cyst contaminates food, water or hands
3) in the small intestine, excystation releases trophozoites
4) trophozoites multiply by longitudinal binary fission, remaining in the lumen of the proximal small bowel where they can be free or attached to the mucosa by a ventral sucking disk
5) Encystation occurs as the parasites transit toward the colon

Question 7

what is the mammalian stages of African tryponosomiasis

Answer 7

1) tsetse fly takes blood meal injecting metacyclic tropomastigotes
2) transform in blood stream to trypomastigotes which are carried to other sites
3) multiply by binary fission
4) circulate in blood in acute phase

Question 8

how is leishmaniasis caused

Answer 8

1) Sandfly takes a blood meal injecting promastigote stage
2) promastigotes are phagocytized
3) transform into amastigotes
4) amastigotes multiply in cells of various tissue

Question 9

what are the two groups of sporozoan

Answer 9

• coccidia - gut parasite
• haemosporozoa - blood parasite

Question 10

how do sporozoans reproduce

Answer 10

asexualy - schizogony or multiple fission
sexually - gametes –> zygote –> sporozoites

Question 11

how does malaria cause disease

Answer 11

1) Sporozoites infect liver cells and mature into schizonts
2) they rupture and release merozoites which invade the bloodstream
3) undergo asexual multiplication in the erythrocytes