Parasitology protozoology 1

Question 1

Encystment

Answer 1

secretion of a resistant covering, the cyst wall, around the resting protozoal stage; important for survival in the environment and transmission to a new host

Question 2

Excystation

Answer 2

liberation of the parasite from the cyst

initiates new infection in host

Question 3

Phylum Ciliophora

Answer 3

Ciliates (of little clinical importance)
Ciliates of domestic animals are transmitted in the feces by cyst stages
Animals become infected by ingesting cycts in contaminated food, water, or the environment

Question 4

General info about ciliates

Answer 4

Move by means of cilia, transverse binary fission, macro and micronucleus, transmitted by cysts, most commensal, important parasites in fish

Question 5

Balantidium coli

Answer 5

Large intestine of man, pigs, and primates
Rarely pathogenic
Pathogenic strains cause lesions after invasion of gut

Question 6

Ichthyophthirius multifillis

Answer 6

AKA ich
affects aquarium fish, channel catfish
Found on skin and gills- leads to asphyxiation

Question 7

Summary of ciliates

Answer 7

Usually commensals
Transmitted by cysts or trophozoites (asexual stage)
Identify by macronucleus and cilia
Important only in fish

Question 8

Phylum Sarcomastigophora

Answer 8

Subphylum Sarcodina (Ameba)
Intestinal amoebae

Question 9

Characteristics of ameba

Answer 9

Trophozoite move by pseudopodia and divide by binary fission
Most have a resistant cyst stage
Some have flagellated stages
Most transmitted by contaminated food or water

Question 10

Soil/water amoeba

Answer 10

Are opportunistic parasites, not common

Acanthamoeba species is sometimes seen in racing greyhounds