Lecture 07 - Sarcocystis and Trichomonas

Question 1

What phylum do the sarcocystis belong to

Answer 1

apicomplexa

Question 2

What is the intermediate host

Answer 2

the muscles become infected with cysts containing infectious zoites

Question 3

What is the definitive host

Answer 3

ingests the cysts and become infected with intestinal stage parasites and excretes oocysts or sporocysts into the environment

Question 4

What are the hosts of sarcocystis

Answer 4

herbivorous mammals and humans/primates

some birds, reptiles and potentially fish

Question 5

Humans serve as a definitive host for what species

Answer 5

S. hominis and S. suihominis

Question 6

Humans serve as an intermediate host for what species

Answer 6

S. nesbitti

Question 7

What is the asexual phase of Sarcocystis

Answer 7

trophozoites in muscle tissue cysts seen in intermediate hosts

cysts are large, oval and elongated with compartments a complex wall and merozoites

Question 8

What is the sexual phase of Sarcocystis

Answer 8

sporocysts with sporozoites turn into merozoites which turn into gametic cells and oocysts which move from the intestinal lumen of the definitive host into the environment

Question 9

What is the pathogenesis of Sarcocystis

Answer 9

there is little to no reaction in the gut proliferative stages unless there is a large infective dose

with muscle cysts there is no inflammation when intact but tissue damage occurs when cysts disintegrate causing muscle inflammation, necrosis and vasculitis

Question 10

How long can humans shad oocysts for

Answer 10

10 days to 6 months

Question 11

What are the symptoms of Sarcocystis muscle invasion

Answer 11

painful swellings with fever and occasionally rash and difficulty breathing

Question 12

What are the symptoms of Sarcocystis intestinal invasion

Answer 12

beef: mild nausea and diarrhea/stomach discomfort

pork: acute diarrhea and vomiting, stomach ache and cramps

Question 13

What is the epidemiology of the intestinal form of Sarcocystis

Answer 13

cattle: germany 60- over 90%, asia 40-80%
pigs: worldwide 3- over 30%
humans 1-10%
europe (most common) and asia

Question 14

What is the epidemiology of the muscle form of Sarcocystis

Answer 14

rare, occurs in europe, central and south america, southeast asia, west indies, africa, malaysia

Question 15

How to diagnose Sarcocystis

Answer 15

cysts in feces or muscle biopsy

Question 16

How to prevent Sarcocystis

Answer 16

freeze meat at -20C for 1 day and cook till colour changes

Question 17

What is trichomonas

Answer 17

a facilative anaerobic extracellular parasite

Question 18

What motility does trichomonas present

Answer 18

jerky, rapid movements

Question 19

How does trichomonas gain nutrients

Answer 19

by phagocytosing human, bacteria and yeast cells

Question 20

What is an essential element for the growth of trichomonas

Answer 20

iron

Question 21

What are the natural host of trichomonas

Answer 21

humans

Question 22

What is the pathogensis of trichomonas

Answer 22

it contacts human cells and changes morphology to adhere, it then uses cytotoxic effects to disrupt host tissue

Question 23

What are the virulence factors of trichomonas

Answer 23

mucinase, adhesins, cytolytic enzymes, proteinases