Lecture 07 - Sarcocystis and Trichomonas Flashcards
What phylum do the sarcocystis belong to
apicomplexa
What is the intermediate host
the muscles become infected with cysts containing infectious zoites
What is the definitive host
ingests the cysts and become infected with intestinal stage parasites and excretes oocysts or sporocysts into the environment
What are the hosts of sarcocystis
herbivorous mammals and humans/primates
some birds, reptiles and potentially fish
Humans serve as a definitive host for what species
S. hominis and S. suihominis
Humans serve as an intermediate host for what species
S. nesbitti
What is the asexual phase of Sarcocystis
trophozoites in muscle tissue cysts seen in intermediate hosts
cysts are large, oval and elongated with compartments a complex wall and merozoites
What is the sexual phase of Sarcocystis
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
What is the pathogenesis of Sarcocystis
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
How long can humans shad oocysts for
10 days to 6 months
What are the symptoms of Sarcocystis muscle invasion
painful swellings with fever and occasionally rash and difficulty breathing
What are the symptoms of Sarcocystis intestinal invasion
beef: mild nausea and diarrhea/stomach discomfort
pork: acute diarrhea and vomiting, stomach ache and cramps
What is the epidemiology of the intestinal form of Sarcocystis
cattle: germany 60- over 90%, asia 40-80%
pigs: worldwide 3- over 30%
humans 1-10%
europe (most common) and asia
What is the epidemiology of the muscle form of Sarcocystis
rare, occurs in europe, central and south america, southeast asia, west indies, africa, malaysia
How to diagnose Sarcocystis
cysts in feces or muscle biopsy
How to prevent Sarcocystis
freeze meat at -20C for 1 day and cook till colour changes
What is trichomonas
a facilative anaerobic extracellular parasite
What motility does trichomonas present
jerky, rapid movements
How does trichomonas gain nutrients
by phagocytosing human, bacteria and yeast cells
What is an essential element for the growth of trichomonas
iron
What are the natural host of trichomonas
humans
What is the pathogensis of trichomonas
it contacts human cells and changes morphology to adhere, it then uses cytotoxic effects to disrupt host tissue
What are the virulence factors of trichomonas
mucinase, adhesins, cytolytic enzymes, proteinases
