Toxoplasma gondii Flashcards
order
eucoccindiorida- parasite of epithelial cells
hosts
cats and other felids
intermediate hosts
humans, dogs, livestock, or birds
is there zoonosis?
yes
size
12 micrometers
what does the oocysts contain once sporulated?
2 sporocysts each with 4 sporozoites
life cycle
unsporulated oocysts are shed in cats feces
oocysts form into tachyzoites- rapidly multiply
intermediate host ingest tachyzoites and they localize in muscle tissue and become bradyzoites
cat eats the tissues of the intermediate host with cysts
tissue cysts wall is digested in cats stomach
liberated bradyzoites initiate schizogonous and gametogenous development resulting in production of oocysts
also, organs invade extraintestinal tissues where tachyzoites and bradyzoites proceed as in intermediate host
how long do oocysts take to sporulate?
1-5 days
how do intermediate hosts become infected?
ingesting soil contaminated with oocysts
how do cats become infected
eat the intermediate host harboring tissue cysts or by directly ingesting the sporulated oocysts
_____ may also become infected with tissue cysts after ingestion of sporulated oocysts
wild game- liberated sporozoites spread via blood. tissue cysts form containing bradyzoites
what is the invasive and proliferative stage?
tachyzoite
how can humans become infected?
foodborne- eating raw infected meat
animal to human- ex. cat litter
mother to baby- transplacental
what happens in the human host?
parasites form tissue cysts
these cysts remain there throughout the life of the host
how are humans diagnosed?
serology or biopsy specimen
site of infection
intestinal and extratintestinal tissues
pathogenesis
most animals asymptomatic - depends on organs involved
death of intestinal cells
acute toxoplasmosis- severe with FIV
pneumonia
diagnosis
serological test
ELISA or IFA tests
cats develop ____ after initial infection and shed only ___ in a lifetime
immunity, once
how often are oocysts usually shed in cat feces?
1-2 week period
treatment
humans avoid feces and eating uncooked meat
no vaccine approved
Nonsulfonamides and sulfonamides
serious concern of exposure of human ___ to hazard of death
fetuses
what is toxoplasmosis?
transplacental transmission- many side effects to fetus
toxoplasmosis can effect either a ____ host or a ____ host
nonimmune, immune
