24. toxoplasma Flashcards
lifecycle of toxoplasma
DH cats- release unsporulated oocysts
oocysts sporulate
IH host eat oocysts- form cysts in tissues or active parasite invade and kill cells
humans can eat these infected IH and can spread by vertical transmission into the placenta
what is the definitive host of Toxoplasma
cats
Toxoplasma gondii replicate in —
DH cats small intestine
form oocysts
cats will remain as carriers for life
cats act as environmental contamination for —
toxoplasma gondii
cat feces cause 94-4000 oocysts per square meter
what do oocysts of T. gondii look like
how long do T. gondii oocysts take to become infectious
48-72 hours
— of T gondii replicate rapidly and cause disease
tachyzoite
what happens to a cell when invaded by T. gondii
Tachyzoites- can enter any type of cell, cross barriers, will invade cell and multiply until cell explodes
if T. gondii makes it to the brain will switch to slow growing and form latent cysts
what version of T. gondii can be transferred orally
latency- cysts formed in the brain
animal dies and another animal eats the infected host and will cause reactivation of the T. gondii
how to tell acute vs chronic T. gondii infection
what % of people are infected with Toxoplasma
2 cause of death due to food-borne illness
30%- most asymptomatic
amish have much higher- due to increased exposure to uncooked meat
where can Toxoplasma move to inside a host
everywhere
can cross GI, blood-brain, placenta, and eye
congenital toxoplasma infection is most dangerous
during the first trimester
if mother is infected for the 1st time during pregnancy
Toxoplasma infection in pregnant sheep cause
early- death, resorption, expulsion of fetus
mid-gestation- abortion, still birth, mummified
late- sub clinical - eye issues?
do you need to have immune deficiency to be infected by Toxoplasma
no
cause flu like symptoms in healthy people
Neospora caninum life cycle
DH dog
IH- animals
does NOT move to humans
will cross placenta- repeated vertical transmission
