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A thick-walled structure that contains the zygote of an apicomplexan parasite and releases the infective sporozoites.


(Zoology) an encysted zygote of sporozoan protozoans that undergoes sporogony to produce infective sporozoites


(ˈoʊ əˌsɪst)

the encysted zygotic stage in the life cycle of some sporozoans.
References in periodicals archive ?
Cryptosporidium infected animals shed a large number of oocysts (108-109 OPG of fecal material) (Romero-Salas et al., 2016).
Wild and domestic cats are the only known hosts of Toxoplasma, in which the parasite forms egglike stages, called oocysts, in their faeces.
The study finds that end-users continue to show a marked preference for medicated starter feed, in light of its ability to prevent animals from developing cocci oocysts, and promote immunity.
Chickens are infected with coccidiosis after picking up oocysts from the ground or from their litter.
The transmissive stages, oocysts, are resistant to the classic chlorine treatment, and difficult to filter out of the water due to their small sizes.
The life stage of Cyclospora that causes infection is called the oocyst. Oocysts can spread when they are passed in the bowel movements of infected people and end up on hands, food, water or other objects.
It spreads via oocysts, which appear in the faeces at the onset of cryptosporidiosis, and can continue to be found in excrement for several weeks - even after symptoms have subsided, the report says.
egg, cysts, oocysts and also the availability of paratenic hosts during scavenging has rendered the wild boars particularly more prone to the endoparasitic infections (Kassai, 1999).
parvum oocysts were so minute that their presence in any acute diarrhea was not detectable until 1970s (Ryan et al., 2014).
Oocysts (eggs) are passed in the stool and then develop into the infective stage--sporulated oocysts.
Poor hygiene also contributes to the spread of infection within a flock.The disease is spread from bird to bird through unsporulated oocysts (eggs), which are passed through droppings of infected birds.
The parasite can be transmitted to humans and animals mainly through: the fecal-oral route, through the ingestion of oocysts that may be present in contaminated water, soil and vegetables; consumption of raw or undercooked meat and animal products containing tissue cysts; and transplacental route (FRENKEL et al, 1970).