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(invertebrate zoology)
The encysted zygote of some Sporozoa.



one of the stages in the development of protozoans of the class Sporozoa. The oocyst forms as a result of the encyst-ment of a fertilized egg cell. It is covered with a strong protective membrane. The contents of the oocyst generally divide into several nonmotile spores (in Coccidia) or motile sporozoites (in Gregarinidia). In Hemosporidia the oocyst produces thousands of sporozoites, which subsequently leave the oocyst.

References in periodicals archive ?
The most commonly practiced modified Ziehl Neelsen (ZN) acid fast staining is a key player in the detection of Cryptosporidium oocysts in fecal smears (Rekha et al., 2016).
People can help reduce the spread of Toxoplasma by keeping their cats inside and disposing of cat faeces in a bag in the trash, not outdoors or in the toilet because wastewater treatment is not effective in killing oocysts. (ANI)
Normally, most birds pass small numbers of oocysts in their droppings without apparent ill effects.
Given its impact, it is little wonder that Cryptosporidium is treated as a bioterrorism agent, and the European Water Directive insists on shutting down the distribution plants should the oocysts be found in drinking water.
Inactivation of Cryptosporidium parvum Oocysts and Clostridium perfringens Spores by a Mixed-Oxidant Disinfectant and by Free Chlorine.
The oocysts can be highly resistant to chemical disinfectants, including chlorine.
For examination of Cryptosporidium oocysts, the faecal smears were prepared and stained by Modified Ziehl-Neelsen technique using ZN Acid Fast Stains Kit (Himedia, India) (Henriksen and Pohlenz, 1981).
Infected animals can shed a huge number (108-109/g) of oocysts (Ortegamora and Wright, 1994), which cause infection in humans and animals by contaminating the surface water of routine usage (Maurya et al., 2013).
The Cornell Feline Health Center says that cats who eat flies and other bugs may get infected that way, too, if the insects have oocysts on their bodies.
If the unsporulated oocysts come into contact with moisture, they sporulate (infectious) and once ingested by other birds as they scratch and feed, they get infected.The oocysts can also be transmitted through shoes, farm equipment, contaminated water and feeds.
(2012) argue, environments frequented by cats can be widely contaminated with oocysts of T gondii and farms with a higher number of cats are generally the most contaminated.
We observed 15 (3.2%) samples positive for coccidian oocysts out of 470 samples through microscopy.