However, oocysts deposited in the environment must undergo additional development before they are infective. The sporulated oocyst can remain infective in the environment for prolonged periods of time, usually 2 to 3 months. Under certain conditions, they can remain viable for a year or more. Coccidial oocysts survive best in moist, shaded areas. They survive very well at freezing temperatures, and are fairly resistant to common detergents.
Coccidiosis is particularly a problem in confined animals.
Concentration of confined animals creates heat and moisture which stimulates sporulation of oocysts. Further, transmission of oocysts is enhanced when soiled animals lick each other and when feed bunks and water troughs become contaminated with feces. Young goats, for example, may acquire massive infection when climbing in feed bunks where they and others defecate and then eat. Outbreaks of coccidiosis also can occur in animals on range or pasture, especially in dry years when animals concentrate around watering points which increases contamination of water and soil. Coccidiosis is mainly a problem in young livestock, indicating that immunity may play a role in the protection of older animals.