This protozoan normally lives in moist environments and is ingested by grazing calves and cattle. Although it is normally found in adult cattle with few clinical signs, numbers of this parasite increase associated with scours in calves and diarrhoea in adult cattle. This protozoan is often a pseudoparasite caused by contamination of feces by passerine birds.
Isospora typically require only one host in which to complete their life cycles. Some species of Isospora have facultative intermediate (paratenic or transfer) hosts. Coccidia are host-specific, and there is no cross-immunity between species of coccidia.
Coccidiosis is seen universally, most commonly in young animals housed or confined in small areas contaminated with oocysts.
The most frequently isolated species in cattle are:
- Isospora suis
- Cicek H et al (2007) Prevalence of coccidia in beef cattle in western Turkey. Parasitol Res 101(5):1239-1243
- Oda K & Nishida Y (1990) Prevalence and distribution of bovine coccidia in Japan. Nihon Juigaku Zasshi 52(1):71-77
- Merck Vet Manual
- Koudela B et al (1986) Coccidiosis in suckling calves raised on large farms. Vet Med (Praha) 31(12):725-732