A review of Cystoisospora felis and C. rivolta-induced coccidiosis in cats

Authors: Dubey, Jitender

Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/28/2018
Publication Date: 11/15/2018
Citation: Dubey, J.P. 2018. A review of Cystoisospora felis and C. rivolta-induced coccidiosis in cats. Veterinary Parasitology. 263:34-48. https://doi.org/10.1017/S0031182018000604.
DOI: https://doi.org/10.1017/S0031182018000604

Interpretive Summary: Toxoplasmosis, caused by the single celled parasite, Toxoplasma gondii, continues to be a public health problem worldwide. This parasite infects all warm-blooded hosts, including humans. It causes mental retardation and loss of vision in children, and abortion in livestock. The ingestion of food and water contaminated with resistant stage of the parasite, the oocyst, is a major mode of transmission of this parasite. Of all the hosts infected, only cats are known to excrete oocysts in feces. Cats can excrete millions of oocysts after eating an infected prey, such as a mouse or a bird. Cats can re-shed Toxoplasma oocysts after superinfection with a nonpathogenic coccidian parasite, Cystoisospora felis. In the present paper, the authors reviews biology of Cystoisospora species in cats and discusses public health importance of interaction of Toxoplasma and Cystoisospora. This review will be of interest to parasitologists, veterinarians, and public health workers.

Technical Abstract: Until the discovery of Toxoplasma gondii oocysts in cat feces in 1970, little was known of coccidiosis in cats. Until 1970, three coocidian parasites based on different sized oocysts were recognized, the parasite with large oocysts (~40 µm long and called Isospora felis), medium sized oocysts (~25 µm long, called Isospora rivolta), and small sized oocysts (14 µm or less, called Isospora bigemina) were known and they were considered not host-specific. Later, it was demonstrated that these parasites were host-specific and had also extra-intestinal stages. The Isospora bigemina turned out to be more than 25 organisms belonging to T. gondii, Hammondia spp., Sarcocystis spp., Besnoitia spp, and Neospora spp; these subjects have been reviewed previously in detail. The present paper summarizes biology of Isospora felis, and I rivolta (now transferred to genus Cystoisospora), including taxonomy, life cycle, diagnosis, treatment and public healthy significance. Re-excretion of T. gondii oocysts from chronically infected cats after superinfection with Cystoisospora felis oocysts is discussed. There are only two species of Cystoisospora species in cats, C. felis and C. rivolta; Isospora novocati and Cystoisospora frenkeli named for I. rivolta-like parasites of cats are considered synonym of C. rivolta.