Prevalence of Cryptosporidium, Giardia and Isospora species infections in pet cats with clinical signs of gastrointestinal disease

This study reports the prevalence of Cryptosporidium, Giardia and Isospora species in cats showing signs of gastrointestinal disease. Records from a United Kingdom commercial diagnostic laboratory between December 2003 and December 2005 were reviewed. Of 1355 cats, Cryptosporidium species oocysts were found in 13 cats (1%), Giardia species trophozoites in 74 (6%), and Isospora felis oocysts in 46 (3%). In a second group of 48 cats, prevalence of Giardia species was 15% using an immunoassay for detection of antigen compared to 4% detected with microscopy. Prevalence of Giardia (9%) and Isospora (9%) species was higher in cats less than 6 months old. Gender and breed did not affect prevalence. There was a trend for Cryptosporidium and Isospora species infections to be detected in late autumn and early winter. Regional differences in prevalence were not detected. None of these organisms show a characteristic pattern of clinical signs. This study demonstrates that enteric protozoal infection is common in domestic cats showing signs of alimentary disease.