Feline Coronavirus Prevalence in 493 Cats With Chronic Diarrhea

ABSTRACT Background Chronic diarrhea (CD) is common in cats, with unknown etiology in many cases. Objectives To establish the prevalence of feline coronavirus (FCoV) and other enteropathogens in cats with CD. Animals Veterinarians at a feline specialty practice examined 493 cats with CD. The breed of three (0.6%) was unknown; 373 (75.7%) were non‐purebred, and 117 (23.7%) purebred. Methods Retrospective database review of 586 fecal sample results of an RT‐PCR and PCR diarrheal panel. Results Feline coronavirus was found in 321 (65.1%) of 493 cats with CD. FCoV RNA and Clostridium perfringens toxin DNA were detected in 377 (64.3%) and 319 (54.4%) samples respectively: 206 (35.2%) samples were positive for both pathogens. Feline coronavirus was the sole pathogen detected in 118 (23.9%) cats. Samples from 203 cats under 1 year old were significantly (p = 0.0001) more frequently FCoV positive than samples from older cats (166/224 [74.1%] samples vs. 211/362 [58.3%]). FCoV RT‐PCR positivity peaked in February (p = 0.016) and March (p = 0.0064). Other detected pathogens included Giardia spp. (8.4%; 49/586 samples); Tritrichomonas blagburni (8.4%; 46/586); Cryptosporidium (5.1%; 30/586); Campylobacter jejuni (3.4%; 17/497); Campylobacter coli (1.6%; 8/497); Salmonella spp. (0.8%; 5/586); panleukopenia virus (0.8%; 5/586); and Toxoplasma gondii (0.5%; 3/586). Sixty‐nine cats gave 162 samples: 54/69 (78.3%) cats were FCoV positive, 39/54 (72.2%) persistently so. Conclusions If FCoV is non‐pathogenic, as often assumed, its having the highest rate of positivity in CD cases is difficult to explain. If pathogenic and overlooked, key diagnostic and therapeutic opportunities might be missed.