Epidemiology of feline infectious peritonitis among cats examined at veterinary medical teaching hospitals

Objective-To determine proportions of cats in which feline infectious perit onitis (FIP) was diagnosed on an annual, monthly, and regional basis and id entify unique characteristics of cats with FIP. Design-Case-control study. Sample Population-Records of ail feline accessions to veterinary medical te aching hospitals (VMTH) recorded in the Veterinary Medical Data Base betwee n January 1986 and December 1995 and of all feline accessions for necropsy or histologic examination at 4 veterinary diagnostic laboratories. Procedure-Proportions of total and new feline accessions for which a diagno sis of FIP was recorded were calculated. To identify characteristics of cat s with FIP, cats with FIP were compared with the next cat examined at the s ame institution (control cats). Results-Approximately 1 of every 200 new feline and 1 of every 300 total fe line accessions at VMTH in North America and approximately 1 of every 100 a ccessions at the diagnostic laboratories represented cats with FIP. Cats wi th FIP were significantly more likely to be young, purebred, and sexually i ntact males and significantly less likely to be spayed females and discharg ed alive than were control cats. The proportion of new accessions for which a diagnosis of FIP was recorded did not vary significantly among years, mo nths, or regions of the country. Conclusions and Clinical Relevance-Results indicated that FIP continues to be a clinically important disease in North America and that sexually intact male cats may be at increased risk, and spayed females at reduced risk, fo r FIP. The high prevalence of FIP and lack of effective treatment emphasize s the importance of preventive programs, especially in catteries.