ELIMINATION OF FELINE CORONAVIRUS INFECTION FROM A LARGE EXPERIMENTALSPECIFIC PATHOGEN-FREE CAT BREEDING COLONY BY SEROLOGIC TESTING AND ISOLATION

This study describes the clinical course of an inadvertent feline ente ric coronavirus (FECV) outbreak in two units of a 550-animal, specific pathogen-free (SPF), experimental cat breeding colony and outlines tw o protocols for successful eradication. In Protocol I, a small number of queens and toms with negligible (negative 1:100) FCoV antibody tite rs were identified and placed into isolation quarters, with only a sin gle animal per room. They were observed for 9 months and their antibod y titers followed at intervals. In Protocol II, queens were segregated into 6 different communally housed groups (A-F) based on the magnitud e of their initial FCoV antibody titers. Group A contained mainly cats with negligible titers, while Group F contained cats with predominant ly high (greater than or equal to 1:400) titers. Groups B through E we re each comprised of cats with antibody titers that ranged from neglig ible to high. FCoV antibody titers were then determined at monthly int ervals and animals were either kept in the same group or moved to lowe r or higher titered groups depending on their antibody titers with tim e. All of the cats in Protocol I maintained negligible FCoV antibody t iters during the 9-month period. After 9 months, Protocol II cats had segregated into two main antibody classes; Groups A and B had negligib le antibody titers, while Group F contained cats with uniformly high a ntibody levels. All of the cats from Protocol I, and all of the cats f rom Groups A and B of Protocol II, were then bred. Kittens born to the se cats were weaned when 6 to 10 weeks old; all were determined to be free of FECV infection at 16 weeks of age. Several cases of feline inf ectious peritonitis (FIP) occurred among cats produced in this colony during the first two years following the initial FECV outbreak. Virus isolated from one of the cats with FIP behaved in animal inoculation s tudies as an FIP virus (FIPV), while the predominant virus isolated fr om the feces of healthy seroconverting cats behaved as an FECV. This o ccurrence gave credence to the theory that FIPV is a simple mutation o f FECV that is generated during outbreaks of FECV.