Detection of feline coronavirus in captive Felidae in the USA

Feline coronavirus (FCoV) is an important pathogen of domestic and nondomestic Felidae. Investigation into the prevalence of FCoV in exotic Felidae has relied primarily on serology. The usefulness of genetic detection of FCoV using reverse transcription and nested polymerase chain reaction (RT/nPCR) for viral screening was investigated. Seventy-five biologic samples, primarily feces, from captive felids from 11 institutions were tested using PCR. Serum samples collected from all but 12 of these animals were tested for antibodies to type I and type II FCoV by indirect immunofluorescence. Twenty-four animals were positive using RT/nPCR for virus. Twenty-nine animals were seropositive to type I and/or type II FCoV. From serologic data, infection with a virus antigenically related to FCoV type I occurred most commonly. Serology did not correlate with virus shedding because 13 animals were seronegative to FCoV type I and II but positive using RT/nPCR for virus. Conversely, 20 animals were seropositive but negative using RT/nPCR for FCoV. Some of the populations in which virus was detected had experienced health problems, including feline infectious peritonitis (FIP), necrotizing colitis, and mild enteritis. In addition to its role in FIP, this virus may play a role in gastrointestinal diseases of infected animals. This study demonstrates that FCoV is a significant infectious agent of captive felids because over half of the animals tested were positive by viral genetic detection, serology, or both. Dependence upon one method for detection of infection is unreliable.