POLYMERASE CHAIN-REACTION (PCR) FOR THE DIAGNOSIS OF NATURALLY-OCCURRING FELINE CORONAVIRUS INFECTIONS

A nested RT-PCR (RT-nPCR) assay was developed for the detection of fel ine coronavirus (FCoV) RNA in feces, tissues, and body fluids of infec ted cats. The assay is targeted to the 3' nontranslated region of the feline coronavirus (FCoV) genome and will detect most if not all FCoV field strains. The assay is highly sensitive and can detect FCoV RNA i n the plasma of experimentally infected cats from 2 days post-inoculat ion onward. To explore the use of RT-nPCR as a diagnostic tool, serum, plasma, or ascitic fluid of -18 field cats with FIP was tested. FCoV RNA was detected in 14 of these cats (78%), but the use of RT-nPCR for FIP diagnosis is limited by the occurrence of healthy FCoV carriers; these cats shed FCoV in the feces and, in a number of cases, also pres ent detectable virus in their plasma.