ACUTE ARTHRITIS OF CATS ASSOCIATED WITH FELINE CALICIVIRUS INFECTION

Twelve specific pathogen-free cats were infected either by intra-artic ular inoculation or by contact exposure to one of two strains of felin e calicivirus (FCV), either F65, a field strain originating from an ou tbreak of lameness in a group of cats, or a vaccine strain. Following either route of exposure, both strains induced signs typical of FCV in fection including oral and nasal ulceration, conjunctivitis and ocular discharge. These signs were of equal severity for both virus strains, but overall, following either route of infection, F65 induced more se vere disease than the vaccine strain, with marked pyrexia, lethargy an d lameness. Vaccine virus only induced a relatively mild lameness foll owing intra-articular inoculation. Gross pathological and histopatholo gical lesions were seen in some of the joints, but again changes were more severe in the F65-exposed cats. Virus was isolated from both norm al and affected joints from both groups of F65-exposed cats, and from a joint from each cat inoculated intraarticularly with vaccine virus. Mild transient lameness was also seen in one of two control cats inocu lated intra-articularly, but no pathological changes were seen or viru s isolated from joints. A. cDNA probe used in RNA dot blot hybridisati on experiments was found to be specific and more sensitive than virus isolation in detecting FCV in selected tissues. This may be useful in future studies on the pathogenesis of FCV disease and in studies on vi ral persistence in FCV carriers.