WINN FELINE FOUNDATION For the Health and Well-being of All Cats

One of the most poorly understood and enigmatic feline viruses is the feline coronavirus (FCoV), a large enveloped positive-stranded RNA virus. Two primary forms of FCoV are recognized, a relatively harmless enteric form (FECV) and the feline infectious peritonitis (FIP) disease causing form (FIPV). FIP is invariably a lethal, systemic immune-mediated disease. The most popular etiological hypothesize is that it arises in some cats infected with the FECV form when this relatively benign form mutates into a pathogenic FIPV form. This theory has been referred to as the ‘internal mutation theory’ (Vennema et al., 1998; Pedersen et al., 1984; Pedersen et al., 2009). Although FECV is very common among cats, especially in multi-cat households, catteries, and shelters, mortality from FIPV is fortunately generally low. Multi-cat situations of several years’ duration will likely have a brush with FIP. It is no cause for either fear or ostracization. It is, however, a reason to make efforts to understand this disease and its means of control.