An extended outbreak of infectious peritonitis in a closed colony of European wildcats (Felis silvestris).

Feline infectious peritonitis is a multisystemic disease of domestic and exotic cats caused by a coronavirus. An outbreak of feline infectious peritonitis was investigated in a closed colony of European wildcats (Felis silvestris) at a zoological garden. Over a six-year period, a putative fading kitten syndrome occurred in six of 11 litters born and severe lesions of infectious peritonitis occurred in five of the eight wildcats retained in the colony during this period. Lesions were more acute in the early stages of the outbreak and included perivascular pyogranulomatous inflammation with exudative serositis. Lesions occurred only in males. Vascular lesions were common in the liver of all affected wildcats, serositis occurred in the abdominal and thoracic cavities in most cases and meningeal lesions were present in two cases. Immunohistochemistry with specific antisera detected viral antigen within macrophages in all lesions. This outbreak demonstrates that the lesions of feline infectious peritonitis can become modified over time and that the virus can persist in a closed colony, possibly via carrier wildcats.