Feline infectious peritonitis in a mountain lion (Puma concolor), California, USA

Feline infectious peritonitis (FIP) is a fatal immune-mediated vasculitis of felids caused by a mutant form of a common feline enteric virus, feline enteric coronavirus. The virus can attack many organ systems and causes a broad range of signs, commonly including weight loss and fever. Regardless of presenta-tion, FIP is ultimately fatal and often presents a diagnostic challenge. In May 2010, a malnour-ished young adult male mountain lion (Puma concolor) from Kern County, California, USA was euthanized because of concern for public safety, and a postmortem examination was performed. Gross necropsy and histopathologic examination revealed necrotizing, multifocal myocarditis; necrotizing, neutrophilic, and his-tiocytic myositis and vasculitis of the tunica muscularis layer of the small and large intes-tines; and embolic, multifocal, interstitial pneu-monia. Feline coronavirus antigen was detect-ed in both the heart and intestinal tissue by immunohistochemistry. A PCR for coronavirus performed on kidney tissue was positive, con-firming a diagnosis of FIP. Although coronavirus infection has been documented in mountain lions by serology, this is the first confirmed report of FIP.