Abstract
One of the most common infectious causes of cat mortality is feline infective peritonitis (FIP), along with panleukopenia and viral upper respiratory tract infections. FIP is more likely to affect cats whose immune system is weak or suppressed. It is thought that the infection of macrophages and monocytes plays a major role in the pathogenic process. In order to set a definitive diagnosis for this infectious disease, a histopathological examination of tissues, and feline coronavirus (FCoV) detection by immunohistochemistry (IHC) is necessary. In this investigation, 15 cats between the ages of 5 and 24 months with clinical suspicion of FIP, underwent post-mortem necropsy, pathohistological and immunohistochemical examination. The results showed that all the cats had abdominal effusion with pyogranulomas throughout the abdominal serosa. Ten out of fifteen cats were FIP positive using immunohistochemical methods. This method also showed the antigen deposition in the macrophages thus confirming their role in the pathogenesis of FIP.