Diagnostic features of clinical neurologic feline infectious peritonitis

Feline infectious peritonitis (RP) is a fatal Arthus-type immune response o f cats to infection with FIP virus, a mutant of the ubiquitous feline enter ic coronavirus (FECV). The disease may occur systemically or in any single organ system, and primary neurologic disease is a common subset of such man ifestations. We examined 16 domestic cats with clinical neurologic FIP and 8 control cats with nonneurologic FIP, with the intention of identifying th e ante- and postmortem diagnostic tests that most contribute to accurate di agnosis. Of the 16 cats with neurologic FLP, 15 were less than 2 years of a ge and all 16 originated from large multiple-cat households. The most usefu l antemortem indicators of disease were positive anti-coronavirus IgG titer in cerebrospinal fluid, high serum total protein concentration, and findin gs on magnetic resonance imaging suggesting periventricular contrast enhanc ement, ventricular dilatation, and hydrocephalus. Postmortem diagnosis was facilitated by FIP monoclonal antibody staining of affected tissue and coro navirus-specific polymerase chain reaction. Most cats with neurologic and o cular forms of FIP had patchy, focal lesions, suggesting that recently deve loped technologies described in this report may be useful for evaluation of cats with suspected FIP.