Feline Infectious Peritonitis (FIP): NAVLE Diagnosis and Antiviral Treatment Guide

FIP is one of the most complex and frequently tested feline infectious diseases on the NAVLE. For decades it was a death sentence. That changed with GS-441524 antiviral therapy. You need to understand the classic diagnostic approach AND the current treatment landscape.

Pathogenesis

Feline Enteric Coronavirus (FECV) infects 80–90% of cats in multicat households, causing mild enteritis or nothing at all. In a small percentage of cats, FECV mutates within macrophages to become FIPV. The mutation occurs in the Spike protein or ORF3c gene region. FIP is NOT spread cat-to-cat—the mutant virus is poorly infectious and FIP arises de novo within the individual cat. Young cats (<2 years) and old cats (>10 years) are overrepresented. The pathological hallmark is pyogranulomatous vasculitis—immune complex deposition in vessel walls driving systemic disease.

Clinical Forms