FIPV

FIPV, or feline infectious peritonitis virus, is a coronavirus that infects cats and is the etiologic agent of feline infectious peritonitis (FIP). It is a mutated variant of the feline coronavirus (FCoV). Most FCoV infections are mild or asymptomatic; in a minority, mutations arising within an individual cat give rise to FIPV, which can replicate within macrophages and trigger a systemic and often fatal inflammatory response.

There are two main clinical forms of FIP caused by FIPV. The effusive, or wet, form features fluid accumulation in body cavities such as the abdomen or chest, leading to distension and breathing difficulties. The non-effusive, or dry, form causes granulomatous lesions in organs including the liver, kidneys, brain, or lymph nodes, with signs such as fever, weight loss, lethargy, and organ-specific dysfunction. Other symptoms can include jaundice, eye or neurological abnormalities, and reduced appetite.

Transmission and epidemiology: FCoV is highly contagious among cats, especially in multi-cat environments. FIPV itself is not generally considered easily contagious between cats, since the mutation that creates FIPV typically occurs within an individual host. Nonetheless, high exposure to FCoV-infected cats increases the risk of FIP in susceptible individuals.

Diagnosis is challenging and relies on a combination of clinical signs, laboratory findings (such as elevated protein levels in serum and with effusions), and analysis of any effusion. Serology cannot reliably distinguish FIP from exposure to FCoV. Definitive diagnosis often requires histopathology showing characteristic lesions and FCoV antigen, or detection of FIPV RNA in affected tissues or fluids.

Treatment and prognosis: There is no widely approved cure. Management is primarily supportive, addressing symptoms and secondary infections. Some antiviral therapies have shown promise in studies and compassionate-use programs, but availability and regulatory status vary by country. A vaccine against FIP is available in some regions but has limited proven efficacy and is not universally recommended.