Feline panleukopenia virus (also called feline parvovirus and feline viral enteritis) is a highly contagious and often fatal virus that causes enteritis and feline distemper in cats. FPV is a small, single-stranded, non-enveloped DNA virus. The virus can persist in the environment for long periods and is resistant to many disinfectants. It replicates efficiently in rapidly dividing cells.

After infection, FPV targets dividing cells, including those in the lymph nodes, bone marrow, thymus, intestinal lining, and developing fetuses.

The virus attacks leukocytes, compromising the immune response of the affected cat. Cats that experience mild infection or recover from acute illness develop long-lasting protective immunity.

How It Spreads

Infected cats shed high levels of the virus in the early phase of infection. The virus is shed predominantly in the feces, but is also present in saliva, urine, and vomit. Survivors may continue shedding the virus in feces for up to six weeks after recovery.

Who is at higher risk? FPV is widely present in the environment, and most cats and kittens are exposed at some point in their lives. Although infection can occur at any age, young kittens, sick cats, and unvaccinated cats are at greater risk of developing illness. Cats in community settings such as pet shops, animal shelters, boarding facilities, and unvaccinated feral colonies are also more likely to be affected.

The virus spreads when a healthy cat comes into contact with the secretions, feces, or contaminated objects of an infected cat. Infection typically occurs through the mouth or nose after exposure. The virus can persist in an unsanitized environment for long periods and can be transported via fomites such as bedding, food dishes, and clothing.

The virus can pass through the placenta in pregnant queens, which may result in fetal mummification, abortion, or stillbirth. In some cases, infection around the time of birth can impair development of the cerebellum in kittens, leading to cerebellar hypoplasia, a condition linked to poor coordination and tremors.

Feline Panleukopenia Virus Symptoms

Infection severity varies widely. Some cats, particularly healthy adults, may show only mild signs or none at all, while others develop severe, life-threatening disease. In peracute cases, sudden death may occur with few or no warning signs.

Clinical signs of feline panleukopenia usually develop after an incubation period of 2 to 7 days and may include:

• Fever
• Depression
• Loss of appetite
• Lethargy
• Vomiting, often beginning 1 to 2 days after the onset of fever
• Diarrhea
• Severe dehydration

The clinical signs typically last 5 to 7 days. Young kittens are particularly vulnerable and carry the highest mortality risk following infection.

Symptoms in people: FPV is not considered zoonotic and causes no harm to humans. For an overview of other common cat diseases, see our resource hub.