Pet Points: Feline peritonitis difficult to detect

Veterinarians face difficult diagnostic and treatment dilemmas in the clinic daily. One of the most challenging is a disease called Feline Infectious Peritonitis.

It is associated with a virus called coronavirus, which is common in cats. The feline coronavirus usually causes a mild infection that passes easily between cats in a group setting. It can be found at some point in 30 percent of household pets and in 80-90 percent of cats in feral colonies.

Any cat infected with the coronavirus is at risk for developing FIP, but fortunately that happens in only a small percentage of cats.

The difficulty is that there is no single noninvasive test or a good treatment for this often fatal disease. The common problems we see in a cat with FIP is a fever that does not respond to antibiotics, lethargy, poor appetite and weight loss. Many infected cats are anemic.

To diagnose FIP, veterinarians rely on blood tests and fluid analysis. Biopsy or other tissue samples are frequently needed to confirm the diagnosis.

There are two forms of the disease.

The wet form is associated with yellow or straw-colored fluid in the abdomen and occasionally in the chest.

The dry form, without fluid accumulation, is more difficult to diagnose but just as lethal.

The clinical disease is often found in young cats, and crowding apparently makes them more susceptible.

"The way clinical FIP develops as an immune-mediated disease is unique, unlike any other disease of animals or man," according to the Cornell Feline Health at Cornell University in Ithaca, N.Y.

Vaccinations have not been seen as an answer and are not recommended. Both wild and domestic cats are at risk.

Most infected cats are under 2 years old, and the risk decreases until about age 5. As cats approach 13 years old, their susceptibility again increases. Besides crowding, other contributing factors include parasitism, poor sanitation and especially feline immunodeficiency virus and feline leukemia virus.

Any sick cat may have FIP, and its prognosis is always poor. However, there is some hope on the horizon. Researchers at Cornell are making progress in understanding this infection.

Hopefully, new developments will improve our chances of diagnosing and treating this dreadful disease in cats.

Lawrence Gerson is a veterinarian and founder of the Point Breeze Veterinary Clinic. His biweekly column is intended to educate pet owners. Consultation with a veterinarian is necessary to diagnose and treat individual pets. If you have a question you'd like addressed in Pet Points, email Please include your name and municipality or neighborhood.