Feline infectious peritonitis: Strategies for diagnosing and treating this deadly disease in young cats - Veterinary Medicine
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Feline infectious peritonitis: Strategies for diagnosing and treating this deadly disease in young cats
Although this lethal infectious disease is difficult to diagnose definitively, by performing multiple diagnostic tests, you may be able to rule out other diseases and put together enough puzzle pieces to form a relatively complete clinical picture.



Most cats with effusive disease die or are euthanized within a few weeks of the onset of clinical signs.2 The dry form tends to move more slowly, and cats may survive for several months from when signs are first noted. Cats with neurologic involvement often have a short survival time.


An intranasal vaccine (Felocell FIP—Zoetis) is licensed for cats > 16 weeks old. This attenuated, temperature-sensitive strain of FIP virus is presumed to trigger protective IgA antibodies. Based on independent testing, the efficacy of this product is questionable, and it is not regarded as a core vaccine.16

Because the virus can survive in the environment for several weeks, a new cat should not be introduced into a single-cat household until three months after the demise of the cat with FIP. In multicat households, fecal PCR testing has been proposed as a way to identify those cats that are shedding feline coronavirus and assess the risk to a newcomer. However, fecal excretion can be sporadic, and these tests suffer from low sensitivity. If a new cat is introduced, it is prudent the owner select an adult rather than a kitten, as older cats are innately more resistant to infection with feline coronavirus.

In shelter environments, feline coronavirus is generally endemic, and efforts to eradicate it are futile. However, the incidence of FIP can be reduced through management strategies such as preventing overcrowding and diagnosing and treating common intestinal and respiratory infections. These factors are thought to stress the immune system and predispose juveniles to the development of FIP.17

Most cats in breeding facilities are also infected with feline coronavirus, and kittens are predictably exposed from contact with the queen or the contaminated environment. As infection with feline coronavirus occurs around 9 or 10 weeks of age, isolation of the litter at 6 weeks of age may be helpful.17 However, strict quarantine regulations are needed, including separate caretakers and air space. As genetic factors probably influence the development of FIP, any queen or tom with two or more infected litters should be removed from a breeding program.2


In many patients, diagnosing FIP requires a careful assessment of the entire clinical picture and systematic collection of supportive and corroborative data. Clinicians need a good understanding of the tests available and must be prepared to counsel clients about the limitations and reliability of diagnostic methods. A definitive antemortem diagnosis may be difficult, particularly in cats with the dry form of the disease, and it may be necessary to reach a conclusion based on overall likelihood rather than irrefutable test results.

Audrey K. Cook, BVM&S, MRCVS, DACVIM, DECVIM-CA, Department of Small Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843

Whitney R. Nelson, DVM, DACVIM, Pieper Memorial Veterinary Center, 730 Randolph Road, Middletown, CT 06457


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