Management of cats with FIP

Any cat in a hospital is potentially a source of FCoV infection. Therefore, routine hygiene measures should be taken to avoid inadvertent spread of FCoV infection between cats. In a case of a cat with FIP, this cat is highly likely to shed FCoV and therefore strict precautions to avoid infection of other cats is particularly important. However, any in-contact cats within the cat’s own home will probably have already been exposed to the FCoV from the cat, so there is no particular benefit in isolating the cat at home. It remains controversial whether FIP-inducing mutants are shed from a cat with FIP.

In situations where a cat with FIP has been euthanased and there is no cat left in that household it is recommended to wait 2 months before obtaining a new cat. If other cats in that household remain, they most like carry FCoV. Before introducing a new cat into that household, several things have to be considered including environment, number and density of cats as well as their age, and it is prudent to wait at least several months in any case before introducing new cats.

Treatment

Treatment (or euthanasia) should only be considered after every effort has been made to obtain a definitive diagnosis. Once FIP is established, in most cats it is fatal. There have been reports of occasional cats surviving up to several months after diagnosis of FIP. It is not clear whether this improvement was caused by treatment. There have even been some very occasional reports of cats that have “recovered” from FIP, but in these cases a definitive diagnosis of FIP had not been obtained.

As FIP is caused by inflammatory and inappropriate immune-responses to FCoV, supportive treatment is aimed at suppressing that inflammatory and inappropriate immune-response, usually with corticosteroids. There are, however, no controlled studies that indicate whether corticosteroids have any beneficial effect or not. Occasional cases treated with corticosteroids have shown improvement for up to several months, but these are anecdotal reports.

Numerous other treatments have been tried, but data from only one controlled field study have been published. In this placebo-controlled study of 37 cats treatment with feline interferon omega showed no benefit compared to the placebo [Ritz et al, 2007]. Other drugs (table 1) have been used, but there are no controlled studies to support their efficacy.

Table 7-1. Drugs that have been suggested for use in FIP

The prognosis for cats with FIP is very poor. In one recent published study the median survival after diagnosis was 9 days. Factors that indicate a short survival time are low lymphocyte count, high bilirubin, presence of high amount of effusion. Cats that show no improvement within 3 days are unlikely to show any benefit from treatment and euthanasia should be considered.