Most infections are either asymptomatic or cause diarrhea, especially in kittens, as maternally derived antibody wanes at between 5 and 7 weeks of age.

There is a general consensus that FIPVs arise from mutations enabling them to enter or replicate more successfully in monocytes (a type of white blood cell).

[9] FCoV is common in places where large groups of cats are housed together indoors (such as breeding catteries, animal shelters, etc.).

The most common form of spreading is through saliva, as most multiple cat homes share food and water dishes.

[citation needed] The hallmark clinical sign of effusive FIP is the accumulation of fluid within the abdomen or chest, which can cause breathing difficulties.

[citation needed] Dry FIP will also present with lack of appetite, fever, jaundice, diarrhea, and weight loss, but there will not be an accumulation of fluid.

[citation needed] Diagnosis of the effusive form of the disease has become more straightforward in recent years.

Because FIP is an immune-mediated disease, treatment falls into two categories: direct action against the virus itself and modulation of the immune response.

Antivirals (in the narrow sense) act by interfering with the enzymes or other biological processes in the FIP virus.

In several countries oral GS-441524 tablets (and its injectable prodrug remdesivir) became legally available to vets for the treatment of FIP in cats, for example in Australia,[22] the Netherlands,[23][a] and the United Kingdom (since August 2021).

DNA vaccination with plasmids encoding FIPV proteins failed to produce immunity.

A 2018 film titled Aeris, by Paul Castro Jr. and Aly Miller, and starring Frank Deal, Arabella Oz and Betsy Aidem, is about a kitten born with FIP that is purchased from a pet store and the owners' twelve days with it.