FIP Genetic Study

Information for Breeders

A new research project is being launched by the UC Davis School of Veterinary Medicine to discover the genetic causes of feline infectious peritonitis (FIP). Burmese and Birman breeders are strongly encouraged to participate, however, all cats and breeds are welcome. For more information please contact: Subject Line: Sock FIP

FIP – the disease

Feline infectious peritonitis (FIP) is the most important infectious cause of death among cats between 3 months and 3-5 years of age. Once FIP becomes clinically manifested, it is inevitably fatal. FIP is particularly devastating in cats from shelter and pure breed cattery environments. The infection in shelters is greatly enhanced by environmental factors, such as overcrowding and inappropriate sanitation. FIP is caused by genetic mutations within feline enteric coronavirus (FECV).

FIP – the genetics

FIP among cattery-reared cats is also influenced by some of the same environmental factors as found in shelters, but about 50% or more of the incidence appears to be genetically related. The disease occurs in all breeds, but is particularly prevalent within certain bloodlines within breeds. Breeder’s have become well acquainted with the strong tendency of FIP cats to occur among closely related cats and to be closely associated with certain matings. Toms have been particularly implicated in passing on this genetic predisposition, because they contribute more greatly to breed genetics by producing more litters and more offspring than females. However, the disease and its susceptibility is not sex-linked, and queens also affect predisposition.

FIP – the study

The nature of the genetic resistance and susceptibility to FIP is not known. Although FIP susceptibility could be due to a single gene effect, susceptibility and resistance to FIP is more likely associated with defects in several genes (i.e., a complex genetic trait). We feel that the time is both here and right to undertake whole genome scanning on cats to identify potential genetic markers that influence a significant proportion of cats dying of FIP. The technology exists or will shortly exist to do such a study, but it will require DNA samples from cats that appear to be either inordinately resistant or susceptible to FIP.

Who can participate?

We have chosen the Burmese and Birman breeds to study FIP heritability factors. However, we welcome DNA samples from any cats associated with FIP, pure or random bred. The Burmese and Birman populations are sufficiently large, some bloodlines within these breeds have been strongly associated with FIP, and Burmese and Birman breeders have proven to work well with institutions, groups, and individuals to research other genetic traits. We are asking all Burmese and Birman breeders to participate, but especially those that have bloodlines that they know to be either seemingly resistant or susceptible to FIP. Comparing two closely related but distinct breeds will also add power to the research study. The genes that are responsible for FIP in one breed are undoubtedly the same as the genes involved in FIP in the other.

What is required to participate?

A genetic association study will be performed that requires DNA samples from cases and controls. Cases are cats that have FIP! We must collect DNA from from all Burmese and Birmans dying of the disease. Controls are cats without FIP that have a similar genetic make-up and environment as cats with FIP. Good controls for each FIP case would be unaffected siblings and parents. When possible, we would like at least one control for FIP cases, preferably both parents and a sibling, but will accept cases with no controls. We also want samples from healthy cats who are five years and older who have no known history of FIP in their lines. DNA can either be collected as FIP cases appear, with the hope of getting the right controls, or DNA can be banked on all cats before FIP is apparent. Then, if a cat develops FIP, the opportunity to obtain DNA from the cases and the appropriate controls is not lost.

How do I submit samples?

DNA samples are easily obtained from cheek swabs using commonly obtained cotton swabs, such as Q-tips (instructions here). The swabs are mailed along with information on the particular cat, disease status of siblings, half-siblings parents, grandparents, etc., and pedigree information. The FIP status must be accurate!

FIP – the diagnosis

Collection of accurate information will require time and expenses. The diagnosis of FIP must be accurate, and this may require veterinary visits, testing, and even necropsies. Histories that include breed, gender, age and clinical signs are very important, as are data from complete blood counts, globulin levels, blood chemistry panels, coronavirus antibody titers, abdominal and chest fluid analyses, and serum protein electrophoreses (on cats with high protein). Fortunately, we can help interpret histories and test results when necessary, instructing your veterinarian on how to do a fast necropsy and on how to send appropriate tissues for confirmatory testing (at no cost to the veterinarians or the breeders). We will also examine necropsy reports made by your veterinarian or a veterinary pathologist, and if distance permits, to see cats at UCDavis. Different genetic factors may control wet versus dry FIP; thus, we must also know the form.


FIP carries a stigma for many breeders and therefore animals and samples will be given new codes and privacy and secrecy maintained. However, the obtaining of samples will require cooperation between breeders and even between breeders and owners that have acquired cats as pets. Many participants will have to do some sleuthing, make contacts from the past, and arrange or instruct on how samples may be collected and submitted. This will be a great scientific adventure with great potential pay-off.

What is the pay-off?

The goal is to identify cats that possess either genetic resistance or susceptibility markers for FIP, so that FIP can be more readily managed and perhaps will no longer be the major infectious cause of death of our younger cats. Breeders have reached similar goals for a number of genetic diseases, such as progressive retinal atrophies, hypertrophic cardiomyopathies, and polycystic kidney disease. Please join us in this latest endeavor to assure the health of our cats through genetic knowledge and application.

If you would like more information about SOCK FIP, or to join the fight, please go to our Contact Us page.

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SOCK FIP can now receive donations through PayPal. All donations to SOCK FIP will support FIP Research at UC Davis