FELINE INFECTIOUS PERITONITIS - THE PURRING DISEASE

Democratic Virus - Enigmatic Disease - Titers - Breeding - Fighting Back

THE PURRING DISEASE

In most of its many forms FIP does not appear to cause more then discomfort to the cat it kills. Kittens, bellies swollen with fluid from peritonitis, are observed to purr even when dying. Since cats purr for many reasons including pain and stress management, it is incorrect to assume that cats afflicted with FIP do not suffer.

The Democratic Virus

Primarily a disease of the very young and the very old, FIP is fatal to all felidae: be they purebred, random bred or feral, be they domesticus or panthera. It evolves in the most exclusive catteries, in public shelters, in cat-friendly barnyards, in zoological parks, and in our homes - anywhere cats come together. Free-roaming, caged, immaculately maintained, abysmally kept, the vigorous, the weak, as a primary disease or opportunistic secondary infection—FIP seems indiscriminant in its targets.

An Enigmatic Disease

FIP is the result of a common and relatively benign Corona virus of the cat’s gut gone bad coupled with an overzealous immune response. The precursor virus is transmitted by exposure of cats to each other’s feces. Immunity developed to the virus is very short-lived and cats continuously infect and re-infect each other. This infection is not obvious to the observer because in most cases infection does not appear to bother the cat. Estimates of just how common Corona virus infection is vary, but probably most cats world wide have at some time been infected. However, once the virus effects entry into a group of cats, it is there to stay, replicate, mutate, and eventually to evolve into FIP.

Not much is really known for sure about FIP. Unlike Feline Leukemia which ravaged catteries, and shelters a little more then a decade ago (and for which there is an antigen test and a vaccine), there is little cat breeders can do to prevent an occurrence of FIP once the Corona virus gains entry into their facility. Efficacy of the existing vaccine and its application are still being debated. Management tools for the breeder (early weaning, isolation, and grouping) are expensive, labor intensive, and difficult to implement. Testing (titers and RT-PCR) is not a straightforward process and is fraught with misunderstanding, misinterpretation, and misapplication.

Once FIP virus gains entry through the intestinal wall, it gains a protected ride inside the cat’s white blood cells to anywhere in the cat’s body! It can infect any major organ resulting in a huge assortment of symptoms. This infection causes a complex cascade of events in which the cat’s own immune system effects the majority of tissue damage which eventually kills it. The name, feline infectious peritonitis, from which the acronym FIP is derived, is only the most obvious, and earliest documented, but not necessarily most common form, of the disease. (In fact, it is not a peritonitis at all but a vasculitis.)

Titers Are Only Virus Footprints

Titering (a test to determine presence of antibodies against the virus in the blood stream) only proves that the cat has at some time in its life been exposed to Corona virus. Any of the Coronaviridae, the entire family of viruses which infect people, wild fowl, dogs and even pigs, will produce a Corona virus titer in the cat. A titer does not mean that the virus is still present in the cat’s body, or that the virus was a benign strain or pathogenic one, or that it is currently being shed by the cat. There are almost as many different Corona titers as there are strains of virus. Titers cannot be compared between laboratories. There is wide variation in sensitivity and accuracy. Some titers look for only one strain of Corona, others target all strains. For cattery management the list recommends only a few laboratories with titers sensitive enough to detect small quantities of antibodies.

RT-PCR or “DNA” tests are currently being offered to clinicians by a few commercial laboratories to assist in diagnosing FIP. The relevance of fecal shedding as a condition of FIP disease is not proven. In addition, RT-PCR results can be corrupted by a single molecule, rendering the process prone to false negatives and false positives. Finally the procedure as offered is currently too expensive to use as a device for detection of chronic shedders. Shedding tests would have to be done monthly for up to five months to clear any cat as a potential chronic shedder—a very expensive proposition for the cattery. Unfortunately few laboratories understand the criteria and requirements for catteries trying to use RT-PCR and serum titers for accessing viral infection and clearing in their cats. Their primary focus remains that of the veterinarian—diagnosis of FIP.

But most unfortunate of all, these tests continue to carry the misnomer of “FIP titer” or “FIP test.” Many cats have been diagnosed and euthanized because a positive result on one of these was interpreted as proof of FIP, when all it meant was exposure to a Corona virus, ANY Corona virus, anywhere, anyplace, anytime. A healthy cat with a positive titer is still a healthy cat! A healthy cat shedding virus is still a healthy cat! Remember statistically only one out of ten Corona infections results in FIP.

FIP should be a diagnosis arrived at by combining clinical symptoms such as anorexia, fever, pleural or abdominal effusion, weakness in hind quarters, and uveitis with corroborative laboratory findings (of which a positive titer is only one small piece), such as Albumin-Globulin ratio, neutrophilia, non regenerative anemia, cytology and total protein of effusions, AGP levels, etc. That said, the final arbiter for FIP remains a tissue biopsy or post mortem histological examination of tissues.

A High Price for Breeding Cats

It is said that anyone who breeds cats long enough will eventually have at least one case of FIP. Occasionally occurring in pan-epidemic form, many breeders have given up in despair. Increasingly, responsible breeders have found that the possibility of FIP developing in any kitten placed in a pet home is worthy of discussion with prospective pet buyers, especially in view of the seemingly random way FIP continues to choose its victims. Offering FIP guarantees means promising to replace a kitten lost not guaranteeing the kitten will remain FIP-free. Many breeders shoulder all responsibility even though the infection may occur via other cats after the kitten has left their care. For now it is the best they can do, while back in the cattery, expensive testing and spaying and neutering of parent cats may be taking place.

But Now We’re Fighting Back

Because FIP is primarily a problem of colony cats or cats derived from colonies, and because Feline Corona Virus and FIP behave differently in the field then they do in laboratory models, many breeders are banding together through the Orion Foundation, Inc., a non profit organization, to fund research that holds out the best promise for relief. Areas of special interest include (1) The application of RT-PCR (Reverse Transcriptase -Polymerase Chain Reaction) in detection of chronic shedding cats, (2) What constitutes natural immunity to Corona virus, and (3) Support for a Second FIP World Conference.

There is no more room for secrecy, blame and suspicion. And those who know that are the breeders coming together through the Orion Foundation FIP email list to help each other deal with the emotional, financial and management uncertainties created by FIP in the cattery.