AMY'S ARTICLES-part 1 & 2 THE MANY FACES OF FIP

"Johnny was born the first part of November in 1998," says Christie Meyer, a behavior consultant and dog trainer in Fowlerville, Michigan. She'd volunteered to foster kittens and hand-raised the three littermates for the local humane society.

To protect her other pets she kept the kittens isolated from her adult white cat, Commit, until the babies tested negative for the most common killer cat diseases, feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV). After this health clearance, the litter mingled freely with the rest of Meyer's furry crew.

Meyer quickly fell in love with the smallest orange boy she named Johnny. Johnny purred all the time, and when he didn't sleep on Meyer's neck, he curled up with the dogs. "Both dogs rolled onto their backs and the kittens would curl up between their legs on their belly," she says.

While his two littermates appeared normal and eventually found new homes, Johnny never weighed more than a pound and a half. He began to run an intermittent fever, and when he also developed eye problems by the end of January, Meyer had little Johnny evaluated by the veterinarian where she worked.

The doctor suspected Johnny the kitten had a deadly form of a common coronavirus. He was barely three months old.

DEFINING THE DISEASE

Feline Infectious Peritonitis (FIP) kills cats of all species, from house pets to cheetahs. It mostly affects young (under age 1) or very old domestic cats and experts estimate that up to 90 percent of pet cats are exposed to coronavirus during their lives.

Most commonly, cats catch coronavirus from contact with the infected stool from another cat. They may not get sick at all, or suffer only short-term diarrhea, then develop immunity, and recover. Immunity doesn't last very long, though, and cats continuously infect and re-infect each other particularly in multiple cat environments. For that reason, cats from shelters, catteries, feral colonies and the like are at highest risk.

According to FIP researcher Dr. Diane Addie, a senior lecturer in Veterinary Virology at the University of Glasgow, Scotland, about 10 percent of kittens and cats infected with coronavirus ultimately come down with FIP.

Cats almost never get FIP from another FIP-infected cat. Instead, the harmless form of a coronavirus--the "good twin"--mutates into the "evil twin," the FIP form. While it sounds like bad science fiction, each FIP virus is unique to individual cats.

FIP virus targets and makes its home inside macrophages, specialized cells of the immune system. Once FIP virus passes through the intestinal wall into the bloodstream, these infected white blood cells turn into virus factories and carry their lethal cargo everywhere. That results in the cat's body attacking its own infected cells and tissues. A variety of symptoms develop, depending on which organ(s) become infected.

The effusive or "wet" form of FIP causes leakage of fluid into the abdomen so affected cats look like they have a beer belly. The "dry" form of the disease offers no specific outward sign. In either form of the disease, owners report the cats just don't "act right."

Not all cats develop every symptom but some of the more common ones include a fever that comes and goes; swollen belly and/or trouble breathing (wet FIP); loss of appetite; weight loss; eye problems (color changes, cloudiness, or spots); depression or loss of energy; seizures or balance problems. FIP has been called the purring disease, because these kitties seem to crave more attention and purr more--perhaps to help themselves feel better.

FIP frustrates and scares veterinarians and cat lovers alike because it not only kills cats--there's no easy way to diagnose the disease. The tests offered by some commercial laboratories are confusing at best and at times could be considered criminally misleading.

TESTS GONE WRONG

Back in January 1999, Meyer's veterinarian relied on a commercial blood test from Antech Diagnostics which claimed to be able to tell the difference between the "evil twin" FIP-virus and the innocuous coronavirus. She was relieved when Johnny tested negative not once, but twice.

So Meyer and her veterinarian looked for other causes for the kitten's illness. After describing Johnny's symptoms to specialists at Michigan State they decided to treat him for toxoplasmosis caused by a parasitic protozoan. Johnny's eye infection and transient fever were treated, but never went away. "He ate like a maniac, but never gained, and never really acted sick," says Meyer. "Johnny was always happy, he was always social, and he always purred and interacted with me and the dogs."

But by early February, Johnny's appetite waned and he declined despite further treatment. The little orange boy died on Valentine's Day, before Meyer could keep the euthanasia appointment she'd made.

"I would have euthanized him at six weeks if he was a sick cat, but he never was," she says. After Johnny's death, the University of North Carolina conducted extensive tests and confirmed he died from FIP. "We never had a definitive diagnosis until he died. It was good to finally know," says Meyer.

Meyer has since learned that there is no test available to prove your cat has FIP--or that he doesn't have the disease. In fact, an even more devastating and heart-breaking scenario has played out over the years when cats determined to be "positive" with so-called definitive FIP-tests are euthanized--and yet are perfectly healthy.

BUILDING A DIAGNOSTIC WALL

Niels Pedersen, DVM, Ph.D., of the University of California-Davis, is an expert on viral diseases and developed a blood test for antibodies to the enteric corona virus more than two decades ago. He hates the fact that this test has ended up killing healthy cats. "The test is only one tool, but should not be used as a primary means of diagnosis," says Dr. Pedersen.

The confusion arises because common tests measure the "titer" (levels of immune components) in the cat's bloodstream. A cat exposed to and infected with a coronavirus--and there are several kinds--may test positive for the "good twin."

But a positive titer simply means exposure took place and the virus left a fingerprint (antibody) behind. "You don't get FIP unless you have antibody," says Susan Little, DVM, a feline specialist practicing in Ottawa, Canada, and vice president of the WINN Feline Foundation. However, the presence of antibodies alone does not mean your cat has FIP, nor does it predict a cat will get sick.

To complicate matters further, different labs offer variable interpretations of what constitutes a "negative" or "positive" corona titer level. Your kitty may test positive from one lab, and negative from another using the same sample. False positives and false negatives can result from contamination, too.

So what can be done? "Build a diagnostic wall," says Melissa Kennedy, DVM, PhD, an assistant professor and board-certified veterinary microbiologist at the University of Tennessee.

While a single test or symptom may mean nothing by itself, taken together--brick by brick--they can build a strong presumptive diagnosis, sort of a smoking gun that points to the disease. "If everything else looks like FIP and the serology [tests] doesn't, then ignore the serology," says Dr. Kennedy.

The feline coronavirus (good twin) can be detected by a variety of tests that evaluate blood values, detect antibodies to the virus, or find the virus itself in the cat's plasma, whole blood, sometimes the feces, or even the straw-colored fluid commonly found in wet FIP. In addition, blood changes typical of FIP infection such as anemia and elevated protein levels can be strong evidence.

But the only definitive test for FIP must be performed on tissue samples usually only available after the cat has died. In rare cases these samples can be obtained while the cat's alive. That involves ultrasound-guided "true cut" biopsies of the typical FIP lesions on a living cat, but only when the feline remains healthy enough to withstand the anesthetic procedure.

Dr. Pederson and others believe environmental influences and genetics share equal blame for the disease. Eliminating the virus from the environment may be next to impossible--you'll learn more about that in the next article. But researchers suspect some cats inherit a susceptibility to FIP that allows mutation to take place, while others inherit resistance.

The notion is supported by an interesting mouse study that showed when a particular gene (interferon-gama) was absent or deficient, the mice developed peritonitis that paralleled FIP. Researchers now investigate to see if FIP-resistance might be linked to interferon-gama response, or to some other mechanism. UC-Davis seeks to develop a genetic test to help identify those cats that are more or less likely to develop FIP.

"You can genetically define cats that are resistant or susceptible," says Dr. Pederson. Why is that important? If susceptibility and resistance can be predicted, responsible cat fanciers may be able breed FIP-resistant kittens and perhaps ultimately reduce incidence of this deadly disease. "We're still five years away, but we do it in other species," says Dr. Pedersen. "We'll do it in cats."

Part 2

Feline Infectious Peritonitis (FIP) arises from infection with a normally harmless coronavirus (good twin) that mutates inside a cat's body into the deadly form (evil twin). This Jekyll and Hyde disease has so many vague symptoms that mimic other illnesses it could be called the "great pretender."

For instance, a swollen abdomen filled with straw-colored fluid typical of wet FIP may instead be a treatable liver disease. Dr. Little says in addition to liver disease, lymphoma, FIV, and toxoplasmosis often are mis-diagnosed as FIP.

Many cats develop wet signs that go away as the body resists the infection, and progress into dry FIP that takes even longer to resolve. But ultimately, "FIP takes apart the immunity," says Dr. Pedersen, and cats may later have wet signs return. The vague symptoms in combination with nonspecific tests make diagnosis almost impossible.

"This is a disease with a dismal prognosis," says Dr. Little. No effective treatment has been identified, but treatment won't hurt and could actually help the cat feel better for as long as possible.

Offering treatment depends on the individual cat, your expectations and resources, and your veterinarian's experience and expertise. Decide with your veterinarian at what point treatment should stop. Monitor results so that your cat continues to enjoy a good quality of life.

KEEPING KITTY COMFORTABLE

Cats with wet FIP rapidly get very sick and die or are humanely euthanized. Fluid buildup makes breathing difficult, so draining the effusion keeps your cat more comfortable until further decisions can be made about his care. "You've got nothing to loose," says Danielle A. Gunn-Moore, BSc, PHD, a specialist in feline medicine and head of the feline clinic at the University of Edinburgh, in England. "Once you've drained them they may feel quite well for a time."

Palliative treatment also gives you the time to make life-and-death decisions for your cat. Such choices aren't as hurried in dry FIP, since these cats may linger for several months. Treatment helps keep kitties comfortable until they can no longer be helped.

Standard FIP therapy suppresses the immune response usually with prednisolone, says Dr. Little. Steroids also stimulate the appetite to keep sick cats eating. Dr. Little also cites chlorambucil, a cancer drug that helps suppress the immune system. While some practitioners include an oral low dose of human interferon in the treatment plan, Dr. Little says it won't hurt but probably doesn't help much, either.

A calorie-dense diet helps the cats that don't want to eat very much. Helpful vitamin and antioxidant supplements include vitamin A, thiamine, vitamin B complex, vitamin C and E. "I think lots of cuddles really give them the best quality of life," says Dr. Gunn-Moore.

PROTECTING YOUR OTHER CATS

Because Meyer didn't know that her kitten Johnny had FIP until after his death, she hadn't kept him separated from her other cat. "I tested my other cat Commit, and found out he was positive," she says. Meyer called the test company and according to their guidelines, Commit's results indicated he would show symptoms and die within six months.

Meyer was devastated--she'd lost one loving kitten and now learned Johnny had also signed Commit's death warrant. "So I had a nervous breakdown," says Meyer. Had she followed the recommended protocol, Commit would have been euthanized.

But Meyer couldn't bear to lose another cat friend, and instead opted to wait and see. She watched for symptoms, and worried . . .

When other cats live in the same house with an FIP cat, they've already been exposed to the "good twin." You can't control or predict which cats are resistant or susceptible. Isolation of the sick cat only increases his stress level, which can speed the progress of the disease. Today, the experts agree it's not necessary to separate your sick cat from his kitty buddies.

EXPERIMENTAL HOPE?

This frustrating disease has prompted some researchers to push the treatment envelope by using "off-label" (non-approved) therapies alone or in combination. For instance, Dr. Addie theorizes that the drug thalidomide reduces both the inflammatory and immune response of the disease while leaving the beneficial cell mediated (anti-viral) response intact. So far, only a small number of FIP cats have been treated with this drug and while it appeared to prompt a remission in one, all the kitties subsequently died anyway.

You'll find boasts of FIP cures on the Internet, but take these with a large grain of salt. The experts believe these cats likely recovered from one of the many look-alike conditions and never had FIP.

Some experimental treatments seem to offer more hope than others. Treatment with the Aventis drug Trental (pentoxifylline), an immune modulating drug, needs to go through clinical trials but is used to treat FIP cats, usually as early as possible in conjunction with prednisone. Anecdotal reports so far note no side effects.

Virbagen Omega (made by Virbac) is recombinant feline interferon omega (IFN omega) first used in the treatment of FIP by Japanese veterinarian and scientist Takuo Ishida. Other researchers haven't been able to reproduce Dr. Ishida's success rate, although some results prove promising. While feline interferon should be investigated further, it's not currently available in either the U.S. or Canada and remains prohibitively expensive.

Using Dr. Ishida's protocol, Dr. Addie and Dr. Gunn-Moore achieved 12 to 18-month remissions in some FIP cats. "Success is very much anecdotal because until the cats die we haven't necessarily got a diagnosis," says Dr. Gunn-Moore. "We do need scientific trials, but we need to build up anecdotal evidence to know what questions to ask." She says the feline interferon is given as injections by the owner at home similarly to administering insulin to a diabetic cat. That reduces the cat's stress of running back and forth to the clinic.

IS PREVENTION POSSIBLE?

Vaccines work by stimulating the body's natural immunity. "No vaccine can induce better immunity than a natural infection," says Dr. Pedersen, but there is no significant natural immunity to FIP. In fact, a strong antibody response makes FIP worse. "I can't imagine any vaccine able to provide protection given what we know," says Dr. Pedersen.

What about the commercial FIP vaccine? According to Dr. Pedersen and other experts, no concrete independent studies have shown this vaccine induces any significant protection against FIP. The vaccine can't be given until kittens reach 16 weeks of age--and that's much too late to help. By that time, susceptible kittens have already been exposed, infected, and their bodies may already have transformed coronavirus into the deadly evil twin version. Mutations happen more readily in quickly multiplying cells, so growing kittens are the most common victims.

So why not get rid of the "good twin" by eliminating coronavirus altogether? Dr. Pedersen says researchers in Holland and Japan are working on that very problem, and trying to develop a vaccine that protects against enteric coronavirus.

MANAGING RISK

"You can't be coy," says Dr. Gunn-Moore. "You have to think about poop to control this virus. Kitten poop is more important than cat poop." Eliminating coronavirus from the environment isn't easy because infected cats constantly shed coronavirus into the litter box and re-infect each other. Different strains of the virus are worse than others, though, and dose of the virus--how much is there and ongoing exposure--has a great impact.

Hygiene is key. The virus stays viable for up to two months if not killed, but it can be easily destroyed with plain soap and water. Use a non-tracking litter to help control the spread of the virus, scoop daily and clean boxes weekly. Stress increases viral shedding, so reduce stress and improve hygiene by providing enough litter boxes for all the cats--one box per cat, plus one. Locate them away from food sources to reduce the chance of oral contamination.

Eighty to ninety percent of cats in the multicat households are coronavirus positive. Living with other cats also increases feline stress levels. Dr. Gunn-Moore says to reduce the dose of the virus and risk factors by decreasing the number of cats to ten or fewer. That doesn't mean getting rid of the cats you love. Instead, you can reduce risk by dividing up your cats into stable groups of two to four cats each.

Use protective clothing including shoe covers to keep from transmitting the virus from group to group, especially in households where FIP has occurred or when dealing with kittens. Ideally, shelters should house cats singly, and not co-mingle cats, says Dr. Gunn-Moore. Most closed households with less than ten cats eventually spontaneously eliminate coronavirus from the environment.

Even the most fastidious and caring cat owners, shelters, and breeders lose cherished cats to this disease. If you do lose a cat to the heartbreak of FIP, you can still safely adopt another furry wonder after you've thoroughly cleaned the house. Waiting about three months ensures the coronavirus is dead in the environment.

Surviving cat buddies don't necessarily become ill, either. Today at age nine, Meyer's cat Commit still tests positive for coronavirus (not FIP, she now understands!) and remains a healthy, active cat. While poor little Johnny was susceptible, Commit is resistant to FIP.

Meyer no longer fosters kittens from the shelter, though. She doesn't want to risk further exposing her cats or other susceptible felines to the potential for disease. "Nobody knows how each cat will react," she says. "That's what's scary."

On Friday, November 19, 2005 at the CWA Annual Conference, Dr. Susan Little (president of the Winn Feline Foundation) announced the launch of Winn's Bria Fund for FIP Research sponsored by Susan Ginrich and the Center of Health Transformation, in memory of her special cat Bria. Those interested in donating should contact the Winn Feline Foundation at www.winnfelinehealth.org.

AMY'S ARTICLES-part 1 & 2 THE MANY FACES OF FIP

Tuesday, July 31, 2007