What is Feline Infectious Peritonitis?
Feline Infectious peritonitis (FIP) is one of the deadly viral diseases that can infect the cat population. It is caused by feline coronavirus. Although less than 1% of the cat population is affected by the FIP virus, the disease is fatal in almost 100% of cases.
How is FIP transmitted amongst cats?
The virus is transmitted via the fecal-oral route. In infected cats, the virus replicates in the intestines and is passed in the feces into the environment. Cats that are in close contact with an infected cat can become infected by ingesting the virus when grooming or eating. The coronavirus then replicates in the upper respiratory tract of newly infected cats before being spread throughout the body. One of the commonest scenarios is an infected (but asymptomatic) queen passing on the disease to her kittens.
Not all cats that are exposed to feline coronavirus go on to develop full-blown signs of FIP. In fact a large proportion of the cat population has antibodies to the disease, indicating that at some point in their life they were exposed to the virus. Cats with transient infections may show no signs of illness or only mild signs, such as diarrhea.
What are the risk factors associated with FIP?
There are several risk factors that contribute to the likelihood of developing a severe case of feline infectious peritonitis:
• Age: cats under two years and geriatric cats are most susceptible to disease
• Multi-cat households/catteries: there tends to be a much higher prevalence of disease in facilities with multiple cats
• Stress: stressed animals have a weaker immune response to disease
• FeLV/FIV infection: cats with Feline Leukemia Virus (FeLV) or Feline Immunodeficiency Virus (FIV) have debilitated immune systems
• Genetics: some breeds have been suggested to be prone to developing clinical signs of FIP (e.g. Persian, Burmese, Birman)
• Strain of virus: some strains of coronavirus are more virulent than others
What are the symptoms of cats infected with FIP?
Cats that develop the generalized (usually fatal) form of FIP show a wide range of signs, depending on the virulence of the strain, their immune response, and the organs that are infected. There are two recognized forms of FIP: the wet or effusive form, and the dry or non-effusive form. The effusive/wet form is characterized by accumulation of fluid in the body cavities, whereas the dry form causes focal lesions to develop in the peritoneum and on various organs (e.g. kidneys, liver, pancreas, lungs, etc.).
The onset of feline infectious peritonitis is typically gradual and insidious. Initially owners may notice non-specific signs of illness such as:
• Loss of appetite
• Weight loss
• Persistent fever
• Depression
• Steady increase in the size of the abdomen – “potbellied” appearance
• Dull or rough hair coat
• Stunting in kittens
• Vomiting or diarrhea
Any of the clinical signs listed above is reason enough to take your cat to the vet. If you suspect your cat is ill, never hesitate to consult a veterinarian.
How does the veterinarian diagnose cases of FIP?
While wet FIP can be relatively easy to diagnose, it can be quite difficult to definitively diagnose cases of dry FIP. The vet will require a detailed history of your cat’s illness, and will also perform a full physical exam. The physical exam often turns up findings such fluid or masses in the abdomen, ocular disease, jaundice, and neurological signs. Blood samples are required for hematology, blood chemistry, and serology.
There are a number of serological tests (e.g. ELISA, IFA) that look for antibodies against feline coronavirus – none are considered 100% reliable. A positive test only indicates that there has been previous exposure to the virus. A healthy cat should never be euthanized solely on the basis of a positive serology test. Negative serology results can rule out dry FIP, but not wet FIP. Further tests such as collection of abdominal fluid, x-rays, ultrasound, or microscopic examination of tissues are often indicated to gain a conclusive diagnosis.
Can FIP be treated?
Unfortunately, no treatment has been shown to be routinely effective in treating cats with FIP. Most cats are usually treated with high doses of steroids (e.g. prednisolone), antiviral drugs (e.g. interferon), and supportive therapy. Once the clinical signs of FIP appear, though, the disease is generally regarded to be incurable and fatal. Many vets will advocate euthanasia once an accurate diagnosis has been made.
How can I prevent my cat from becoming infected with FIP?
Because of the high prevalence of the virus in the cat population, control of FIP is difficult. Although an intranasal vaccine for FIP is available, it has low efficacy and thus will not fully protect against infection with FIP. Furthermore, vaccinated cats may test positive for FIP antibodies, which complicates monitoring of disease. The FIP vaccine should only be used as an adjunct to other control measures.
If a case of FIP has been confirmed in a household, the following steps should be taken to prevent further spread of the disease:
1. Hygiene: Bleach is an effective disinfectant for coronavirus. Disinfect the premises, cages, water and food dishes, etc. Litter boxes should be emptied daily and disinfected weekly with bleach.
2. Litter boxes should not be kept near food/water dishes so as to prevent cross-contamination.
3. Minimize stress: as stress is considered a risk factor, stressful situations such as fighting or overcrowding should be minimized.
4. Cats with concurrent disease such as FIV or FeLV should be separated as they are particularly susceptible to infection.
5. Infected cats should be isolated from healthy cats.
6. Cats should not be moved in or out of the premises for at least 6 months
7. Breeding should suspended for at least 6 months
8. Kittens with FIP-positive mothers should be weaned early (at about 5-6 weeks) and later tested for disease at around 10-12 weeks of age
9. All new cats should test negative for coronavirus before being introduced into a household
If you are concerned about the spread of FIP in your household, ask your veterinarian about developing an effective control program.
(photo: westerndave)