There are many diseases in cats that can be serious or potentially fatal. Most of these diseases are treatable or preventable. Rabies, for example, is a public health threat that is almost always fatal, but is also very easy to prevent with an inexpensive and safe vaccination.
But no disease has the power to make veterinarians feel as helpless as FIP, or Feline Infectious Peritonitis.
FIP is a reaction to infection with a coronavirus that causes widespread organ failure. It mostly affects cats housed in groups (such as breeding facilities or shelters), is typically spread by contact with infected feces, and usually strikes cats under one year of age. Symptoms include fever, fluid accumulation in the belly or chest, weight loss and poor appetite. FIP is 100% fatal.
The virus at the heart of FIP is called Feline Enteric Coronavirus (FCoV). This virus is extremely common and causes an intestinal infection. Many cats will display no outward symptoms, while others may show mild flu-like symptoms. In some cats, the coronovirus mutates and causes the devastating syndrome of FIP.
Coronavirus readily sticks to clothing and carpeting and can easily survive in cat litter dust. Households with 5 or more cats, or facilities where large numbers of cats are housed and allowed to mix freely are at a higher risk for coronavirus infection and subsequent development of FIP.
The mutation that causes FIP is more likely to occur in immune compromised cats. Cats under one year, with their immature immune systems, and cats from overcrowded facilities make up the majority of FIP cases.
The good news is that FIP itself is considered an infectious disease but not a contagious one.
The difference between infectious and contagious lies mostly in how the disease is spread. Contagious diseases are those that can be spread from an infected individual to another individual. The flu and the common cold are good examples of contagious human diseases, while bordetella is contagious between dogs and feline distemper is contagious between cats. An infectious disease is one that does not spread between individuals. Lyme disease, for example, is spread by the bite of a tick, but your dog cannot catch Lyme disease from another dog.
The coronavirus that causes FIP is highly contagious, but once it mutates and causes FIP, it is no longer contagious between cats. Most cats that are infected with the coronavirus will lead normal length lives. It is when this virus becomes entrenched in a breeding facility or shelter that it can be absolutely devastating.
Vaccination for FIP is difficult, because of the complexity in targeting the mutations that cause the disease. The only vaccine that exists remains controversial, with questionable effectiveness. The vaccine can only be administered to cats over four months old, at which point the damaging coronavirus has already made its insidious attack on at risk populations.
Treatment for patients suspected of having FIP is not recommended. There are no effective treatments and experimental treatments usually only prolong suffering. However, FIP and feline coronavirus are not contagious to dogs or people.