If your kitten is warm with a fever and isn't moving around much, then it's possible he has feline infectious peritonitis (FIP). Lots of viruses and bacteria can cause these symptoms, though, so your vet will look for other signs before diagnosing your pet.
Feline Coronavirus and FIP
A group of viruses collectively called coronaviruses are responsible for FIP. These little pathogens are actually really common. Many cats carry or have carried them, but most never develop FIP or display any symptoms of sickness at all. Only about 5 to 10 percent of cats with coronavirus develop FIP, according to Cornell University College of Veterinary Medicine. Coronavirus turns into FIP only when it can hijack your kitty's white blood cells, which tends to occur in kittens and adult cats with a weak immune system.
Many kittens and cats with FIP display only "dry" symptoms, meaning there's no runny nose or sneezing. The most common dry symptoms are a fever, lack of appetite and apparent depression. Low concentrations of nutrients in your kitty's bloodstream and the ongoing immune system response to the viral invaders makes your kitten really tired, so he probably won't feel like moving around much. The fever from FIP fluctuates and does not respond to antibiotic treatments, although your vet may still prescribe antibiotics to fight secondary infections, according to Purdue University Indiana Animal Disease Diagnostic Laboratory.
The effusive or "wet" symptoms of FIP are much more pronounced than the dry ones. Kittens showing signs of wet FIP may still have a fever or show other signs of dry FIP in addition to wet symptoms. Leaking eyes and a runny nose are common visible symptoms of wet FIP. The disease causes fluid to build up in your cat's abdomen, which makes his belly noticeably bloated, according to the Stanford Cat Network. Your kitten may also wheeze or have trouble getting air into his lungs.
Diagnosis and Treatment
FIP is tough to diagnose, because testing for the virus only reveals if your cat has been exposed to a coronavirus. Even if he does test positive for this pathogen, it doesn't mean that FIP is causing his current symptoms. Sadly, there's not much you can do to treat your cat if he does have FIP, although some kitties manage to push the disease into remission and live for months or years with few problems. Your cat doesn't have to suffer during the course of the disease; supportive care can keep your cat happy and comfortable during the ordeal. Veterinary medical researchers are also actively pursuing promising treatment options that may put an end to the deadliness of this disease in the future.
Quentin Coleman has written for various publications, including All Pet News and Safe to Work Australia. He spent more tan 10 years nursing kittens, treating sick animals and domesticating semi-feral cats for a local animal shelter. He graduated from the University of Delaware with a bachelor's degree in journalism.