Feline Infectious Pertonitis or FIP in cats

it is a viral disease caused by a mutant form of corona virus ,, cause 95% mortality rate in affected cases 
can affect wild and domestic cats too , especially cats within 3 months to 3 years of age 

Symptoms :
there are two forms of the virus 
a) Dry form or non-effusive form
b) Wet form or effusive form

Dry form Signs :
non-responsive Fever
loss or lack of appetite
jaundice
lesions in the eye layers 

Wet form or effusive form :
non-responsive Fever
loss or lack of appetite
also characterized by :
accumulation of fluid in the body cavities like abdomen and chest
accumulation of fluids in abdominal cavity cause potbellied abdomen with non painful palpation , 
while it cause labored breathing when it accumulates in the chest cavity with sneezing and runny nose 

Diagnosis :
Diagnosing FIP is challenging. there is currently no test that can distinguish between the harmless intestinal coronavirus and the deadly FIP coronavirus. A positive coronavirus antibody test may support the veterinarian’s suspicions, but by itself is inconclusive. 
There are other tests that can help support a diagnosis of FIP, such as ultrasound or body fluid analysis, but no test is definitive.
Your pet’s veterinarian may take sample of fluid from abdominal or thoracic cavity for further evaluation.

How is FIP treated?

There is no effective treatment for FIP, which is fatal in more than 95 percent of cases. In mild cases of the dry form, it may be possible to prolong the survival period, but most cats with the wet form of the disease die within two months of the onset of signs. 

Preventing the disease :
The only way to protect your cat from this aggressive disease is to practice routine disinfection of your cat's living areas, food/water utensils, and cages.
It is essential to isolate new litters of kittens from other cats (not their mother) to prevent contact with this disease. 
If the mother is found to be infected, taking the kittens away will not improve their chances, since by that time they have already been exposed to the virus. Indeed, the antibodies in her milk may protect them from infection while they are still small.

References :
http://www.petmd.com/cat/conditions/infectious-parasitic/c_ct_feline_infectious_peritonitis?%24Version=0&%24Path=%2F&%24Domain=.petmd.com%2C%20%24Version%3D0

https://www.aspca.org/pet-care/cat-care/feline-infectious-peritonitis