Feline infectious peritonitis is divided into exudative and non-exudative types. The exudative type is also called the water retention type. Within seven to forty days of the onset of the disease in cats, fluid will slowly accumulate in the abdominal cavity, the abdominal circumference will continue to increase, and the abdominal wall will feel fluctuating when palpated. ​​​​​​​ In the non-exudative type, ascites and pleural effusion almost never occur, but granulomas occur in the liver, kidneys, mesenteric lymph nodes, etc.