Feline Infectious Peritonitis (FIP) is a serious viral disease that affects cats, caused by a mutation of the feline coronavirus. It primarily targets the cat's immune system and can lead to severe inflammation in various organs, particularly the abdomen and chest. Symptoms of FIP can include fever, weight loss, and fluid accumulation in the abdomen or chest. The disease is often fatal, and there is currently no definitive cure. However, early diagnosis and supportive care can help manage symptoms and improve the quality of life for affected cats.