Feline Enteric Coronavirus (FeCV)
What Causes FIP?
FIP is caused by a virus called Feline Enteric Coronavirus (FeCV), which is very common in cats and usually only causes mild diarrhea.
However, in about 5-10% of infected cats, the virus undergoes a mutation inside the cat's body and transforms into the virulent FIP virus.
Transmission: The common enteric coronavirus spreads easily through infected feces (shared litter boxes), saliva, or contaminated food bowls. However, once mutated into FIP, the dangerous form itself does not typically spread directly from cat to cat.
High-Risk Cats: Kittens and young cats under 2 years old, older cats, or cats under high stress (overcrowding, recent surgery) with weaker immune systems are most vulnerable.
Types and Symptoms
Wet (Effusive) FIP: Fluid builds up in the abdomen or chest cavity. Symptoms include a noticeably swollen/distended belly, difficulty breathing, chronic fever, lethargy, and weight loss.
Dry (Non-effusive) FIP: Little to no fluid accumulation, but inflammatory lesions develop in organs (liver, kidneys, eyes, brain). Symptoms include eye cloudiness/blindness, neurological issues (seizures, unsteadiness), along with persistent fever and weight loss.
Treatment and Prevention
While FIP was historically considered 100% fatal, modern antiviral treatments have significantly changed the outlook.
Antiviral Therapy (GS-441524 & Molnupiravir): The primary and highly successful treatment involves antiviral drugs such as GS-441524 (injections or pills) or Molnupiravir. A standard course typically lasts 84 days (12 weeks) and achieves cure rates of 80–90% when started early.
Immediate Veterinary Assessment: If FIP is suspected, a vet will perform blood tests (CBC, organ panels), imaging, or test abdominal fluid to confirm the diagnosis.
Supportive Care: Vets may prescribe anti-inflammatories, immune boosters, appetite stimulants, or perform fluid drainage if abdominal/chest fluid causes severe breathing distress.
Hygiene and Prevention: Keep litter boxes clean, disinfect them regularly, avoid housing too many cats in cramped spaces, and minimize stress for your cat.
