Mutation of Feline Infectious Peritonitis In Adult Cats Your cat can be infected with Peritonitis without any symptoms

Mutation of Feline Infectious Peritonitis In Adult Cats

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Feline infectious peritonitis is a severe and often fatal disease that is caused by a mutated form of the common feline coronavirus (FCoV). The FCoV does not cause clinical signs of illness in most cats.

Feline infectious peritonitis (FIP) is a viral disease that can affect any cat, but it most often affects young cats between 3 months and 18 months old. It's caused by a coronavirus found in the intestinal tract of infected cats. Each time the virus replicates, it undergoes mutations that cause changes in its genetic structure; these mutations lead to different strains of FIP. 

Inflammation In The Lungs And Abdomen

FIP is a coronavirus that causes severe lung and abdomen inflammation and can be fatal. Older cats are less likely to get the disease, but there have been exceptions to this rule. There have been cases where older cats have tested positive for coronavirus-associated disease (CAVD), which may or may not be related to FIP. It's possible that they had something similar to FIP, such as CAVD, with no genetic mutations associated with FIP (FIA). 

It Tends To Occur In Young Cats

The disease tends to occur in young cats more susceptible to viral infections. While older cats are not necessarily immune to coronavirus infections, they're much less likely to develop FIP. Older cats also have a higher mortality rate if contracting the disease.

To study clinical and laboratory features of the virus and develop viable treatments, clinical records of 127 cats highly suspected of FIP were studied. It was found that age and neutering status was correlated with the virus, but sex, breed, and onset month were not. 

Mutation Into New Forms

In research, it was found that many of the feline infectious peritonitis (FIP) cases were caused by a type of coronavirus called FIPV-2c, which had previously been seen only in young cats with no past exposure to coronaviruses. This suggests that the virus mutated into its current form after it infected kittens whose immune systems had not yet matured enough to fight off infection. 

Reaction Of Cat’s Immune System To The Virus

If a cat is infected with FIP, her immune system mistakenly perceives the coronavirus as a foreign invader. The immune system will create antibodies to fight off this invader, but unfortunately, it's not just the coronavirus that gets attacked; it's also some of your cat's own tissue. Antibodies attack cells in the blood vessels and elsewhere in the body because they're confused by what they think is an enemy. 

Changing The Structure Of The Gp3 Protein

A group of researchers studied cats that had tested positive for FIP and found that some amino acids in another protein, known as GP3, of this particular strain had mutated, changing the structure of the GP3 protein. It was also found that some cats with FIP had antibodies to GP3 but not to other parts of the virus. This suggests that there are different strains of feline infectious peritonitis virus. 

Unclear Why FIP Mutation Associated With Older Cats

It is unclear why this FIP mutation is associated with older cats. Therefore, researchers are investigating further. They do know how the mutation could be linked to an older cat's immune system, diet, lifestyle, or location, which may affect its exposure to other viruses. 

Symptoms Of FIP

Generally, the virus is asymptomatic with no signs, but the most common signs of the infection are similar to those of other forms of FCoV, just more severe. In fact, it is estimated that around chance of the virus is around 25% in single-cat households and as high as 75–90% in group-housed cats without any symptoms.

Symptoms include fever, lethargy, vomiting or diarrhea, weight loss, dehydration, poor appetite, and coughs/difficulty breathing due to fluid build-up in the lungs or chest cavity. However, the virus is generally fatal; the vet may prescribe some pet medications to relieve the cat from symptoms. Antibiotics for cats like Amoxicillin for cats or Cefpodoxime Proxetil are generally the best options to treat the virus. 

Types of FIP

There are two different forms of feline infectious peritonitis:

Wet FIP is the most common form and occurs when a mutated strain of the FCoV infects a cat's blood cells. As this mutation progresses, it causes severe damage to the body's organs, especially those in the gastrointestinal tract.

Dry FIP is less common than wet but still accounts for about half of all cases in domestic cats; in this form, there isn't any obvious evidence on an X-ray or other imaging test that suggests organ failure has occurred. 

Treatment Of FIP Syndrome

In a study of a 7-months-old male domestic shorthair cat, it was found that there is no specific treatment for FIP since the disease is usually fatal in cats, and only supportive treatment can be provided. However, you can do the following to help

  • If your cat has been diagnosed with FIP, you should keep him indoors and away from other cats to avoid spreading the infection.

  • If he must go outside, ensure he is strictly supervised and never allowed to roam or play on his own. If possible, keep him on a cat harness and leash so he cannot access other cats.

  • If you have multiple cats in the house, keep them in separate rooms and use different cat feeders, cat litter boxes, water bowls, and scratching posts for them.

  • With multiple cats in the home, you can use a Feliway diffuse to reduce conflict between them.

  • The bacteria can also be spread between cats through direct contact with their blood and bodily fluids such as saliva or urine. Therefore, bathe your cat regularly with cat shampoo to keep him clean.

  • Also, maintain a healthy diet for the cat to ensure he does not get any weakness due to virus-like vomiting and diarrhea symptoms. You can choose packed food like Royal Canin cat food to ensure a healthy diet.

  • If your fur baby feels depressed because of the isolation, you can opt for interactive cat toys to keep him entertained.


The virus that causes FIP is a coronavirus, which is found in many animals and can be transmitted from one animal to another. Researchers aren’t sure how the older cats were exposed to the virus. Still, they did find that all of them had antibodies against the strain of coronavirus that causes feline infectious peritonitis (FIP). This suggests they were previously infected with a different strain of coronavirus before getting sick with FIP.

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