Feline Infectious Peritonitis (FIP)

 

What is Feline Infectious Peritonitis?

 

Feline coronaviruses are found commonly in cats worldwide and are transmitted via the oral-fecal route, butthey  are not infectious to other species, including humans. The feline coronavirus usually does not cause outward signs of infection or it may only cause mild diarrhea and/or respiratory symptoms for a cat. (4)

 

Feline infectious peritonitis (FIP) is caused when either a mutation in the feline coronavirus occurs or by an abnormal immune system reaction to it. Usually a cat is experiencing some form of stress at the same time as well,  which may play a role in the feline coronavirus causing the FIP infection. (2) Stress for a cat could be caused by a number of things. Moving to a new home, being adopted, other infections occuring within the animal at the same time, elective surgeries or even small changes within a household all can cause a great deal of stress for a cat.

 

Once the virus has mutated, the body allows the normally less virulent feline coronavirus to multiply inside white blood cells (macrophages) instead of the intestine cells where it normally replicates. This results in the mutated feline coronavirus travelling in white blood cells throughout the body and spreading the virus to a much greater area within the cat. (1)

 

The cat’s immune system reacts strongly and quickly to the virus being sent around the body. As the immune system tries to kill the infected white blood cells, it causes severe damage in many areas. (4) The damage  throughout the body results in an often fatal disease known as feline infectious peritonitis.

 

Although a large number of cats may be infected with the less harmful feline coronavirus (up to 50% in a single cat household or 90% in boarding/breeding facilities), only about 5% will actually develop symptoms of FIP disease. (4)

 

Development of FIP is nearly always fatal within a few weeks. (7)

 

Who is affected?

 

Cats of all ages and either sex can develop FIP, but the disease is most frequent in cats 6 months to 2 years old.(8) Kittens are particularly vulnerable, especially those in shelters and boarding/breeding facilities. (4)

 

If kittens are raised within colonies of FIP infected cats, they may become infected with the virus from their mother or from a virus carrier (infected cats with no obvious signs of the disease). It has been suggested that this disease may be able to move across the placenta from mother to developing kitten, but how often this occurs is unknown (5). It has been suggested that this disease may be able to move across the placenta from mother to

Usually kittens become infected with the virus when the natural protection against viruses and other diseases (passive immunity) they received from their mother via nursing decreases around 5 to 10 weeks of age (2). Early weaning of kittens and removing them from a FIP infected environment, while their maternal immune protection is still intact, can help reduce transmission of the virus to the them. (3)

 

Cats living in multiple cat households are at greater risk of contracting the disease (1). Most cats become infected with the feline coronavirus through ingesting it, but transmission by inhalation is also possible. Because cats shed particles of the virus in their feces, litter box exposure and  grooming are common sources of infection. This is especially a factor if multiple cats share a common litterbox or if cats groom one another frequently.(6)