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Feline Coronavirus/ FIP

Feline coronavirus (FCoV) is a highly contagious intestinal infection that causes few problems in most infected cats.  In some cats, however, the intestinal form of the virus mutates and gives rise to feline infectious peritonitis (FIP), a disease that is fatal.  Two forms of FIP may occur, wet (or effusive) and dry (or non effusive).


Enteric FCoV is highly contagious via faecal-oral transmission, which means that the virus is swallowed in contaminated materials.  Most infected cats will intermittently shed the virus.  Eventually most cats stop shedding the virus, although persistent shedding occurs in some.  Interestingly, lifelong shedders do not usually develop FIP, and the FIP virus is rarely shed in faeces.

Clinical Signs

Enteric FCoV may cause no signs or only mild diarrhoea.

FIP usually affects cats younger than 2 years of age and also elderly cats.  Signs of the wet form of FIP include fever, pale gums (anaemia), jaundice (yellow discolouration of the skin and whites of the eyes), difficulty breathing, and a distended abdomen.  With the dry form of FIP, signs reflect the organ system that is affected.  Neurologic signs (such as seizures), eye inflammation (uveitis), and difficulty breathing may be seen.  Fever and weight loss are also common with the dry form.

Diagnostic Tests

There is no single, definitive laboratory test for FIP.  As a result, a number of tests are commonly performed to look for evidence of the disease.  Abnormalities may include the following:

-        A complete blood count may show anaemia.

-        A blood biochemistry profile may show increased blood proteins, as well as signs of abnormal liver and kidney biochemistry. 

-        Radiographs may show fluid in the chest or abdomen, especially with the wet form of FIP.  Radiographs and an abdominal ultrasound may show other abnormalities in the lungs and abdominal organs.

-        Protein analysis of fluid removed from the chest or abdomen can support the diagnosis of FIP.

-        Further tests (faecal examination, urinalysis, others) may be recommended to rule out other diseases that cause similar signs.

Tests for antibodies in the blood can indicate exposure to FCoV, but they are not diagnostic of FIP because they do not distinguish enteric FCoV from FIP.  Antibody titres also do not indicate whether faecal shedding of the virus is present. 

Histopathologic evaluation of tissue samples is currently the only water tight method of diagnosing FIP.

Treatment Options

Since enteric FCoV often causes few signs or only mild, short-lived diarrhoea, specific therapy is often not necessary.  No known treatment reduces the chance that FCoV-infected cats will develop FIP.

Treatment for FIP is unrewarding and death will ensue regardless.  Supportive care with nutritional supplementation, removal of chest fluid, intravenous fluid therapy, and antibiotics for secondary infections may help prolong and improve the quality of the cat’s life.  Supressing the immune system with steroids and other drugs may benefit a small number of cats by reducing the formation of the FIP antibody-antigen complexes. 

Although various treatments have been recommended for FIP, little scientific evidence exists regarding their benefit. 


Prognosis for the intestinal form of FCoV is good.

Cats with FIP have an extremely grave long-term prognosis, as the disease is sadly fatal.