| Credentials Statement Special Interest Facility Location Newsletter EMail Main Page |
| Leahy Animal Hospital |
|
Newsletter
Issue 4 Feline Infectious Peritonitis Our final newsletter for 1998 will address the diseases in the cat caused by the coronavirus group. Unlike Felv and FIV (see our previous 1998 newsletters) coronavirus infection does not cause either cancer or a true Feline AIDS like syndrome. It may actually be that the disease is more related to the body's unusual immune response to infection than the organisms themselves. Two major types of infection are seen: a mild to moderate gastrointestinal infection or flu like syndrome caused by the enteric coronavirus and a wasting disease caused by the infectious peritonitis coronavirus. This virus is named for a "classic" syndrome of accumulation of fluid in the abdomen which is secreted or made by the lining of the body cavity itself which is named the peritoneum. The fluid, which is very reactive and high in protein is believed to be a response to the virus infection by the immune system and can be very sudden (acute) or slow and insidious (chronic) in nature. This response to infection may also cause fluid to accumulate in the chest (pleural effusion). Other forms of this response may cause either reactive masses (termed granulomas) in body organs, such as the liver and kidneys and brain, or irritation and thickening of the body's lining membranes (ie. peritonitis, pleuritis, meningitis, enteritis). Kidney failure may occur due to non specific reaction or due to specific syndrome of glomerulonephritis which is due to inflammation and reaction of the kidneys filtering mechanism itself. Finally, general non specific wasting may occur with little abnormalities seen in organ function. Research has demonstrated that the body responds to infection with this virus with a marked antibody response that may go awry and actually cause the syndromes that affect the cat. Termed immune complex disease (a combination of antibody and virus antigen or protein), it is very similar to the disease systemic lupus erythematosus in humans. These immune complexes settle or are deposited in the various organs and cause the inflammatory reactive response that cause the problems. Death generally occurs due to the dysfunction of the organs involved. Not every cat that is exposed to the virus will develop devastating disease. In fact it is probably true that many of our pet cats have been exposed but have maintained a response that remains protective rather than destructive. The true incidence of disease must remain unknown. Diagnostic testing can be difficult as the two viruses (enteric coronavirus and FIP) can show patterns of cross reactivity in antibody testing. Even FIP specific tests which are now recently available are subject to question. Interpretation is very difficult in some cases. Just because a cat may low or moderate titer to coronavirus does not mean that the cat has the disease that can be associated with active infection. Enteric coronavirus infection is generally a self limiting disease may progress to cause relentless diarrhea and death in some cats. FIP is a terminal disease and diagnosis should me made with great consideration of clinical signs and laboratory testing. Treatment options are often limited to supportive care as determined by each cat's specific problems. The use of immune modulating treatment with drugs that alter the body's response to the virus may be useful to some cases. These decisions are best made in consultation with a specialist for those who wish to pursue treatment for their cat in the face of a very poor prognosis. Both virus infections are thought to be spread by aerosol inhalation just as our many cold and flu viruses. Infection is thought to be feline specific with no demonstration of antibody titers in dogs or humans. Prevention is currently questionable. A vaccine is available for FIP that is given intranasally and has been shown to demonstrate local and systemic antibody response. The question is what does this mean in relation to the disease syndromes that occur. Does vaccination eliminate the possibility of the destructive immune response to the virus which occurs in affected cats? In other words does it prevent disease or chronic infection? We currently do not recommend routine vaccination. |