Pet Columns, Office of Public Engagement, College of Veterinary Medicine at the University of Illinois at Urbana-Champaign

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Feline Leukemia Virus: A Feline Epidemic


Pet Column for the week of September 25, 2006


Office of Public Engagement
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907
Brookelyn Nitzkin
Information Specialist

As many know, AIDS is an epidemic that affects millions of people every year. The human AIDS virus is a retrovirus and is related to a virus called the feline leukemia virus (FeLV). Although similar to AIDS in its viral characteristics, FeLV behaves differently in our feline friends.

The AIDS virus causes destruction of T cells and immuno-suppression. FeLV may cause lymphoma and lymphocytic leukemia--cancer in the lymph nodes and blood. Cats infected with FeLV have a 60-fold increased risk of developing lymphoma, explains Dr. Gail Scherba, a virologist and veterinarian at the University of Illinois Veterinary Teaching Hospital in Urbana, Ill. However, many cats who carry the FeLV virus are asymptomatic.

Sick cats often become ill with general signs of diarrhea, lethargy, fever, enlarged lymph nodes and generally nonspecific symptoms. This is what makes this disease particularly tricky. A cat may or may not look sick. Unexplained weight loss is the most common symptom. Suppression of the bone marrow is a very common and serious syndrome associated with the virus. The bone marrow is responsible for producing the cells that help fight infection as well as red blood cells which make up an important part of the blood.

The virus is readily spread from cat to cat, making social cats particularly susceptible. The virus can be shed in nasal secretions, saliva, feces, urine or milk. This makes bite wounds and nursing particularly straight forward pathways for transmission. Close, direct contact between cats is the most likely method of transmission.

A veterinarian can perform a test to help determine if a cat is infected with the virus. One test is called an ELISA (enzyme-linked immunosorbent assay) and is done with a simple blood test. These tests check for the presence of virus in the blood. Another, more complicated, test called a PCR (polymerase chain reaction) can also be done to check for the virus.

Unfortunately, there is no cure for FeLV; it is simply a disease that must be managed. Maintaining a cat on a well-balanced, high-nutrition cat food will help keep your cat healthy. Cats infected with FeLV should receive wellness exams a bit more regularly to monitor the perhaps subtle changes in a cat's health. An infected cat is more susceptible to various other diseases and a good vaccination program should be kept up to help your cat fight off other infections. There are some drugs which help boost immune competency in cats and are sometimes used to help protect your cat from infection from other diseases. AZT, a drug used to treat the human AIDS virus, has been clinically tested on cats and has shown potential to help treat this disease in the future.

Prevention of this disease involves separation of non-infected cats from infected cats. In some cases this means keeping a cat indoors. Dr. Scherba said, "Cats tend to do fine indoors. They are perfectly happy."

There has been a vaccine marketed in the past, but the vaccine has shown to be fairly ineffective at helping to prevent the disease. Dr. Scherba cautions that vaccines are never 100 percent effective at preventing disease, they simply help prime the immune system so it can react more strongly and completely. However, some studies have shown that cats who received the vaccine and who got the disease actually got a more severe form of the disease.

Dr. Gail Scherba says, "Another good way to prevent this disease is to make sure that any animal that is being adopted from a shelter has been tested for the feline leukemia virus." This disease is easy to miss and early detection of this disease can help to increase the health of an infected cat as well as potentially stop it from spreading through a multi-cat household.

For more information about FeLV, contact your local veterinarian.