The Pet Health Care Gazette

“How do I know if my cat has feline leukemia?” This is one of the most common questions cat owners ask me in my veterinary practice. And the simple answer to that question is: You don’t know whether your cat has feline leukemia unless you have a blood test for feline leukemia performed.

What is Feline Leukemia?

Feline leukemia, also known as FeLV, is caused by a virus known as the feline leukemia virus. It is a contagious disease which is passed from cat to cat, usually through close contact with one another. The feline leukemia virus is present in bodily fluids, including saliva, urine, tears, feces, blood and discharges from the nose. Therefore, the FeLV virus can be spread when cats groom one another, share food or water bowls, share litter boxes or fight with one another. The virus can also be passed to newborn kittens from their mother even before the kittens are born.

The feline leukemia virus is not passed readily without direct contact. There is little risk of a cat owner carrying the virus home to their on clothing, skin or other inanimate objects. Therefore, cats which live exclusively indoors and have no contact with other cats have very little risk of exposure to feline leukemia. However, those cats that live outdoors and frequently socialize with or fight with other cats are at risk.

What Symptoms does Feline Leukemia Cause in Cats?

Many cats which test positive for the feline leukemia virus are perfectly healthy cats with no evidence of disease at all. In fact, many cat owners are completely unaware of the fact that their cat is infected with the feline leukemia virus prior to having their cat’s blood tested for the feline leukemia virus. However, feline leukemia can mimic many other diseases when it does become symptomatic.

When we think of leukemia in people, we tend to think of a cancer which involves the bone marrow or the lymphatic system. These types of cancers can occur in cats infected with the feline leukemia virus but are actually relatively rare.

More commonly, cats infected with the feline leukemia virus experience suppression of their immune system due to the virus. This immunosuppression can cause an infected cat to become more susceptible to secondary infections. These secondary infections may be viral, bacterial or fungal and can affect any body system. Therefore, the symptoms associated with them can be quite variable depending on what type of infection occurs and where it exerts its effects. Basically, any time a cat becomes ill, feline leukemia needs to be considered as a potential cause and needs to be ruled out in the diagnosis. In fact, the American Association of Feline Practitioners (AAFP) recommends testing any sick cat for feline leukemia virus infection, regardless of previous test results, in their Feline Retrovirus Management guidelines. (These guidelines provide what most veterinarians consider the “gold standard” when dealing with the feline leukemia virus and the feline AIDs virus, the two common retroviruses seen in cats.)

What About Cats Which Test Positive for the Feline Leukemia Virus but do not have Symptoms?

There was a time in the past when healthy cats which tested positive for the feline leukemia virus were euthanized (put to sleep) almost automatically. Fortunately, that is no longer the case. We now realize that cats testing positive for feline leukemia but showing no symptoms of disease can live long, healthy lives. These cats should lives should:

• live indoors
• be spayed or neutered
• not be fed a raw diet
• be examined by a veterinarian regularly, at least twice yearly, and have routine blood screens (including a complete blood count and blood chemistry profile) and urinalysis (urine testing) done at least yearly. Hematological (blood) disorders are common in cats with feline leukemia, so some veterinarians may advise blood testing, particularly the complete blood count, twice yearly.

In the event that a previously healthy feline leukemia positive cat becomes ill, a thorough diagnostic plan and aggressive treatment should be instituted as soon as possible.

Treatment for Cats Which are Showing Symptoms of Feline Leukemia

Cats which are ill as a result of infection with the feline leukemia virus pose a challenge in treatment. Symptomatic treatment is a must with these cats and may include fluid therapy to combat dehydration, antibiotics for secondary bacterial infections and other treatments depending on your cat’s symptoms.

A number of antiviral drugs are available as well as several drugs which help to modulate the immune system. However, none of these drugs has been adequately evaluated in cats as a treatment for feline leukemia. Testing in this area is ongoing and more testing is needed. However, these drugs may be used in the treatment of feline leukemia and include:

• Zidovudine (AZT)
• Feline interferon omega
• Acemannon
• Bacille Calmette-Guerin (BCG)
• Didanosine
• Diethylcarbamazine (DEC)
• Levamisole
• Lymphocyte T-cell immunomodulator
• Propionibacterium acnes
• Serratia marcescens
• Staphylococcus protein A
• Suramin

Of these drugs, AZT and feline interferon omega show the most promise in treating feline leukemia symptoms at this time.

This entry was posted on Sunday, January 10th, 2010 at 8:53 pm and is filed under Cats, General Pet Health Care, Uncategorized. You can follow any responses to this entry through the RSS 2.0 You can leave a response, or trackback from your own site.