FeLV (Feline Leukemia Virus)

FeLV is retrovirus, a family of viruses which has many members. It is considered to be the most common cause of serious illness and death in domestic cats. It causes a breakdown in your cat's immune system causing your cat to become susceptible to many diseases which it might otherwise be able to fight off.

If you are considering taking a stray cat into your home, you should bly consider having it tested for FeLV, as well as any other possible diseases. This should especially be considered if you already have cats in your home, to avoid infecting your current cats.

FeLV should be suspected and investigated under all circumstances that your cat becomes severely ill. Some cats that survive may develop cancer.

Spread:

• FeLV is typically spread when the saliva of an infected cat comes into contact with another cat.  This can occur from mutual licking and grooming, shared food and water bowls. It is also possible to spread through litter box use.
• Exposure to FeLV does not always lead to infection. Prolonged, extensive cat-to-cat contact is required for efficient spread, because the virus is rapidly inactivated by warmth and drying.

Possible Signs:

• anemia, depression, jaundice, weight loss, decreased appetite, diarrhea or constipation, blood in the stool, enlarged lymph nodes, respiratory distress, decreased stamina, excessive drinking and urination, chronic colds, pneumonia, skin and mouth sores, reproductive problems (miscarriages, weak kittens)

Transmission to humans (and dogs):

• As of yet, there is no evidence that transmission occurs, despite decades of extensive research. However, as with any disease, the possibility that FeLV can be transmitted to human beings and cause disease cannot be ruled out completely.
• There is currently no evidence that FeLV is carried by, or causes any illness, in dogs.

Vaccines:

• Several vaccines are available to help protect your cat against FeLV infection. These vaccines are produced by various methods, and either contain the inactivated ("killed") whole virus, or a "subunit" protein of the virus. However, the principle of protection is the same for each of these vaccines.
• Some cats may experience some discomfort for a few hours or for a day or two after vaccination. On rare occasions, an allergic reaction to a component of the vaccine may occur. This will result in fever, diarrhea, and discomfort. Your veterinarian can treat this reaction.
• The FeLV vaccines are as safe as other commonly used feline vaccines. As with any vaccine in animals or humans, some reaction to the vaccine may occur in a relatively small number of vaccinations.
• Effectiveness: Please remember that no vaccine is 100% effective. Unfortunately, a small percentage of FeLV-vaccinated cats will not be protected against exposure to FeLV
• Vaccinations should start at nine to ten weeks of age, and the second dose of the should be given three to four weeks later. Your cat should then receive an annual revaccination ("booster").
• There is currently no evidence that FeLV is carried by, or causes any illness, in dogs.

Cure:

• As of yet, there is no cure for FeLV.
• Regimens have been developed and in certain cases those regimens may produce a temporary remission. These results are dependent on the physical condition of the cat and the type of disease that is present. These drug therapies may allow the cat to continue in a reasonably healthy state for a period of several weeks to several months. These however, are only remissions and not permanent cures. Chemotherapeutic drugs are very potent, and to avoid an overdose, the effects must be monitored carefully.

Prevention:

• Be sure to have your cat tested. There are currently 2 types of FeLV blood tests in common use.
• These tests are: ELISA, a kit test, which can be performed in your veterinarian's office
      & the IFA, also called the Hardy test or slide test.This must be sent out to a diagnostic laboratory for testing.
• Keeping your cat indoors will drastically reduce it's risks of becoming infected
• Separate positive and negative cats.

Multi Cat Households:

• The FeLV vaccines are not 100 percent effective. Because of this, there is still a degree of risk when a vaccinated cat is housed with a FeLV-positive cat.
• It is recommended that FeLV-positive cats & FeLV-negative cats not be housed together, even if the FeLV-negative cat has been vaccinated. Of course a cat vaccinated against FeLV will have a far greater chance of successfully withstanding an exposure to FeLV than a cat with no vaccine.
• If you must keep an FeLV-positive cat, be sure it is kept away from all other cats (housed in a different room) and that it has it's own food & water bowls, as well as it's own litter box/pan.

New Cats:

• FeLV is considerably unstable and will not survive outside an infected cat for an extended length of time. It is recommended to wait at least 30 days before a new cat is brought into the household/facility in which a FeLV-positive cat once lived
• Cleaning:
  Thoroughly disinfect or replace the food dishes, litter pans, and bedding that were used by the infected cat.
  Tile or hard surfaced floors should be cleaned and disinfected with a diluted bleach solution (approx. 4 oz. household bleach to 1 gal. water).
  Thoroughly vacuum rugs to eliminate the virus from carpeting.
• These plus the thirty-day quarantine, should be sufficient to eliminate the virus within the household.

Kittens & Pregnant Cats:

• FeLV is transmitted from the mother to their kittens either in utero or after birth. A very high percentage of kittens born to infected mothers will eventually succumb to an FeLV infection or an FeLV-related disease.
• FeLV-positive cats should absolutely not be allowed to breed.

Euthanasia

• The idea of euthanizing a positive cat is one that must be addressed in each individual case, in consultation with the attending veterinarian.
• Euthanasia is not necessary to control the transmission of the virus, as long as your cat is kept indoors and away from all other cats.
• However, you must remember, that the cat may develop an FeLV-related illness and become so uncomfortable that euthanasia may become the only humane course of action.

Some of the preceding has been adapted from the Cornell Feline Health Center's information on Feline Leukemia Virus and other veterinary resources.
This is presented for informational use only.
Please see your veterinarian if you suspect any illnesses in you pet(s).