What You Should Know About Feline AIDS

Feline immunodeficiency virus, or FIV, is a widespread viral infection that attacks the immune system of cats. It is caused by the same family of viruses that triggers AIDS in humans and has much the same devastating impact on infected cats. It is often referred to as “feline AIDS.”

The virus devastates a cat’s immune system, stopping it from effectively combating other diseases and infections. Infected cats eventually fall prey to a wide variety of secondary illnesses that overwhelmingly prove fatal. There is no cure, but cats can live for up to 10 years – much of it in seeming good health – before succumbing.

It is estimated that between one percent and 14 percent of the cat population is infected with FIV. The disease is transmitted from cat to cat by blood and saliva. This happens primarily through biting and scratching so outdoor and male cats that fight with other cats are at greatest risk. FIV has also been found in milk and can be transmitted from mother to kitten. Transmission among household cats through normal contact is thought to be unlikely. Nor can the disease be transmitted to humans.

How FIV Progresses

FIV has three stages of infection:


An infected cat will often suffer from numerous diseases and infections, including anemia, infections of the gums and mouth, cancer and skin disorders. The cat may also suffer neurological problems that cause seizures, problems maintaining balance and dementia, as well as behavioral changes like inappropriate elimination. Co-infection with feline leukemia virus can occur. Many cats may seem healthy but they are still infected.

The key to diagnosing FIV is determining whether these problems are the result of a suppressed immune system caused by the virus. Your veterinarian will take a medical history, do a complete physical examination and administer an FIV blood test designed to see whether a cat has developed antibodies to the virus. If antibodies are present, it indicates the virus is present in the body. This test is called ELISA or IFA.

It is a good idea to test kittens because they contract the virus when nursing, but it is also possible for a test to show wrongly that a kitten is infected; a nursing kitten can also carry the antibodies of an infected mother without being infected itself. A kitten that tests positive should be retested after six months of age, when it carries its own antibodies and test results will be more reliable.

A cat that tests positive or appears to have FIV will likely undergo further tests to measure its general health and the impact the disease is having on individual organs.


There has been no proven effective treatment for FIV infection. If your cat has no clinical signs, no treatment may be recommended. In this situation, regular follow-up visits to your veterinarian are important to insure the condition does not progress. If immunodeficiency and secondary infections have developed, your veterinarian will choose treatments to combat them. These are likely to consist of antibiotics for bacterial infections, nutritional support, fluid therapy for dehydrated cats and parasite control.

Several therapies used to treat people with AIDS have been used in cats with FIV infection with the goal of boosting their immune systems and slowing the progress of the disease. These treatments include:

Home Care

Optimal treatment for your cat requires a combination of home and professional veterinary care. Follow-up is crucial.


A vaccine has recently become available to help reduce the risk of your cat acquiring FIV. In addition to vaccination, eliminating interactions with infected cats and stopping your cat from fighting greatly helps reduce the risk. Keeping your cat indoors and neutering males are probably the most important keys to prevention.

Ideally, FIV-infected cats should be isolated from cats that do not carry the virus. This is to eliminate any chance of transmission to your uninfected cats. However, transmission among household cats through normal contact is thought to be unlikely.

Some veterinarians believe that FIV positive cats should be quarantined to a separate area in a household away from other cats and should have no contact with FIV-negative cats. However, this is difficult to do in some multi-cat households. Many FIV positive and FIV negative cats live together without problems. If you do mix your cats, you need to understand the possible risk of infection to your healthy cats, however slight.

For multi-cat households, the recommendation is for all cats in the household should be tested for FIV. Quarantine all FIV-negative cats to one area. Retest these cats in three months. If they are negative at that time, they are considered free of FIV. Cats are considered free of infection when two negative test results separated by three months have been obtained. Though you want the new cat to be a member of the household as soon as possible, it is important to observe the quarantine period to eliminate any risk to your existing cats.

Retest all FIV-positive cats. Cats that test negative for FIV after having testing positive on the first test should remain isolated. Re-testing should be carried out after three additional months.

Kittens should not be allowed to nurse if their mothers are infected because the virus can be passed through the milk.

Please note: Positive titers to FIV can occur from some vaccinations. This can product a positive test result. If your cat tests positive to FIV and is NOT sick, please determine if your cat has been vaccinated recently. Titers to the vaccine can occur for up to 13 months after vaccination.