Cats can be affected by two different retroviral infections, Feline Immunodeficiency Virus (FIV) and the Feline Leukemia Virus (FeLV). We highly recommend that cat owners and people interested in owning cats do their own research about these conditions as much information is available, and we won't cover it all here. However, we do want to give a little crash course because in doing our research we stumbled over a lot of bad and outdated information and we want to offer an easy-to-read launching point for anyone considering adopting a cat with one of these conditions or anyone whose own cat has been diagnosed.

People frequently speak about FIV and FeLV in the same breath as if they are interchangable. In fact, they are VERY different viruses with VERY different outcomes. They do share some similarities including that they are viral infections, they reduce the cat's immune system, they are contagious among cats, and they are not contagious to humans or other pet species. The differences far outweigh the similarities.

FIV

Spread through deep bites and sexual contact. Not spread through grooming or shared dishes and litter boxes.

Not frequently spread from mothers to kittens.

Somewhat effective vaccine available but rarely recommended.

Most cats are asymptomatic carriers and may have the virus for 10 or more years before the cat demonstrates symptoms of the illness such as more frequent occurrence of respiratory infections and increased risk of cancer.

FeLV

Spread through persistent exposure to an infected cat's saliva, tears, and/or mucus. Grooming and shared dishes and litter boxes are common infection sources.

Often transmitted from mothers to kittens.

Mostly effective vaccine commonly available and often recommended in younger cats.

Cats exposed to FeLV may fight off the illness completely, may develop a latent infection (in which case the virus survives in the bone marrow but may not produce any symptoms for many years or ever), or may develop a persistent infection. Among those with a persistent infection, lifespan varies but typically these cats will succumb to a secondary illness (such as lymphoma) within about three years. Cats with latent infections may live a completely normal life or may develop a FeLV related disease later in life following a significantly stressful event.

Testing

When testing for either of these viruses it is important to retest! False positives are common for both tests so be sure to perform repeat testing before deciding on a course of action.

FIV testing will show a positive result based on the presence of antibodies, meaning that vaccinated cats will test positive. It is not possible at this time to determine whether a cat has the virus or has been vaccinated for the virus. Vaccines for FIV aren't used commonly, so it makes sense to treat cats with confirmed positive results as if they definitely are FIV positive.

FeLV testing is more complicated. There is the SNAP test which tests for the presence of the virus in the blood and the IFA test which determines in their is viral agents in the bone marrow. The IFA test is extremely accurate in determining if a cat has a persistent infection. A positive SNAP result may not necessarily indicate a persistent infection as cats can sometimes clear the virus before it enters the bone marrow and also because positive SNAP results are often false positives (some studies have indicated false positive rates of up to 32%, though these estimates vary). In our rescue, it is our practice to confirm all positive SNAP test results with the IFA test several weeks after the original screening. If IFA test result is negative, test with SNAP test again in 3 months to determine if cat has fought off the virus. If still positive, they will probably be infected for life.

Quality of Life

For both viruses, quality of life for these animals is generally similar to that of uninfected cats. With FIV infected cats, lifespan may be somewhat decreased as they may become immunocompromised in their senior years. Cats with a persistent FeLV infection (as indicated by the IFA test) usually live short lives, but they tend to maintain good general health and typical quality of life for the vast majority of that time. They simply succumb quickly when a associated condition (such as lymphoma) occurs.

Management

Most of the recommended methods for improving the prognosis and lifespan of these cats is similar to what we recommend for any cat. Spay and Neuter, keep them indoors always, feed a high quality diet, and keep stress levels low.

FIV cats often live happily with other cats and rarely spread the disease particularly if they are neutered as this reduces aggression (and thus deep bite wounds are very rare) and eliminates the possibility of sexual transmission. At our rescue, we tend of prefer our FIV positive cats are either adopted to single-cat households or adopted to homes with other FIV positive cats, but many families successfully have FIV negative and positive cats living together without concerns. Wellness check ups are recommended every six months and frequent teeth cleanings may be needed. Annual bloodwork can help catch illnesses early and improve outcomes.

FeLV cats need to be kept separated from cats who are not infected as FeLV is a serious disease and is spread through friendly contact. They can live happily with other FeLV positive cats, however. FeLV cats also require twice a year check ups and being very proactive about their health can help extend their lifespan. Frequent bloodwork (twice annually) can help catch illnesses early and improve outcomes. Use of steroid drugs in the FeLV infected cats should be avoided if at all possible.

Ideal Homes for Cats with These Infections

Obviously, homes who already have a cat with one of these infections may be interested in adopting a cat who is positive for FIV or FeLV in order to own a second cat without risking the transmission of a virus to a healthy cat. We encourage owners who wish to have another cat in the home and whose current cat is FIV or FeLV positive to consider adopting a cat with the same condition. We typically do have at least a few FIV and FeLV positive cats available for adoption from our rescue!

FIV positive cats do well in most environments, but should definitely be maintained as indoor only cats. Adopting a FIV positive cat is not very different from adopting an uninfected cat as long as you can be vigilant and proactive about your cat's health!

FeLV positive cats can be ideal for those who may be seeking the love an companionship of a cat but who hesitate to adopt due the length of commitment required for a young uninfected cat (whose lifespan could be 15-20 years). Considerations for adopting a FeLV positive cat are similar to those of a senior adult cats in that they may not have as long left to live and more frequent veterinary visits may be needed; however, unlike a senior cats, young FeLV positive cats maintain their youthful spirit and energy levels. Adopting a FeLV positive cat provides the gift of a wonderful, loving life to a cat who may have difficulty finding an understanding forever home.

I have treated more than 20 cats coinfected with FIP and FeLV. Hopefully this can help other cats, please contact me if you have a cat with fever, diarrhoea, lethargy, etc.:
http://joshpmck.wixsite.com/fiptreatmentcats/how-the-treatment-works