Feline Immunodeficiency Virus (FIV) Infection

Feline immunodeficiency virus (FIV) is a retrovirus from the same family of viruses as human immunodeficiency virus (HIV). As with HIV, it is termed a ‘slow virus’ as it can be many months or years before cats show signs of immunodeficiency and some cats never show any signs of the infection.

Has my cat got feline AIDS?

Being FIV positive is not the same as having feline AIDS. AIDS describes the terminal stages of disease which may not occur for many years. FIV positive means that your cat has been infected by the virus.

Are my family at risk?

NO, although HIV in humans belongs to a similar group there is no risk of cross infection.

Are other cats in the household likely to be infected?

Other cats in your household may already be infected but the risk of transmission in stable households (where no new cats are introduced) is considered low. The virus does not survive long in the environment so there is no need to disinfect surfaces or bedding the infected cat is in contact with – normal cleaning routines are adequate.

How do cats get FIV?

FIV is transmitted primarily by biting through transmission of saliva which has a large concentration of virus in it. Cats that are known fighters (a history of cat bite abscesses) have a higher chance of being FIV positive. Normal social interactions such as grooming, have a very low risk of transmitting FIV. Kittens can also be infected from an infected queen, either transplacentally or via the queen's milk. This method of transmission is much less common, so it should not be assumed that kittens born to a FIV positive queen are infected.

How is FIV diagnosed?

FIV is diagnosed on a blood test by looking for an immune response (antibodies) to the virus. If this test is positive it is likely that your cat is infected by the virus. False positive and negative results do occur for a variety of reasons. Because antibodies in the bloodstream of an infected queen pass via the milk into her kittens without transmission of the virus, a positive test result in a kitten under 6 months of age should be rechecked when they are older.

Will my cat recover?

Once a cat is infected with the virus it will remain infected for the rest of its life. Many cats remain healthy for many years and some never show ill effects of the FIV infection.

What type of disease can FIV cause?

FIV may damage the cat’s immune system and therefore make it susceptible to other infections or increase the risk of certain cancers. In cats where immune deficiency is more obvious, they may develop chronic or recurrent infections that fail to respond to regular treatment or unusual or rare conditions such as fungal infections. There are many types of FIV and it appears that in Australia our most common forms of FIV are not particularly harmful to the cat. Where infections do cause a problem, common clinical signs of FIV infection include:

1. Gingivitis/stomatitis (inflammation of the gums/mouth)
2. Weight loss
3. Poor appetite
4. Fever
5. Inflammation of the membrane around the eyes (conjunctivitis)
6. Swollen lymph glands
7. Vomiting and diarrhoea
8. Anaemia
9. Respiratory tract infections
10. Skin infections

A lot of these signs are very non-specific and cats can have these symptoms without having FIV.

Is there any treatment?

Secondary infections can be effectively treated with antibiotics etc. but no specific treatment for the virus is available. Some cats have been treated with human anti-HIV drugs such as AZT with limited success. Anti-oxidants such as evening primrose oil may be helpful particularly in the early stages of infection.

Should I have my cat euthanased?

Generally this is not necessary unless your cat is showing chronic ill effects that cannot be managed effectively. Like HIV, cats with FIV have a long period where they appear healthy and show no clinical signs. This period can last for many years during which your cat can have a normal, happy life.

How can I help my cat?

You can help your cat by ensuring it has a healthy life style and good quality food. Avoid raw meat as it contains more bacteria and parasites that your cat’s immune system may not be able to cope with. Regular worming, flea treatments and yearly booster vaccinations for other diseases are recommended. Any infections should be treated promptly and aggressively. It is advisable to keep your cat indoors as this reduces the likelihood of your cat picking up infections from other cats, prevents hunting (which prevents picking up infections from their prey) as well as reducing the risk of spreading the virus from your cat to other cats. Keeping your cat indoors if it was previously allowed to roam may affect its quality of life and the benefits and disadvantages of this need to be weighed up.

How do you stop cats becoming infected?

As most cats become infected from bite wounds during fighting, the risk of infection can be minimised by making sure your cat is neutered and, where possible, kept indoors so it does not come into contact with other cats. If this is not possible, it should at least be kept in at night as this is the most common time for cat fights.

A vaccine is available in Australia to prevent FIV infection. Cats that do not come into direct contact with other cats do not need to be vaccinated. The vaccine is unlikely to be 100% effective so it is important to continue to minimize transmission by preventing bite wounds where possible.

An important point to remember is that when we test for FIV we test for antibodies against the virus. Once a cat is vaccinated, it should develop antibodies to FIV and will therefore be positive on a test. It is then very difficult to tell whether your cat contracts FIV from an infected cat following vaccination. Tests available to differentiate between vaccinated and infected cats in Australia are poorly available at this point. It is important that you discuss vaccination of FIV carefully with your veterinarian to determine whether your cat really needs vaccination against this disease.

One cat in my household is FIV positive and the others are not, what should I do?

There are three options:

1.  Rehome the FIV positive cat to a house with no other cats.

2.  As the risk of infection spreading to your other cats by social contact is low, many people choose to keep the FIV positive cat. Where possible, the positive cat should have a separate feeding bowl from the other cats and food should not be left down for all cats to share. It is best not to introduce new cats into the household as this may increase territorial fighting and FIV transmission.

3.  Test all other cats and vaccinate those that are negative. Whilst vaccination is certainly not 100% effective in preventing transmission it may help reduce the risk of your other cats being infected. As stated above, as testing for FIV involves detecting antibodies to the virus, once you have vaccinated your cat it is only possible to tell if the vaccinated cat(s) is infected by having specialized blood tests performed (PCR) which are currently poorly available in Australia. This means it may be difficult to know if your non-FIV infected cats have contracted the virus once they have been vaccinated.