Feline Immunodeficiency Virus (FIV) Explained

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What is FIV?

Feline Immunodeficiency virus (FIV) was first discovered in the United States, where workers at a cat rescue centre noticed that some of the cats where showing similar clinical signs to people with acquired immunodeficiency syndrome (AIDS). Much research since has shown that FIV is very similar in nature to the AIDS virus, HIV. FIV has been found in roughly 7% of the UK cat population. Like HIV, FIV (which is sometimes referred to as Cat Aids) can attack the immune system; this can lead to a decrease in white blood cells which can compromise the cat's ability to fight off infections. But, most FIV infected cats seem to go on to lead completely normal lives.

What are the signs of FIV?

Most cats with FIV lead completely normal lives and look completely normal. After the cats initial contact with the FIV virus it may suffer from a short period of mild illness, during which time the cat may be slightly feverish, loss of appetite and have slightly raised Lymph nodes. (Lymph nodes are commonly referred to as glands – in much the same way you might say ‘my glands are up’). However these initial clinical signs often go unnoticed, after this follows a period of good health, which can last for many years. Later in life there is a gradual deterioration in health, this often shows as lethargy, loss of appetite, fever and weight loss. The cat may also become susceptible to chronic infections such as recurring flu, chronic rhinitis or gingivitis.

Which cats get FIV?

FIV is most common in middle-aged to older un-castrated cats, hence the importance of having a cat neutered at an early age. This is because the main route of transmission of the virus is by biting during fights. Saliva has been found to contain large amounts of the virus and a single bite can cause infection. As cat saliva contains virus other routes of transmission include mutual grooming and the sharing of feed bowls, but these are less common. FIV can be passed from mother to young both through infected milk and whilst the kittens are still in the womb. Biting during mating is thought to spread the virus more than true sexual transmission and it is thought unlikely that biting insects such as fleas can spread the infection.

Will my cat die of FIV?

Eventually FIV can cause deterioration of the cat's health, but only after a long period of apparent good health. In several studies it was found that FIV positive cats lived as long as FIV negative cats (in one study they were found to live longer!). Thus FIV positive cats continue to live healthy lives for many years.

How can I protect my other cats?

FIV can sometimes spread between cats that live together; however, it is much more likely that a negative cat will be infected by a strange cat when out and about, therefore FIV positive cats should be kept indoors at all times. This is because fighting is the most common way FIV spreads. FIV is a very fragile virus and does not survive on food bowls and litter trays. This means it is quite safe for positive and negative cats to use the same cat basket and to stroke your own cat after handling a FIV positive cat. This also means that it is safe to put your FIV positive cat into a cattery, since FIV can’t be passed on hands or clothes. However going to a cattery is often a stressful experience, so any infection picked up at the cattery can have more serious consequences than on a FIV negative cat.

What treatment is there for FIV?

There is no specific treatment for FIV, the main aim however is to stabile the cat and give it a good quality of life. AZT and other drugs have been used to delay the onset of AIDS in HIV people and these do work to a limited extent in cats, but cause anaemia usually in the first few weeks of treatment. Some cats that are mildly affected improve on evening primrose oil (one 55pmg capsule daily) and this may be of use in the asymptomatic period (prior to symptoms showing). However prompt and specific treatment of other illnesses is much more important due to their weakening immune system.

Tests for FIV infection

There are several different tests for FIV. Most vets will be able to do a quick blood test to check for FIV antibodies. However this test is not always 100% reliable and your vet may want to send the sample away to an outside laboratory for confirmation. There they will check the sample for actual viral particles.

Can I catch FIV?

FIV is a cat-specific virus and although there are a lot of similarities between FIV and HIV, there is no way it can infect people or other species. This means there is no risk to people in contact with an FIV positive cat.

Can I vaccinate my cat?

Unfortunately there is no FIV vaccine at the present time although labs around the world are trying to develop one as quickly as possible.

Further information

Ask your vet if you have any specific questions or there is further general information on the Feline advisory bureau website at www.fabcats.org

Simon Tappin MRCVS