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A Guide To Feline Immunodeficiency Virus (FIV)

Aimee Labbate
  • Aimee Labbate

  • RCVS: 700039


What is FIV?

Feline immunodeficiency virus (FIV) is an important virus that infects cats worldwide. It is similar to HIV infection in humans, although both FIV and HIV are species specific, meaning that they cannot infect any other species. The FIV infects white blood cells (immune cells) causing damage or cell destruction – this results in suppression of the immune system, leaving the cat more vulnerable to infections that they would normally be able to fight off. Sadly it is incurable and once infected the cat will usually show symptoms of the disease within 2-5 years.

How is FIV spread by cats?

Cats are usually infected through infected saliva from cat bites. Less commonly, it can be spread through grooming and from an infected cat to her kittens.

The signs develop very slowly and are not usually evident for a number of years after infection; although this does mean that the infected cat can potentially spread the infection to other cats before anyone has realised that they are carrying the disease.

What are the symptoms of FIV in cats?

The clinical signs of FIV infection are usually due to an inability to fight off infections, so typically include:

  • Lethargy
  • Repeat infections e.g. respiratory, skin, eyes and gastrointestinal
  • Fever
  • Loss of appetite
  • Weight loss
  • Chronic diarrhoea
  • Inflammation of the gums and mouth (gingivostomatitis)
  • Swollen glands

How is FIV in cats diagnosed?

The vet may be suspicious of FIV based on the clinical history and physical examination. They can run blood tests to diagnose the condition, although there are sometimes false positive and false negative results, in which case blood can be sent to an external lab for more accurate testing.

Kittens born to FIV positive mothers may have antibodies against the infection but without having the infection itself. This can mean that they test positive using an FIV antibody test until they are 5-6 months old. An alternative test that looks for the virus itself is therefore often used in young kittens to avoid a false positive result, or the antibody test is repeated after six months of age.

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Can FIV in cats be treated?

No. While FIV is unfortunately incurable, it can usually be managed for an extended period of time, depending on the severity of the symptoms at diagnosis, the strain that the cat is infected with and their immune response. Anti-viral drugs are sometimes used to try and reduce the effects of FIV but they are expensive and cannot cure the infection.

Given that FIV weakens the immune system your cat will need close monitoring and special management that should include:

  • Keeping them indoors to prevent them from spreading the infection to other cats. Try to keep them separate from any other cats in your household, although the risk of infection being passed between cats during grooming or sharing bowls is low.
  • Neutering to reduce the risk of them roaming and fighting, thereby potentially spreading the infection to other cats.
  • Regularly treating against fleas and worms, and they should not be raw fed, due to their inability to fight off any germs present in the food.
  • Regular veterinary checks.
  • Prompt diagnosis and treatment of any secondary infections, as these are likely to be more of a problem for a cat who has FIV.

Will my cat recover from FIV?

Sadly not. FIV is not treatable, but the symptoms normally develop gradually over an extended period of time and can usually be managed until the condition worsens. The average life expectancy is 5-6 years from infection.

Can I prevent FIV in my cat?

There is currently no FIV vaccination available in the UK. It is recognised that neutering offers the best way of protecting your cat, by reducing the chances of them fighting.

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