FIV (Feline Immunodeficiency Virus) image of catis caused by a retrovirus that breaks down the immune system’s ability to fight off disease. Although often confused with FelV (Feline Leukaemia Virus), FIV is less common and is comparatively slow-acting. It’s also far less contagious, and cannot be spread to people or other species; so it can only be passed from cat to cat in the correct circumstances.

One thing FIV is NOT is ‘Feline AIDS’. As with HIV, only the final, terminal stage of FIV is considered equivalent to the onset of AIDS in humans – and it’s a stage most FIV-positive cats never reach(1). When properly managed, FIV is by no means a death sentence. As with HIV in humans, an FIV+ cat may remain perfectly healthy for many years – and many cats are asymptomatic their entire lives, eventually passing away from unrelated ailments or old age. Dr Diane D. Addie, Lecturer in Veterinary Virology at the University of Glasgow, says, “At least three studies in FIV+ cats have shown a life span equal to uninfected cats”(2).

Read on to learn more about caring for your FIV+ cat. Click the links below.


Symptoms of FIV
How do I know if my cat is FIV Positive?
My cat has tested positive for FIV! Should I have him put to sleep?
How to prevent FIV?
Can I vaccinate my cat against FIV?
Prevention of the spread of FIV
Caring for your FIV Positive cat
The future of FIV treatment
In Summary

Symptoms of FIVimage of cat

The clinical signs of FIV are many and varied, and can include chronic and recurrent infections of the skin, mouth, urinary tract and upper respiratory tract, progressive weight loss and poor coat, seizures, kidney failure, certain types of cancer, neurological disease., or none of the above.

Bearing in mind that many FIV+ cats will never exhibit any related symptoms, even once the first infection occurs, it can be many years before the cat becomes chronically ill, (if it does at all) provided each infection is promptly treated and the cat is well cared for. It is also best to minimise exposure to illness by keeping FIV+ cats indoors and separate from sick cats. Generally, a cat will live it’s normal life span without presenting any symptoms other than gingivitis and tooth decay.


How do I know if my cat is FIV Positive?

Diagnosis of FIV can be made quickly and cheaply by your vet by way of a simple blood test. However, you may receive a false result in certain cases and follow up testing may be required later. For example, when a kitten is born to an FIV+ mother you can receive a “false positive” result where the test may show the kitten is FIV+ when they may not be. If a kitten tests positive, you must test again once they are over 6 months old for an accurate result. Also, if a cat has been infected with FIV in the last 6 months, a test may show a “false negative”. It is also extremely important to be aware of the fact that, if a cat has previously been vaccinated against FIV they will test positive, even though they do not have FIV. There is an additional test now available that will determine the difference between a cat who has been vaccinated against FIV, and a cat is genuinely FIV+.


My cat has tested positive for FIV! Should I have him put to sleep?image of cat

Short answer… absolutely not! Would you have a human euthansed under the same set of circumstances? If the answer is no, then why would you euthanse your cat? As we will further explain, a cat with FIV can have a long and happy life of good quality, assisted by the right care and management as you would with any condition. Unfortunately many vets will tell you the right thing to do is to euthanase your FIV+ cat, without even knowing there is now an additional test to determine if the cat is testing positive because it’s been previously vaccinated. Then again, many vets also believe that cats with cat flu should be euthanased too. Again, would you euthanase a human with the flu? Why is a cat any different?

However, should your cat reach a stage where it is experiencing recurring, chronic illness and is suffering, then of course you should consider that euthanasia may now be an option you need to consider.

If your cat is FIV+, it is absolutely vital to find a vet who is knowledgeable and understanding in this area.


How to prevent FIV?

With FIV transmission occurring primarily via deep bite wounds, there are two simple ways to reduce the chance of infection in your healthy cat:

  1. Make sure your cat is desexed; ideally at a young age to minimise the risk of fighting with other cats particularly free roaming, undesexed, male cats who are the main carriers of FIV; and
  2. Give your cat an enriching, ‘indoors-only’ life.(3)


Can I vaccinate my cat against FIV?image of cat

There is some controversy regarding the effectiveness of the FIV vaccination, and more independent studies are needed. Basically, the main problem lies with the fact that, like most viruses, FIV constantly mutates. For this vaccine to be more effective, it needs to be continually re-developed for all new strains. Given that the FIV vaccination interferes with test results, it is important to discuss the advantages and disadvantages with your vet before deciding to have your cat vaccinated against FIV.


Prevention of the spread of FIV

It is very uncommon for a FIV+ cat to transmit the virus to other feline members of the household. Although the virus is present in saliva, it is extremely fragile and quickly dies after leaving its host; so unlike the highly contagious FelV, it is not transmitted by mutual grooming or the normal sharing of food bowls or litter boxes, or by a playful nip (where no blood is drawn). This is good news too for shelters that hold FIV+ cats, because the virus does not survive in the environment outside the cat’s body for more than a few seconds and is readily destroyed by most disinfectants(4). Shelters can be considered safe spaces for FIV-negative cats to share with their friendly FIV+ buddies with correct management.

While kittens can contract FIV either in utero or via their infected mother’s milk, it is rare. And as mentioned previously, the test results are not accurate until the kittens are more than six months old. The primary way FIV is transmitted is through fighting or mating that result in deep bite wounds. FIV can be transmitted via blood-to-blood or saliva-to-blood, but cannot be transmitted via saliva-to-saliva.


Caring for your FIV positive catimage of cats

Good care and lots of love can help your FIV+ cat to enjoy a long and happy life. Whilst healthy, your cat’s vaccinations may be kept up to date, and the vet should check their eyes, gums, skin and lymph nodes, as well as their weight, at least twice a year.

A nutritionally complete and balanced diet is essential. Uncooked foods (such as raw meat and eggs) and unpasteurised dairy products should be avoided, as the risk of food-borne bacterial and parasitic infections is higher in immune-suppressed cats(5). Ongoing diet supplementation with L-Lysine is also widely recommended for immune system support; it can be sprinkled onto food and is very inexpensive.

At any sign of illness, take your cat to the vet straight away, as early treatment can prevent many problems. Antibiotics can control infections, and FIV+ cats who reach a chronic stage may rely on antibiotics more frequently.


The future of FIV treatment

There is limited knowledge regarding medical treatment of FIV infection, but research is ongoing into combination and anti-retroviral drugs, immune-modulating medications, and anti-oxidants. Veterinary virologists and pathologists have long promoted FIV as an appropriate animal model for studying HIV, and cats also stand to benefit from the many years of HIV research that has been immensely helpful in humans. Recent breakthroughs in HIV therapies could, in fact, turn out to be transferable to feline patients, which would be an exciting development for veterinary medicine(6). For now, the abovementioned lifestyle changes, regular vet checkups and careful supervision will ensure your FIV+ cat leads a happy and healthy life for as long as possible.


In summary

To ensure your FIV+ cat leads a happy and healthy life for as long as possible:

  1. Keep your cat indoors only
  2. Provide good quality, non raw food and include L-Lysine daily
  3. Ensure vet checkups at least twice a year and as needed

It is not at all uncommon for FIV+ cats to live a happy, well balanced life in excess of 15 years. A couple of members of the CatRescue 901 team have their own FIV+ cats, as well as FIV negative cats. All cats (and humans) live happily together, with no risk to their FIV negative cats because the cats live in harmony.


  1. ‘Five Myths and Facts About FIV’:
  2. ‘CatChat – FIV Information’:
  3. ‘Feline Retrovirus Infection’:
  4. ‘Feline Immunodeficiency Virus’:
  5. ‘Future Combination Antiretroviral Treatment for FIV?’:


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