What Should I Know About FIV in Cats?

Perhaps you’ve heard that feline immunodeficiency virus can make cats feel sick. It’s true that the autoimmune disease can cause symptoms like fever, poor appetite, weight loss, a lacklustre coat, diarrhoea, dental disease and slow-to-heal wounds, but some cats experience no symptoms at all.

Dr Julie Levy, professor of Shelter Medicine Education at the University of Florida, says that “most cats typically live many, many years without any negative impacts”. The risks of a cat contracting FIV are low. According to the Blue Cross, between two and five percent of cats in the UK are thought to be infected, though there is a lot of regional variation.

The biggest risk is to unneutered male tomcats who can transmit the infection via biting and bodily fluids. For this reason, the RSPCA strongly recommends that all cats are neutered at four months of age, as neutering can reduce a male cat’s urge to mate, roam and fight.

How is FIV spread?

FIV is spread through bite wounds; it can’t be spread among cats who groom each other. However, the Blue Cross still recommends that you seek to rehome a cat who is diagnosed with FIV if you have a multi-cat household. If you choose to keep your FIV-positive cat with other cats, as many owners do, you can minimise the risk of transmission by using separate bowls and disinfecting bowls and litter trays after use. The virus dies on inanimate objects, but only after a few hours.

The risk of transmitting the virus through sexual contact is also low, but that doesn’t mean it’s a good idea to let FIV-positive cats breed, as there’s a chance that an infected mother could pass the virus to her kittens.

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FIV can’t be transmitted to other pets or people. Although it isn’t easily transmitted between cats, there remains a small risk, which is why the Blue Cross recommends that FIV-positive cats are kept indoors. This doesn’t just protect other cats, it also reduces the risk of the FIV-positive cat catching an infection.

How will I know if my cat has FIV?

Infected cats may not show any signs of the virus. In the earliest stage, called the acute phase, an infected cat may have symptoms like swollen lymph nodes, fever and loss of appetite. However, signs are often so subtle that owners may miss them. The next phase is the asymptomatic phase and, as the name suggests, it’s a time when infected cats show no obvious signs of illness. This phase can last for years and some FIV-positive cats never develop symptoms of severe disease at all. 

Only cats who enter the progressive phase show obvious signs of illness. At this stage, FIV-positive cats may be so immunocompromised that they end up with secondary infections like upper respiratory infections, dental disease or urinary tract infections. Still, Dr Levy stresses: “FIV is not a death sentence. Most FIV-positive cats live healthy lives for many years.”

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Is FIV preventable?

There is no vaccine currently available in the UK. In 2002, an FIV vaccine was introduced in the US, but it had a significant drawback. “The tests for FIV are antibody tests and when you get vaccinated, you make antibodies,” Dr Levy explains. For this reason, cats who were vaccinated tested positive for FIV, which proved confusing for vets further down the line. Since the risk of transmission in neutered cats was so low, many American vets didn’t recommend the vaccine and Dr Levy suspects this led to it being discontinued.

While there is no vaccine, there are other ways to protect your pets. Dr Levy says that spaying and neutering, which have been shown to limit aggression, are the most important thing you can do to reduce the risk of your cat developing FIV. Keeping cats indoors, either as solo pets or with other well socialised cats, also drastically decreases the risk of FIV.

Should you adopt a cat with FIV?

The RSPCA will only re-home an FIV-positive cat if it thinks they’ll be happy living an indoor lifestyle in a household with no other felines. This proviso aside, FIV-positive cats are just like other feline friends: they need balanced diets, exercise, mental stimulation and regular vet checks to maintain good health. FIV can’t be transmitted to humans, so there is zero risk to adopters who welcome FIV-positive cats into their homes.

What are the treatment options?

There is no cure for FIV and, since your cat may never show symptoms of illness, treatment may not even be necessary. But prevention is essential: in addition to spaying and neutering, keeping on top of vet visits, dental care and a healthy diet can help reduce the risk that an FIV-positive cat will develop a secondary infection.