FeLV in Cats: What a Positive Test Means and What to Do Next

What to do after a positive quick test

The in-clinic test looks for a viral protein called p27 in the blood. A positive usually means the virus is in the bloodstream right now.

The first step is to test again with a different method. Your vet can send blood to a lab for an antigen test or a PCR test, or run a different brand of quick test. The PCR test looks for the virus’s genetic material inside blood cells. Confirmation matters most for a healthy cat that has never been outdoors: the chance of infection was low to begin with, so a positive is more likely to be false. The two kinds of test don’t always agree, and sometimes it takes more than one round to get a clear answer.

If the positive is confirmed, test again after six weeks or more. Some cats get the virus under control and turn negative, usually within about 16 weeks of being infected. A cat that is still positive after six weeks probably has a persistent infection, though a few need further testing before anyone can say for sure.

While you wait, give the cat a room of their own, with separate bowls and a separate litter box. This is temporary. A positive test is not, on its own, a reason to put a cat to sleep, and veterinary guidelines say so explicitly.

What about my other cats?

Every cat in the home should be tested. If the positive cat has lived with the others for a while, eating together, grooming each other and sleeping in a pile, the others have probably met the virus already. Many cats that meet the virus build up resistance and never become persistently infected. Cats differ, though, and only a test will show where each one stands.

If the others were only recently exposed, a first negative result isn’t final. Most infected cats test positive within 30 days of exposure, and some take longer, so a second test a few weeks later is worth doing.

Cats that test negative should be vaccinated against FeLV, even if they will be kept apart from the positive cat for good. The vaccine takes time to work, so wait at least three weeks after the last dose of the first vaccine series before letting a vaccinated cat near the positive one. The vaccine lowers the risk, but it can’t stop every infection.

Among adult cats living with a positive cat, about 10% to 15% of those that test negative now go on to test positive later. Usually that’s a hidden infection waking up, and less often a new one. For that reason vets recommend testing every cat in the home at least once a year.

Whether the cats can share space again depends on the test results and your household. That’s a decision to make with your vet.

How long do cats with FeLV live?

It depends on the type of infection, and the follow-up tests are how your vet tells them apart.

When the virus stays active in the body, vets call it a progressive infection. These cats usually have shorter lives, and many develop an FeLV-related illness within a few years of being infected. Individual cats vary a great deal, though. Some stay well for years, and others go downhill quickly, especially cats that are already anemic or unwell when diagnosed.

When a cat gets the virus under control, it’s called a regressive infection, and the outlook is much better. The virus stays hidden in the cat’s cells, but it’s thought to reactivate only rarely, and as long as it doesn’t, these cats can expect a normal lifespan. Stress, pregnancy or another illness can wake it up, sometimes years later. Very rarely, a cat whose blood tests no longer show the virus still develops an FeLV-related illness such as lymphoma.

A less common pattern is a focal infection, where the virus stays in certain tissues. Blood tests can then switch between positive and negative, which is one more reason your vet may want to test more than once.

How FeLV spreads

The virus lives mainly in saliva, and it usually takes long, close contact to pass from one cat to another. Grooming each other, sharing bowls and biting during fights can all spread it. Sharing a litter box carries less risk. A mother cat can also pass it to her kittens during pregnancy or through her milk, and kittens catch it far more easily than adult cats do.

Outside a cat, the virus doesn’t last long. It breaks down quickly on dry surfaces, though it survives a little longer in a wet bowl. If a cat with FeLV has lived in your home and you want to bring in a new cat, a thorough clean is enough. There’s no need to wait a set number of weeks.

There is no recorded case of a person being infected with FeLV. The only people who need to take care are those with a weakened immune system: an FeLV-positive cat picks up other infections more easily, and some of those can pass to people. If that applies to someone in your home, tell your vet.

FeLV is often mixed up with FIV, the feline immunodeficiency virus. FIV spreads mainly through bite wounds from fighting, and many cats live into old age with it. FeLV can spread between cats that simply get along and groom each other, and it’s much more serious. Our FIV guide covers that virus in detail.

Day-to-day care for a cat with FeLV

There is no cure for FeLV. The aim is to keep your cat well for as long as possible and to catch problems early.

Keep your cat indoors, so other cats aren’t exposed. A cat with FeLV may also have weaker immunity, and staying in keeps them away from infections they’d pick up outside.

See the vet at least every six months, with a blood count each time, plus blood chemistry and a urine test once a year. The vet will look closely at the mouth, lymph nodes, eyes and skin, because problems often show up there first.

Skip raw meat and raw dairy. They can carry bacteria and parasites that a healthy cat might shrug off but a cat with FeLV may not.

Weigh your cat at home. When you see your cat every day, slow weight loss is easy to miss, and it’s often one of the first signs that something has changed. If you write the number down regularly, a downward trend becomes obvious.

Stress can also wake a hidden infection back up. A predictable routine, enough litter boxes and feeding spots, and a quiet place to retreat to all help your cat relax. Stress in cats is often subtle, and our guide to recognizing stress in cats covers the quieter signs.

About one in four cats with a progressive infection eventually develops lymphoma, a cancer of the immune cells, and regular checkups and a weight record are how it gets caught early. Despite its name, FeLV causes lymphoma, anemia and weakened immunity far more often than leukemia itself.

Gum and mouth inflammation is also linked to FeLV, so regular dental checkups belong in the routine too. If your cat does become ill, the treatment depends on the illness, and your vet can walk you through the options.

Preventing FeLV: testing and the vaccine

Every cat should be tested before a first FeLV vaccine. The vaccine lowers the chance that a cat exposed to the virus ends up with a persistent infection, but it does nothing for a cat that is already infected. Vaccination usually doesn’t affect later quick tests, but some test kits warn that a recently vaccinated cat can test positive, so tell your vet when your cat was vaccinated.

Guidelines differ a little on kittens. Some recommend the vaccine for every kitten, at least where FeLV is common. Others class it as non-core and recommend it only for kittens likely to meet other cats. Your vet will know how common FeLV is where you live.

For adult cats, the vaccine is worth discussing if your cat goes outdoors, lives with cats that do, or shares a home with an FeLV-positive cat. A cat that stays indoors with FeLV-negative companions has very little chance of meeting the virus. Our vaccination guide covers the schedule and the other vaccines.

Questions to take to your vet

At the next visit, it’s worth asking:

• Which test should confirm the result, and when should we retest?
• Should my other cats be tested and vaccinated?
• How should the household be set up while we wait for results?
• Once we know the type of infection, how often should my cat be seen?
• Which changes at home should prompt a call?

Frequently Asked Questions

Can a cat that tested positive for FeLV become negative? Yes. Some cats that test positive at first get the virus under control and test negative on a later quick test, usually within about 16 weeks of being infected. The virus stays in their cells and may still show up on a PCR test, but these cats usually don’t pass it on and often live a normal lifespan. That’s why vets recommend retesting six weeks or more after a first positive result.

How long do cats with FeLV live? It depends on the type of infection. Cats with a persistent (progressive) infection usually have shorter lives, and many develop an FeLV-related illness within a few years of being infected, though some stay well for years. Cats that get the virus under control (regressive infection) do much better and often live a normal lifespan.

Can an FeLV-positive cat live with other cats? FeLV spreads through close, friendly contact such as grooming and sharing bowls, so a positive cat should be kept apart from negative cats until the results are clear. Every cat in the home should be tested, and the negative ones vaccinated, though the vaccine can’t stop every infection. Whether the cats can live together later is a decision to make with your vet.

Can FeLV spread to humans? No. There is no recorded case of a person being infected with FeLV. If someone in your home has a weakened immune system, tell their doctor and your vet, because an FeLV-positive cat picks up other infections more easily, and some of those can pass to people.