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So your cat has FeLV, now what?

Updated: Oct 22, 2019

Whether you just decided adopted a cat, or if your furry friend has been with you forever, finding out that your cat has a chronic, debilitating, and sometimes deadly disease is discouraging and even scary. While there are several known chronic viruses that can infect and affect cats, one of the best known, and impactful disease is Feline Leukemia Virus, or FeLV for short. FeLV is a cat only disease and does not pose a risk to humans. FeLV is often transferred from one cat to another by routine activities including: licking, nursing of new kittens, or through feces.

So What is FeLV, and what are its symptoms?

FeLV is a part of a large family of “retroviruses” which really means they have a cunning ability to infect your feline friend and make itself a permanent “guest” in their body. While most cats that contact FeLV, will develop acute (or severe) initial response, many will eventually clear the virus from their blood, however, FeLV has other plans. FeLV will eventually integrate itself into the cat’s own DNA, and may lay dormant for weeks, months, or even years to come with your cat appearing overall happy. For reasons we do not fully understand FeLV will become activated and may result in a variety of symptoms, many of which are disheartening.

So what do most cats with active FeLV look like? Active FeLV will often lead to cats which are weak, lose appetite and weight, vomit, show signs of gum disease and conjunctivitis (eye infection), and finally Leukemia. Leukemia, or white blood cancer, will weaken the immune system thereby leading significant disease and death. Many cats with Leukemia have only a few months to live, devastating news to any cat owner.

How are cats tested for the presence (or absence of FeLV)?

Testing for FeLV is often done at your local veterinarian office, and are often part of an initially health checkup of new cats or routine checkups for outdoors cats. A vet will often need to bleed your cat and will process the blood sample to determine whether FeLV (or its traces) are found in their blood. This test is useful in that it informs the cat owner whether the cat has been exposed to FeLV in the past, but unfortunately, blood tests do not provide an indication regarding FeLV activity in your cat. In fact, most vets agree that a cat testing position for FeLV must be re-tested at least once, and preferably by a different, more sensitive (but also more expensive) blood test. In this second test the blood is tested for the presence of the virus’ own DNA, but again no real indication of FeLV activity is provided.

Because FeLV is transmitted by licking or grooming (saliva), measuring virus titers (a fancy work for virus numbers) can provide indication not only on whether your cat has FeLV but also whether the virus is being produced in high levels that can endanger other cats or the cat’s own health. Saliva testing is tricky, and only tests with high sensitivity (for example measuring 100 viruses at a time) are informative. Similar to retesting of blood, testing for the virus own DNA in the saliva is crucial to provide good sensitivity for the test.

Does FeLV have a cure?

Although scientists have learned a lot about FeLV and its effects on felins, to date there is no cure for FeLV or its symptoms. Pharmaceutical companies focusing on FeLV prevention developed a somewhat effective vaccine, however, as with most vaccines prevention is never 100%. Some companies suggest that homeopathic drugs can help control FeLV, but many of these claims were not tested by proper scientific studies and should be taken with a grain of salt. To date, there is no real cure for FeLV or its symptoms. The best approach is to vaccinate your cat against FeLV.

So what should I do with my FeLV+ cat?

Whether your cat tested positive or negative for FeLV, they are your friends forever. Because no one (including your local vet) can predict when the disease will present itself, you should stay keep an extra eye on signs that include the symptomes we indicated above. If your FeLV+ cat is part of several other cats in your household (or outside) it is best to neuter/spay your cat to reduce the likelihood of spreading FeLV. A separate food and water bowls will also reduce the likelihood of transmitting the disease to other cats, as would buying a separate litter box. Monitoring infected cats for the levels of FeLV in their saliva will give some indication(s) to whether your FeLV is active in your cat. Testing for indoor cats should be done annually while outdoor cats should be tested every 6 months or so. If you have multiple cats, you should be testing all of them regularly.

This blog was prepared by LLC. CatDX mission is to develop and provide accurate affordable pet testing. We know that going to your vet can be stressful and expensive so we developed a saliva test for FeLV at a fraction of the cost. Learn more at

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