# Is Feline Leukemia Contagious to Other Cats? Is feline leukemia in cats contagious? Yes, the virus that causes it spreads easily from cat to cat through close contact, but it does not spread to people or dogs. The cancer itself (lymphoma or leukemia) is not contagious, so a cat with cancer cannot pass cancer to another cat. What spreads is feline leukemia virus (FeLV), and only between cats. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## Quick Answer - FeLV spreads from cat to cat, mainly through saliva during grooming, shared food bowls, and bites [1][2]. - FeLV does not infect people or dogs. It infects domestic cats and some wild cat species [3][4]. - Lymphoma and leukemia are cancers, not infections. A cat with lymphoma cannot give cancer to another cat [5]. - About 30 to 40 percent of exposed cats develop a regressive infection, meaning their immune system controls the virus. These cats do not actively infect other cats [1]. - Testing every cat before it joins a household, plus vaccination for at-risk cats, is the core of prevention [1][3]. ## What Feline Leukemia Virus Actually Is Feline leukemia virus is a retrovirus. Retroviruses insert copies of their own genetic material into the cells they infect, which is why they can stay in a cat's body for life [2]. FeLV is one of the most common infectious diseases in cats, though widespread testing and vaccination have cut its prevalence over the past 25 to 30 years [1][3]. The name is a bit misleading. FeLV does not only cause leukemia. It is the most common cause of cancer in cats, and it can also cause blood disorders and immune deficiency [2]. When the immune system is weakened, ordinary bacteria, viruses, and fungi from the everyday environment can cause serious illness in an FeLV-positive cat [2]. There are two broad outcomes after exposure. Some cats clear the virus or control it (regressive infection). Others stay persistently infected and can spread the virus to other cats [1]. ## Is Feline Leukemia Contagious to Other Cats? Yes. FeLV is contagious between cats, and this is the single most important fact for multi-cat homes. The virus passes through close, friendly contact and through fighting. ### How the virus spreads - Grooming and mutual licking (saliva is the main route) [1] - Shared food and water bowls - Bite wounds from infected cats - A mother cat to her kittens, before or shortly after birth Casual, distant contact is much less risky than living together, sharing bowls, or fighting. This is why an FeLV-positive cat and an FeLV-negative cat in the same home need a real plan, not just separate rooms on paper. ### What does NOT spread FeLV does not infect people. It also does not infect dogs. The virus is a cat virus, and it can spill into wild cat species such as lions and other wild felids, but it is not a human or canine pathogen [3][4]. Lymphoma and leukemia are cancers, not germs. If your cat has lymphoma, that cancer cannot be transmitted to your other cats, your dog, or you [5]. What can be shared is the virus that raises cancer risk, and only between cats. ## Signs Owners Notice Early FeLV infection often causes no obvious signs at all. Many cats look completely normal for months or years. When signs appear, they tend to fall into three groups. - **Blood problems.** Anemia (low red blood cells) is common and can cause pale gums, weakness, and fast breathing [3]. - **Cancers.** Lymphoma is the most common cancer in cats and is frequently linked to FeLV infection [5]. Signs depend on where the tumor sits and can include weight loss, vomiting, or a mass. - **Immune suppression.** Repeated infections, mouth disease, abscesses, and respiratory disease are more common in FeLV-positive cats [3]. Because these signs overlap with many other conditions, you cannot tell FeLV status by looking at a cat. Testing is the only way to know. ## Causes and Risk Factors The cause is infection with FeLV. The risk factors are about exposure and immune status. - **Outdoor access.** Outdoor cats face more contact with infected cats [3]. - **Unneutered males.** They fight more and are at higher risk [3]. - **Living with an infected cat.** Shared bowls and grooming drive transmission [1]. - **Other illnesses.** Cats with respiratory disease, mouth disease, or abscesses are at higher risk [3]. Prevalence in the United States and Canada sits around 2 to 3 percent of all cats, but it climbs to as high as 30 percent in cats that are ill or at high risk [1]. In one 2023 study of stray cats in the Lisbon area of Portugal, 8.5 percent tested positive [6]. These numbers show why testing matters most in cats with a known exposure or a suspicious illness. ## How FeLV Is Diagnosed Your veterinarian starts with a simple blood test, usually a point-of-care test run in the clinic. These tests detect a viral protein called p27 [6]. Here is the catch. A positive result on a rapid test does not always mean the cat is truly infected. In a 2026 study of shelter cats in Mississippi, the true prevalence of FeLV in apparently healthy cats was only 0.8 percent, and at that low prevalence the positive predictive value of the rapid test was about 40 percent [7]. In plain words, most positive rapid tests in healthy cats turn out to be false positives. In sick cats, where true prevalence was 5.3 percent, the same test was far more reliable, with a positive predictive value near 99 percent [7]. That is why a positive result should be confirmed with a second test, often a PCR test that looks for proviral DNA [6][7]. For a full breakdown of how these tests differ, see [Feline Leukemia FeLV and FIV Testing: Snap Tests vs PCR Differences](/knowledge/veterinary-medicine/at-home-diagnostics/feline-leukemia-felv-and-fiv-testing-snap-tests-vs-pcr-differences). If your cat has cancer, your veterinarian may also run blood work, imaging, and a biopsy to identify the tumor type. FeLV status and cancer diagnosis are two separate questions. ## Treatment Options There is no cure that removes FeLV from the body. Treatment focuses on the problems the virus causes and on keeping the cat comfortable. ### Supportive care - Treating secondary infections promptly [2] - Managing anemia and other blood disorders [3] - Nutrition and hydration support - Stress reduction, since stress can worsen immune function ### Cancer treatment If lymphoma or leukemia develops, chemotherapy is often the main option. Protocols vary by tumor type and by the cat's overall health. A 2026 case report described a 13-year-old FeLV-negative cat with a rare acute lymphoid leukemia that survived more than a year after diagnosis on multi-drug chemotherapy [8]. That is one case, not a promise, but it shows that some cats with blood cancers can do well with treatment. Your veterinarian calculates every drug dose from your cat's weight, organ function, and specific diagnosis. Never give a cat medication meant for people or another pet. ### Antiviral and immune support Some veterinarians use immune-modulating drugs or antivirals in selected FeLV-positive cats. Evidence for these approaches is limited, and response varies. Your veterinarian will decide whether any of these options fit your cat. ## Recovery, Outlook, and Long-Term Management The outlook for an FeLV-positive cat depends heavily on which infection pattern it has. - **Regressive infection.** The immune system controls the virus, no viral particles circulate in the blood, and the cat cannot actively infect other cats [1]. These cats are very unlikely to show clinical signs, though the virus can reactivate if the cat becomes immunosuppressed through illness or medication [1]. - **Progressive infection.** The virus keeps replicating. These cats can spread FeLV to other cats and are at risk of anemia, cancer, and immune suppression. The disease worsens over time and is usually fatal [3]. Long-term management for any FeLV-positive cat includes: - Keeping the cat indoors to protect it and other cats - Regular veterinary checkups, often twice a year - Prompt attention to any new sign of illness - Good nutrition and parasite control - Avoiding immunosuppressive drugs unless clearly needed [1] If your cat has low white cell counts or platelet problems from FeLV, your veterinarian may also discuss conditions like [Feline Immune-Mediated Neutropenia: Diagnosis and Management](/knowledge/veterinary-medicine/clinical-methods/feline-immune-mediated-neutropenia-diagnosis-management) or [Feline Immune-Mediated Thrombocytopenia: Diagnosis and Management](/knowledge/veterinary-medicine/clinical-methods/feline-immune-mediated-thrombocytopenia-diagnosis-management). ## Prevention Prevention has three parts: testing, vaccination, and managing contact. ### Test before mixing cats Test any new cat before it meets your resident cats. Test again after any known exposure, since it can take time for the virus to show up. A negative test in a healthy cat is reassuring but not perfect, given the test limitations described above [7]. ### Vaccinate at-risk cats An effective FeLV vaccine exists and has helped drive down prevalence over the past 25 years [1]. Vaccination is most useful for cats with outdoor access or any chance of contact with an infected cat. For details on who benefits most, see [FeLV Vaccine for Cats: Who Needs It and Leukemia Protection Efficacy](/knowledge/veterinary-medicine/preventive-care/felv-vaccine-for-cats-who-needs-it-and-leukemia-protection-efficacy). ### Manage contact in the home | Situation | What to do | |---|---| | New cat joining the home | Test before introduction, then isolate until results are back | | One cat positive, one negative | Separate bowls, litter boxes, and feeding areas. Prevent fighting | | Positive cat with regressive infection | Cannot actively infect others, but monitor for reactivation [1] | | Positive cat with progressive infection | Keep separate from negative cats. Do not share bowls | | Kittens from a positive mother | Test and discuss vaccination timing with your veterinarian | ### Spay and neuter Neutering reduces roaming and fighting, which lowers exposure risk [3]. ## Limitations and When to Contact a Veterinarian No article can tell you what is happening in your specific cat. Individual cases need a veterinarian who can examine your cat, review its history, and run the right tests. **Contact your veterinarian the same day if you notice:** - Pale gums, weakness, or collapse - Fast or labored breathing - Not eating or drinking for more than 24 hours - A new lump, sudden weight loss, or persistent vomiting **Go to an emergency clinic now if you see:** - Open-mouth breathing or severe distress - Bleeding that will not stop - Seizures or sudden inability to walk **Schedule a routine visit if:** - You are bringing a new cat into a home with other cats - Your cat had a known fight with an unknown cat - Your cat's FeLV status has never been checked and it goes outdoors ## Frequently Asked Questions ### Can I get feline leukemia from my cat? No. FeLV does not infect people. It is a cat virus, and it can affect domestic cats and some wild cat species, but it is not a human pathogen [3][4]. You can safely care for an FeLV-positive cat without risk of catching the virus yourself. ### Can my dog catch feline leukemia from my cat? No. FeLV does not infect dogs. The virus is specific to cats and closely related wild felids [3][4]. Your dog can share a home with an FeLV-positive cat without catching the virus. ### Is lymphoma in cats contagious to other cats? No. Lymphoma is a cancer, not an infection, so it cannot be passed from one cat to another [5]. What can pass between cats is FeLV, the virus that raises the risk of lymphoma. That is why testing and vaccination matter even when a cat already has cancer. ### Can two cats live together if one has FeLV? It depends on the infection pattern and the cats' behavior. A cat with a regressive infection does not actively shed virus and is unlikely to infect a housemate [1]. A cat with a progressive infection can spread the virus, so separate feeding areas, separate litter boxes, and no fighting are essential. Your veterinarian can help you build a plan that fits your home. ### How often should an FeLV-positive cat see the vet? Most veterinarians recommend checkups about every six months for an FeLV-positive cat. These visits let your veterinarian catch anemia, infections, or tumors early, when treatment options are broader [3]. Call sooner if you notice any change in appetite, energy, or breathing. ## Related Articles - [FeLV Vaccine for Cats: Who Needs It and Leukemia Protection Efficacy](/knowledge/veterinary-medicine/preventive-care/felv-vaccine-for-cats-who-needs-it-and-leukemia-protection-efficacy) - [Feline Leukemia FeLV and FIV Testing: Snap Tests vs PCR Differences](/knowledge/veterinary-medicine/at-home-diagnostics/feline-leukemia-felv-and-fiv-testing-snap-tests-vs-pcr-differences) - [Feline Immune-Mediated Thrombocytopenia: Diagnosis and Management](/knowledge/veterinary-medicine/clinical-methods/feline-immune-mediated-thrombocytopenia-diagnosis-management) - [Feline Immune-Mediated Neutropenia: Diagnosis and Management](/knowledge/veterinary-medicine/clinical-methods/feline-immune-mediated-neutropenia-diagnosis-management) - [Toxoplasma in Cats: Zoonotic Risk and Immunocompromised Owners](/knowledge/veterinary-medicine/parasite-control/toxoplasma-in-cats-zoonotic-risk-and-immunocompromised-owners) - [Ringworm In Cats](/knowledge/veterinary-medicine/parasitic-diseases/ringworm-in-cats) - [Feline Leukemia Treatment: Managing FeLV in Cats](/knowledge/veterinary-medicine/senior-and-chronic-care/feline-leukemia-treatment) - [Can Dogs Get Feline Leukemia Virus? What Owners Should Know](/knowledge/veterinary-medicine/preventive-and-routine-care/feline-leukemia-virus-in-dogs) - [How Long Can a Cat Live With Feline Leukemia?](/knowledge/veterinary-medicine/senior-and-chronic-care/how-long-cats-live-feline-leukemia) - [Feline Leukemia Virus](/knowledge/viruses/pet-viruses/feline-leukemia-virus) - [Feline Leukemia Virus Progressive Infection](/knowledge/viruses/pet-viruses/feline-leukemia-virus-progressive-infection) ## References 1. [Feline Leukemia Virus](https://www.vet.cornell.edu/departments/cornell-feline-health-center/health-information/feline-health-topics/feline-leukemia-virus). Cornell University College of Veterinary Medicine. 2. [Feline Leukemia Virus Brochure](https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/feline-leukemia-virus-brochure). Cornell University College of Veterinary Medicine. 3. [Feline Leukemia Virus (FeLV) - Cat Owners](https://www.merckvetmanual.com/cat-owners/disorders-affecting-multiple-body-systems-of-cats/feline-leukemia-virus-felv). Merck Veterinary Manual. 4. [Cross-species transmission of host adaptation of feline leukemia virus between domestic cats and the wild felid Leopardus guigna](https://pubmed.ncbi.nlm.nih.gov/42288833/). Veterinary research, 2026. 5. [Feline lymphoma associated with feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) infections in Brazil- Systematic review](https://pubmed.ncbi.nlm.nih.gov/41111634/). Veterinary and animal science, 2025. 6. [Prevalence and genetic characterization of feline leukemia virus in portuguese stray cats](https://pubmed.ncbi.nlm.nih.gov/40133929/). BMC veterinary research, 2025. 7. [Feline leukemia virus point-of-care lateral flow tests have low positive predictive value in apparently healthy shelter cats](https://pubmed.ncbi.nlm.nih.gov/41868399/). Frontiers in veterinary science, 2026. 8. [Feline leukemia virus-negative acute lymphoid B-cell aleukemic leukemia in a cat with prolonged survival](https://pubmed.ncbi.nlm.nih.gov/41929732/). The Canadian veterinary journal = La revue veterinaire canadienne, 2026. ## Further Reading - [Merck Veterinary Manual: Cat Owners](https://www.merckvetmanual.com/cat-owners) - [Cornell Feline Health Center: Health Information](https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information) - [American Veterinary Medical Association: Pet Care](https://www.avma.org/resources-tools/pet-owners/petcare)