How Do Cats Get Feline Leukemia?

Feline leukemia (FeLV) is a retrovirus that affects only domestic cats and some of their nondomestic relatives. The virus works by suppressing the infected cat̵7;s immune system leading to other health problems, such as anemia and cancer. According to WebMD, 85 percent of infected cats who show signs of illness die within three years of their diagnosis making FeLV the second greatest cause of cat death. Understanding how FeLV is contracted can help you protect your cat from infection.

  1. Virus Transmission

    • Sharing water bowls is one way cats can transmit the virus to other cats.

      FeLV is transmitted between cats through bodily fluids. For example, if an infected cat bites another cat, the virus may be transmitted via the attacking cat̵7;s saliva. Mother cats can transmit the virus to her nursing kittens through her milk. Blood and nasal secretions also can carry the virus. Cats who live together and share food or water bowls can pass the virus to one another as can cats who groom one another. Feces and urine also can carry the virus but because it cannot live long outside of the cat̵7;s body, the risk of transmission through this type of contact is smaller.

    At-Risk Cats

    • Cats who spend time outside are at an increased risk of catching FeLV.

      Not all cats are equally at risk for FeLV. Male cats contract feline leukemia at higher rates than do female cats, particularly if they spend time outdoors. Cats whose mothers were infected are also at greater risk of contracting the virus. Unfortunately, kittens are one of the most susceptible groups. Any cat who lives with large numbers of other cats is also at increased risk, especially if new cats are introduced to the group without being tested for the virus. Because many cats do not show any signs of infection, these seemingly healthy cats easily can infect other felines who share their home or environment.

    Reducing Risk of Transmission

    • Cats can be immunized against feline leukemia, but the immunization does not provide complete protection. According to the ASPCA, however, cats who are healthy, more than 3 months old and immunized, have a greatly reduced risk of infection. The immunization is usually given in two injections administered three weeks apart. Cats should be tested for the virus before they are immunized since they can be infected even if they show no symptoms of the virus. Living with only one cat in a household can reduce the risk, especially if the cat stays indoors. Just 3 percent of cats who live alone have feline leukemia. If new cats are added, they should be quarantined from the rest of the feline household until they test negative for FeLV.

    Consequences of Transmission

    • If your cat tests positive for feline leukemia, the diagnosis is not an immediate death sentence. Many immune systems are able to fight off the virus. The Virginia-Maryland Regional College of Veterinary Medicine also says some cats develop a ̶0;latent infection,̶1; which may not cause problems immediately but may become active later. In some cases, these latent infections cause bone cancer. Finally, the cat̵7;s immune system may become less effective so she can become susceptible to diseases, such as cancer and other health problems. Veterinarians will treat these problems as they arise, but no cure is available for feline leukemia so the virus will result in the cat̵7;s death, usually in less than three years from the diagnosis.