Feline Leukemia Virus
Feline Leukemia infection (or FELV), is caused by the Feline Leukemia Virus. The virus is transmitted from one cat to another. Transmission is through saliva, and this usually involves bite wounds. The virus can also be transmitted from infected mothers to their offspring in the uterus or through nursing, or other less aggressive forms of contact (lovers and fighters). Mutual grooming and sharing food and water dishes is a possible means of transmission. The likelihood of transmission depends upon the age and health of the exposed cats. Young cats are the most susceptible to infection, so it is the most critical time to protect them from the disease.
Feline Leukemia Virus is specific to cats. There is no risk to humans or to other non-felines. Although there is an association between the Leukemia virus and Leukemia or lymphoma (the white blood cell cancer), not all patients with the cancer have the virus, and not all patients with the virus have the cancer.
Vaccination and prevention: Keeping cats indoors and away from potentially infected cats is the best method of prevention and control. Vaccination (especially of kittens) is an important means of preventing disease. The Androscoggin Animal Hospital and the American Association of Feline Practitioners strongly recommends vaccinating all kittens against FELV infection. Kittens are the most susceptible population of cats, and it is difficult to know that a cat will be exclusively indoors and not exposed to infected cats. The initial vaccination series is 2 vaccinations 3-4 weeks apart, and then there is a booster at 1 year. Subsequent booster intervals should be discussed with your Veterinarian. It is important to discuss the risks and benefits of all vaccinations with your Veterinarian.
The virus is not capable of living in the environment for very long, so healthy cats can be added to households where an FELV positive cat was present. It also means that indirect transmission from the environment, although possible, is unlikely. Reasonable precautions include cleaning and sterilizing all dishes and litter boxes, or replacing them with new items.
Diagnosis: The diagnosis of FELV infection involves blood testing. The initial testing can be performed in the clinic, and results are available within 15 minutes. The symptoms of the disease vary but can include fever, various forms of cancer, blood disorders, and infections. All cats should be tested before they are added to a household, and all sick cats should be re-tested for FELV infection.
Positive cats: Cats that have been diagnosed with FELV should remain indoors. This is to prevent transmission of the FELV virus to other cats, and to protect the infected cat with a compromised immune system from contracting illnesses that could be very serious. If there are other cats already in the home, then they are at risk to develop the disease. The chances of becoming positive are around 10-15%. This again depends on the age and health of the other cats. Isolating the positive cat from the non-infected cats can drastically reduce or eliminate the chance of infection. Vaccination can also help protect exposed cats, but in the face of constant and prolonged exposure, it is not guaranteed.
Infected cats should be examined by a Veterinarian every 6 months to ensure the best possible health.
Prognosis: The prognosis for FELV positive cats depends upon the age at which the cat has become infected. Younger cats can become very sick very quickly, and they can die from the disease or from complications related to a suppressed immune system. Older cats may not show any signs of illness for many years if they are cared for properly.