Feline Leukemia Virus

Russell Veterinary Hospital, P.C.​Lakeside Veterinary Medicine

"All Creatures Great and Small..."

Feline Leukemia Virus (FeLV) is a virus that is transmitted between cats through close, intimate contact.  This virus is actually quite prevalent in this area of the country,  specifically Warren, Chautauqua, and Cattaraugus counties.  Infection rates are much higher in multi-cat households and in cats that go outside.  It is one of the most important causes of sickness and death in the cat population.


FeLV can be found in the saliva, tears, urine, and milk of infected cats.  Common modes of transmission include nose to nose contact, contact with saliva or urine, mutual grooming, shared litter trays and food dishes.   Cats that go outdoors are commonly infected through bite wounds.  This virus can also be transmitted across the placenta from mother to fetus. 

Disorders caused by FeLV Infection

There are several disorders that can be caused by FeLV infection.  Immunosuppression is quite common.  This means the cat’s immune system is not functioning properly making the cat susceptible to many different types of infections.  Cancer, including leukemia and lymphoma, are common side effects of  FeLV infection.  Approximately 70 % of all feline lymphomas are FeLV positive.[1]  Other side effects of this virus include infertility, abortions, vomiting, and diarrhea.



There is a test to see if your cat is infected with this virus, which also tests for FIV infection as well.  The test requires a small amount of blood and takes about 20 minutes to run.  We would strongly recommend testing any new cat joining the household.


There is no good treatment for this disease.  Supportive care for any secondary infections is the best thing you can do.  Preventing your FeLV positive cat from stress and exposure to infections is very important.  It is imperitive to keep your cat indoors 100% of the time to prevent any other cat from becoming infected.  Bringing your infected cat in regularly (every 6 months) for physical exams, dental exams, body weight, etc. is very important.  Most FeLV positive cats will die within 3-5 years of infection, but some can live more than 5 years.


There is a highly effective vaccine to prevent FeLV infection.  We vaccinate any cat that goes outside or is exposed to cats that go outside.  As stated earlier, it is important to test your cat for FeLV before vaccinating especially if there are other cats in the household.


[1] Guptill, Lynn.  VCS 506.  Purdue University School of Veterinary Medicine. 2006

2 Kahn, Cynthia.  The Merck Veterinary Manual 9th ed.  2005