Risk Factors for FeLV
Sick cats are four times more likely than healthy cats to be infected with FeLV. Researchers estimate that about 50 percent of cats with severe bacterial infections, and 75 percent of cats with toxoplasmosis, a protozoan disease, also have FeLV infections.
Males are 1.7 times more likely to be infected than females, and younger cats are more susceptible to infection than older cats. FeLV is found mostly in cats from 1 to 6 years old; the average age is 3 years.
Outdoor cats are more likely to be infected with FeLV. Less than 1 percent of healthy indoor cats in the United States are infected with FeLV, compared to 1 to 2 percent of healthy outdoor cats, and more than 13 percent of sick stray cats. FeLV is more common in multicat households than in single-cat households, especially when cats go outdoors.