Prevalence of disease in nonviremic cats previously exposed to feline leukemia virus.

Feline leukemia virus status and antibody titer to feline oncornavirus-associated cell membrane antigen (FOCMA) were determined on plasma from 183 outpatient cats and 61 cats from 2 closed, FeLV-positive, multiple-cat households. Cats with FOCMA antibody titer had a significantly (P less than 0.02) higher prevalence of history of disease than did cats without FOCMA antibody. Diseases included upper respiratory tract infections, abscesses, ear infections, lower urinary tract infections, gastrointestinal disease, pneumonia, uterine infection, lymphadenopathy, fever of unknown origin, and bacterial infections. The FOCMA antibody titer was determined by use of an indirect fluorescent antibody test; titer greater than or equal to 1:16 was considered to be positive results. Lower mean FOCMA antibody titer was observed in young cats with history of disease (P less than 0.05) than in young cats without history of disease or in older cats with or without history of disease. Prevalence of FOCMA antibody titer was identical (38%) in young and adult cats, indicating cats likely were exposed to FeLV as kittens because a higher prevalence of FOCMA antibody titer in older cats would otherwise be expected.