Studies of mouse polyoma virus infection. III. Distribution of antibodies in laboratory mouse colonies.

Eight mouse colonies were surveyed for prevalence of antibody to mouse polyoma virus. Frequency of HI antibody varied from 0 to 84 per cent in adult mice in different colonies. Antibody was infrequent in mice less than 3 months of age, and increased in frequency with age. There was no evidence that infection was specific for particular mouse strains. The highest frequency of infection was found in colonies in which breeding mice are housed in proximity to mice inoculated with polyoma virus or passage tumors, and within an infected colony, the incidence of infection was greatest in rooms housing mice inoculated with polyoma virus. Mice from a colony free of antibody became infected when held in room or cage contact with virus-inoculated mice, but at very low rates except in mothers of inoculated litters. These results were interpreted as indicating that artificial contamination of the environment is an important factor in determining the prevalence of infection in the colonies observed. There was no correlation between polyoma infection and spontaneous leukemia in AK. mice.