Incidence of serum-precipitating antibodies to farmer's lung antigens in Hokkaido.

The prevalence of serum-precipitating antibodies to Micropolyspora faeni and Thermoactinomyces vulgaris was studied by immunoelectrophoresis in 442 dairy farmers living in Hokkaido, the northernmost district of Japan. The prevalence rates of antibodies to M. faeni and T. vulgaris were 24.2 and 11.6%, respectively. The rate of antibodies to M. faeni was higher among females than males. This difference may be due to the large number of nonsmokers among females. Prevalence of antibodies to M. faeni or M. faeni and T. vulgaris was associated with a higher hay acreage and longer working hours per day in the cowshed, and not to the size of the dairy herd. These results were partly different from those reported from other countries.