Cohort studies of immunologic lung disease among Wisconsin dairy farmers.

Traditionally, hypersensitivity pneumonitis (HP) or farmer's lung disease (FLD) was thought to be the major occupational respiratory problem of farmers. In recent years, other acute conditions, particularly organic dust toxic syndrome (ODTS), have been recognized as significant features of the agricultural respiratory disease picture. The differences between HP and ODTS are discussed in this article. A cohort of workers on 90 dairy farms has been under study since 1975. Prevalence of FLD was calculated at 4.2/1,000. Extensive immunologic testing of this group was conducted. Serum antibody reactivity to farmer's lung antigens was related to chronic symptoms of bronchitis and occupational asthma, but not FLD. Serology may be thought of as a measure of exposure, but not FLD.