Chest symptoms and farmer's lung: a community survey.

259-265. Farmer's lung is one of the commonest causes of extrinsic allergic alveolitis, but there have been few studies of representative samples of farmers. A survey was carried out in Devon among 91 farmers and their families in order to estimate the prevalence of respiratory symptoms and of positive precipitin reactions to thermophilic fungi. Answers to a questionnaire about respiratory symptoms and smoking habits revealed among the men a prevalence of symptoms comparable with that found in other surveys of agricultural populations in the United Kingdom but with a lower proportion of smokers. A positive answer to a question about attacks of breathlessness associated with fever or shivering appeared to differentiate people suffering from farmer's lung. Twenty-three per cent of the population had precipitins to and two of these individuals also had precipitins to other fungi. There were statistically significant differences in the proportions of positive precipitin tests found in smokers, ex-smokers, and non-smokers. Six known cases of farmer's lung were included in the sample and all had positive precipitins.