Health effects of exposure to thyme dust in a group of thyme growing farmers.

Medical examinations were performed in a group of 47 thyme farmers from eastern Poland while threshing thyme (Thymus vulgaris). As a reference group 63 urban dwellers were examined not exposed to organic dusts. The examinations included an interview concerning the occurrence of respiratory disorders and work-related symptoms, physical examination, lung function tests, skin prick tests with four microbial allergens and agar-gel precipitation tests with 12 antigens. 63.8% of thyme handling farmers reported occurrence of work-related symptoms while threshing thyme. The most common complaints were: blocking of the nose (reported by 18 farmers--38.3%), dry cough (14 persons--29.8%) and general weakness (13 persons--27.7%). The mean spirometric values in the farmers group were within a normal range and did not show a significant post-work decline. The farmers showed positive skin reactions to microbial antigens in the range of 4.3-14.9%, and a frequency of positive precipitin reactions 0-56.5%. The reference group responded to most allergens with a significantly lower frequency of positive results compared to the examined group. In conclusion, thyme farmers engaged in threshing this herb represent a group of elevated professional risk because of high incidence of work-related symptoms and common occurrence of positive skin and precipitin reactions to bacterial and fungal allergens associated with organic dust.