ORGANIC DUST EXPOSURES FROM COMPOST HANDLING - CASE PRESENTATION AND RESPIRATORY EXPOSURE ASSESSMENT

Inhalation of dust from contaminated organic materials may result in a cute respiratory tract illness. Possible mechanisms include toxic and cellular reactions to microbial and other organic products or immunolo gic responses after prior sensitization to an antigen. A case is prese nted of a 52 year old male who developed fever, myalgia, and marked dy spnea 12 hr after shoveling composted wood chips and leaves. Inspirato ry crackles, hypoxemia, and bilateral patchy pulmonary infiltrates wer e seen. Precipitating antibody tests for the usual antigens were incon clusive. He improved over 3 days. In order to assess the environmental conditions the patient had experienced, we returned to the site to re produce and measure respiratory exposures during hand loading of the c ompost. Visible clouds of fine particulate were easily generated durin g handling activities. Microscopic examination of these dusts indicate d a predominance of spores. Endotoxin concentrations from inspirable a nd respirable dust samples ranged from 636 to 16,300 endotoxin units/m 3. Levels of contaminants found were consistent with those associated with respiratory illness in other agricultural settings. Two respirato ry disorders, hypersensitivity pneumonitis (HP) and organic dust toxic syndrome (ODTS), may occur after exposure to organic dusts containing fungal spores and endotoxins. Despite extensive clinical and environm ental investigations, we were unable to differentiate these two disord ers, and suggest they may represent parts of a spectrum of responses t o complex organic dusts, rather than completely distinct clinical enti ties. (C) 1993 Wiley-Liss, Inc.