Exposures to respirable, airborne Penicillium from a contaminated ventilation system: clinical, environmental and epidemiological aspects.
The occurrence of apparently work related, recurrent respiratory symptoms in two clerical workers was investigated. NIOSH was asked to investigate after 2 of 14 office workers reported coughing, wheezing, dyspnea, malaise, and fever; symptoms worsened during the work day and week and lessened on weekends and holidays. In the affected office and a comparison office, samples of airborne microorganisms and dust from forced air ventilation units were cultured to determine the presence of abnormal organisms. A standardized respiratory disease questionnaire plus additional questions relating to hypersensitivity pneumonitis (HP) were asked of the 14 workers in the affected office and 11 in the comparison office. The two affected workers were clinically examined for erythrocyte sedimentation rate (ESR), chest X-ray, pulmonary function tests, gallium scan, bronchoalveolar lavage, and response to steroid therapy. In the affected office, heater/cooler units had not been cleaned in 2 years and were heavily contaminated, mostly with Penicillium molds. Airborne samples from both offices yielded 50 to 90 colony forming units (CFU) per cubic meter of air when ventilation units were not in operation. However, when units were operating, CFU increased 50 to 80 times in the affected office but less than 5 times in the comparison office. No significant differences in worker symptoms were found between offices. Of the two cases, one, who did not smoke and was not atopic, had normal chest X-ray, mildly obstructed pulmonary function, ESR of 60 to 90, abnormal gallium scan, and increased T-cell lymphocytes in lavage. This case responded to steroids and was diagnosed as probable HP. The other case, an atopic smoker, had no abnormal findings and was diagnosed as having bronchial asthma, possibly aggravated by intense exposure to fungal antigens. The authors suggest that these findings may have broad implications for public health.