Abstract

A study has been made of the atmospheric pollution by aspergillus spores of a large animal provender mill in which various grains are unloaded, stored, and processed, and a comparison has been made with the degree of pollution of the urban atmosphere in the neighbourhood. The catch-rate of the spores in the normal working atmosphere of the mill has been found to be 30 times higher than that obtained in the urban atmosphere, and for this reason the health record of a group of operatives has been considered with particular reference to the occurrence of pulmonary aspergillosis. Despite the risk of exposure within the mill no evidence has been found of an increased liability to develop the disease.

The particular groups of aspergilli isolated by culture during this study have all been reported to have been associated with aspergillosis in man, and the relevant papers give evidence of a pathogenic rather than a saprophytic role. The study therefore provides quantitative data relating atmospheric spore content and the risk of pulmonary infection in man, a subject which as yet has received little attention.

In this study it has been found that of all the grains handled in the mill, maize is associated with the highest degree of contamination, so that the aspergillus spores in the atmosphere of the mill may have originated chiefly from this source.