Mycoses caused by inhalation of mycotoxin-producing-fungi growing indoors

Abstract

Various fungi are present in the indoor air. Many of them are known to produce mycotoxins, but the relation of the toxin of these fungi to human diseases is not well known. The only exception is the recent finding that gliotoxin produced by Aspergillus fumigatus play a significant role as a virulence factor in the development of the infection, i.e. aspergillosis. Stachybotrys chartarum is a ubiquitous fungus commonly found in our living environment. Although inhalation of the fungus has been suspected as a possible cause of acute idiopathic alveolar hemorrhage in infants, the definite relation is yet to be known. The fungus produces various secondary metabolites such as trichothecenes, we suspected that the repeated inhalation of the fungus may cause some damage to the human lung. To learn the effect of the long-term inhalation of the fungus, we repeatedly injected the spores of the fungus into mouse trachea. The histopathological examination of the mice disclosed the development of pulmonary hypertension. When isolates of S. chartarum with or without trichothecene production were used, the isolate with trichothecene production solely developed pulmonary hypertension, which fact suggests the possible role of the trichothecene in the development of the vascular changes. Further investigation is now under way.