Effects of Intranasal Exposure to Spores of Stachybotrys atra in Mice

The effects of highly toxic and nontoxic spores of Stachybotrys atra were investigated in mice after six intranasal administrations of 1 × 105 and 1 × 103 spores in phosphate-buffered saline during a 3-week period. Toxic spores contained the trichothecene mycotoxins, satratoxins G and H, as well as the immunosuppressant stachybotrylactones and-lactams. No trichothecenes were detected in the nontoxic spores, and they contained only minor amounts of stachybotrylactones and-lactams. In mice injected with toxic and nontoxic spores, the platelet count was decreased and leucocyte and erythrocyte counts, hemoglobin concentration, and hematocrit were increased. No IgG antibodies to S. atra were detected in sera of mice exposed intranasally to spores. No histological changes were detected in spleen, thymus, or intestines of mice. The mice receiving 1 × 105 toxic spores intranasally developed severe inflammatory changes within both bronchioles and alveoli. Hemorrhage was detected in alveoli. The mice receiving 1 × 105 nontoxic spores also developed inflammatory changes in the lungs, but these changes were significantly milder than those in mice receiving toxic spores. The mice receiving 1 × 103 toxic spores developed inflammatory changes in the lungs that were less severe than those in the mice receiving 1 × 103 toxic spores. No inflammatory changes were detected in the mice receiving 1 × 103 of nontoxic spores. The present findings indicate that exposure to S. atra spores containing toxins (satratoxins) can be a significant health risk.