Number of Species: Approximately 200 species
There are approximately 200 different species of Aspergillus, sixteen of which have been documented as etiological agents of human disease. The diseases caused by these species rarely occur in individuals with normally functioning immune systems. Toxin production is dependent on the species or a strain within a species and on the food source for the fungus. These fungi are found in soil, compost piles, plant debris, and stored grain, as well as on water damaged building materials.