Fungal toxins, or mycotoxins, are biomolucules produced by fungi which can be toxic to animals and humans. Many fungal toxins interfere with RNA synthesis and can damage DNA. Aspergillus Flavus and Aspergillus parasiticus are strong carcinogens. Trichothecenes produced by Stachybotrys chartarium and Asperigullus versicolor were present in most samples of tested material and dust from buildings with current or past water damage. Of fifteen samples, nine of these came from buildings without visible damage or mould.
Aspergillus mold culture.
(Photo available through Environmental Health Perspectives)
More Information available at World Health Organization.