Molds and Mycotoxins: A Brief Review

Diseases caused by molds and their toxic metabolites, mycotoxins, have been recognized since ancient times — from Assyrian tablets describing noxious pustules on grain in 600 BCE, to 132 documented epidemics of ergotism in Europe between the 6th and 18th centuries, to an epidemic of alimentary toxic aleukia that killed approximately 100,000 people in Russia in 1944. There are more than 100,000 species of mold; approximately two dozen can cause health problems in humans. Mycotoxins are secondary metabolites produced by molds as a survival mechanism — destroying competing bacteria so the mold can secure its food source. This same mechanism led to the discovery of penicillin by Alexander Fleming in 1928, which has saved an estimated 200 million lives. This review covers the major classes of mycotoxins (aflatoxins, fumonisins, ochratoxins, and trichothecenes), their specific health effects including carcinogenesis, nephrotoxicity, immune suppression, and neurotoxicity, and the clinical presentation of indoor mold exposure. The CDC, following Hurricane Katrina, concluded that excessive exposure to mold-contaminated materials can cause health effects in susceptible persons regardless of the type of mold. The WHO has confirmed that occupants of damp or moldy buildings are at increased risk of respiratory symptoms, infections, and asthma. The paper reviews sick-building syndrome, indoor air quality, and the routes of mycotoxin exposure. It concludes with a call to action: mold mycotoxicosis was called “the neglected disease” by Forgacs in 1962, and clinicians should include molds and mycotoxins in their differential diagnosis to help it become “the accepted disease.”