Mycotoxins as biological weapons
Mycotoxins are toxic secondary metabolites produced by fungi that can pose serious health risks to humans and animals when inhaled or ingested. They have garnered attention as potential biological weapons due to their ability to be easily isolated and utilized in harmful ways. Favorable environmental conditions, such as extreme weather, can lead to increased mycotoxin production, posing a threat to food supplies—approximately 25 percent of the world’s grain is believed to be contaminated at any given time.
Mycotoxicosis, or poisoning from mycotoxins, can result in a wide range of health issues, including respiratory failure, liver and kidney damage, and neurocognitive dysfunction. Key genera of fungi like Aspergillus, Fusarium, and Penicillium are significant contributors to mycotoxin contamination. Among these, T-2 mycotoxin is noted for its potency and has been linked to historical instances of biological warfare. The presence of toxigenic molds in domestic environments can also lead to "sick house syndrome," highlighting the importance of understanding both health implications and potential threats posed by these fungal toxins.
As research continues, the dual nature of mycotoxins as both environmental contaminants and possible biological agents remains an area of concern for public health and security agencies.
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Subject Terms
Mycotoxins as biological weapons
DEFINITION: Natural secondary byproducts of fungi that can produce toxic effects when ingested or inhaled.
SIGNIFICANCE: Forensic scientists are sometimes called upon to identify mycotoxins and toxigenic molds, which can cause severe health problems with long-term exposure. Mycotoxins are also a concern to law-enforcement agencies because these agents can be readily isolated and, thusx have potential for use as biological weapons.
Mycotoxin production occurs when favorable environmental conditions allow fungi to grow on plants or plant-based materials. Mold and mycotoxin contamination can increase in extreme environmental conditions, such as drought, excessive precipitation, floods, sudden frost, and constant high humidity. Most of the world’s croplands, forests, and population centers are in temperate zones, prime breeding grounds for toxigenic fungi. Estimates suggest that at any given time approximately 25 percent of the world’s grain supply is contaminated with mycotoxins. It has also been estimated that at least 10 percent of all buildings in North America are contaminated with toxigenic molds at levels that pose a risk to health.
The severity of mycotoxicosis, or mycotoxin poisoning, depends on the toxicity of the mycotoxin, the extent of exposure, and the age and health of the victim. The human health impacts of mycotoxicosis are multiple, including allergies, chronic bronchitis, skin necrosis, respiratory failure, loss of bone marrow, liver and kidney failure, skin irritation, loss of appetite, tremors, vasoconstriction, headache, chronic fatigue, cancers, vomiting, gastric and intestinal irritation, hemorrhaging, tachycardia, severe immunodeficiency, neurocognitive dysfunction, anxiety, tremors, fibromyalgia, lupus, ataxia, and reproductive problems. Because of these toxic effects, mycotoxins are part of an ongoing controversy over their use as biological weapons to produce neurological impairment.
Toxigenic fungi associated with animal and human food chains are in three main genera: Aspergillus, Fusarium, and Penicillium. Although Aspergillus and Penicillium species are important mycotoxin producers—Penicillium alone can produce twenty-seven different mycotoxins—Fusarium are most significant in their effects on crops, poultry, livestock, and farmworkers. Claviceps fungi are responsible for historical epidemics of ergotism, and Stachybotrys chartarum, considered one of the most poisonous molds on Earth, is commonly found in human dwellings.
Stachybotrys chartarum and Chaetomium are fungi often identified within domestic housing and considered the source of “sick house syndrome.” The fungi are found in dark, moist indoor environments such as wall cavities, attics, basements, and ventilation systems. The fungi produce black spores resembling soot that grow aggressively on moist drywall and are carried by circulating air. Several high-profile sick house toxic tort cases have been litigated in the United States.
Trichothecene mycotoxin (T-2 mycotoxin), a derivative of Aspergillus, Stachybotrys, and Fusarium, is considered among the most potent naturally occurring toxins. T-2 mycotoxin is the only biological active toxin effective through inhalation, ingestion, and dermal exposure. Declassified US government documents suggest that T-2 mycotoxins have been identified as agents of biological warfare since the mid-1970s in Laos, Afghanistan, Cambodia, and the Arabian Peninsula. It has been asserted that T-2 mycotoxin exposure is a causal agent of the illness known as Gulf War syndrome.
Bibliography
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