Frederick Fung

Health effects of mycotoxins: A toxicological overview

Diseases caused by fungi are spread by direct implantation or inhalation of spores. Fungi can cause adverse human health effects to many organ systems. In addition to infection and allergy, fungi can produce mycotoxins and organic chemicals that are responsible for various toxicologic effects. We reviewed the published literature on important mycotoxins and systemic effects of mycotoxins. Scientific literature revealed a linkage between ingesting mycotoxin contaminated food and illness, especially hepatic, gastrointestinal, and carcinogenic diseases. Issues related to mycotoxin exposure, specific diseases, and management are discussed. Although there is agreement that diet is the main source of mycotoxin exposure, specific health effects and risk assessment from indoor nonagricultural exposure are limited by the paucity of scientific evidence currently available. Further research on the health effects of inhaling mycotoxins in indoor settings is needed.

Health Effects of Indoor Fungal Bioaerosol Exposure

Occupational and environmental health professionals are confronted with issues concerning the health effects of indoor fungal bioaerosol exposure. This article reviews current data on the health effects of indoor mold exposure and provides practical suggestions for occupational and environmental health practitioners regarding how best to manage these exposures based on published human studies. We conducted MEDLINE searches and reviewed all English language studies on indoor mold exposure (visible survey or objective sampling) and human health effects published from 1966 to November 2002. The main findings of the studies are analyzed in conjunction with plausible association of health effects and fungal exposure. Five case control studies, 17 cross-sectional surveys, and 7 case reports met the selection criteria. Current evidence suggests that excessive moisture promotes mold growth and is associated with an increased prevalence of symptoms due to irritation, allergy, and infection. However, specific human toxicity due to inhaled fungal toxins has not been scientifically established. Methods for measuring indoor bioaerosol exposure and health assessment are not well standardized, making interpretation of existing data difficult. Additional studies are needed to document human exposure-disease and dose-response relationships.

Stachybotrys, a mycotoxin-producing fungus of increasing toxicologic importance.

BACKGROUND Stachybotrys as a fungus has been implicated as a source of mycotoxins. While the toxicity of several well-known mycotoxins (aflatoxins) is well documented, recent studies on Stachybotrys have raised the question that mycotoxins produced by this fungus may be responsible for the health effects of occupants in water-damaged buildings. METHODS Published articles regarding Stachybotrys-related mycotoxins were reviewed with particular focus on human toxicity. RESULTS A critical review of papers, reports, and studies on Stachybotrys mycotoxins revealed only descriptive reports of suspected animal and human poisoning secondary to consumption of mold-contaminated food products. No studies of good toxicologic and epidemiologic designs answer whether airborne mycotoxins produced by Stachybotrys could produce specific human toxicity. CONCLUSIONS Current data on the toxicology of mycotoxins produced by Stachybotrys demonstrate that this group of mycotoxins is capable of producing immunosuppression and inflammatory insults to gastrointestinal and pulmonary systems. Case control study and case reports have suggested a possible association with environmental exposure to Stachybotrys mycotoxins, although a firm causal relationship has not been firmly established. Additional studies are needed to document that humans with sufficient exposure to these mycotoxins develop compatible clinical and pathologic pictures as demonstrated in animal models.

Alternaria - Associated Asthma

In addition to house dust mites, there is increasing evidence that mold allergens, especially Alternaria, are implicated in contributing to allergic reaction, rhinitis, and asthma indoors. Situations leading to the exacerbation of asthma in an employee were investigated and subsequent medical evaluations were performed. An industrial hygiene study was conducted and bioaerosol testing revealed several mold allergens were present. However, based on the medical evaluation and testing results (skin prick test and radioallergosorbent test [RAST]), it was concluded that Alternaria was inducing the respiratory reaction. Alternaria was present in the drip pan of the air conditioner unit and remedial actions were taken to remove the mold. Post-remedial bioaerosol sampling results revealed Alternaria was no longer present in the air and the employee returned to the office without recurrence of symptoms. Practically, several factors should be considered prior to concluding an association between exposure and illness. First, the employees symptoms and signs should be consistent with a medical diagnosis. Second, there should be either in vitro or in vivo evidence of exposure. Third, environmental assessment should reveal evidence of plausible biological exposure. Fourth, there should be substantial improvement or even resolution of the illness after appropriate remediation of the health hazard. This case study illustrates the importance of teamwork by industrial hygienists and occupational health physicians in treatment and prevention of occupational and environmental diseases.

The Fundamentals of Mold-Related Illness: When to Suspect the Environment is Making a Patient Sick

Abstract Disorders related to indoor air quality have become a major concern for primary care physicians, who often are asked to evaluate patients whose symptoms may be caused or aggravated by indoor exposure to mold. In this article, we review the common types of indoor mold and discuss the management of mold exposure and related illnesses.

Styrene-Induced Peripheral Neuropathy

CASE REPORT Styrene is a colorless, oily liquid most commonly found in paints, plastics, and resins. Like many solvents, styrene can cause intoxication and central nervous system depression when inhaled in high concentrations for extended periods. Rarely, styrene has been implicated as a cause of peripheral neuropathy. We describe a case of a previously healthy 57-year-old man who developed signs and symptoms consistent with a peripheral neuropathy after applying a fiberglass resin to the inside of a septic tank over a 2-day period. Nerve conduction tests verified examination findings. Styrene exposure should be minimized through the use of respirators and protective clothing to prevent this type of toxicity.