Sick Building Syndrome: possible association with exposure to mycotoxins from indoor air fungi

HK Hudnell1, RS Shoemaker2
1US Environmental Protection Agency, Research Triangle Park, NC 27711 USA
2McCready Outpatient Services Center, Pocomoke City, MD 21851 USA

Introduction. Chronic human illness associated with residential or occupational buildings, commonly referred to as sick building syndrome (SBS), may be a multifactorial condition, involving in some cases volatile organic compounds, CO or CO2, pesticides, biologic agents, temperature and humidity, lighting, and neuropsychological status. Recent evidence indicated that the primary causative factor in a subset of SBS cases may be exposure to mycotoxins from indoor air fungi. A variety of fungal genera, including Stachybotrys, Aspergillus, Penicillium and Cladosporium, have been identified on interior cellulose materials following water intrusion. Many species have been shown to produce mycotoxins and release spores to air. Mycotoxin exposure has been associated with effects on the nervous, digestive, respiratory, cutaneous, urinary, reproductive, immune and other systems (1). Dr. Shoemaker's data from a series of cases are described to illustrate a new approach to diagnosis and treatment of mycotoxin-induced SBS. Methods. As in other biotoxin-induced chronic human illnesses for which techniques to identify toxins in tissues are unavailable, diagnosis was based on exposure potential, the presence of multiple system symptoms, and the absence of probable alternative causes of illness. Samples of fungi were observed growing in each building and analytically identified to assess exposure potential. Symptoms were systematically assessed in direct interview.

A test of visual pattern detection ability, visual contrast sensitivity (VCS), was administered to each patient to assess its usefulness as an objective indicator of neurotoxicity in mycotoxicosis. Alternative explanation of illness were assessed with clinical and laboratory techniques, as well as with questions on medical history, potential for exposure to other toxins and life style. Cases were treated solely with an orally administered, non-absorbable polymer, cholestyramine (CSM), that binds salts from bile through anion exchange. CSM was previously used to successfully treat chronic illness induced by other biotoxins (2), presumably by preventing toxin recirculation through enterohepatic reabsorption, thereby enhancing toxin elimination rates.

Results. One or more genera of toxin forming fungi was identified in each building. All cases reported neurologic symptoms and symptoms involving at least three other systems. All cases showed depressed VCS in the presence of normal visual acuity, indicative of a neurologic effect. No probable alternative causes of illness were identified. Following 2 weeks of CSM therapy in the absence of re-exposure, all cases showed normal VCS and at least a 90% resolution of symptoms. Relapse occurred only with re-exposure and resolved with re-treatment. Conclusions. Even in the absence of measures of airborne spore concentrations and mycotoxin levels in tissue, these results strongly support the hypothesis of mycotoxicosis in these SBS patients. Multiple system symptoms, the objective indication of a neurologic effect provided by VCS, relapse with re-exposure and successive recoveries following CSM therapy are consistent with this diagnosis. The CSM response in these chronically ill patients unresponsive to previous treatments has no known explanation other than enhancement of toxin elimination rates. This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.
References. 1. HM Ammann. Is indoor mold contamination a threat to health?
2. RS Shoemaker & HK Hudnell. Possible estuary associated syndrome: symptoms, vision and treatment.