Of microbes and men.

UNLABELLED: Moisture accumulation in building structures, the microbial ecology of water-damaged sites and human exposure to biological contaminants are complex phenomena and may result in various types of indoor air pollution and adverse health outcomes. Commonly reported are building-related irritation symptoms, respiratory infections and non-specific symptoms and occasionally neurological impairment. Various diseases have been associated with mold exposure, e.g. an increased risk of asthma development and exacerbation as well as clusters of hypersensitivity pneumonitis, pulmonary hemorrhage in infants and rheumatic diseases. The causal agents of these illnesses, still poorly understood, may be linked to the complex interactions between bacteria and fungi with environmental growth substrates and other microorganisms which lead to a wide diversity of exposures. Fungi and bacteria growing on building materials may produce toxic secondary metabolites, and the material appears to be a key determinant of metabolite production. Modern building technology has provided new ecological niches for microbes which readily exploit faults in moisture control. To better describe microbial exposures in buildings, current method development focuses on chemical markers of biomass and assays for specific genetic sequences. PRACTICAL IMPLICATIONS: Dampness and moisture phenomena in buildings, resulting microbial and chemical exposures and individual human responses are complex phenomena. While the causative links between exposing agents and health responses are still not well understood, the essential issue is to prevent the problems with good design, construction and maintenance.