Fungal extracellular polysaccharides in house dust as a marker for exposure to fungi: Relations with culturable fungi, reported home dampness, and respiratory symptoms

Background: Epidemiologic studies have demonstrated an association between indoor fungal growth and respiratory symptoms. However, in only a few studies was fungal exposure actually measured. Objective: The purpose of this study was to evaluate the measurement by enzyme immunoassay of extracellular polysaccharides of Aspergillus and Penicillium species (EPS-Asp/Pen) in house dust as a marker for fungal exposure and to study the relations between EPS-Asp/Pen levels and home dampness and respiratory symptoms in children. Methods: Extracts of house dust samples from bedroom and living room floors and mattresses from homes of 31 children with chronic respiratory symptoms and 29 children with no chronic respiratory symptoms were analyzed for EPS-Asp/Pen. Results: EPS-Asp/Pen were readily detectable (40 to 46,513 nanogram equivalent/g dust) in 161 house dust extracts, with highest concentrations in living room Boor dust. EPS-Asp/Pen levels were 2 to 3 times higher on carpeted floors than on smooth floors. EPS-Asp/Pen were significantly correlated with total culturable fungi (r = 0.3 to 0.5) and with house dust mite allergens (r = 0.3 to 0.5). EPS-Asp/Pen levels in living room floor dust were positively associated with occupant-reported home dampness. This was not observed for EPS-Asp/Pen in bedroom floor and mattress dust. EPS-Asp/Pen levels in living room Boor dust were positively associated with respiratory symptoms, EPS-Asp/Pen in bedroom floor and mattress dust showed a reversed association with respiratory symptoms, possibly because of allergen-avoidance measures taken in the bedroom. Conclusion: The enzyme immunoassay for fungal EPS-Asp/Pen may be a useful method for exposure assessment of indoor fungi.