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Double blind placebo controlled exposure to molds: exposure system and clinical results *
Author(s) -
Meyer H. W.,
Jensen K. A.,
Nielsen K. F.,
Kildesø J.,
Norn S.,
Permin H.,
Poulsen L. K.,
Malling H. J.,
Gravesen S.,
Gyntelberg F.
Publication year - 2005
Publication title -
indoor air
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.387
H-Index - 99
eISSN - 1600-0668
pISSN - 0905-6947
DOI - 10.1111/j.1600-0668.2005.00351.x
Subject(s) - placebo , penicillium chrysogenum , medicine , trichoderma harzianum , aerosolization , toxicology , inhalation , anesthesia , pathology , biology , microbiology and biotechnology , horticulture , alternative medicine , biological pest control
The objective was to develop an experimental setup for human exposure to mold spores, and to study the clinical effect of this exposure in sensitive subjects who had previously experienced potentially building-related symptoms (BRS) at work. From three water-damaged schools eight employees with a positive histamine release test to Penicillium chrysogenum were exposed double- blinded to either placebo, approximately 600,000 spores/m3 air of P. chrysogenum or approximately 350,000 spores/m3 of Trichoderma harzianum for 6 min on three separate days. A statistically significant rise in symptoms from mucous membranes appeared from the 9-graded symptom scale after exposure to T. harzianum or placebo. Dichotomizing the data, whether the participants experienced at least a two-step rise on the symptom scale or not, gave borderline increase in mucous membrane symptoms after exposure to P. chrysogenum. In conclusion this is, to our knowledge, the first study to successfully conduct a human exposure to a highly controlled dose of fungal material aerosolized directly from wet building materials. This short-term exposure to high concentrations of two different molds induced no more reactions than exposure to placebo in eight sensitive school employees. However, a statistical type II error cannot be excluded because of the small sample size.