Enumerating outdoor aeromycota in suburban West Bengal, India, with reference to respiratory allergy and meteorological factors

Aeromycota may act as a reservoir of aeroallergens and upon inhalation may ;induce IgE-mediated Type 1 hypersensitivity reaction in pre-sensitized individuals. The total aerospora of an outdoor occupational setting (agricultural farm) in Suburban West Bengal was sampled for two years (2002-2004) by a Burkard sampler. Concurrently, the cultivable aeromycota were trapped by an Andersen 2-stage sampler, Cultured and tested for allergenic potential by skin prick test. The relationships between various climatic factors (temperature, relative humidity, rainfall and wind speed) and the distribution of aerospora were explored by Spearman correlation test. The antigenic extracts of 15 fungal species belonging to Alternaria, Aspergilli/Penicilli, Cladosporium, Curvularia, Drechslera, and Nigrospora evoked 10.8-54.8% skin reactivity in subjects with clinical history of respiratory allergy. The aerospora with skin sensitizing potential collectively represented a considerable fraction (52.3-58.4%) of the total aeromycota. The airborne concentration of Alternaria spores was higher than its borderline value of 100 spores m(-3) in May and June, whereas Cladosporium spore count exceeded its threshold limit value (3,000 spores m(-3)) in December, suggesting that this particular time of the year poses allergenic risk for individuals sensitive to these aerospora. Daily minimum temperature and rainfall appeared to be the most important meteorological factors to affect the concentration of aerospora in the study area.