Measurement of indoor fungal contaminants causing allergy among the workers of paper-related industries of west Bengal, India

Qualitative and quantitative differences in dominant airborne fungal spores at premises related to the paper industry were assessed to determine their potential to incite respiratory allergy among employees. The 2-year study (September, 1999-August, 2001) was carried out using a two-stage Andersen viable particle sizing sampler. A total of 26 fungal types from all the survey sites were recorded during the period of which the most dominant were Aspergillus niger (36.1%), Cladosporium cladosporioides (30.2%) and Fusarium solani (11.62%). As with previous reports airborne fungal levels were shown to be non-normal in distribution, while the Friedman test showed that, except for airborne spores from the fungi above plus Aspergillus fumigatus (2.6%) and Curvularia lunata (3.03%), overall the other types were insignificant in relation to their incidence. Clinical investigations by skin prick test with antigenic extracts of the eight commonest spore types clearly demonstrated their allergenic nature. It was evident that among the 53 patients tested, the highest positive reaction (2+ or more intensity) was produced by Aspergillus niger (30.1%) followed by Aspergillus fumigatus (22.6%), Cladosporium cladosporioides (20.7%) and Curvularia lunata (18.8%). Allergenic symptoms were more pronounced during monsoon (44.5%) and post-monsoon (40.7%) but less frequent in the summer (14.8%). It is proposed that the high frequency of positive response among workers was due to an increased prevalence of these fungal forms in their work environment resulting from the moderate temperatures (28-32degreesC) and high RH (80-88%) that favour mould growth and sporulation.