Quantifying indoor fungal aerosol levels in slums: implications for public health

Quantitative and qualitative assessment of indoor allergens and pathogens and their effect on human health is a less explored area of research. The present study aims to evaluate the indoor culturable airborne fungal load in households located in two distinct slum areas located in the tropical humid climatic zone of West Bengal, India, and its health exposure risk. The settle plate method assessed the fungal load followed by morphological, microscopic, and molecular characterization (18S rDNA). Both slum areas were highly contaminated, with ~2000–28000 SFU m−3 of fungal load with a significantly high Simpson Diversity Index, D ≥ 0.90. Six different fungal species were isolated, Aspergillus being the predominant one, and their sequences were submitted in GenBank with Accession nos. Aspergillus niger- OR139843; Fusarium oxysporum- OR098541; Cladosporium xanthochromaticum- OR659486; Rhizopus stolonifer- OR656943; Neurospora sp.- OR131033; Apergillus nomiae- OR131035. Complementing the pathogenicity of isolated fungal strains, the health hazard index of both sites was observed to be at the higher end (HI > 1). Seasonal, temporal, and meteorological variations impact the indoor fungal load and its associated risk accordingly. Hence, we may conclude that indoor fungal load is a major determinant of the health risk quotient of the residents in indoor spaces. A comprehensive and detailed assessment of airborne fungal load in different spatial-geographic regions is required to understand its dynamics with meteorological, temporal, seasonal, occupational, and human interventional variables.