Natural occurrence of Aspergillus fumigatus in cane sugar mills.

The environmental distribution of Aspergillus fumigatus in 2 cane-sugar mills and one paper factory in northern India is compared with 2 localities in Delhi. The preponderance of the species at the U.D. Sugar Mills, Shamli, was contrary to its low prevalence in the University of Delhi campus and at Subzimandi, the vegetable and fruit market of Delhi. Aspergillus fumigatus accounted for 42.5% of the total aerial fungal colony counts recorded in the Shamli Mills as against 2% in Delhi. The predominant aerial fungus at Subzimandi was A. niger whereas aspergilli were overshelmingly outnumbered by other fungi in the University of Delhi campus. Within the Shamli Mills, the bagasse-containing sites had a significantly higher aerial prevalence (50.3%) of A. fumigatus than the bagasse-free sites (13.5%). Furthermore, A. fumigatus was more prevalent in the operational (57.2%) than in the non-operational period (23.8%) of the mills. The high frequency of isolations of A. fumigatus from and its dense population in sugar-cane bagasse seemed to suggest a special association of the fungus with this substrate.