Fungal Bioaerosols at Five Dairy Farms: A Novel Approach to Describe Workers Exposure

Abstract

Occupational exposure to harmful bioaerosols in industrial environments is a real treat to the workers. In particular, dairy-farm workers are exposed to high levels of fungal bioaerosols on a daily basis. Associating bioaerosol exposure and health problems is challenging and adequate exposure monitoring is a top priority for aerosol scientists. Using only culture-based tools do not express the overall microbial diversity and underestimate the large spectrum of microbes in bioaerosols and therefore the identification of new airborne etiological agents. The aim of this study was to provide an in-depth characterization of fungal exposure at Eastern Canadian dairy farms using qPCR and next-generation sequencing methods. Concentrations of Penicillium/Aspergillus ranged from 4.6 x 106 to 9.4 x 106 gene copies/m3 and from 1 x 104 gene copies/m3 to 4.8 x 105 gene copies/m3 for Aspergillus fumigatus. Differences in the diversity profiles of the five dairy farms support the idea that the novel approach identifies a large number of fungal taxa. These variations may be explained by the presence of different and multiple sources of fungal bioaerosols at dairy farms. The presence of a diverse portrait of fungi in air may represent a health risk for workers who are exposed on a daily basis. In some cases, the allergen/infective activity of the fungi may not be known and can increase the risks to workers. The broad spectrum of fungi detected in this study includes many known pathogens and proves that adequate monitoring of bioaerosol exposure is necessary to evaluate and minimize risks.\n\nImportanceWhile bioaerosols are a major concern for public health, accurately assessing human exposure is challenging. Highly contaminated environments, such as agricultural facilities, contain a broad diversity of aerosolized fungi that may impact human health. Effective bioaerosol monitoring is increasingly recognized as a strategic approach for achieving occupational exposure description. Workers exposure to diverse fungal communities is certain, as fungi are ubiquitous in the environments and the presence of potential sources increase their presence in the air. Applying new molecular approaches to describe occupational exposure is a necessary work around the traditional culture approaches and the biases they introduce to such studies. The importance of the newly developed approach can help to prevent workers health problems.