Airborne dermatophyte propagules concentration in cowsheds as an underestimated reservoir of potential zoonoses

Abstract

Abstract Aims Indoor air quality in stables, cowsheds or henhouses has recently become in interest due to the potential risks of zoonotic infections. Cowsheds are commonly known to have high fungal loads, particularly if insufficient attention is paid to the monitoring and control of the indoor microclimate around three elements, that is heating, ventilation and lighting. The aim of this study was to determine the concentrations and spectrum of dermatophyte propagules in the indoor air of cowsheds. Methods and results Air samples were collected on five farms, and the dermatophyte species were identified using MALDI-TOF MS analysis. The quantitative analysis of the fungal pollutants showed an average of 0.084 dermatophyte propagules (CFU) per m3 of flowing air in spring and 0.0239 CFU/m3 in the summer. Dermatophyte species were identified in case of 64.6% of the obtained colonies. Trichophyton verrucosum as dominant species was isolated on all five farms. In turn, Nannizzia gypsea was isolated on four farms and Trichophyton mentagrophytes as well as Paraphyton cookei were isolated on two farms. Conclusions This study demonstrated that indoor aerosol appears to be one of the underestimated risks of dermatophyte infections. Moreover, the risk of zoonotic infections is posed by airborne zoophilic dermatophytes, especially T. verrucosum, whose prevalence of infections has been increasing in recent years. Significance and impact of the study The ability of dermatophytes to infect animals and humans is thought to be a consequence of not only their adaptation to new ecological niches but also occurring as an aerosol component, which we demonstrate for the first time in this study. The microclimate of the cowshed may be an underestimated reservoir of zoophilic dermatophytes, which pose a zoonotic threat to farmers, animal breeders and veterinarians.