Characterizing fecal bioaerosols in dairy barns using microbial source tracking markers and bovine enteric viruses

in the naturally ventilated barn. Bacteriophages were never detected. The Cub recovered higher concentrations of bacterial markers than comparison gelatin filter button samplers, by average factors of 6.3-21.0. Recovery of viruses by the Cub appeared comparable to button samplers. Results inform the development of bioaerosol sampling strategies on dairy farms, which could be used for biomonitoring during outbreaks and understanding endemic spread of infectious disease on and between livestock farms.IMPORTANCEHighly pathogenic avian influenza (HPAI) is a pressing health concern for the dairy industry, and recent advances have highlighted a need to understand its distribution in fecal bioaerosols on and around dairy farms. Microbial source tracking (MST) markers and bovine enteric viruses could be key tools in advancing this line of research, but their application and limitations with respect to air sampling have not been well-studied. This study assessed the distribution of bacterial MST markers and bovine enteric viruses on a working HPAI-free dairy farm. The results provide a basis for selecting among several competing markers and sampling technologies and highlight areas where additional development is needed to formulate effective bioaerosol sampling strategies for dairy farms.