Detection of Influenza virus and in air sampled from co-infected ferrets and analysis of their influence on pathogen stability.

Unlabelled: Secondary infection with has contributed significantly to morbidity and mortality during multiple influenza virus pandemics and remains a common threat today. During a concurrent infection, both pathogens can influence the transmission of each other, but the mechanisms behind this are unclear. In this study, condensation air sampling and cyclone bioaerosol sampling were performed using ferrets first infected with the 2009 H1N1 pandemic influenza virus (H1N1pdm09) and secondarily infected with strain D39 (Spn). We detected viable pathogens and microbial nucleic acid in expelled aerosols from co-infected ferrets, suggesting that these microbes could be present in the same respiratory expulsions. To assess whether microbial communities impact pathogen stability within an expelled droplet, we performed experiments measuring viral and bacterial persistence in 1 μL droplets. We observed that H1N1pdm09 stability was unchanged in the presence of Spn. Further, Spn stability was moderately increased in the presence of H1N1pdm09, although the degree of stabilization differed between airways surface liquid collected from individual patient cultures. These findings are the first to collect both pathogens from the air and in doing so, they provide insight into the interplay between these pathogens and their hosts.

Importance: The impact of microbial communities on transmission fitness and environmental persistence is under-studied. Environmental stability of microbes is crucial to identifying transmission risks and mitigation strategies, such as removal of contaminated aerosols and decontamination of surfaces. Co-infection with is very common during influenza virus infection, but little work has been done to understand whether alters stability of influenza virus, or vice versa, in a relevant system. Here, we demonstrate that influenza virus and are expelled by co-infected hosts. Our stability assays did not reveal any impact of on influenza virus stability, and a trend towards increased stability of in the presence of influenza viruses. Future work characterizing environmental persistence of viruses and bacteria should include microbially-complex solutions to better mimic physiologically relevant conditions.