Genetic evidence of three mammalian viruses in breathing-level air adjacent to artificial bat roosts situated in a university campus

To gain insights on which airborne viruses were being shed by local bats, air samples were collected using a NIOSH bioaerosol sampler BC-251 and a BioSpot-VIVAS™ as bats exited their artificially constructed bat roosts to engage in nightly insect-hunting activities. The emphasis of this work was to find infectious airborne viruses, and for this exploratory study, we attempted virus isolation in three different mammalian cell lines. After cytopathic effects were observed post-inoculation of the cells with material collected during one of the air samplings, an unbiased PCR technique was used to generate amplicons which were cloned into a plasmid vector for sequencing. Sanger-sequencing revealed that the plasmid insert sequences were similar but not identical to those of previously identified alphacoronavirus, circovirus, and paramyxovirus genomic sequences, suggesting they were from novel virus species. However, they were from viruses known to infect bats and other mammals, indicating that air sampling can provide insights into viruses shed by flying bats. Such information is useful, as knowledge of viruses present at the human-wildlife interface can help public health authorities prepare medical responses in case of a spillover event.