The effect of bioaerosol sampling on the viability of aerosolized influenza A

Influenza virus kills thousands of humans annually around the globe. The primary mode of transmission for influenza virus occurs via an aerosol that is generated when infected individuals cough, sneeze, or talk (CDC 2018). Exposure assessment methods for influenza virus aerosols need to be developed to assess risk among workers in occupations were aerosol hazards are present (e.g., health care). Furthermore, developing methods to assess the viability of virus collected during filter-based aerosol sampling will improve exposure assessment methods. The purpose of this study was to determine the effect that filter-based sampling has on the viability of influenza virus. A bioaerosol chamber was used to generate influenza virus and sample the aerosolized influenza virus onto a polystyrene filter. This study consisted of 10 trials that each lasted 30 minutes. For each trial, a polystyrene filter was spiked with influenza virus and then compared to the aerosolized sample from the bioaerosol chamber. After the chamber trial was completed, both filters were washed with Hanks Balanced Salt Solution to remove the viral particles from the filter. After the filters were washed, viral RNA was extracted from the viral solution using the QIAamp Viral RNA Mini Kit. Quantification of the viral particles was completed using quantitative reverse transcription polymerase chain reaction. Viability of the influenza virus was analyzed using propidium monoazide dye. Average total RNA copies were analyzed for the spiked and aerosolized samples. Average total RNA copies were less for aerosolized samples compared to spiked filter samples, suggesting that the aerosolization process may decrease the number of viral particles that are collected on the filter. Viability was analyzed by determining the percent of intact membranes for the spiked and aerosolized samples. No difference was observed in the proportion of intact influenza virus membranes among aerosolized and spiked samples, suggesting that aerosolization and sampling had no effect on the viability of the influenza virus when compared to spiked filter samples.