10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Determining Distribution of Infectious Viruses in Aerosol Particles Using Water-Based Condensational Growth Technology
MAOHUA PAN, Leah Carol, John Lednicky, Arantzazu Eiguren Fernandez, Susanne Hering, Hugh Fan, Chang Yu Wu, University of Florida
Abstract Number: 1250 Working Group: Bioaerosols
Abstract Inhalation of virus aerosols can cause a wide range of adverse health effects and even severe casualties, depending on the species and distribution of the viruses in aerosol particles. The objective of this study was to determine the distribution of infectious viruses in airborne particles in the size range of 30 nm-300 nm, using bacteriophage MS2 as a surrogate for human viruses, with the newly introduced VIable Virus Aerosol Sampler (VIVAS). Aerosol particles containing MS2 bacteriophage were generated from a Collison nebulizer, conditioned by a dilution dryer, size selected by a differential mobility analyzer (DMA), and then collected by the VIVAS. Their physical size distributions were measured by a scanning mobility particle sizer (SMPS), while the counts of infectious viruses and the total viruses collected were quantified by the culture and quantitative reverse transcription-polymerase chain reaction (RT-qPCR) methods, respectively. For deionized (DI) water as the spraying medium, the amount of infectious and total viruses increased as particle size increased and reached the maximum at around 100 nm. This distribution pattern followed the aerosol’s volume size distribution, instead of number size distribution. For Beef Extract (BE) and Artificial Saliva (AS), the same pattern following the aerosol’s volume size distribution was observed. However, the number of infectious and total viruses per particle as a function of the particle size varied with the spraying medium: DI water approximated a cubic power scaling, AS approximated a quartic power scaling, and BE was between quadratic and cubic power scaling. A conceptual model was built to explain the different distribution patterns of viruses inside the particles - viruses could be homogeneously distributed or aggregated together inside or on the surface of the particles based on the hydrophilic/hydrophobic properties of the spraying media, resulting in different power scaling size distribution. Moreover, the survivability of MS2 with AS as the spraying medium was much higher than those with BE and DI water as the spraying media, suggesting that AS could provide better protection for MS2, which is likely due to the prevention of viable MS2 from reaching the air-water interface. Compared with prior studies that relied on assumed sampler efficiency, this study provides accurate assessment of the infectivity and transmissibility of airborne viruses for the first time without any such an assumption. Implication of the knowledge learned from this study could be very useful in guiding the design of an effective strategy to prevent the transmission of infectious virus aerosol, as viruses generated from different spraying media could end up with different sizes and transmitted through different pathways.