AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
The Influence of Simulated Sunlight and Relative Humidity on the Inactivation of Influenza Virus in Aerosols
MICHAEL SCHUIT, Sierra Gardner, Paul Dabisch, BNBI / DHS NBACC
Abstract Number: 426 Working Group: Bioaerosols
Abstract Influenza viruses are significant contributors to the global burden of infectious disease both in the United States and worldwide. Influenza transmission is believed to occur both through direct contact with contaminated fomites and by aerosol, the latter of which facilitates the rapid spread of this organism and contributes to its status as both a seasonal and pandemic public health threat. Laboratory studies with influenza virus in aerosols or liquids have generally indicated that persistence of the virus is highest at lower temperatures, in the absence of UV light, and at either low or very high humidity levels. These data support the findings of epidemiological studies demonstrating greater incidences of influenza illnesses during winter in temperate regions and little to no seasonal variability in the tropics. Sunlight is a seasonal variable known to affect the survival of many microorganisms in aerosols. However, the impact of sunlight on the survival of influenza virus in aerosols has not been previously quantified. The present study examined the survival of the PR8 strain of Influenza A virus in aerosols using an environmentally controlled rotating drum test chamber. Tests were conducted with and without simulated sunlight at both 20 and 70% relative humidity. Viral inactivation rates were quantified using a one-phase exponential decay fit to time series aerosol concentration data. Inactivation rates measured in this study were dependent on the level of simulated sunlight but were not significantly different between the two relative humidity levels tested. In darkness, the decay constant mean ± SD was 0.001 ± 0.019, which was not significantly different from zero (n=10, p=0.85). However, at full intensity simulated sunlight the mean decay constant was 0.252 ± 0.059, equivalent to a half-life of approximately 3 minutes. Under these conditions, short-range aerosol transmission of the virus may be possible, but the virus would be unlikely to survive in an infectious state over long distances. These results corroborate epidemiological findings that sunlight levels are inversely correlated with influenza transmission, and can be utilized to better model influenza transmission, as well as to inform efforts to understand and limit the transmission of this virus in a variety of settings.