10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Stability of Variant H1 Subtype Influenza Viruses in Aged Aerosols and Their Infectivity in the Ferret Model
JOANNA PULIT-PENALOZA, Jessica Belser, Terrence Tumpey, Taronna Maines, Centers for Disease Control and Prevention
Abstract Number: 1225 Working Group: Infectious Bioaerosol
Abstract The relative importance of influenza virus transmission via aerosol inhalation is not fully understood and the subject of some debate. Detection of influenza virus RNA in the air collected directly from infected individuals and from contaminated spaces occupied by infected individuals, as well as mathematical modeling studies, suggest that aerosol transmission may represent a critical mode of seasonal influenza virus transmission in humans. Prototypical lab influenza viruses were shown decades ago to maintain viability in aerosols; however, there is a paucity of data available on currently circulating influenza viruses that significantly differ genetically and antigenically from their predecessors. In this study, we modified a previously established aerosol exposure system to assess stability in aerosols of four swine-origin variant H1 influenza viruses, isolated from humans in recent years, and a human seasonal influenza virus. Following nebulization of influenza virus into the primary exposure chamber, airflow through the chamber was interrupted to allow aerosol particles to age under still air conditions at 23-24°C and 45-55% relative humidity. Time-dependent loss of infectious virus was observed as evidenced by higher total viral RNA levels over total viable virus. Among the H1 viruses tested here, stability in aerosols correlated with transmissibility between ferrets, the gold standard animal model of influenza infections in humans. The influenza viruses that were transmissible through the air with 100% efficiency among ferrets displayed higher stability in aerosols than the viruses that transmitted with lower efficiency. Virus-laden aerosols aged for 15 or 30 min were able to productively infect ferrets at low doses, despite diminished viral viability compared with aerosols that were generated immediately prior to ferret exposure. Collectively, these data underscore the high infectivity of influenza viruses in aerosols, and support the need for continued refinement and innovation of laboratory methods to investigate mammalian exposure to inhaled pathogens. The results of this study further our understanding of the public health threat posed by novel influenza viruses as they continue to cross the species barrier to cause human infections.