Viable influenza A virus in airborne particles from human coughs.
Lindsley-WG; Noti-JD; Blachere-FM; Thewlis-RE; Martin-SB; Othumpangat-S; Noorbakhsh-B; Goldsmith-WT; Vishnu-A; Palmer-JE; Clark-KE; Beezhold-DH
J Occup Environ Hyg 2015 Feb; 12(2):107-113
Patients with influenza release aerosol particles containing the virus into their environment. However, the importance of airborne transmission in the spread of influenza is unclear, in part because of a lack of information about the infectivity of the airborne virus. The purpose of this study was to determine the amount of viable influenza A virus that was expelled by patients in aerosol particles while coughing. Sixty-four symptomatic adult volunteer outpatients were asked to cough 6 times into a cough aerosol collection system. Seventeen of these participants tested positive for influenza A virus by viral plaque assay (VPA) with confirmation by viral replication assay (VRA). Viable influenza A virus was detected in the cough aerosol particles from 7 of these 17 test subjects (41%). Viable influenza A virus was found in the smallest particle size fraction (0.3 um to 8 um), with a mean of 142 plaque-forming units (SD 215) expelled during the 6 coughs in particles of this size. These results suggest that a significant proportion of patients with influenza A release small airborne particles containing viable virus into the environment. Although the amounts of influenza A detected in cough aerosol particles during our experiments were relatively low, larger quantities could be expelled by influenza patients during a pandemic when illnesses would be more severe. Our findings support the idea that airborne infectious particles could play an important role in the spread of influenza.
Aerosols; Aerosol-particles; Particulates; Viral-infections; Viral-diseases; Infectious-diseases; Environmental-exposure; Exposure-levels; Airborne-particles;
Author Keywords: aerosols; air microbiology; airborne transmission; cough; infectious disease transmission; influenza
William G. Lindsley, National Institute for Occupational Safety and Health, 1095Willowdale Road, M/S 4020, Morgantown, WV 26505-2845
Healthcare and Social Assistance
Journal of Occupational and Environmental Hygiene