AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Influenza Virus in Respiratory Droplets from Humans with Community Acquired Infection
JING YAN, Jovan Pantelic, Michael Grantham, Barbara Albert, Fengjie Liu, Sheryl Ehrman, Donald Milton, University of Maryland School of Public Health
Abstract Number: 186 Working Group: Bioaerosols
Abstract Influenza virus causes from 3000 to 49000 deaths each year in the U.S. and pandemics can cause deaths in the 100,000s to millions. An understanding of influenza virus transmission is crucial for public health interventions. Influenza virus has three transmission routes: direct contact, large droplet spray, and aerosol transmission. The relative importance of these routes of transmission has been debated in recent years, although droplet transmission has traditionally been considered to be most important. Here, we report the results of a study of characterization of respiratory droplets from infected individuals. Recruitment of students, staff, and neighbors of the University of Maryland, College Park, MD took place from December 2012 to March 13, 2013. If subjects had either a positive rapid test or fever 37.8°C plus a cough or sore throat and were within the first 3 days of onset of symptoms, we collected nasopharyngeal (NP) swabs, throat swabs and 30 minutes exhaled breath samples obtained using the Gesundheight-II exhaled breath aerosol collection device. Each sample was cultured for influenza virus by both blind passage and a fluorescent focus assay using low passage MDCK cells. We used RT-qPCR with CDC primer and probe sets to type and quantify the viral RNA in each sample.
278 samples were obtained from 178 subjects. We cultured influenza virus from 81.9% of NP samples, 77.5% of throat samples, and most importantly 44.1% of fine aerosol samples were culture positive. At the time of this report, we have completed RNA assays for 87 coarse (> 5 µm diameter) and 88 fine (≤ 5 µm) aerosol samples from persons with H3 subtype influenza A. We detected viral RNA in 37% (32/87) of the coarse aerosol samples and 77% (68/88) in the fine aerosol samples. Additional results investigating the relationship between culturability and other study variables, including coughing frequency, will be presented. The high rate of RNA detection in and especially the frequent recovery of influenza virus by culture of fine aerosol samples in this study suggest a contribution of fine particle aerosols in the transmission of influenza.