AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Non-invasive Measurement of Viral Load in Distal-Airway Lining Fluid through Characterization and Collection of Exhaled Breath Aerosols
SOMAYEH YOUSSEFI, Jennifer German, Donald Milton, University of Maryland School of Public Health
Abstract Number: 731 Working Group: Bioaerosols
Abstract Infectious fine particle aerosols are generated from the human lung during influenza and other acute respiratory infections (ARIs) and may play an important role in transmission. These aerosols are generated from closure and reopening of small airways and shear forces during coughs. Little is known about frequency and intensity of influenza infection in the distal airways in mild-moderate influenza illness. Current breath samplers measure shedding, but not whether shedding is driven by intensity of infection or of aerosol generation. Our objective is to determine the concentration of infectious virus in lung lining fluid by collecting exhaled breath. Viral loading is defined as the ratio of the virus amount in the collected aerosol to the volume of the collected aerosols. We recruited 10 individuals with qRT-PCR confirmed ARI to give 10-minute breath samples. We used a novel exhaled breath aerosol (EBA) collector. This system uses condensation growth to collect aerosols ³9 nm and impact them on ice. Participants wore a nose clip, breathed particle-free humidified air and repeatedly exhaled slowly to residual volume then inhaled to total lung capacity. We characterized aerosol number and size distributions with an aerodynamic particle sizer and scanning mobility particle counter and computed volume of the collected aerosols including corrections for humidity changes and sampling losses. Following collection, EBA samples were thawed, transferred to an Eppendorf tube and immediately refrozen and stored at -80ûC until analysis. The one participants infected with influenza A H3, exhaled ~10 particles/cm3 (GM= 158 nm, GSD= 1.5). The total exhaled aerosol volume over a 10 minute sample was 41x10^-12 liter. We detected 1.67x10^4 RNA copies. Lung viral loading was 4.12x10^11 copies/ml. Results from participants with other viral infections are pending.