Innovative Sampling Methodology for Detecting Viral Aerosols in Exhaled Breath: Enhancing Understanding of Influenza Transmission in Child Care Settings
ANUBHAV KUMAR DWIVEDI, Emily Hong, Hunter Richards, Zhenyu Ma, Herek L. Clack, Khalil Chedid, Emily Martin, Andrew Hashikawa, Linsey Marr, University of Michigan
Abstract Number: 379
Working Group: Health-Related Aerosols
Abstract
Introduction
Influenza viruses represent a perennial public health challenge, with their transmission intricately linked to the presence of infectious virus particles. The MITIGATE FLU project, a multi-faceted endeavor, aims to deepen our comprehension of influenza transmission dynamics, integrating laboratory, animal, and human studies. Notably, the human study component focuses on preschool children, aiming to elucidate the relationship between influenza infection incidence and the concentration of influenza viruses in child care center environments, encompassing both surfaces and air, in the region of SE Michigan.
Recognizing the complexity of investigating transmission routes for respiratory viruses, particularly concerning short-range exposure and transmission dynamics, we have devised an innovative sampling methodology specifically tailored for detecting viral aerosols in exhaled breath. This approach addresses the practical challenges inherent in directly collecting breath samples from young children, presenting a novel solution to enhance our ability to identify potential airborne transmission pathways of infectious viruses in child care settings.
Experimental Procedure
Our methodology entails promoting individual children (aged 3-6 years) to use a toy microphone as they talk to, sing to, and make animal noises as prompted by a robotic toy known as Moxie. The microphones have affixed to them a filter cassette via PVC tubing (OD of ⅜”), that is connected to sampling pump (5 LPM), facilitating the collection of exhaled aerosols onto membrane filters, composed of Polytetrafluoroethylene with a 2.0 µm pore size and 37 mm diameter.
Subsequent to sampling, the collected aerosols are subjected to dissolution in an aqueous buffer for downstream analyses. Notably, the efficiency of our sampling method is evaluated using real-time droplet digital polymerase chain reaction (RT-ddPCR), a robust molecular technique enabling accurate quantification of viral load in collected samples.
Validation of our sampling approach involves conducting speaking tests within a controlled clean room environment, wherein expelled aerosol particles generated during speech are sampled and characterized using optical particle counters (OPC) and condensation particle counters (CPC). This validation step ensures the fidelity and efficacy of our methodology in capturing and quantifying aerosolized viral particles, particularly in scenarios mimicking real-world conditions relevant to child care settings.
The successful implementation of our innovative sampling approach holds profound implications for understanding the potential for environmental transmission of respiratory viruses, particularly influenza, in child care environments. By elucidating airborne transmission pathways and identifying periods of heightened virus circulation, our methodology offers invaluable insights to inform targeted infection prevention strategies, ultimately mitigating the burden of respiratory virus infections in child care settings.