10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Concentration Profile of Influenza Virus in Day Care Centers
YU-CHUAN YEN, Yi-Lian Lee, Pei-Shih Chen, Kaohsiung Medical University
Abstract Number: 1080 Working Group: Bioaerosols
Abstract Day care attendance is considerable risk factor of influenza infection among children. Thus, early characterization for airborne influenza virus in high risk environment is of extreme importance. In addition, exhaled aerosol may carry airborne pathogens and play an important role for infectious diseases outbreak. Therefore, the purpose of present study in to investigate the airborne influenza virus of two day care centers with different ventilation system during four seasons, the air quality of two centers were also monitored simultaneously. Furthermore, influenza virus in exhaled air was also studied to understand the profiles of different disease status, and different host ag in this present study. To our knowledge, this is the first study regarding quantifying the concentration of airborne influenza virus in day care centers, either did assess influenza virus in exhaled air of infected children.
The concentration profile of airborne influenza virus was successfully characterized by filter with real-time qPCR assay in day care centers during Spring, Summer, Fall, and Winter, respectively. It was demonstrated that the positive rate of influenza virus in winter of two centers was significantly higher than other seasons, although the concentration of airborne influenza virus was significantly higher in summer due to the higher flu-like disease prevalence. In regard to the seasonal trend of other indoor pollutants, the concentration of total airborne cultivable bacteria and fungi was significantly higher in summer, but the concentration of carbon monoxide, carbon dioxide and number of ultra fine particle were highest in winter. In regard to the correlation between influenza virus and environmental factors, the positive rate of airborne influenza A virus and influenza B virus have an negative correlation with indoor temperature. In addition, it was also found out that the positive rate of influenza A virus and influenza B virus were all positively correlated with the concentration of indoor carbon monoxide regardless the difference of ventilation system. Furthermore, the concentration of airborne influenza A virus in both day care centers was positively correlated with the cold prevalence of children. In comparison with the Indoor Air Quality Recommended Values of Taiwan Environmental Protection Administration, the airborne cultivable bacteria concentration in both centers was 7－11 fold higher than the recommended value, and the failure rate of carbon monoxide and carbon dioxide was exceed fifty percentage.
An exhaled aerosol sampling device, developed in the present study, was demonstrated to provide an easy, noninvasive method to characterize the concentration of influenza virus in exhaled air. We have revealed the influenza virus could be exhaled during the latency period, and the concentration was increased when subject suffered cold symptom. It was also demonstrated that the older subject among five to six, the less virus could be exhaled. In addition, the concentration of influenza virus in exhaled air has a significantly positive correlation with the positive rate of airborne influenza virus.
In conclusion, we successfully demonstrated that the filter with real-time qPCR is a very sensitive and fast method to quantify airborne influenza virus in day care centers and in exhaled air of infected children. Airborne influenza virus was negatively correlated with temperature and positively correlated with carbon monoxide and other environmental factors were also investigated. In addition, airborne influenza virus was positively correlated with the number of infected children. Furthermore, profile of influenza virus during the whole disease period was also demonstrated.