1 BSL-3 Laboratory, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical Universitygrid.284723.8, Guangzhou, China.
2 Department of Respiratory and Critical Care Medicine, Nanfang Hospital, Southern Medical Universitygrid.284723.8, Guangzhou, Guangdong, China.
3 Department of Epidemiology, School of Public Health, Southern Medical Universitygrid.284723.8, Guangzhou, China.
4 Guangdong Center for Disease Control and Prevention, Guangzhou, China.