1. School of Public Health, Hebei Medical University, Shijiazhuang, People’s Republic of China
2. Hebei Key Laboratory of Pathogens and Epidemiology of Infectious Diseases, Hebei Provincial Center for Disease Control and Prevention, Shijiazhuang, People’s Republic of China
3. Shijiazhuang Qiaodong Sewage Treatment Plant, Shijiazhuang, People’s Republic of China
4. Hebei Key Laboratory of Environment and Human Health, Shijiazhuang, People’s Republic of China