1. Dongguan Key Laboratory of Environmental Medicine, School of Public Health Guangdong Medical University Dongguan People's Republic of China
2. Department of Hospital Infection Management Dongguan Maternal and Child Health Care Hospital Dongguan People's Republic of China
3. Department of Occupational Disease Huizhou Hospital for Occupational Disease Prevention and Treatment Huizhou People's Republic of China
4. Department of Preventive Medicine, School of Public Health Guangdong Medical University Dongguan People's Republic of China