1. Health Research and Management Programme, Department of Preventive and Social Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Department of Community Health, Sirindhorn College of Public Health, Yala
2. Department of Community Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok
3. Department of Social and Environmental Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok
4. Department of Environmental Science, Faculty of Environment, Kasetsart University, Bangkok
5. Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok
6. Department of Preventive and Social Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Department of Preventive and Social Medicine, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand