1. Department of Global Health, School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki City 852-8523, Japan
2. Department of Health System and Health Policy Research, Lao Tropical and Public Health Institute, Vientiane Capital, Lao PDR
3. Museum of Tropical Medicine, Institute of Tropical Medicine, Nagasaki University, Nagasaki City 852-8523, Japan