1. Department of Parasitology and Tropical Medicine, Seoul National University College of Medicine, and Institute of Endemic Diseases, Seoul National University Medical Research Center, Seoul 110-799, Korea.
2. Department of Parasitology, College of Medicine, Kangwon National University, Chuncheon 200-701, Korea.
3. Department of Parasitology and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 660-751, Korea.
4. Department of Parasitology, College of Medicine, Yonsei University, Seoul 120-752, Korea.
5. Department of Parasitology, College of Medicine, Chungbuk National University, Chongju 361-763, Korea.
6. Korea Association of Health Promotion, Seoul 157-704, Korea.
7. Department of Hygiene and Prevention, Ministry of Public Health, Vientiane, Lao PDR, Korea.
8. Department of Parasitology, College of Medicine, Korea University, Seoul 136-705, Korea.