1. Department of Parasitology and Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju 660-751, Korea.
2. Department of Parasitology and Medical Research Institute, Chungbuk National University School of Medicine, Cheongju 360-763, Korea.
3. Department of Parasitology, Hanyang University College of Medicine, Seoul 133-791, Korea.
4. Department of Parasitology, College of Medicine, Korea University, Seoul 136-705, Korea.
5. Korea Association of Health, Seoul 157-704, Korea.
6. Guangxi Centre for Disease Prevention and Control, Nanning, Guangxi, China.