1. Department of Parasitology, College of Medicine, Dankook University, Cheonan 330-714, Korea.
2. 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.
3. Department of Environmental and Tropical Medicine, Konkuk University, School of Medicine, Chungju 380-701, Korea.
4. Department of Parasitology and Institute of Health Science, Gyeongsang National University College of Medicine, Jinju 660-751, Korea.