1. Chungnam Development Institute, Gongju 314-140, Korea.
2. Department of Parasitology, College of Medicine, Dankook University, Cheonan 330-714, Korea.
3. Department of Parasitology, Biomedical Center for Brain Korea 21 and Institute of Health Science Gyeongsan National University School of Medicine, Jinju 660-751, Korea.
4. Department of Parasitology and Institute for Medical Science, College of Medicine, Inha University, Incheon 400-103, Korea.
5. 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.