1. Department of Parasitology, College of Medicine, Cheju National University, Cheju 690-756, Korea.
2. Department of Preventive Medicine, College of Medicine, Cheju National University, Cheju 690-756, Korea.
3. Department of Clinical Pathology, Hanmaeum Hospital, Korea.
4. Department of Clinical Pathology, Cheju Hankook Hospital, Korea.
5. Department of Family Medicine, Cheju Medical Center, Korea.
6. Department of Parasitology, College of Medicine, Seoul National University, Seoul 110-799, Korea.
7. Department of Parasitology, Catholic University of Korea, College of Medicine, Seoul 137-701, Korea.