1. Department of Parasitology, Seoul National University College of Medicine, and Institute of Endemic Diseases, Seoul National University Medical Research Center, Seoul 110-799, Korea.
2. Department of Medical Zoology, National Institute of Health, Seoul 122-701, Korea.
3. Department of Parasitology and Institute of Tropical Medicine, College of Medicine, Yonsei University, Seoul 120-752, Korea.
4. Korea Association of Health Promotion, Seoul 157-016, Korea.
5. Shinan-gun Health Center, Manho-dong, Mokpo 530-130, Korea.