1. Department of Parasitology and Medical Research Institute, Chungbuk National University College of Medicine, Chongju, Chungbuk 361-763, Korea.
2. Gyeongin Regional Food and Drug Administration, Incheon 402-835, Korea.
3. 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.
4. Department of Parasitology, College of Medicine, Ewha Womans University, Seoul 158-710, Korea.
5. Department of Parasitology, Korea University College of Medicine, Seoul 136-705, Korea.