1. Department of Parasitology and Institute of Endemic Diseases, Seoul National University College of Medicine and SNUMMC, Seoul 110-799, Korea.
2. Korea Association of Health, Seoul, 157-016, Korea.
3. Department of Parasitology, College of Medicine Hanyang University, Seoul 133-791, Korea.
4. Guangxi Institute of Parasitic Diseases Control, Nanning, Guangxi, China.
5. Liaoning Province Public Health and Anti-Epidemic Station, Shenyang, Liaoning, China.
6. Institute of Parasitic Diseases Chinese Academy of Preventive Medicine, Shanghai, China.