1. Department of Internal Medicine, College of Veterinary Medicine, Seoul National University, Seoul 151-742, Korea.
2. College of Veterinary Medicine, Chonbuk National University, Jeonju 561-756, Korea.
3. Force Health Protection, 18th Medical Command, Unit #15281, Box 754, APO AP 96205-5281, USA.
4. 5th Medical Detachment, 168th Multifunctional Medical Battalion, 18th Medical Command, Unit #15247, APO AP 96205-5247, USA.
5. Department of Environmental Medical Biology, College of Medicine, Yonsei University, Seoul 120-749, Korea.
6. Center for Vector-Borne Diseases, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.