1. Department of Parasitology, Seoul National University College of Medicine, Seoul 110-799, Korea.
2. Institute of Endemic Diseases, SNUMRC, Seoul 110-799, Korea.
3. Department of Family Medicine, College of Medicine, Dongguk University, Kyongju 780-714, Korea.
4. Department of Thoracic and Cardiovascular Surgery, Inha University Medical Center, Sungnam, 461-712, Korea.