1. Department of Molecular Biology and Genetics; Bilkent University; Ankara 06800 Turkey
2. Electron Microscope Laboratory, Institute of Tropical Medicine; Nagasaki University; Nagasaki Nagasaki 852-8523 Japan
3. Department of Internal Medicine, Institute of Tropical Medicine; Nagasaki University; Nagasaki Nagasaki 852-8523 Japan
4. Division of Molecular Epidemiology; Nagasaki University School of Medicine; Nagasaki Nagasaki 852-8523 Japan