1. Department of Parasitology; Faculty of Medicine; Sam Ratulangi University; Manado 95114 Indonesia
2. Department of Infectious Diseases; Tokai University School of Medicine; Isehara Kanagawa 259-1193 Japan
3. Department of Medical Microbiology and Parasitology; Shanghai Medical College of Fudan University; Shanghai 200032 China
4. Department of Infectious Diseases; Keio University School of Medicine; Tokyo 160-8582 Japan