1. Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
2. Division of Infectious Diseases, Department of Medicine, Phramongkutklao Hospital, Bangkok, Thailand.
3. Department of Parasitology, Phramongkutklao College of Medicine, Bangkok, Thailand.
4. Department of Helminthology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.