Acknowledgements
We are grateful to the Honourable Under Sedretary of State for Health, Dr. Mam Bunheng, for permission to conduct these surveys. We wish to record our deep appreciation of the encouragement received from H.E. Govenor Mr. N. Phoeung，Kratie, Dr. T.Y. Abudulcoyaume，Director, National Malaria Centre, and Dr. Cheam Saem，Director, Kratie Provincial Health Office. Special gratitude is expressed to Dr. D. Socheat，Vice Director, National Malaria Centre, Dr. C.S. Ly, Kratie Provincial Health Office，and Dr. Mey B. Denis, National Malaria Centre, for joining us during the preceding and present survey. We are grateful to the technical staff of Kratie Provincial Health Office, and who were very kind and helpful. We also express appreciation to teachers and children of the primary schools we surveyed for their good cooperation.
