**Acknowledgements**

We gratefully acknowledge Prof. Amin Soebandrio MD, PhD, Clin. Microbiol, Director of the Eijkman Institute for Molecular Biology for his encouragement and advice, and Prof. A. Asadul I. Tahir, MD, PhD, FICS, Dean of the Faculty of Medicine, Hasanuddin University for the support to DS. JKB is supported by the Vietnam Major Overseas Programme grant from the Wellcome Trust.
