Abstract
1 Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
2 National Public Health Service for Wales Aberystwyth, Bronglais Hospital, Aberystwyth, Ceredigion SY23 1ER, UK
3 Institute of Rural Sciences, University of Wales, Aberystwyth, Ceredigion SY23 3AL, UK
4 Department of Molecular Parasitology, Bernhard Nocht Institute for Tropical Medicine, D-20359 Hamburg, Germany
5 Medical College, University of Hué, Hué, Vietnam