1. Swiss Tropical Institute, Basel, SwitzerlandNavrongo Health Research Centre, Ministry of Health, Navrongo, Ghana
2. Max-Planck-Institut für Infektionsbiologie, Berlin, Germany
3. Navrongo Health Research Centre, Ministry of Health, Navrongo, Ghana
4. University of Heidelberg, Heidelberg, Germany
5. National Institute of Public Health, Prague, Czech Republic
6. Swiss Tropical Institute, Basel, Switzerland