1. Department of Medicine, College of Medicine, University of Malawi, Private Bag 360, Blantyre 3, Malawi
2. Queen Elizabeth Central Hospital, Chichiri, Blantyre, Malawi
3. The Florey Institute, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
4. Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
5. Department of Obstetrics and Gynaecology, College of Medicine, University of Malawi, Private Bag 360, Blantyre 3, Malawi
6. Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany