1. *Institute of Cell, Animal and Population Biology, Division of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom;
2. †Institute of Endemic Diseases and
3. ‡Department of Biochemistry, University of Khartoum, Sudan;
4. ¶National Institute for Medical Research, The Ridgeway, London, United Kingdom
5. §Centre for Medical Parasitology at Institute of Medical Microbiology and Immunology, University of Copenhagen, and Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark; and