1. Department of Microbiology and Tropical Medicine
2. Institute of Biological Science, University of Wales, Aberystwyth SY23 3DA, United Kingdom
3. Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai 200025, China
4. Queensland Institute of Medical Research, Brisbane, Queensland 4006, Australia
5. Biostatistics Unit, The George Washington University and Sabin Vaccine Institute, Washington, DC 20037