About the Authors
Division of Parasitology, National Institute for Medical Research, Mill Hill, London, United Kingdom
The authors have declared that no competing interests exist.
Conceived and designed the experiments: CRC MJB. Performed the experiments: CRC CWM FH. Analyzed the data: CRC CWM MJB. Contributed reagents/materials/analysis tools: CWM MJB. Wrote the paper: CRC MJB.