1. Department of Global
Health
and Population, Harvard School of Public Health, Boston, Massachusetts, United States
2. Department of Environmental
Health, Harvard School of Public Health, Boston, Massachusetts, United States
3. Child Survival Theme, Medical Research Council, The Gambia Unit, Fajara,
The Gambia
4. Department of
Biostatistics, Harvard School of Public Health, Boston, Massachusetts,
United States
5. Veterinary
Epidemiology and
Public Health Group, Royal Veterinary College, London, U.K.
6. GlaxoSmithKline Biologicals, Wavre, Belgium
7. MRC-HPA Center for Environment
and Health, Department of Epidemiology and Biostatistics, Imperial College London, London, U.K.