1. Centers for Disease Control and Prevention, Atlanta, Georgia, USA
2. University of Georgia, Griffin, Georgia, USA
3. Asociación Benéfica PRISMA, Lima, PeruJohns Hopkins University, Baltimore, Maryland, USA
4. Asociación Benéfica PRISMA, Lima, Peru
5. Universidad Peruana Cayetano Heredia, Lima, Peru; and #University of Arizona, Tucson, Arizona, USA
6. Johns Hopkins University, Baltimore, Maryland, USA