[1] USN, Med Res Ctr Detachment, Lima, Peru
[2] Inst Nacl Salud, Lima, Peru
[3] CENETROP, Santa Cruz, CA, Bolivia
[4] SEDES, Cochabamba, Bolivia
[5] Hosp Naval, Guayaquil, Ecuador
[6] Asociac Rayos Sol, Asuncion, Paraguay
[7] Univ Peruana Cayetano Heredia, Inst Med Trop Alexander Humboldt, Lima, Peru
[8] Minist Salud, Direccion Gen Epidemiol, Lima, Peru
[9] Univ Nacl Mayor San Marcos, Lima 14, Peru
[10] Univ Calif Davis, Davis, CA 95616 USA