[1] Ctr Dis Anal Fdn CDAF, Lafayette, CO USA
[2] Natl Ctr Prevent & Control HIV CENSIDA, Mexico City, Mexico
[3] Inst Tecnol & Estudios Super Monterrey ITESM, Mexico City, Mexico
[4] WHO, Pan Amer Hlth Org, Mexico City, Mexico
[5] Natl Inst Med Sci & Nutr, Mexico City, Mexico
[6] WHO, Pan Amer Hlth Org, Washington, DC USA
[7] Ctr Dis Anal Fdn, 1120 W South Boulder Rd,Suite 102, Lafayette, CO 80026 USA