1. School of Medicine, Autonomous University of Sinaloa, 80246 Culiacan Sinaloa, Mexico
2. The Sinaloa State Public Health Laboratory, Secretariat of Health, 80200 Culiacan Sinaloa, Mexico
3. Pediatric Hospital of Sinaloa, 80200 Culiacan Sinaloa, Mexico
4. The Women's Hospital, Secretariat of Health, 80127 Culiacan Sinaloa, Mexico
5. Unidad de Medicina Familiar No. 21, IMSS, 82700 La Cruz de Elota Sinaloa, Mexico
6. Laboratorio de Investigación Biomédica, Hospital Regional de Alta Especialidad de Oaxaca, 71256 Oaxaca, Mexico