1. Faculty of Medicine, Autonomous University of San Luis Potosí, Centro, 78000 San Luis Potosí, México
2. Faculty of Medicine, Autonomous University of San Luis Potosí, San Luis Potosí, México
3. Hospital General ISSSTE, San Luis Potosí, México
4. Faculty of Health Sciences, Anáhuac University México, Huixquilucan, México
5. Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK