Funding for this research was provided by:
Consejo Estatal de Ciencia, Tecnología e Innovación (2016-1 272601, 00257091, 0362010)
Dirección General de Asuntos del Personal Académico, Universidad Nacional Autónoma de México (IN215018, N202408, IN218214)
Received: 10 September 2019
Accepted: 19 November 2019
First Online: 27 November 2019
Ethics approval and consent to participate
: Sample collections in this study were conducted under the ethical principles and approval of both the Mexican Commission on Ethics and Research of the Health Ministry of the state of Morelos (Comisiones de Ética y de Investigación del Ministerio de Salud del Estado de Morelos); and the Commission on Ethics in Research of the Facultad de Medicina of the Universidad Nacional Autónoma de México (UNAM) (Comité de Ética de Investigación de la Facultad de Medicina de la Universidad Nacional Autónoma de México). The guidelines of the committees are based on the Mexican Official Norm (Norma Oficial Mexicana NOM-012-SSA3-2007), which regulates the ethical principles of every research on humans and on laboratory animals, as well as on the Declaration of Helsinki, which set ethical principles regarding human experimentation developed by the World Health Organization (WHO). Based on these guidelines, our study only used samples from volunteers, who were informed about research objectives and sampling procedures. An informed consent letter was obtained from all participants or from one parent of each minor (under 18 years-old).
: Not applicable.
: The authors declare that they have no competing interests.