An official website of the United States government
The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you’re on a federal
government site.
The site is secure.
The https:// ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
Arillo-Santillán E, Fernández E, Hernández-Avila M, Tapia-Uribe M, Cruz-Valdés A, Lazcano-Ponce EC.Arillo-Santillán E, et al.Salud Publica Mex. 2002;44 Suppl 1:S54-66.Salud Publica Mex. 2002.PMID: 12055746Spanish.