Text and Data Mining valid from 2019-04-08
Received: 6 January 2019
Accepted: 29 March 2019
First Online: 8 April 2019
Ethics approval and consent to participate
: Ethical approval was obtained from the Faculté des Sciences de la Santé of Bangui.
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.