Received: 11 October 2018
Accepted: 27 August 2019
First Online: 3 September 2019
Ethics approval and consent to participate
: The study protocol was reviewed and approved by the Faculty of Health Sciences Institutional Review Board (IRB) of the University of Buea, Cameroon and written informed consent was obtained from all participants.
: Not applicable.
: The authors declare that they have no competing interests.