Received: 30 September 2019
Accepted: 24 August 2020
First Online: 9 September 2020
Ethics approval and consent to participate
: Ethics Research approval was obtained from the Human Health Research Ethics committee of Stellenbosch University (S13/09/171). The Ministries in Nigeria gave permission for the study to be conducted (Education, Health, Welfare and Environment). All participants gave written consent after the study was explained to them orally.
: All authors have approved and consented to the publication.
: No conflict of interest declared.