Funding for this research was provided by:
South African Medical Research Council (P790)
National Research Foundation of South Africa (100015)
The World Academy of Science (100015)
Received: 12 March 2020
Accepted: 5 August 2020
First Online: 14 August 2020
Ethics approval and consent to participate
: Ethical clearance was sought from the University Ethics committee, University of Fort Hare.
: Not Applicable.
: The authors declare that they have no competing interests.