1. School of Agricultural, Earth & Environmental Sciences, University of KwaZulu-Natal, Scottsville, South Africa;
2. School of Chemistry and Physics, University of KwaZulu-Natal, Scottsville, South Africa;
3. Faculty of Medicine, National University of Science and Technology (NUST), Bulawayao, Zimbabwe;
4. School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa