Department of Health Sciences, School of Health and Applied Sciences,Namibia University of Science and Technology, Private Bag 13388, Windhoek,Namibia;
Department of Medical Microbiology, University of Zimbabwe College of Health Sciences, P.O.Box A178, Harare, Zimbabwe;
Department of Health Sciences, School of Health and Applied Sciences,Namibia University of Science and Technology, Private Bag 13388, Windhoek,Namibia;
Department of Mathematics and Statistics, Namibia University of Science and Technology,Private Bag 13388, Windhoek, Namibia;