1. Department of Medical Virology, Faculty of Health Sciences; University of Pretoria; Pretoria South Africa
2. Department of Pathology, Faculty of Medicine; National University of Science and Technology; Bulawayo Zimbabwe
3. Centre for HIV and Sexually Transmitted Infections; National Institute for Communicable Diseases; Johannesburg South Africa
4. Faculty of Health Sciences; University of the Witwatersrand; Johannesburg South Africa