1. Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban 4013, South Africa
2. School of Health Science, University of KwaZulu-Natal, Durban 4013, South Africa
3. Department of Medical Microbiology, University of KwaZulu-Natal, Durban 4013, South Africa
4. JC Wilt Infectious Disease Research Centre, National Microbiology laboratory, Public Health Agency of Canada, Winnipeg, MB R3E 3L5, Canada
5. Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB R3T 2N2, Canada