1. Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
2. Enteric Diseases Reference Unit, National Institute for Communicable Diseases (NICD), a division of the National Health Laboratory Service (NHLS), Johannesburg, South Africa
3. Outbreak Response Unit, NICD, a division of the NHLS, Johannesburg, South Africa
4. Health and Social Development Department, Pretoria, South Africa
5. South African Field Epidemiology and Laboratory Training Programme, NICD, a division of the NHLS Johannesburg, South Africa
6. NHLS (Northern Branch), Pretoria, South Africa
7. Enteric Diseases Laboratory Branch, Centers for Disease Control and Prevention, Atlanta, USA
8. Lancet Laboratories, Pretoria, South Africa
9. PathWest Laboratory Medicine WA, Australia