[1] Univ Venda, Dept Microbiol, ZA-0950 Thohoyandou, Limpopo Prov, South Africa
[2] Univ Limpopo, MRC, Diarrhoeal Pathogens Res Unit, Pretoria, Gauteng, South Africa
[3] Univ Pretoria, Dept Med Virol, ZA-0001 Pretoria, Gauteng, South Africa
[4] Natl Hlth Lab Serv, Pretoria, Gauteng, South Africa
[5] PATH, Seattle, WA USA