[1] Univ Cape Town, Div Med Virol, Cape Town, Western Cape, South Africa
[2] Groote Schuur Hosp, Natl Hlth Lab Serv, Cape Town, Western Cape, South Africa
[3] Univ Cape Town, Dept Med, Div Neurol, Cape Town, Western Cape, South Africa
[4] Hawkes Bay Fallen Soldiers Mem Hosp, Dept Neurol, Hastings, New Zealand
[5] Univ Cape Town, Div Chem Pathol, Cape Town, Western Cape, South Africa