1. Hepatology and Gastroenterology Research Unit, Department of Internal Medicine, University of Pretoria, Pretoria 0002, South Africa
2. Ampath Pathology Laboratories, Pretoria, South Africa
3. DST-NRF Centre of Excellence at the Percy FitzPatrick Institute, Molecular Ecology and Evolution Programme, Department of Genetics, University of Pretoria, Pretoria 0002, South Africa