1. Department of Microbiology, Science Faculty, Stellenbosch University, Stellenbosch 7600, South Africa
2. Experimental Medicine Research Group, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Parow 7505, South Africa
3. Department of Physiological Sciences, Science Faculty, Stellenbosch University, Stellenbosch 7602, South Africa
4. Division of Neurosurgery, University of Cape Twon, Cape Town 7925, South Africa