John’s present position is Principal Pathologist, Associate Professor and Head, Centre for Opportunistic, Tropical and Hospital Infections of the National Institute for Communicable Diseases in Johannesburg, South Africa. Academic affiliation is the Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand. He holds qualifications in medicine, pathology (microbiology and parasitology), and travel medicine, and is a fellow of the Faculty of Science of the Royal College of Pathologists of Australasia and of the Australasian College of Tropical Medicine.

Areas of interest are clinical and diagnostic microbiology, especially parasitic and zoonotic diseases.