About the Authors

Megan S. C. Lim

Affiliation Research Department of Infection and Population Health, University College London, London, United Kingdom

Jill Murray

Affiliations National Institute for Occupational Health, National Health Laboratory Service, Johannesburg, South Africa, School of Public Health, University of the Witwatersrand, Johannesburg, South Africa

Robert J. Dowdeswell

Affiliation Rustenburg Platinum Mines Limited: Precious Metals Refiners, Rustenburg, South Africa

Judith R. Glynn

Affiliation London School of Hygiene and Tropical Medicine, London, United Kingdom

Pam Sonnenberg

p.sonnenberg@ucl.ac.uk

Affiliation Research Department of Infection and Population Health, University College London, London, United Kingdom

Competing Interests

RD is an employee of Rustenburg Platinum Mines Limited and a part-time consultant to Anglo Platinum Ltd. There are no patents, products in development or marketed products to declare. This does not alter the authors' adherence to all the PLoS ONE policies on sharing data and materials.

Author Contributions

Conceived and designed the experiments: ML JM RD JG PS. Performed the experiments: ML JM RD. Analyzed the data: ML RD. Wrote the paper: ML JM RD JG PS.