About the Authors
Natural Resources Institute, University of Greenwich, London, United Kingdom
South African Centre for Epidemiological Modelling and Analysis (SACEMA), University of Stellenbosch, Stellenbosch, South Africa
The authors have declared that no competing interests exist.
Conceived and designed the experiments: GAV SJT. Performed the experiments: GAV. Analyzed the data: SJT GAV. Wrote the paper: SJT GAV.