1. STEPS Centre, Institute of Development Studies, University of Sussex, Brighton BN1 9RE, UK
2. Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
3. Institute of Zoology, Zoological Society of London, Regent's Park, London NW1 4RY, UK
4. Department of Veterinary Medicine, Disease Dynamics Unit, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
5. Environmental Change, Public Health England, Didcot OX11 0RQ, UK