1. VLA Weybridge, New Haw, Surrey KT15 3NB, United Kingdom
2. Centre for the Study of Evolution, University of Sussex, Brighton BN1 9QL, United Kingdom
3. VLA Starcross, Staplake Mount, Starcross, Exeter EX6 8PE, United Kingdom
4. Disease Ecology Group, Faculty of Veterinary Science, University of Liverpool, CH64 7TE, United Kingdom