About the Authors
Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
Animal Sciences Group, Wageningen University and Research Centre, Lelystad, The Netherlands
Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
The authors have declared that no competing interests exist.
MdRvBH, AM, and MK designed and carried out the epidemiological investigations. MvB performed the analyses. DK, CAD, and JAPH checked and commented on the methodology. MvB wrote the paper. All authors edited and commented on the text.