1. Center for Infectious Disease Control; National Institute for Public Health and the Environment (RIVM); BA Bilthoven The Netherlands 3720
2. Institute of Microbiology and Epizootics, Centre of Infection Medicine, Department of Veterinary Medicine; Freie Universität Berlin; Berlin Germany 14163
3. Department of Environmental and Occupational Health Sciences; University of Washington; Seattle WA 98195-7234
4. Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine; China Agricultural University; 100193 Beijing China