1. 1School of Life Science, Beijing Institute of Technology, Beijing 100081, PR China
2. 2Bisgaard Consulting, Viby, Denmark
3. 3Institut für Mikrobiologie, Veterinärmedizinische Universität Wien, A-1210 Wien, Austria
4. 4Department of Veterinary Animal Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg C, Denmark
5. 5Department for Farm Animals and Veterinary Public Health, Clinic for Poultry and Fish Medicine, University of Veterinary Medicine Vienna (Vetmeduni Vienna), Veterinaerplatz 1, 1210 Vienna, Austria