1. Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
2. Institute of Microbiology and Epizootics, Centre for Infection Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
3. Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche, Perugia, Italy
4. Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna, Reggio Emilia, Italy