1. National Agricultural Research Foundation (N.AG.RE.F.), Veterinary Research Institute, PO Box 60272, 57001 N.AG.RE.F. Campus, Thermi, Thessaloniki, Greece
2. Department of Applied Biology, University of Perugia, Borgo 20 Giugno, 74, 06121 Perugia, Italy
3. ADAS Gleadthorpe, Meden Vale, Mansfield, Nottingham, NG20 9PF, UK
4. Faculty of Veterinary Medicine, CIISA, Av. Da Universidade Técnica, Pólo Universitário do Alto da Ajuda, 1300-477 Lisbon, Portugal