1. Department of Virology, Faculty of Veterinary Medicine, Ankara University, Diskapi, 06110 Ankara, Turkey
2. Department of Virology, Faculty of Veterinary Medicine, Atatürk University, 25240 Erzurum, Turkey
3. Department of Veterinary Medicine, University of Bari Aldo Moro, 70010 Valenzano, Bari, Italy
4. Veterinary Medical Research Institute, Hungária Krt 21, H-1143 Budapest, Hungary
5. Department of Virology, Graduate School of Health Sciences, Ankara University, Diskapi, 06110 Ankara, Turkey
6. University of Veterinary Medicine, István Utca 2, H-1078 Budapest, Hungary