Authors
Konstantin Borisov Simeonov
Department of Epizootiology and Animal Infectious Diseases, National Diagnostic and Research Veterinary Medical Institute “Prof. Dr. G. Pavlov”, Sofia, Bulgaria
Keytlin Venelinova Todorova
Department of Epizootiology and Animal Infectious Diseases, National Diagnostic and Research Veterinary Medical Institute “Prof. Dr. G. Pavlov”, Sofia, Bulgaria
Petia Dinkova Genova-Kalou
Department of Virology, National Centre of Infectious and Parasitic Diseases, Sofia, Bulgaria