OUTBREAK OF INFLUENZA A VIRUS (H5N1) IN DALMATIAN PELICANS SREBARNA RESERVE, BULGARIA, 2015

Abstract

On March 25, 2015, a highly pathogenic avian influenza viruses were isolated from the carcasses of a 3 Dalmatian pelicans (Pelecanus crispus) in Bulgaria. Polymerase chain reaction (PCR) and H5N1-specific real-time reverse transcription polymerase chain reaction (rRT-PCR) analysis showed, that the H5 and N1 avian influenza virus was presented in the lung, trachea, proventriculus, cloaca and brain tissue of the dalmatian pelicans. Subsequent sequence analysis found the following motif of basic amino acids at the cleavage site of hemagglutinin: PQRERRRKRGLF, which is characteristic of highly pathogenic avian influenza viruses. Phylogenetic analysis of a part from segment 4 of A/dalmatian pelican/ Sreburna/Bulgaria/2015 (H5N1) showed a close genetic relationship with influenza viruses A (H5N1) clade 2.3.2.1. Тhe establishment of HPAI H5N1 in 2015, belonging to the genetic clade 2.3.2.1, circulating in Southeast Asia and in Bulgaria for the second time since 2010, shows the great potential for the trans-continental distribution of the virus and its ability to cause not only epizootic outbreaks, but also panzootic waves.