Abstract
Background: Duck viral enteritis commonly known as duck plague (DP) is an acute and a contagious fatal disease of duck, geese and swan caused by duck plague virus (DPV). It poses serious threat to growth of duck farming in Haor (Wetland) area of Bangladesh.
Aim: The study aimed to detect circulating duck plague viruses (DPV) by molecular characterization followed by phylogenetic analysis, targeting UL30 gene from infected ducks of five Haor (wetland) districts of Bangladesh and observation of variation in the genome sequence of between the field virus and vaccine strain of DPV.
Methods: A total of 150 samples (liver-50, intestine-50 and oropharyngeal tissue-50) were collected from DP suspected sick/dead ducks of 50 affected farms of Kishoreganj, Netrokona, B-Baria, Habiganj and Sunamganj districts of Bangladesh. For identification of DPV in collected samples, polymerase chain reaction (PCR) was utilized. Nucleotide sequences of amplified UL30 gene were compared to other DPV strains available in GenBank.
Results: In PCR, out of 150 samples, 90 (60%) were found positive for DPV. Organ wise prevalence was higher in liver (72%) followed by intestine and oro-pharyngeal (44%) whereas area wise was from 56.28 to 62.96%. Two of the isolates, BAU/KA/DPV(B1)/2014 from Kishoreganj and BAU/KA/DPV(B4)/2014 from Sunamganj were sequenced and phylogenetic analysis revealed that these isolates are evolutionarily closely related to Chinese isolates of DPV. In addition, the isolates of DPV, BAU/DPV (B1)/2014 and BAU/DPV (B4)/2014 showed the highest (98%) similarity with each other. Nucleotide sequence of the isolate (BAU/KA/DPV (B1)/2014) showed higher variability in nucleotides (264nt.) compared with that of the vaccine strain (Accession no. EU082088), which may impact on protein function and additional drug sensitivity.
Conclusion: From the findings of molecular study, it can be assumed that both Bangladeshi isolates and all the Chinese isolates of DPV may have common ancestry.

Key words: Duck plague virus, PCR, duck embryo, nucleotide sequence