Comparative molecular analysis of contemporary isolates of duck plague virus from haor areas of Bangladesh

Duck plague (DP) is one of the most important viral diseases which affects the duck population across the globe including Bangladesh. The present work was conducted to detect DP virus (DPV) from haor areas using a molecular-based approach and compared with the contemporary isolate through molecular and phylogenetic analysis. For this purpose, 38 individual samples were collected from the Netrokona (n=20) district of the Mymensingh division and Kishoreganj (n=18) district of the Dhaka division. The identification of DVP was carried out by polymerase chain reaction (PCR) targeting DPV specific DNA polymerase genes followed by sequencing. PCR positive viral samples were used to propagate into 11-13 days old embryonated duck eggs through chorio-allantoic membrane (CAM) route for virus isolation. DPV were then propagated into duck embryo fibroblast (DEF) monolayer cell culture and confirmed by PCR. Among the 38 samples, 27 isolates were confirmed as DPV with the PCR amplicon size of 446 bp. Pathogenicity tests through the inoculation into day-old ducklings confirmed pathogenic strain. The PCR products of the isolated DPV specific DNA polymerase gene were sequenced commercially and submitted to GenBank (GenBank Accession No. KX768734.1). The sequence showed resemblance to isolates previously reported in India (GenBank Accession No. KX511893.1, KJ451479.1, KM012009.1), and China (GenBank Accession No. EF643559.1). Sequencing data also revealed nucleotide differences between Anatid herpes 1_BAU_DMH (previous report from our laboratory) and the present isolates. Further characterization, such as nucleotide and amino acid sequencing, would help to understand the strains along with its epidemiology.