Pathology, pathotype and phylogenetic analyses of a natural outbreak of highly pathogenic avian influenza (HPAI) virus in farming ducks of Bangladesh

摘要: The present study was aimed at pathological investigation and genomic analysis of a highly pathogenic avian influenza (HPAI) virus from a natural outbreak of ducks in Bangladesh. Characteristics clinically signs observed were tremor of neck, head pressing on ground and diarrhoea with higher mortality. At necropsy hemorrhages and congestion were observed in upper respiratory tract, intestinal mucosa, ovarian follicles and meninges. Brush paint hemorrhages on pancreas were characteristics. Using histopathology, widespread hemorrhages were seen in parenchymatous organs. The lungs alveoli were drown with serofibrinous fluid. Focal necroses were common in pancreas and hepatocytes showed cytoplasmic vacuolation. Typing and sub-typing of the viruses were carried out by amplifying and sequencing matrix protein (M), hemagglutinin (HA) and neuraminidase (NA) genes. These genes were used in phylogenetic analyses and the studied viruses were belonging to clade 2.3. 2.1. Presence of amino acid Glutamine (Q/238) and Glycine (G/240)(H5 numbering) and “PQGERRRKR* GLF” motif in the HA cleavage site indicating the affinity of the viruses to avian species and HPAI viruses respectively. Ducks in farming system are susceptible to clinical infection with HPAI. Continuous molecular and epidemiological surveillance onto the genomics of AIV in ducks is needed to monitor further mutation and emergence of pandemic AIV.