Background: Avian influenza type A viruses (AIV) can infect a broad range of hosts including human and birds, making them an important viral pathogen with zoonotic potential. Ducks are a known reservoir for many avian viruses including the AIV.
Objectives: To sequence the entire genome of duck-derived H3N2 and ran comprehensive phylogenetic analysis on them to study their origin.
Methods: In this study, 962 cloacal swabs were collected from domestic ducks at several live poultry markets (LPMs) of Gilan, Mazandaran and Golestan provinces of Iran in the year 2017.
Results: Preliminary assays such as haemagglutination inhibition assay (HI), Neuraminidase Inhibition assay(NI) and RT-qPCR suggested that 0.5% of the birds were infected by H3 low pathogenic influenza viruses (LPAI). Three isolates were selected for whole genome sequencing. The cleavage site of the HA genes showed a PEKQTR/GLF motif, an indicator of LPAI. Furthermore, BLAST and phylogenetic analyses of the HA gene showed high homology to the Eurasian lineage of H3N8 AIV (95.5%-97.1% to several European and East Asian isolates). However, the NA genes showed high homology (at most 96.5-96.9%) to those belonging to AIV N2 subtype. Furthermore, internal genes showed high homology (96%-98%) to a variety of duck-origin subtypes and glycoprotein combinations, which were different for each segment. This showed a complex reassortment between different subtypes.
Discussion: This report is the first whole genome sequencing and complete characterisation of H3N2 AIV from Iran.
Conclusion: Such surveillance should continue to study the evolution and possible emergence of viruses with pandemic potential.
Keywords: H3 subtype; Iran; avian influenza virus; domestic ducks; live poultry market.
© 2022 The Authors. Veterinary Medicine and Science published by John Wiley & Sons Ltd.