Molecular evaluation and genetic characterisation of Newcastle disease virus's haemagglutinin‐neuraminidase protein isolated from broiler chickens in Iran

BACKGROUND: Newcastle disease (ND) virus (NDV) is one of the major pathogens in poultry farms that causes severe economic damages to the poultry industry, especially broiler chicken and turkey farms. Despite the endemicity of ND and its many epidemics in the country, the nature of the Iranian strain of the Newcastle virus is still largely unknown. This study aimed to characterise and evaluate NDV isolates obtained from commercial poultry farms in Iran in 2019 through haemagglutinin‐neuraminidase (HN) gene sequencing. METHOD: HN gene of each NDV isolate was amplified and sequenced using specific primers followed by phylogenetic analysis of full length of HN gene open reading frame and amino acid (aa) sequence of HN. RESULTS: Phylogenetic analysis of the HN gene showed that the virus is very closely related to genotypes VII and III. Analysis of HN gene nucleotide sequences showed that all isolates encode proteins with a length of 571 aa. CONCLUSION: Results of the present study are useful for a better understanding of molecular epidemiology of indigenous NDV strains and determining important molecular differences between fields and commonly used vaccine strains related to main immunogenic proteins.