Molecular Detection of Lentogenic Strain of Newcastle Disease Virus in Commercial Broiler Chickens Using Sentinel Birds in Iran: The First Report

Newcastle disease (ND) is a highly contagious disease that affects many species of birds and causes significant economic losses to the poultry industry worldwide and the pathogenicity of Newcastle disease virus (NDV) strains varies with different virulence. We aim to detect lentogenic (low virulence) ND virus (ND/IR 2010) using sentinel birds and molecular detection system in commercial broiler farms in Iran as the first molecular case.
Partial sequencing of Fusion gene (F) which revealed that ND/IR 2010 carries the motif (112) GRQGRL (117) indicates that they are lentogenic genotype. Phylogenetic analysis, based on sequences of the F gene, revealed that our isolate should be classified as class II genotype I NDVs and related to the V4-like vaccine strain.
Since the V4 vaccine strain is not used as vaccine in Iranian poultry industry, thus findings in this study are important and interesting. The results of alignment of gene showed that ND/IR 2010 has 99.9% amino acid homology with V4, I2 and some other lentogenic NDV from South East Asia (in particular to duck origin virus).
This study adds to the understanding of the ecology of ND viruses in Iran and emphasizes the need for constant surveillance for more focus on lentogenic strains and their role in commercial farms and water fowl population as a neglected viral infection agent.