Biological and Molecular Characterization of Newcastle Disease Virus Circulating in Chicken Flocks, Egypt, During 2014-2015

Newcastle disease (ND), a highly contagious disease, is responsible for disturbing disease outbreaks in poultry flocks worldwide. This study was carried out to isolate and characterize the circulating Newcastle Disease Virus (NDV) strains in different chicken flocks (broilers, commercial egg layers and breeders) in four Egyptian governorates (Gharbia, El Behera, Dakahlia and Kafer EL Shiekh) during 2014 and 2015. Forty-eight suspected NDV infected flocks were examined clinically and used for virus isolation and characterization. The mortality rates among the examined flocks were 5-85 %. The deduced amino acid sequences of F protein gene revealed that four NDV isolates possessed the motif 112 R/K-R-Q-K/RR116at the C-terminus of the F2 protein and F (phenylalanine) at residue 117, indicating that they are velogenic genotype. The present study revealed the circulation of NDV class II genotype VII in Egyptian chicken flocks.