Newcastle disease (ND) is a very contagious disease in chickens and turkeys and one of the most important diseases of poultry in the world. The infection causes sudden death with high mortality. ND in recent years showed symptoms more severe than previous symptoms of this disease. NDV infection of genotype VII has been reported to cause this outbreak in several commercial poultry farms. In this study the isolated viruses were molecularly characterized by RT-PCR targeting the partial F-gene of NDV. Partial F gene sequence analysis showed that the isolated NDV strains belong to genotype VII with the characteristic amino acid sequences of the F0 protein proteolytic cleavage site motifs (112RRQKRF117) for the velogenic NDV (vNDV) strains. From the isolated and molecular identified NDV Genotype VII four selected isolates (NDV/Chicken/EG-MN/NRC/2015, NDV/Chicken/EG-QU/NRC/2015, NDV/Chicken/EG-SH/NRC/2015 and NDV/Chicken/EG -SH2/NR/2015) were sequenced for NDV F gene and nucleotide sequences were submitted to GenBank and given accession numbers (MF418017), (MF418018), (MF418019) and (MF418020); respectively.
Though no significant genetic changes observed, the multiple vNDV outbreaks in vaccinated chicken require continuous monitoring of the evolution and the epidemiology characteristics of the vNDV as well as evaluation of the used vaccines.