A B S T R A C T
Newcastle disease (ND) is a highly contagious disease causing huge economic losses to the poultry industry due to high morbidities and mortalities. This study was aimed to isolate and characterize the new sub-genotype NDV strains in Qalybia Governorate during 2017 and 2019. Sixty eight samples were collected from Sixty eight broiler chicken flocks suffering from high mortality reach to 80% with distinctive clinical signs and post-mortem lesions of NDV. NDV strains isolated through inoculation in specific pathogen free (SPF) eggs and were identified by hemagglutination (HA) and hemagglutiation inhibition(HI) techniques. There were 16/20 (about 80%) of selected suspected farm were positive for NDV With HI test . These hemagglutinating agents were confirmed as NDV strains through molecular characterization using one step RT-PCR targeting the partial F-gene of NDV. Sequencing and phylogenetic analysis were successfully performed with eight NDV isolates which possessed the motif 112 R/K-R-Q-K/RR116 at 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 Qalybia chicken flocks.