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Antigenic Diversity of Newcastle Disease Viruses Isolated from 52 Breeder and Broiler Flocks in Egypt.

Hussein H A, Emara M M, Samy A M and Shalaby M A

Department of Virology, Faculty of Veterinary Medicine, Cairo University, Giza- Egypt.

Newcastle disease virus (NDV) is a single serotype with sufficient antigenic differences among the isolates and strains. In this study, 75 field samples were collected from 52 different broiler and breeder flocks representing different governorates in Egypt. Attempts for virus isolation using embryonated chicken eggs (ECE) and cell culture were carried out. The antigenic diversity and biological properties of the 71 ECE-isolated local field strains of NDV were studied using different assays including hemagglutination, hemagglutination inhibition and hemolysis activity. Out of 20 selected local NDV isolates that were propagated in different cell lines, 14 field strains were successfully adapted on Vero cells. These cell culture adapted local strains of NDV were further antigenically characterized using ELISA, neutralization test, and genomic detected by reverse transcription- polymerase chain reaction assay (RT-PCR). The obtained results clearly demonstrate the differences in the surface polypeptides of these viruses and confirm the antigenic variability and heterogeneity of the local field strains of NDV, even within the same content.