Xiufan Liu
Yangzhou University,China
Title: Antigenic difference of HN protein between the vaccine strain and the challenge strain of Newcastle disease virus significantly affects virus shedding and transmission
Biography
Biography: Xiufan Liu
Abstract
Newcastle disease (ND) is caused by virulent Newcastle disease virus (NDV), which leads to heavy economic losses to poultry industry. Even though intensive vaccination programs have been implemented in many countries, virulent NDV can still be frequently isolated in well-vaccinated flocks. We tested the protection efficiency of LaSota and two sub-genotype VIId vaccines, NDV/AI4 and O/AI4, while O/AI4 was constructed by replacing the HN gene of the vaccine strain NDV/AI4 with that of the variant NDV strain JS-14-12-Ch. The cross-neutralization and Cross-hemagglutination inhibition tests between JS-14-12-Ch and the three vaccine strains indicated the significant antigenic difference between JS-14-12-Ch and LaSota as well as NDV/AI4, but not between JS-14-12-Ch and O/AI4. The results of vaccine protection tests showed that O/AI4 provided improved protection as determined by a significant decrease in both the number of birds shedding, the amount of virus shedding, and virus replication in visceral organs from challenged birds. This study suggested that ND vaccine strain which antigenically and genetically matches with prevalent field strains provides significant better protection than the conventional ones, in terms of reducing virus shedding and transmission.