Submitted to: International Poultry Forum Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 1/12/2013
Publication Date: 1/22/2013
Citation: Cardenas-Garcia, S., Diel, D.G., Susta, L., Lucio-Decanini, E., Brown, C., Yu, Q., Miller, P.J., Afonso, C.L. 2013. Development of a genotype specific live Newcastle disease vaccine by replacing the fusion (F) and hemagglutinin-neuramindase (HN) genes into a LaSota vaccine backbone. International Poultry Forum Proceedings. p. 28. Interpretive Summary:
Technical Abstract: All Newcastle disease viruses (NDVs) are part of a single serotype; however, current vaccine strains display between 15 and 18% amino acid differences at the F and HN protein compared with current virulent viruses. Previous studies have shown that increased amino acid similarity between NDV vaccines and field viruses is important to decrease virus shedding after challenge. In the present study, a lentogenic recombinant virus was generated by replacing the F and HN genes from a genotype XIII virus circulating in Pakistan into the Lasota vaccine backbone (genotype II). The pathogenicity of the recombinant virus was attenuated by changing the fusion protein cleavage site. Intracerebral pathogenicity index, clinical signs, and virus shedding were also evaluated to determine if the vaccine virus was capable of replicating or causing disease in chickens. One day old SPF chicks were vaccinated with live virus and 14 days after vaccination were challenged with the homologous virulent virus from Pakistan to test its performance in comparison with the LaSota vaccine strain. Results from these experiments demonstrate that this experimental vaccine replicates in birds and does not cause disease; even more, this vaccine conferred 100% survival, prevented clinical signs, and decreased oropharyngeal virus shedding compared with the LaSota strain. In conclusion, this recombinant virus seems to be a good candidate to be used as live vaccine.