|CARDENAS-GARCIA, STIVALIS - University Of Georgia|
|DIEL, DIEGO - US Department Of Agriculture (USDA)|
|LUCIO-DECANINI, EDUARDO - Applied Research(INVESTIGACION APLICADA)|
|BROWN, CORRIE - University Of Georgia|
Submitted to: Biologicals
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/9/2014
Publication Date: 12/12/2014
Citation: Cardenas-Garcia, S., Diel, D., Susta, L., Lucio-Decanini, E., Yu, Q., Brown, C.C., Miller, P.J., Afonso, C.L. 2014. Development of an improved vaccine evaluation protocol to compare the efficacy of Newcastle disease vaccines. Biologicals. 43:136-145. doi: 10.1016/j.biologicals.2014.11.003.
Interpretive Summary: Commercial Newcastle Disease Virus (NDV) are made using NDV strains that were first isolated in the 40s. If given correctly these vaccines can prevent birds from dying or getting sick with Newcastle disease, however these vaccines do not prevent virus replication and are not capable of eradicating virulent NDV. Here we have made vaccines that are similar to NDV currently circulating in China, South Africa and Pakistan and show evidence that by making the vaccine more genetically similar to the challenge strain we can decrease the amount of virus shed in saliva and feces and we can increase survival and decrease clinical signs. We also show that the capacity of the vaccine to replicate significantly affect the performance of recombinant vaccines.
Technical Abstract: The failure to control and to eradicate Newcastle Disease (ND) with vaccination alone in countries where the etiological agent of the disease, virulent Newcastle Disease Virus (vNDV) is endemic underscores the need to improve the efficacy of currently available NDV vaccines and vaccination approaches. Neither the current live, inactivated, nor subunit vaccines completely prevent infection, virus replication and shedding of vNDV challenge strains. In order to maximize reduction of viral replication upon challenge and to increase clinical protection, we have created antigenically matched live attenuated recombinant NDV strains that express the surface glycoproteins of vNDV strains of genotypes VII and XIII, and compared the protection conferred by those vaccines to the protection produced by current commercial heterologous vaccine (LaSota) on specific pathogen free birds. Antibody response, virus shedding, clinical signs and survival after challenge with vNDV strains was improved with homologous vaccines. Furthermore, we show that improper vaccine replication in the host significantly affects protection with homologous live vaccines. The recombinant homologous vaccine viruses that did not replicate well lost the advantages conferred by homologous vaccination. We also report here the development of a more effective live attenuated recombinant vaccine against vNDV from genotype XIII.