Next generation vector vaccines for poultry can be administered in the hatchery and are minimally interfered with by maternal antibodies, are safer to use than live attenuated whole virus vaccines and offer the potential for lifetime immunity for the bird. Dr. Richard Currie, CEO, Rapid Genomics, said that a pair of new diagnostic tests for HVT vector vaccine verification and virus exposure characterization have been developed to help poultry producers manage their vaccine administration programs and provide insight into the level of disease challenge present on their farms.
Next generation vector vaccines utilize a virus, such as a turkey herpes virus (HVT), which serves as a carrier for the genetic material from viruses which cause a poultry disease, such as Newcastle disease, infectious bursal disease, Marek’s disease or infectious bronchitis. The nucleotide sequences which are inserted into the turkey herpes virus code for the antigens on the surface of the disease virus. Exposure to these antigens will stimulate an immune response in the chicken and formation of antibodies which will protect the bird if it is exposed to a field strain of the disease virus.
Currie explained during a presentation at the Interactive Forum on Innovation in Poultry Production and Health, presented by Merck Animal Health, at the International Production & Processing Expo (IPPE) on February 13, 2019, that the specificity of the nucleotide sequence where the foreign DNA sequence is inserted into the turkey herpes virus provides a marker that the new genomic test his company has developed can recognize. This test was designed to detect the presence of Merck Innovax vaccines in the bird and there are no false negatives. He said that results can be compared between geographic areas and across time and results are bench marked against other poultry operations' results. This provides valuable feedback on the uniformity of vaccine administration relative to other operations.
The field virus test uses next generation sequencing technology to monitor the prevalence of viral pathogens in a flock. This provides feedback on the efficacy of current vaccination practices and insight for changes that may be required in the future. These tests can help producers investigate the origin and evolution of field viruses on their farm and in their region.