Submitted to: Veterinary Record
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/2/2013
Publication Date: 3/3/2014
Publication URL: http://handle.nal.usda.gov/10113/59837
Citation: Lal, M., Zhu, C., McClurkan, C., Koelle, D., Miller, P., Afonso, C., Donadeu, M., Dungu, B., Chen D. 2014. Development of a low-dose fast-dissolving tablet formulation of Newcastle disease vaccine for low-cost backyard poultry immunisation. Veterinary Record. DOI: 10.1136/vr.101926. Interpretive Summary: Newcastle disease virus circulates worldwide in chickens and the virulent forms cause Newcastle Disease in poultry species. Introduction of virulent viruses into U.S. poultry could have serious impacts on the production and in the trade of poultry and poultry products. The huge reservoir of Newcastle disease makes necessary to develop strategies to reduce the threat to U.S. agriculture. By developing vaccines that are economically suitable to countries or regions of the world that are endemic for highly virulent viruses the threat of Newcastle disease can be reduced. Backyard poultry production is practiced in most rural areas of the world, with these flocks representing around 80% of poultry stocks in many developing countries. Here we have developed and tested a Newcastle Disease tablet vaccine that can be diluted with water and either administered orally in drinking water or via an intraocular and/or intranasal route. The low-dose size tablet format is feasible for use by backyard poultry producers and results in a smaller footprint in the cold chain, thus providing savings for logistics systems in storing and distributing the vaccine in those countries that constitute the greatest reservoir of virulent Newcastle disease virus.
Technical Abstract: The immunization of backyard poultry in rural and peri-urban areas worldwide is critical for providing adequate nutrition and income for small farmers and for ensuring global food security. A vaccine presentation for flocks of 30 to 50 birds that is stable at ambient temperatures could make it affordable for more farmers to vaccinate their flocks. Fast dissolving tablets (FDTs) of Newcastle disease virus (NDV) vaccine were produced by standard freeze drying of the LaSota NDV strain into tablets containing a small numbers of doses and packaged in polymer blister sheets. The NDV-FDT vaccine maintained virus stability for > 6 months at 4°C based on plaque assay and embryo infectious dose data. The viability of the virus in the FDT format was further confirmed by animal immunogenicity and efficacy results in a challenge study, where tablet vaccine elicited a strong immune response and provided 100% protection to vaccinated chickens challenged with a virulent strain of NDV. The vaccine tablet can be diluted with water (no needle or syringe required) and either administered orally in drinking water or via an intraocular and/or intranasal route. Results indicate that the FDTs in low-dose size format are feasible for use by backyard poultry producers. In addition, the compact packaging of the tablets will result in a smaller footprint in the cold chain, thus providing savings for logistics systems in storing and distributing the vaccine.