<OL> <LI> Conduct a pathogenesis study of VG, B1, clone 30, and C2 NDV to determine tissue trophism in the respiratory and gastrointestinal tract using virus isolation and histopathogy. <LI>Develop laboratory trials that simulate field conditions to determine the efficacy of Newcastle Disease Virus (NDV) vaccination using VG B1, clone 30 and C2 vaccines together with IBV (Mass/Ark) can effectively protect against velogenic NDV challenge.<LI>Study the interactions of Mycoplasma gallisepticum when combined with NDV and IBV (Mass/Ark) vaccination in affecting IBV and NDV immunity as determined by velogenic NDV challenge and assessment of the severity of vaccine. <LI>Determine if a severe stressor affects severity of M. gallisepticum when combined with NDV and IBV vaccination in affecting IBV and NDV immunity as assessed by velogenic NDV challenge.
NON-TECHNICAL SUMMARY: Many broiler chicken producers have favored new strains of mild Newcastle Disease vaccine virus. To control disease caused by Newcastle Disease Virus, vaccination programs need to be continuously reviewed. This project will test the effectiveness of these new strains by simulating real life exposure to other common disease causing agents prior to challenge with very virulent NDV.
APPROACH: Exotic Newcastle disease has both a neurological and intestinal forms of disease that has in the past produced major economic damage to the US poultry industry. By simulating real life field exposure to immunosuppressive viruses and other stressors, we will investigate the efficacy of three new Newcastle vaccines to determine if they are effective vaccines. After NDV vaccination, protective immunity will be assessed by challenge with highly pathogenic Newcastle Disease Virus.