兽医科学与医学诊断杂志

Large scale Production of I-2 thermostable Newcastle Disease Vaccine in Sudan

Manan AAA*, Kheir MASS, Ballal A, Wegdan H Ali, Nour TAM

In the present study, a live attenuated Newcastle Disease (ND) vaccine of I-2strain was produced locally. the master seed I-2 virus was first supplied by the Department of Veterinary Pathology of the University of Queensland, Australia, which then handed over by the Department of Veterinary Virology of the Central Veterinary Research Laboratory (CVRL) Sudan. A 11 days old embryonated chicken eggs with a minimal risk of vertical transmission were used for the virus propagation. The ND I-2 Master Seed Lot ( MSL) was prepared in aliquots and stored in a liquid form at -20⁰C. The Working Seed Lot (WSL) was prepared from the MSL and stored in a freeze dried form. The WSL then complied with the main quality tests of identity,safety, immunogenicity, efficacy, microbial contamination, thermostability and the infectivity titer tests.The virulence of the WSL was estimated via intracerepral pathogenicity index test (ICPI), the ICPI was 0.125 and the vaccine was proved to be safe in day old chicks.The immunogenicity measured by mean of ELISA. The GMT titer for the post vaccination serum was statistically significant than the pre vaccinated serum(P=0.001) paired sample t.test.The efficacy against a vvND virus, (ICPI 1.97) was 89% and the WSL was proved to be free from any detectable contaminant microorganisms. The temperature sensitivity for vaccine potency had been determined at different temperature levels and at Fluctuating Room Temperature (FRT). The titer decreased only by 0.2, 4.5 and 4.6 logs at temperatures -20⁰C, 37⁰C and 56⁰C respectively, while in the FRT decreased by 7.53 logs. The virus titer of WSL on the embryonated chickens, eggs was 9.1 EID50/ml.