Thermostability and efficacy of I-2 vaccine against Newcastle disease (ND) in Iran: a pilot study

Thermostable vaccine against Newcastle disease (ND) is a potential alternative to chicken vaccination in villages, since cold chain is not needed in this process. The purpose of this study was to investigate thermostability and efficacy of I-2 vaccine against ND. The vaccine tested for sterility, intracerebral pathogenicity index (ICPI) and 50% embryo infectious dose (EID50). The wet vaccine stored at 20ºC for 1, 2 and 4 weeks named A, B and D, respectively. Each preparation (107.5 EID50) was used to inoculate twenty, 4-week-old chicks via eye drop. All groups except the control were vaccinated twice in 2 weeks interval. Haemagglutination inhibition test used for evaluation of the antibody response. Two weeks after the first vaccination, a peak titer of about log.26 and log.24.6 was observed in A and B groups, but D group did not induce any antibody response in their sera. All the vaccinated groups responded to vaccination after second trial and produced mean titers of log.26.2, log.26 and log.25.4 were observed, respectively.