Thermostability and efficacy of 1-2 vaccine against Newcastle disease [ND] in Iran: a pilot study

ABSTRACT

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 1-2 vaccine against ND. The vaccine tested for sterility, intracerebral pathogenicity index [ICPI] and 50% embryo infectious dose [EID50]. The wet vaccine stored at 20°C for 1,2 and 4 weeks named A, B and D, respectively. Each preparation [10 [7.5] 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.2 [6] and log.2 [4.6] 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.2 [6.2], log.2 [6] and log.2 [5.4] were observed, respectively