Effectiveness evaluation of thermo-stable vaccine against Newcastle disease (ND.TR.IR) produced by the Razi Institute in backyard poultry of Iran - 2015

Newcastle Disease causes many economic losses to the poultry industry in most countries. The disease is endemic in Iran. Backyard poultry is considered as Newcastle virus’s reservoir and these birds there is no vaccination program against Newcastle, or it is done in a restricted manner. Commercial live vaccines are inactive and sensitive to temperature and delivering them to villages and remote areas requires special equipment and high cost to maintain the cold chain. In this study, the effectiveness of a thermo-stable Newcastle vaccine produced by the Razi Institute (ND.TR.IR) was evaluated in backyard poultry. In four province, at least 4 villages were selected as the treatment group and the same number was selected as the control group. At least 30 birds were sampled in each village. In each group, blood samples were collected before vaccination and 2 weeks later and the serum titer of the samples was examined with HI test. For analyzing the data, the arithmetic mean and standard deviation of the samples titers at the rural level were compared before and after vaccination in each group using paired t-test and titer changes between the vaccinated and control groups were compared before and after vaccination using ANOWA Repeated Measures. In this study, of 584 birds from 53 households in 20 villages in treatment group and of 389 birds from 33 households in 14 villages in control group were sampled. The mean serum titer of Newcastle in the treatment group before and after vaccination was 4.51 ± 3.03 and 6.64 ± 2.48 respectively (P <0.001). The increase in mean titer of the treatment group (2.31 log) was statistically higher than that in the control group (0.66 log) (p <0.001). Among 584 birds, 517 (88.5%) sampled in treatment group had titer above 3 in the second turn. The thermo-stable vaccine (ND.TR.IR) produced by the Razi institute is suitable for backyard poultry and immunizes them against Newcastle disease. Appropriate vaccination program for backyard poultry should be made and vaccination in backyard poultry can be effective in preventing the circulation of the field viruses.