Evaluation of the Efficacy of Three Newcastle Disease Vaccines Produced at the National Veterinary Institute, Bishoftu, Ethiopia, at Different Temperature Storage Conditions

Abstract

Newcastle disease, which affects poultry and is endemic in many nations across the world, is caused by Avian Paramyxovirus-1 (APMV-1). This experimental study was conducted from January to June 2021 at the National Veterinary Institute (NVI) to evaluate the virus viability and antibody titer of Newcastle disease vaccines (Hichner’s B1, Lasota, and ThermostableI2) stored at different temperature storage conditions. Chickens (12 treatment groups and 1 control group) were vaccinated and challenged with the virulent ND virus (0.5 × 106.5 embryonic lethal dose fifty (ELD50)). The immune responses (antibody titers) of chickens were evaluated using hemagglutination (HA) and hemagglutination inhibition (HI) assays. The Newcastle disease vaccines (Hachiner’s B1 (ND-HB1), ND-Lasota, and ND-Thermostable I2) stored at +4 °C HI-induced antibody titers of 151 (±103.3), 136 (±53.4), and 145 (±91) on day 14, respectively, whereas on day 21, they increased to 160 (±82) for ND-HB1 and 144 (±74.5) for ND-Lasota. ND-Thermostable I2 showed a decrement to 133 (±44.8). All three vaccines stored at different temperature storage conditions (+4, +23, and +30 °C) used in this experiment induced antibody titers greater than 128 on day 28 post-vaccination, except the Newcastle disease vaccine Thermostable I2 stored at +30 °C. The vaccines collected from private veterinary drugstores (customer vaccines Hachiner’s B1 and ND-Thermostable I2) used in this experiment induced very low antibody titers, less than 128 antibody titers, from days 14 to 21. Statistically significant induced mean antibody titers were observed for chickens that received vaccines stored at different temperature storage conditions for 72 h (p < 0.05), except for the ND-HB1 mean HI-induced antibody titer at days 7 and 28. Further, vaccine protection was confirmed by inoculation of both the vaccinated (treatment groups) and control groups by the virulent ND virus, where the control group started dying three days post-challenge but all chicks that received the vaccines survived. Overall, this study showed the impact of temperature storage conditions on the antibody titer and their effect on the titer of the viable virus in the vaccine, and thereby its protective capacity, warranting appropriate cold chain management of the vaccines along the value chain.