Ghafouri S A, Ghaniei A, Moghani M, Lotfalizadeh N
Department of Clinical Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran.
Arch Razi Inst. 2024 Jun 30;79(3):541-548. doi: 10.32592/ARI.2024.79.3.541. eCollection 2024 Jun.
Newcastle disease (ND) is among the most common and deadliest poultry diseases worldwide. Thermostable Newcastle disease virus (NDV) vaccines have been widely used to protect village chickens against ND due to their decreased dependence on cold chains for transport and storage. The NDV4 Heat-Resistant (NDV4HR) vaccine is an apathogenic, heat-resistant, live vaccine that can induce immunity in chickens. In this study, 60 one-day-old Arain local hybrid broilers were divided into three groups of 20. Group A had the usual vaccination program in broiler flocks (seven days old: B1 type by eye drop and ND killed vaccine intramuscularly; 18 and 28 days old: LaSota strain orally). Group B did not receive any vaccine, and group C received the NDV4HR vaccine orally, six times from the first day to the 35 day of rearing. All groups were nasally challenged with acute Newcastle virus (genotype VIId) on the 35 rearing day. Regarding the hemagglutination inhibition serum antibody titer of the birds after the challenge, group B had the highest (7.12±1.05), and group C (6.37±1.31) had a higher titer than group A (6±1.22). After the challenge with the Newcastle virus, the necropsy findings and clinical symptoms of the disease were almost similar in groups A and C. Group B showed the most signs, with higher casualties than other groups. Regarding weight gain, group C had the highest weight at the end of the study (2204±106). On the second day after the challenge, groups A and B had virus shedding through the trachea and cloaca, while group B shed the virus only through the trachea. Furthermore, on the seventh day after the challenge, group A shed the virus through the cloaca, whereas group B did it through the trachea and the cloaca. On the other hand, there was no virus shedding in group C. This study showed that the NDV4HR vaccine provokes an antibody response that protects the birds against a virulent virus challenge.
新城疫（ND）是全球最常见、最致命的家禽疾病之一。耐热新城疫病毒（NDV）疫苗因其在运输和储存中对冷链的依赖性降低，已被广泛用于保护乡村鸡群免受新城疫侵害。NDV4耐热（NDV4HR）疫苗是一种无致病性、耐热的活疫苗，可在鸡群中诱导免疫。在本研究中，60只1日龄的Arain本地杂交肉鸡被分为三组，每组20只。A组采用肉鸡群常规疫苗接种程序（7日龄：通过滴眼接种B1型疫苗，肌肉注射新城疫灭活疫苗；18日龄和28日龄：口服LaSota株疫苗）。B组未接种任何疫苗，C组从饲养的第一天到第35天口服NDV4HR疫苗6次。在饲养第35天时，所有组均经鼻腔接种急性新城疫病毒（基因型VIId）。关于攻毒后鸡的血凝抑制血清抗体效价，B组最高（7.12±1.05），C组（6.37±1.31）的效价比A组（6±1.22）高。用新城疫病毒攻毒后，A组和C组的尸检结果和疾病临床症状几乎相似。B组表现出的症状最多，伤亡率高于其他组。关于体重增加，C组在研究结束时体重最高（2204±106）。攻毒后第二天，A组和B组通过气管和泄殖腔排出病毒，而B组仅通过气管排出病毒。此外，攻毒后第七天，A组通过泄殖腔排出病毒，而B组通过气管和泄殖腔排出病毒。另一方面，C组没有病毒排出。本研究表明，NDV4HR疫苗可引发抗体反应，保护鸡群免受强毒病毒攻击。
