Department of Pathology and Clinical Pathology, Faculty of Veterinary Medicine, Damanhour University, Damanhour, Egypt.
Animal Health Research Institute, Agricultural Research Center, Tanta, Egypt.
J Comp Pathol. 2021 Jul;186:35-50. doi: 10.1016/j.jcpa.2021.05.003. Epub 2021 Jun 23.
Newcastle disease virus (NDV), a major pathogen of poultry worldwide, causes significant economic losses in the poultry industry. To characterize the ability of recently isolated virulent strains of NDV genotypes VI and VII to cause disease in quails, and to evaluate the efficacy of two NDV vaccines against such strains, Japanese quails were experimentally inoculated with either NDV genotype VI (Pigeon F-VI strain) or VII 1.1 (GHB-328 strain) with or without vaccination with inactivated NDV vaccine of genotype II (La Sota strain) or VII (KBNP strain). Mild to severe neurological signs developed in quails inoculated with the Pigeon F-VI strain from 3 to 14 days post infection (PI) and from 4 to 10 days PI in birds infected with the GHB-328 strain. The mortality rates were 46% and 33% for birds inoculated with NDV VI and NDV VII 1.1, respectively. The severity of histopathological changes depended on the viral isolates used. Vaccination with the La Sota or KBNP vaccine strain successfully protected quails against NDV-induced mortality and decreased the severity of clinical signs, pathological changes and cloacal viral shedding. This study showed that these virulent NDV isolates had mild to moderate pathogenicity in quails and that both vaccines protected against challenge with both virus strains. NDV vaccine genotype VII improved the level of protection against challenge with the VII 1.1 genotype compared with the classic vaccine, but failed to protect quails against challenge with the VI genotype.
新城疫病毒（NDV）是一种全球性的家禽主要病原体，给家禽业造成了重大的经济损失。为了描述最近分离的基因型 VI 和 VII 的强毒 NDV 株在鹌鹑中引起疾病的能力，并评估两种 NDV 疫苗对这些毒株的效力，用 NDV 基因型 VI（鸽源 F-VI 株）或 VII 1.1（GHB-328 株）对鹌鹑进行了实验性接种，而不接种基因型 II（La Sota 株）或 VII（KBNP 株）的灭活 NDV 疫苗。感染鸽源 F-VI 株的鹌鹑在感染后 3 至 14 天（PI）出现轻度至重度神经症状，而感染 GHB-328 株的鸟类在感染后 4 至 10 天 PI 出现轻度至重度神经症状。接种 NDV VI 和 NDV VII 1.1 的鸟类死亡率分别为 46%和 33%。组织病理学变化的严重程度取决于使用的病毒分离株。接种 La Sota 或 KBNP 疫苗株成功地保护鹌鹑免受 NDV 诱导的死亡率，并降低了临床症状、病理变化和泄殖腔病毒脱落的严重程度。本研究表明，这些强毒 NDV 分离株在鹌鹑中有轻度至中度的致病性，两种疫苗都能预防两种病毒株的攻毒。与经典疫苗相比，NDV 疫苗基因型 VII 提高了对 VII 1.1 基因型攻毒的保护水平，但未能保护鹌鹑免受 VI 基因型的攻毒。
