Balam Deepthi, Doddamane Ratnamma, Pushpa Rn Ramani, Isloor Shrikrishna, Bm Veeregowda
Department of Veterinary Microbiology, College of Veterinary Science, Sri Venkateswara Veterinary University, Garividi, India.
Department of Veterinary Microbiology, Veterinary College, Karnataka Veterinary, Animal and Fisheries Science University, Bangalore, India.
Vet Res Forum. 2024;15(6):317-323. doi: 10.30466/vrf.2023.2004035.3904. Epub 2024 Jun 15.
Since decades, Newcastle disease (ND) has become endemic in the poultry population of the Indian subcontinent. ND is a highly contagious disease of poultry and other avian species. However, the genetic nature of ND viruses circulating in the rock pigeons is unraveled. The present investigation is a part of Newcastle disease virus (NDV) surveillance in wild birds. Two velogenic NDV strains could be isolated from apparently healthy rock pigeons, thus establishing the status of carrier/reservoir host. The fusion protein cleavage site in the fusion protein has multiple basic amino acid (RRRKRF) motifs similar to velogenic isolates. Phylogenetic analysis based on complete fusion gene sequences confirmed that the isolates belong to NDV sub genotype XIII 2.2. Further analysis revealed several amino acid substitutions in the hypervariable region, heptad repeat regions and neutralizing epitopes of the fusion protein and heptad repeat regions and antigenic sites of the hemagglutinin-neuraminidase (HN) protein that are critical for fusion. A unique D170A substitution in the neutralizing epitope is identified that is critical for structure and function of the fusion protein. Mutations within the virulence determinants including fusion (F) and HN, elucidate continuous evolution of the viruses among the rock pigeons. Accidental spillover of these mutated viruses into commercial poultry operations may result in disease outbreaks with economic breakdown.
几十年来，新城疫（ND）已在印度次大陆的家禽群体中成为地方病。新城疫是家禽和其他鸟类的一种高度传染性疾病。然而，在岩鸽中传播的新城疫病毒的遗传特性已被揭示。本研究是对野生鸟类新城疫病毒（NDV）监测的一部分。从看似健康的岩鸽中分离出两株强毒株新城疫病毒，从而确定了其作为携带者/储存宿主的地位。融合蛋白中的融合蛋白裂解位点具有多个与强毒株分离株相似的碱性氨基酸（RRRKRF）基序。基于完整融合基因序列的系统发育分析证实，分离株属于新城疫病毒亚基因型XIII 2.2。进一步分析发现，融合蛋白的高变区、七肽重复区和中和表位以及血凝素神经氨酸酶（HN）蛋白的七肽重复区和抗原位点存在多个氨基酸替换，这些对融合至关重要。在中和表位中鉴定出一个独特的D170A替换，这对融合蛋白的结构和功能至关重要。包括融合蛋白（F）和HN蛋白在内的毒力决定因素内的突变，阐明了病毒在岩鸽中的持续进化。这些突变病毒意外传播到家禽商业养殖中可能导致疾病爆发并造成经济损失。
