Reference Laboratory for Veterinary Quality Control on Poultry Production, Animal Health Research Institute, Agriculture Research Center, Giza 12618, Egypt.
Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Uppsala University, SE-75121 Uppsala, Sweden.
Viruses. 2022 May 11;14(5):1030. doi: 10.3390/v14051030.
Since it was first discovered, the low pathogenic avian influenza (LPAI) H9N2 subtype has established linages infecting the poultry population globally and has become one of the most prevalent influenza subtypes in domestic poultry. Several different variants and genotypes of LPAI H9N2 viruses have been reported in Egypt, but little is known about their pathogenicity and how they have evolved. In this study, four different Egyptian LPAI H9N2 viruses were genetically and antigenically characterized and compared to representative H9N2 viruses from G1 lineage. Furthermore, the pathogenicity of three genetically distinct Egyptian LPAI H9N2 viruses was assessed by experimental infection in chickens. Whole-genome sequencing revealed that the H9N2 virus of the Egy-2 G1-B lineage (pigeon-like) has become the dominant circulating H9N2 genotype in Egypt since 2016. Considerable variation in virus shedding at day 7 post-infections was detected in infected chickens, but no significant difference in pathogenicity was found between the infected groups. The rapid spread and emergence of new genotypes of the influenza viruses pinpoint the importance of continuous surveillance for the detection of novel reassortant viruses, as well as monitoring the viral evolution.
自首次发现以来，低致病性禽流感（LPAI）H9N2 亚型已在全球范围内建立了感染家禽种群的谱系，并已成为家禽中最常见的流感亚型之一。埃及已报告了几种不同的 LPAI H9N2 病毒变体和基因型，但对其致病性以及它们如何进化知之甚少。在这项研究中，对四种不同的埃及 LPAI H9N2 病毒进行了遗传和抗原特征分析，并与 G1 谱系的代表性 H9N2 病毒进行了比较。此外，通过在鸡中进行实验性感染评估了三种遗传上不同的埃及 LPAI H9N2 病毒的致病性。全基因组测序显示，自 2016 年以来，属于 Egy-2 G1-B 谱系（鸽样）的 H9N2 病毒已成为埃及主要流行的 H9N2 基因型。在感染鸡中检测到感染后第 7 天病毒排出量有很大差异，但感染组之间的致病性没有明显差异。流感病毒新基因型的快速传播和出现突显了持续监测以检测新型重组病毒以及监测病毒进化的重要性。
