Department Poultry and Fish Diseases, Faculty of Veterinary Medicine, Alexandria University, El-Beheira 22758, Egypt.
Department of Poultry and Fish Diseases, Faculty of Veterinary Medicine, Damanhour University, Damanhour 22511, Egypt.
Viruses. 2022 Jun 29;14(7):1431. doi: 10.3390/v14071431.
The global spread of avian influenza virus (AIV) of clade 2.3.4.4b since 2016 has caused severe losses in wild birds and poultry and has posed a risk for the infection of mammals including humans. The vaccination of poultry has been used to limit the spread of the virus and mitigate its socioeconomic impact. Here, we describe H5N8 epidemics in chickens, turkeys and ducks from different localities in Egypt from 2019 to 2021. About 41.7% ( = 88/211) flocks were tested positive by RT-qPCR for H5N8 viruses with prevalence rates of 45.1% ( = 65/144) and 34.3% ( = 23/67) in vaccinated and non-vaccinated flocks, respectively. A sequence analysis of the hemagglutinin and neuraminidase genes indicated not only the multiple introduction events of H5N8 viruses in Egypt but also the establishment of endemic viruses in commercial poultry in 2020/2021. The recent H5N8 viruses in poultry in Egypt are genetically distinct from the majority of licensed vaccines used in the field. Together, our findings indicate that poultry in Egypt is an endemic center for clade 2.3.4.4b in the Middle East. The efficiency of current vaccines should be regularly evaluated and updated to fully protect poultry flocks in Egypt against H5N8 viruses.
自 2016 年以来，2.3.4.4b 分支的禽流感病毒（AIV）在全球范围内传播，导致野生鸟类和家禽遭受严重损失，并对包括人类在内的哺乳动物的感染构成威胁。对家禽进行疫苗接种已被用于限制病毒的传播并减轻其对社会经济的影响。在这里，我们描述了 2019 年至 2021 年埃及不同地区鸡、火鸡和鸭中 H5N8 的流行情况。大约 41.7%（=88/211）的禽群通过 RT-qPCR 对 H5N8 病毒呈阳性反应，接种和未接种疫苗的禽群的流行率分别为 45.1%（=65/144）和 34.3%（=23/67）。血凝素和神经氨酸酶基因的序列分析不仅表明 H5N8 病毒在埃及多次传入，还表明 2020/2021 年在商业家禽中建立了地方性病毒。埃及家禽中的最近 H5N8 病毒在遗传上与该领域使用的大多数许可疫苗不同。综上所述，我们的研究结果表明，埃及的家禽是中东 2.3.4.4b 分支的地方性中心。应定期评估和更新当前疫苗的效率，以充分保护埃及家禽群免受 H5N8 病毒的侵害。
