In this Review, we examine the concurrent outbreaks of mpox in Africa, focusing on clade 1a, the newly emerged clade 1b, and clade 2b lineage A, and how they differ from the 2022 global outbreak caused by clade 2b lineage B.1. Historically, clades 1a and 2a have caused sporadic, small outbreaks in central and west Africa, respectively, primarily through zoonotic transmission. Clade 2b first caused an outbreak in Nigeria in 2017, and later spread globally via sexual contact in 2022. In August, 2024, WHO declared a global health emergency due to the newly identified clade 1b outbreak in eastern Democratic Republic of the Congo. This outbreak has now expanded to several other countries and is spreading through direct and sexual contact in urban centres and refugee camps. Clades, route of exposure, infectious dose, and host immune response are the main factors influencing clinical presentation of mpox. For clades 1a and 2a, zoonotic transmission plays an important role, whereas for clades 1b and 2b, the spread occurs through sustained human-to-human transmission without zoonotic exposure. For both clades 1a and 2a, lesions have a generalised centrifugal distribution, whereas for clade 2b they are mainly localised to the anogenital area. For clade 1b, data are still emerging, but current cases show a mix of localised lesions and centrifugal distribution. The severity of the disease is higher for clade 1a (case fatality rate up to 12%) compared with other clades (case fatality rates 0–3·6%). Diagnostic challenges include false negative results for clade 1b with existing PCR assays and poor testing access in remote areas. Tecovirimat, the primary antiviral during the 2022 outbreak, has shown reduced effectiveness against clade 1a in preliminary study results, whereas its efficacy against other clades is still under investigation. The modified vaccinia Ankara–Bavarian Nordic vaccine has been shown to be up to 90% effective against clade 2b after two doses and is safe for children, although its effectiveness drops to 20% when used as post-exposure prophylaxis. Given the evolving nature of the monkeypox virus, ongoing research and strong public health responses are key to managing potential future outbreaks.

中文翻译：

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非洲同时爆发的猴痘疫情 — 最新情况


在这篇综述中，我们研究了非洲同时爆发的猴痘疫情，重点关注分支 1a、新出现的分支 1b 和分支 2b 谱系 A，以及它们与 2022 年由分支 2b 谱系 B.1 引起的全球爆发有何不同。从历史上看，分支 1a 和 2a 分别在中非和西非引起了零星的小规模爆发，主要是通过人畜共患传播。分支 2b 于 2017 年首次在尼日利亚引起疫情，随后于 2022 年通过性接触传播到全球。2024 年 8 月，由于刚果民主共和国东部新发现的 1b 分支疫情，世卫组织宣布进入全球卫生紧急状态。这次疫情现已扩展到其他几个国家，并通过城市中心和难民营的直接和性接触传播。分支、暴露途径、感染剂量和宿主免疫反应是影响 mpox 临床表现的主要因素。对于分支 1a 和 2a，人畜共患传播起着重要作用，而对于分支 1b 和 2b，传播是通过持续的人际传播发生的，而没有人畜共患疾病暴露。对于分支 1a 和 2a，病变具有广泛的离心分布，而对于分支 2b，它们主要局限于肛门生殖器区域。对于分支 1b，数据仍在不断涌现，但目前的病例显示局部病变和离心分布的混合。与其他分支（病死率 0-3·6%）相比，分支 1a 的疾病严重程度更高（病死率高达 12%）。诊断挑战包括现有 PCR 检测对分支 1b 的假阴性结果和偏远地区的检测机会不佳。 Tecovirimat 是 2022 年疫情期间的主要抗病毒药物，在初步研究结果中显示对进化枝 1a 的有效性降低，而其对其他进化枝的疗效仍在研究中。改良的安卡拉-巴伐利亚北欧疫苗已被证明在接种两剂后对分支 2b 的有效性高达 90%，并且对儿童是安全的，尽管其有效性在用作暴露后预防时下降到 20%。鉴于猴痘病毒的演变性质，正在进行的研究和强有力的公共卫生应对措施是管理未来潜在疫情的关键。