Reemergence of yellow fever virus in southeastern Brazil, 2017-2018: What sparked the spread?
Reemergence of yellow fever virus in southeastern Brazil, 2017-2018: What sparked the spread?
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DOI：
10.1371/journal.pntd.0010133
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发表时间：
2022-03
影响因子：
3.8
通讯作者：
Fuller T
中科院分区：
文献类型：
--
作者：
Rosser JI;Nielsen-Saines K;Saad E;Fuller T
2017-2018年在巴西东南部爆发的黄热病病毒（YFV）疫情标志着YFV在近世纪来没有YFV的城市州重新出现。与早期的城市YFV传播不同，这次流行是由森林蚊子引起的。这项研究的目的是评估这次疫情的环境驱动因素。利用巴西卫生部对人类和非人灵长类（NHP）YFV病例的监测数据，我们追踪了疫情的时空进展。然后，我们使用每月标准化降水蒸散指数（SPEI）评估了与干旱有关的流行时间，并评估了YFV病例中农村或户外暴露的人口风险因素。最后，我们开发了一个机制框架来映射干旱和YFV之间的关系。人类和NHP病例首先在北方米纳斯吉拉斯炎热干燥的农村地区被发现，然后向东南方向蔓延到更凉爽潮湿的城市州。疫情爆发时，正值巴西东南部所有四个州干旱，米纳斯吉拉斯也出现极端干旱。确诊的YFV病例中，男性（OR 2.6; 95% CI 2.2-3.0）、工作年龄（OR：1.8; 95% CI：1.5-2.1）和报告最近旅行（OR：2.8; 95% CI：2.3-3.3）的几率增加。基于这些数据以及蚊子和非人类灵长类动物的生物学，我们创建了“Mono-DrY”机制框架，显示该地区的异常干旱如何放大YFV在城乡交界处的传播并引发这种流行病的传播。巴西2017-2018年的YFV疫情起源于米纳斯吉拉斯炎热干燥的农村地区，然后向南扩展到城市中心。该地区异常严重的干旱可能造成了环境压力，引发了巴西东南部城市的YFV重新出现。2017-2018年，巴西东南部城市经历了黄热病病毒的不寻常爆发。在世纪早期，这些城市爆发了由伊蚊传播的黄热病。但直到最近的这次爆发，他们已经近世纪没有黄热病了。虽然这次疫情是由森林血蚊传播的，但黄热病在人口稠密的城市地区的重新出现引起了人们对它在城市重新建立持续传播的严重关切，这种传播是由城市伊蚊传播的。我们的研究试图了解黄热病病毒如何以及为什么在这一地区重新合并。我们追踪了疫情，发现它始于炎热、干燥的农村地区，并向南蔓延到凉爽、潮湿的城市地区。这一流行病与严重的干旱同时发生，特别是在这一流行病开始的米纳斯吉拉斯。具有户外或农村危险因素的个人风险最高，特别是在疫情开始时。因此，这场严重的干旱可能促进了黄热病在城乡边界的传播。为了进一步探索这个想法，我们开发了一个基于森林蚊子和吼猴生物学的独特框架。我们的框架“Mono-DrY”显示了严重的干旱如何增加蚊子和猴子的密度，促进黄热病的传播。
The 2017–2018 yellow fever virus (YFV) outbreak in southeastern Brazil marked a reemergence of YFV in urban states that had been YFV-free for nearly a century. Unlike earlier urban YFV transmission, this epidemic was driven by forest mosquitoes. The objective of this study was to evaluate environmental drivers of this outbreak. Using surveillance data from the Brazilian Ministry of Health on human and non-human primate (NHP) cases of YFV, we traced the spatiotemporal progression of the outbreak. We then assessed the epidemic timing in relation to drought using a monthly Standardized Precipitation Evapotranspiration Index (SPEI) and evaluated demographic risk factors for rural or outdoor exposure amongst YFV cases. Finally, we developed a mechanistic framework to map the relationship between drought and YFV. Both human and NHP cases were first identified in a hot, dry, rural area in northern Minas Gerais before spreading southeast into the more cool, wet urban states. Outbreaks coincided with drought in all four southeastern states of Brazil and an extreme drought in Minas Gerais. Confirmed YFV cases had an increased odds of being male (OR 2.6; 95% CI 2.2–3.0), working age (OR: 1.8; 95% CI: 1.5–2.1), and reporting any recent travel (OR: 2.8; 95% CI: 2.3–3.3). Based on this data as well as mosquito and non-human primate biology, we created the “Mono-DrY” mechanistic framework showing how an unusual drought in this region could have amplified YFV transmission at the rural-urban interface and sparked the spread of this epidemic. The 2017–2018 YFV epidemic in Brazil originated in hot, dry rural areas of Minas Gerais before expanding south into urban centers. An unusually severe drought in this region may have created environmental pressures that sparked the reemergence of YFV in Brazil’s southeastern cities. In 2017–2018, cities in southeastern Brazil experienced an unusual outbreak of yellow fever virus. In the early 20th century, these cities had large outbreaks of yellow fever, spread by Aedes mosquitoes. But until this recent outbreak, they had been free of yellow fever for nearly a century. While this outbreak was spread by Haemagogus forest mosquitoes, the reemergence of yellow fever in densely populated urban areas raises serious concerns about it reestablishing ongoing transmission in cities, spread by urban Aedes mosquitoes. Our study sought to understand how and why yellow fever virus remerged in this area. We traced the outbreak, finding that it started in hot, dry, rural areas and spread south into cool, wet urban areas. The epidemic coincided with a severe drought, particularly in Minas Gerais where the epidemic started. Individuals with outdoor or rural risk factors were at highest risk, especially when the epidemic started. Therefore, this severe drought may have promoted the spread of yellow fever at rural-urban boundaries. To further explore this idea, we developed a unique framework based on forest mosquito and Howler monkey biology. Our framework, “Mono-DrY,” shows how severe drought could have increased mosquito and monkey densities, promoting the spread of yellow fever.