Department of Ecology & Evolutionary Biology, Princeton University, Princeton, New Jersey, United States of America.
Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey, United States of America.
PLoS Biol. 2022 Oct 26;20(10):e3001864. doi: 10.1371/journal.pbio.3001864. eCollection 2022 Oct.
The explosive emergence of Zika virus (ZIKV) across the Pacific and Americas since 2007 was associated with hundreds of thousands of human cases and severe outcomes, including congenital microcephaly caused by ZIKV infection during pregnancy. Although ZIKV was first isolated in Uganda, Africa has so far been exempt from large-scale ZIKV epidemics, despite widespread susceptibility among African human populations. A possible explanation for this pattern is natural variation among populations of the primary vector of ZIKV, the mosquito Aedes aegypti. Globally invasive populations of Ae. aegypti outside of Africa are considered effective ZIKV vectors because they are human specialists with high intrinsic ZIKV susceptibility, whereas African populations of Ae. aegypti across the species' native range are predominantly generalists with low intrinsic ZIKV susceptibility, making them less likely to spread viruses in the human population. We test this idea by studying a notable exception to the patterns observed across most of Africa: Cape Verde experienced a large ZIKV outbreak in 2015 to 2016. We find that local Ae. aegypti in Cape Verde have substantial human-specialist ancestry, show a robust behavioral preference for human hosts, and exhibit increased susceptibility to ZIKV infection, consistent with a key role for variation among mosquito populations in ZIKV epidemiology. These findings suggest that similar human-specialist populations of Ae. aegypti in the nearby Sahel region of West Africa, which may be expanding in response to rapid urbanization, could serve as effective vectors for ZIKV in the future.
自 2007 年以来，寨卡病毒（ZIKV）在太平洋和美洲的爆炸性传播与数十万例人类病例和严重后果有关，包括寨卡病毒感染引起的先天性小头畸形。尽管寨卡病毒最初是在乌干达分离出来的，但迄今为止，非洲没有发生大规模的寨卡病毒流行，尽管非洲人类种群普遍易感。这种模式的一个可能解释是寨卡病毒主要传播媒介埃及伊蚊种群之间的自然变异。在非洲以外的全球入侵埃及伊蚊种群被认为是有效的寨卡病毒传播媒介，因为它们是对人类具有高度内在易感性的专家，而非洲范围内的埃及伊蚊种群在物种的原生范围内主要是一般专家，对寨卡病毒的内在易感性较低，因此不太可能在人类群体中传播病毒。我们通过研究非洲大部分地区观察到的模式中的一个显著例外来检验这个想法：佛得角在 2015 年至 2016 年期间经历了一次大规模的寨卡病毒爆发。我们发现，佛得角当地的埃及伊蚊具有大量的人类专业祖先，对人类宿主表现出强烈的行为偏好，并表现出对寨卡病毒感染的易感性增加，这与蚊群变异在寨卡病毒流行病学中的关键作用一致。这些发现表明，附近的西非萨赫勒地区可能存在类似的埃及伊蚊人类专业种群，这些种群可能会因快速城市化而扩张，未来可能成为寨卡病毒的有效传播媒介。
