Assessing the ecologies of arboviruses and mosquito vectors in West and Central Africa

蚊子传播的虫媒病毒是非洲超过7.81亿人（占非洲大陆人口的70%）日益严重（重新）出现的威胁（Weetman et al., 2018）。非洲大陆已经记录了伊蚊传播的黄热病（YFV）、登革热（DENV）、基孔肯雅热（CHIKV）和寨卡病毒（ZIKV）以及伊蚊和库蚊传播的裂谷热（RVFV）病毒感染，但报告不完整。缺乏基于证据的虫媒病毒感染风险图妨碍了对公共卫生和研究资源的充分规划。尽管主要媒介埃及伊蚊、白纹伊蚊和致倦库蚊在中非和西非国家普遍存在（Kreamer et al., 2015）；虫媒病毒感染和暴发的分布和频率在某些国家之间和国家内部显示出惊人的异质性。因此，我们提出了一个关键问题：当地蚊子媒介种群的遗传变异和生物学差异是否影响西非各国虫媒病毒的发生？在此，我们建议基于对媒介叮咬行为、病毒监测和媒介种群遗传结构的深入多国调查，评估人类接触虫媒病毒的差异（通过流行病学和血清学研究）。我们将在具有不同和特定流行病学概况的三个西非和中非国家（贝宁、加蓬和Côte科特迪瓦）开展研究。贝宁（西非）将是虫媒病毒低发病率的环境，加蓬（中非）将是虫媒病毒高发病率的潜在焦点，自2010年以来未报告疫情，Côte科特迪瓦（西非）将是虫媒病毒高发病率的活跃焦点，最近报告了持续的疫情。在每个国家，该研究将在已知的虫媒病毒疫源地或潜在的虫媒病毒疫源地进行，并从人、动物或蚊子中检测到虫媒病毒。由于虫媒病毒主要在非洲大城市报告，本研究将在每个国家的首都（及其周边城镇）进行，以最大限度地观察到虫媒病毒感染。我们将选择三个地点，代表每个农村、郊区或城市地区，以捕捉虫媒病毒流行与蚊子物种多样性、病媒和人群相关的潜在变异性。其结果将直接有助于建立一个可持续的虫媒病毒网络（称为ecovir网络），该网络将致力于改善非洲虫媒病毒的监测、预防和控制。此外，我们将通过我们的培训计划培养训练有素的新一代非洲年轻科学家，他们将来将为非洲的虫媒病毒控制作出贡献。

Mosquito-borne arboviruses are an increasing (re-)emerging threat for more than 781 million people in Africa (70% of the continental population) (Weetman et al., 2018). Aedes-borne yellow fever (YFV), dengue (DENV), chikungunya (CHIKV) and Zika virus (ZIKV) as well as Aedes- and Culex-borne Rift Valley fever (RVFV) virus infections have been documented from the African continent, but reports are sketchy. The absence of evidence-based risk maps for arbovirus infections prevents adequate planning of both public health and research resources. Although the main vectors Aedes aegypti, Aedes albopitus and Culex quinquefasciatus are prevalent in Central and West African countries (Kreamer et al., 2015); the distribution and the frequency of arboviral infections and outbreaks display a surprising heterogeneity between and within certain countries. Thus, we ask the key question: Do genetic variability and bionomic differences in local mosquito vector populations influence arbovirus occurrence across countries in West Africa?Here we propose to assess the difference in human exposure to arboviruses (through an epidemiologic and serologic study) based on in-depth multi-national investigation on the vector’s biting behavior, virus surveillance, and the genetic structure of vector populations. We will conduct our study in three West and Central African countries (Benin, Gabon and Côte d’Ivoire) with different and specific epidemiological profiles. Benin (West Africa) will present a setting with low arboviral occurrence, Gabon (Central Africa) will represent a latent focus with high arboviral occurrence where no outbreaks have been reported since 2010, and Côte d’Ivoire (West Africa) will represent an active focus with high arboviral occurrence where ongoing outbreaks have been reported recently. In each country, the study will be conducted in already known arbovirus foci or potential arbovirus foci with arbovirus detection from either human, animal or mosquitoes. As arboviruses have been reported mainly in large African cities, the study will be conducted in the capital cities (and their surrounding towns) of every country to maximize the probability to observe an arboviral infection We will select three sites representing each rural, suburban or urban area to capture potential variability in arbovirus prevalence in connection with mosquito species diversity, and vector and human populations.The outcomes will help directly to set up a sustainable network on arboviruses (termed EcoVir-network) which will work to contribute to improving the surveillance, prevention and control of arboviruses in Africa. Furthermore, we will build a well-trained new generation of young African scientists through our training program, who will in future contribute to arbovirus control in Africa.