Dry Season Ecology of Malaria Vectors

疟疾媒介的旱季生态学

基本信息

批准号：
10927884
负责人：
Tovi Lehmann
金额：
$ 56.92万
依托单位：
NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10927884
关键词：
Address Adult Aedes Affect Africa African Altitude Animals Anopheles Genus Arboviruses Area Asia Bacteria Behavioral Biology Blood Cessation of life Chest Cities Collaborations Complement Culex (Genus)Culicidae Databases Dengue Destinations Detection Deuterium Development Disease Disease Outbreaks Disease Surveillance Distant Doctor of Philosophy Dryness Ecology Ecosystem Emerging Communicable Diseases Environmental Wind Epidemiology Evolution Female Frequencies Ghana Goals Health High Prevalence Horns Human Infection Insecta Intercept Invaded Journals Kenya Laboratories Location Malaria Mali Mansonia Maps Measures Mediating Metagenomics Methods Migrant Modality Modeling Molecular Monitor Mosquito Control Mosquito-borne infectious disease Movement National Institute of Allergy and Infectious Disease Nature Nematoda Nigeria Nutritional Pan Genus Paper Parasites Pathogen detection Pattern Physiological Plasmodium Population Postbaccalaureate Public Health Publishing Rain Reporting Rift Valley Fever Risk Role Sampling Seasons Senegal Shelter facility Site Source Specimen Surface Time Travel Validation Variant Vector-transmitted infectious disease Virus Water West Nile virus Wolbachia avian plasmodia climate change disease transmission disorder control enzootic food security forest frontier high school improved infection rate insight literature survey malaria mosquito malaria transmission male migration mosquito-borne pathogen novel pathogen prevent programs rural area success summer internship survivorship transmission process urban area vector vector competence vector control volunteer

项目摘要

With a billion cases worldwide and one million deaths annually, vector borne diseases remain important. Malaria is prevalent worldwide with an especially heavy burden in Africa. Outstanding gaps remain in our understanding of vector biology, limiting our impact on vector-borne disease control. 1. To resolve the 'dry season malaria paradox' (above), We evaluated the contribution of aestivation to the persistence of mosquitoes in the Sahel by tracking wild mosquitoes marked by deuterium (2H) from the end of the wet season until the beginning of the subsequent wet season. If local aestivation is the only way An. coluzzii persists, the frequency of marked mosquitoes should remain stable, whereas finding no marked mosquitoes would be evidence against aestivation. After an initial enrichment, 33% of An. coluzzii were strongly marked. Seven months following enrichment, multiple analyses revealed the presence of marked mosquitoes. The results suggest that aestivation is a major persistence mechanism of An. coluzzii, contributing at least 20% of the adults at the onset of rains (Faiman et al. 2022:Nature Ecology and Evolution). This persistence strategy could influence mosquito control and malaria elimination campaigns. 2. Extending previously published results on aerial sampling of mosquitoes 40-290 m above ground in the Sahel (Huestis et al. 2019: Nature, Sanogo et al. 2021: J. Med Ent.), we describe how other mosquito species use this migration modality (Yaro et al. 2022: Frontiers in Epidemiology). A total of 7 genera- Culex, Aedes, Anopheles, Mansonia, Mimomiya, Lutzia, and Eretmapodites comprised 90% of the 2,340 mosquitoes intercepted at altitude over the Sahel of Mali. Of the 50 species identified, 33 represented by multiple specimens were considered high-altitude windborne migrants. At altitude, females outnumbered males 6:1, and >90% of the females have taken at least one blood meal on a vertebrate host prior to departure. High-altitude flight coincided with peak disease transmission between June and November. These hallmarks bolster the role of windborne mosquitoes as carriers of mosquito-borne pathogens (MBPs). The infection rate in these high-altitude migrants for animal plasmodia was 7%, providing a proof of concept that vertebrate pathogens are transported by windborne mosquitoes at altitude. Fourteen of the 33 windborne mosquito species had been reported as vectors to 25 MBPs in West Africa, including malaria, dengue, and Rift Valley fever. These results suggest that the development of aerial pathogen/disease surveillance to map the sources and destinations of vectors and pathogens my complement traditional methods and supply unique information to mitigate public health threats. 3. To determine if mosquitoes engage in high-altitude flights beyond the Sahel, we have expanded aerial sampling into the savannas ecozones (Mali) and into the woodland and equatorial forests (Ghana) as well as in Kenya (East Africa). A total of 36 mosquito species were found in these West African ecozones (in 516 sequenced >150 m), belonging to 7 genera. Windborne mosquitoes occurred more commonly above perennial ecosystems including the equatorial forests than above the Sahel. Twelve mosquito species (33%) were found in a single ecozone, and 6 (17%) prevailed across all ecozones, suggesting that most mosquito species move between neighboring ecozones. Yet, movement between the equatorial forest to the Sahel >750 km may also occur. A one-year study in Kenya has demonstrated that windborne mosquitoes and other insects are common across the continent (Atieli et al. 2023). 4) Dr. Bamou has been working on pathogen detection in the mosquitoes collected at altitude. Pan-genus pathogen detection followed by metagenomics analysis of select specimens indicated infection with arboviruses, including human zoontotic viruses: West Nile virus and M'Poko virus. Additionally, insect specific viruses e.g., Aedes phasmavirus and Araticum virus, were detected, as well as bacteria: Wolbachia spp. and Asaia spp. Fourteen species of avian Plasmodia were identified by sequencing of 49 positive mosquitoes. Infectiousness rate measured as thoracic infection was 2.8%. Culex perexiguus, a known vector of avian plasmodia showed the highest prevalence (50%). Between-ecozone variation was not significant (P>0.1) as expected if these pathogens are spread by mosquitoes that travel across ecozones. Additionally, infection of high-altitude mosquitoes with filariid nematodes was 0.7% (N=300). For the first time, we report detection of arboviruses, bacteria, and eukaryotic pathogens in high-altitude mosquitoes, thus providing proof of concept for their long-distance spread by windborne mosquitoes. 5. Mrs. Rita Frimpong, who has started a PhD program working on the insects collected at altitude in Mali and Ghana, focusing on species impacting public health and food security and comparing them to other taxa in terms of their seasonal and spatial high-altitude flight patterns. Mr. Zachary Dankowicz (High School volunteer/summer intern) has discovered high-altitude ceratopogonid species that may include arbovirus vectors. 6) To understand the scope of mosquito windborne migration, a literature survey of African mosquito borne diseases has been undertaken to generate a unique database of the African mosquito borne diseases from a One Health perspective. Initial analysis of the database produced important new insights into disease surveillance and for assessment of new regional and global threats of mosquito borne diseases. Lehmann et al. 2021: Submitted. The revised paper is being submitted to a journal. 7) Dormancy (aestivation) in Anopheline mosquitoes through the long dry season was demonstrated in An. coluzzii (above), but it has not been replicated in laboratory conditions, hindering progress on questions such as how this state affects malaria vector competence. Following earlier advance in our lab (Krajacich et al. 2020), Mr. Kouam (Postbac) compared survivorship and nutritional reserves of mosquitoes under conditions that mimic the late rainy and dry seasons and include specific larval priming conditions including increased salinity. 8) In a new collaboration with West African Center for Emerging Infectious Diseases (WAC-EID of NIAID CRIED, led by Dr. Scott Weaver, UTMB and Mawlouth Diallo, Institute Pasteur, Dakar) we initiated new studies in Kedougou Senegal on windborne spread of arboviruses and other pathogens in mosquitoes. In this novel study, we compare aerial and ground samples of msoaquitoes and their pathogens above Kedougou--a well-known hotspot for arbovirus activity that has been studies for >50 years with a an aerial station located 110 km in Mali near the border of Senegal to address if arboviruses can spread in windbronem mosquitoes from enzootoic (sylvatic) cycles into new areas and forms outbreaks tens or hundreds of kilometers away.

全球每年有十亿例病例和一百万人死亡，媒介传播的疾病仍然很重要。疟疾在世界范围内流行，非洲的负担尤其沉重。我们对媒介生物学的理解仍然存在巨大差距，限制了我们对媒介传播疾病控制的影响。 1. 为了解决“旱季疟疾悖论”（上图），我们通过跟踪从雨季结束到雨季开始期间用氘 (2H) 标记的野生蚊子，评估了夏眠对萨赫勒地区蚊子持续存在的贡献。随后的雨季。如果当地的夏夏是唯一的出路。 coluzzii 持续存在，有标记的蚊子的频率应该保持稳定，而没有发现有标记的蚊子将是不适合夏眠的证据。经过初步富集后，An 的含量为 33%。 coluzzii 被强烈标记。富集七个月后，多项分析显示存在标记的蚊子。结果表明，夏眠是An的主要持久机制。 coluzzii，在降雨开始时贡献了至少 20% 的成虫（Faiman et al. 2022：自然生态与进化）。这种持久性策略可能会影响蚊子控制和消除疟疾运动。 2. 扩展之前发布的萨赫勒地区地面以上 40-290 m 蚊子空中采样结果（Huestis 等人 2019：Nature，Sanogo 等人 2021：J. Med Ent.），我们描述了其他蚊子物种如何使用此方法迁移方式（Yaro 等人，2022：流行病学前沿）。在马里萨赫勒地区上空截获的 2,340 只蚊子中，共有 7 个属：库蚊属、伊蚊属、按蚊属、曼蚊属、米莫宫属、卢兹蚊属和长足蚊属，占 90%。在已识别的 50 个物种中，有 33 个由多个标本代表的物种被认为是高空风传候鸟。在高海拔地区，雌性与雄性的数量比例为 6:1，并且 >90% 的雌性在出发前至少吸食过脊椎动物宿主的血粉。高空飞行恰逢 6 月至 11 月期间的疾病传播高峰。这些特征增强了风媒蚊子作为蚊媒病原体（MBP）携带者的作用。这些高海拔迁徙动物疟原虫的感染率为7%，这为脊椎动物病原体在高海拔地区通过风传播的蚊子传播提供了概念证明。据报道，33 种风传播蚊子中有 14 种是西非 25 MBP 的媒介，包括疟疾、登革热和裂谷热。这些结果表明，发展空中病原体/疾病监测来绘制病媒和病原体的来源和目的地可以补充传统方法，并提供独特的信息来减轻公共卫生威胁。 3. 为了确定蚊子是否参与萨赫勒地区以外的高空飞行，我们将空中采样范围扩大到了稀树草原生态区（马里）、林地和赤道森林（加纳）以及肯尼亚（东非）。在这些西非生态区（已测序超过 150 m 的 516 个）中总共发现了 36 种蚊子，分属 7 个属。风媒蚊子在包括赤道森林在内的常年生态系统上方比萨赫勒地区更常见。在一个生态区中发现了 12 种蚊子（33%），其中 6 种（17%）在所有生态区中盛行，这表明大多数蚊子种类在相邻生态区之间移动。然而，赤道森林到萨赫勒地区之间也可能发生超过 750 公里的移动。肯尼亚一项为期一年的研究表明，风媒蚊子和其他昆虫在整个非洲大陆很常见（Atieli 等人，2023）。 4）Bamou博士一直致力于在高海拔地区采集的蚊子中进行病原体检测。泛属病原体检测以及对选定样本的宏基因组学分析表明感染了虫媒病毒，包括人类人畜共患病毒：西尼罗河病毒和姆波科病毒。此外，还检测到了昆虫特异性病毒，例如埃及伊蚊病毒和阿拉蒂克病毒，以及细菌：沃尔巴克氏菌属。和亚洲亚种。通过对 49 只阳性蚊子进行测序，鉴定出 14 种禽疟原虫。胸部感染的传染率为2.8%。特克库蚊（Culex perexiguus）是一种已知的鸟类疟原虫载体，其患病率最高（50%）。如果这些病原体是通过跨生态区的蚊子传播的，那么生态区之间的变异并不像预期的那样显着（P>0.1）。此外，高海拔蚊子丝状线虫的感染率为0.7%（N=300）。我们首次报告在高海拔蚊子中检测到虫媒病毒、细菌和真核病原体，从而为它们通过风传播的蚊子进行长距离传播提供了概念证明。 5. Rita Frimpong 女士启动了一个博士项目，研究在马里和加纳高海拔地区收集的昆虫，重点关注影响公共卫生和粮食安全的物种，并将它们与其他类群的季节和空间高海拔进行比较飞行模式。 Zachary Dankowicz 先生（高中志愿者/暑期实习生）发现了高海拔角蜥物种，其中可能含有虫媒病毒载体。 6) 为了了解蚊子经风传播的迁徙范围，对非洲蚊媒疾病进行了文献调查，从“同一个健康”的角度生成了非洲蚊媒疾病的独特数据库。对数据库的初步分析为疾病监测和蚊媒疾病新的区域和全球威胁评估提供了重要的新见解。莱曼等人。 2021：已提交。修改后的论文正在提交给一家期刊。 7)按蚊在漫长的旱季中的休眠（夏眠）在按蚊中得到了证实。 coluzzii（上图），但它尚未在实验室条件下复制，这阻碍了诸如这种状态如何影响疟疾媒介能力等问题的进展。继我们实验室的早期进展（Krajacich 等人，2020）之后，Kouam 先生（Postbac）在模拟雨季后期和旱季的条件下比较了蚊子的存活率和营养储备，包括特定的幼虫启动条件（包括盐度增加）。 8) 在与西非新发传染病中心（NIAID CRIED 的 WAC-EID，由 UTMB 的 Scott Weaver 博士和达喀尔巴斯德研究所的 Mawlouth Diallo 博士领导）的新合作中，我们在塞内加尔 Kedougou 启动了关于经风传播的新研究蚊子中的虫媒病毒和其他病原体。在这项新颖的研究中，我们比较了 Kedougou 上方的 msoaquitoes 及其病原体的空中和地面样本，Kedougou 是著名的虫媒病毒活动热点，人们对位于马里边境附近 110 公里处的一个航空站进行了超过 50 年的研究。塞内加尔将解决虫媒病毒是否可以在风蚊中从地方性（森林）循环传播到新的地区并在数十或数百公里外形成疫情的问题。

项目成果

期刊论文数量（8）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Induction of long-lived potential aestivation states in laboratory An. gambiae mosquitoes.

实验室 An 中长寿命潜在夏眠状态的诱导。

DOI：
发表时间：
2020-08-12
期刊：
影响因子：
3.2
作者：
Krajacich, Benjamin J;Sullivan, Margery;Faiman, Roy;Veru, Laura;Graber, Leland;Lehmann, Tovi
通讯作者：
Lehmann, Tovi

Variation in Tolerance to Parasites Affects Vectorial Capacity of Natural Asian Tiger Mosquito Populations.

对寄生虫耐受性的变化影响自然亚洲虎蚊种群的矢量能力。

DOI：
发表时间：
2019-11-18
期刊：
影响因子：
0
作者：
Dharmarajan, Guha;Walker, Kathryne D;Lehmann, Tovi
通讯作者：
Lehmann, Tovi

Signatures of aestivation and migration in Sahelian malaria mosquito populations.

萨赫勒疟疾蚊群的夏眠和迁徙特征。

DOI：
发表时间：
2014-12-18
期刊：
影响因子：
64.8
作者：
Dao, A;Yaro, A S;Diallo, M;Timbiné, S;Huestis, D L;Kassogué, Y;Traoré, A I;Sanogo, Z L;Samaké, D;Lehmann, T
通讯作者：
Lehmann, T

Could culicine mosquitoes transmit human malaria?

蚊子会传播人类疟疾吗？