Mali International Center for Excellence in Research: Vectors and Hosts of Parasitic Infectious Diseases

马里国际卓越研究中心：寄生虫传染病的媒介和宿主

• 批准号: 10272143
• 负责人: Carole Long
• 金额: $ 133.09万
• 依托单位: NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
• 依托单位国家: 美国
• 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/10272143
• 关键词: 5 year old; Accounting; Address; Affect; Affinity; Africa; Africa South of the Sahara; African; Altitude; Anopheles gambiae; Antibodies; Antibody titer measurement; Antigens; Antimalarials; Arbovirus Infections; Area; Arthropods; Avidity; Award; Bacteria; Binding Proteins; Binding Sites; Biological Assay; Biological Availability; Biology; Blood; Breeding; Burkina Faso; COVID-19; Cells; Centers of Research Excellence; Child; Collaborations; Communicable Diseases; Culicidae; Data; Detection; Diagnosis; Disease; Disease Vectors; Ecology; Education; Endemic Diseases; Environmental Wind; Epidemiology; Equipment; Erythrocytes; Evaluation; Exhibits; Faculty; Finding of Mean Corpuscular Hemoglobin; Foundations; Gene Dosage; Genomic DNA; Ghana; Goals; Growth; Habitats; Hemoglobin; Hemolysis; Heterogeneity; Homologous Protein; Hour; Human; Immunoglobulin G; Immunology; Individual; Infection; Insecta; Intervention; Iron; Kinetics; Knowledge; Laboratories; Lead; Leishmania; Life; Location; Malaria; Mali; Measurement; Measures; Medical; Metabolic; Methods; Microscope; Migrant; Molecular; Monoclonal Antibodies; National Institute of Allergy and Infectious Disease; Natural Selections; Nature; Niger; Oral Medicine; Organism; Oviposition; Oxygen; Parasites; Parasitic Diseases; Pathology; Pharmacy facility; Phlebotominae; Plasmodium falciparum; Plasmodium vivax; Population; Predisposition; Prevalence; Protocols documentation; Public Health; Publishing; Quantitative Reverse Transcriptase PCR; Rain; Research; Research Personnel; Research Training; Residual state; Reticulocytes; Rivers; Rural Community; Sampling; Science; Scientist; Seasonal Variations; Seasons; Security; Sickle Cell; Sickle Cell Anemia; Site; Source; Specimen; Sporozoites; Surveys; Techniques; Technology; Testing; Time; Training; Travel; Universities; Vaccination; Vaccines; Virus; Water; Wolbachia; Work; alpha Globin; alpha-Thalassemia; apical membrane; base; beta Globin; boys; co-infection; egg; feeding; food security; genetic variant; girls; in vivo; international center; iron deficiency; malaria mosquito; medical schools; migration; novel; pathogen; prevent; programs; reduce symptoms; sickling; synthetic construct; vaccine candidate; vaccine trial; vector; vector control

Ecology of Malaria Vectors Our major discovery published last year in Nature (Huestis et al. 2019) that many mosquitoes engage in windborne migration after taking a blood meal and thus may be spreading pathogens over hundreds of kilometers has been the focus of new studies. (1) To assess viability of mosquitoes after high altitude flight, we subjected wild Anopheles gambiae s.l. to a high-altitude survival assay, followed by oviposition (egg laying) and blood feeding assays. Similar to other high-altitude migrating insects, our results showed that mosquitoes are able to withstand >11 hours high-altitude flight and subsequently reproduce and blood-feed on new hosts, thus potentially transmitting pathogens after migration (Sanogo et al. 2020). 2) To compare windborne flight activity of mosquitoes with that of other insects captured by nets (40290 m above ground), we identified sub-samples of aerial-collected insects and compared their activity to the malaria mosquito An. coluzzii. Migration of all species exhibited high temporal and spatial regularity and frequent flights on southerly winds, accounting for the recolonization of the Sahel from southern source populations. Estimates of the annual number of migrants per species crossing Mali at latitude 14N were in the trillions. The magnitude and diversity of windborne insect migration highlight its impact on food security and public health in Africa (Florio et al. 2020 Preprint; under review). 3) To determine if mosquitoes engage in high-altitude flights beyond the Sahel, we have initiated aerial sampling in the dry and wet savanna ecozones, 200 and 400 km south of the Sahel. Our preliminary results reveal that mosquitoes in these areas also engage in high altitude flights. Molecular work to determine the specimens species and infection status will start next year. Additional aerial sampling towards the equator are to begin in Ghana as part of our Gates Foundation GCE Award. Training of the Ghana team is still prevented by COVID19. We are putting together an online training package. 4) We have evaluated in Mali a novel mosquito marking and tracking method that we developed in our laboratory in LMVR/NIAID using a combination of fluorescent marker for rapid field detection of marked individuals and a synthetic DNA tag for versatile marking, thereby extending mosquito tracking complexity over time and space. Our results show that this technique minimally affects mosquito survival, the mark lasts throughout the mosquitos life, and is easily detected in the field (Faiman et al. 2020: Preprint; under review). 5) A new epidemiological project entitled "Evaluating the determinants of the spread of COVID-19 between and within rural communities in Mali, West Africa based on blood-fed mosquitoes" is described separately in project AI001328-01. Impact of Iron Availability on Sickling Kinetics in Malian Children To address the Impact of iron availability on sickling kinetics in Malian Children, our specific aims are to: Assess alpha globin gene copy number and iron bioavailability; examine the distribution of intracellular hemoglobin concentration (mean corpuscular hemoglobin concentration, MCHC) and related RBC parameters; measure hemoglobin composition and oxygen affinity: quantify sickling kinetics of fresh RBCs ex vivo using an automated microscope; and determine rates of hemolysis and red cell turnover in vivo. Together, these measurements will provide the first comprehensive evaluation of naturally existing heterogeneity of hemoglobin composition in the red blood cell and its impact on the kinetics of sickling. In 2020, we have begun setting up the specialized equipment needed to conduct these studies in a new laboratory based in the sickle cell research center in Bamako, Mali. Studies on Malian antibodies to P. falciparum RH5, a major blood-stage vaccine candidate Reticulocyte-binding protein homolog 5 (RH5) is a leading Plasmodium falciparum blood-stage vaccine candidate. Another possible candidate, apical membrane antigen 1 (AMA1), was not efficacious in malaria endemic populations, likely due to pre-existing anti-malarial antibodies that interfered with the activity of vaccine-induced AMA1 antibodies as judged by growth inhibition assay (GIA). To determine how pre-existing antibodies interact with vaccine-induced RH5 antibodies, we purified total and RH5-specific IgGs from malaria-exposed Malians and malaria-naive RH5 vaccinees. Infection-induced RH5 antibody titers were much lower than those induced by vaccination, and RH5-specific IgGs showed differences in binding site and avidity between the two populations. In GIA, Malian RH5-depleted IgGs showed additive or synergistic interactions with RH5 monoclonal antibodies, and additive or sub-additive interactions with vaccine-induced polyclonal RH5 IgGs. These results suggest that pre-existing antibodies will interact favorably with vaccine-induced RH5 antibodies, in contrast to AMA1 antibodies. This study supports continued RH5 vaccine trials in malaria endemic regions. Naturally Occurring Wolbachia in Anopheline Mosquitoes from Mali Wolbachia is a bacterium commonly found in arthropods that is known to reduce susceptibility of culicine mosquitoes to several Arboviral infections. We identified a naturally-occurring strain of Wolbachia in An. gambiae s.l. mosquitoes in the Malian villages of Kenieroba and Dangassa, different from strains previously identified in Burkina Faso. Field and laboratory data indicate that Wolbachia infection reduces the prevalence and intensity of sporozoite infection. We carried out experimental P. falciparum infections and found that Wolbachia reduces the prevalence and intensity of sporozoite infection. More recently we have trained a Malian investigator to do genomic DNA extractions from field-caught desiccated mosquitoes, and we have optimized a new genomic DNA extraction protocol and a qRT-PCR assay to detect Wolbachia. We will examine the seasonal variation in prevalence of infection in Kenieroba and Dangassa and survey other villages in the area to establish the range of distribution of Wolbachia in this region, as well as different larval habitats, to establish whether Wolbachia infection is widespread or limited to specific larval breeding sites. Leishmania in Mali Leishmania is another parasitic disease endemic to Mali. We have examined the impact of malaria control measures such as long-lived be nets and indoor residual spraying, showing that these interventions also impact sandflies and Leishmania infection. We have also done a study of the co-endemicity of filarial and Leishmania infections in different settings in Mali. The presence of the two infections transmitted by mosquitoes and sandflies makes integrated vector control very important in areas like these.

疟疾媒介的生态 我们去年在自然界发表的重大发现（Huestis等人，2019年），许多蚊子在服用血液餐后从事风迁移，因此可能正在扩散数百公里的病原体，这是新研究的重点。 （1）为了评估高空飞行后蚊子的生存能力，我们对狂野的Anopheles gambiae S.L.进行了。进行高海拔生存测定法，然后进行排卵（卵）和血液喂养测定法。与其他高海拔迁移的昆虫类似，我们的结果表明，蚊子能够承受> 11小时的高空飞行，随后在新宿主身上再繁殖和血液喂养，从而有可能在迁移后传播病原体（Sanogo等，2020年）。 2）将蚊子的蚊子与蚊帐捕获的蚊子的飞行活动（地面高40290 m）进行了比较，我们鉴定了空中收集的昆虫的子样本，并将其活性与疟疾蚊子进行了比较。 coluzzii。所有物种的迁移均表现出较高的时间和空间规律性，并在南风上频繁飞行，这是从南方源人群中重新殖民的。估计每种纬度14N的越过马里群体的移民人数为数万亿。昆虫迁移的大小和多样性突出了其对非洲粮食安全和公共卫生的影响（Florio等，2020年预印本；正在审查中）。 3）确定蚊子是否参与了萨赫勒以外的高空飞行，我们已经在萨赫勒以南200和400公里的干稀树草原生态机构中进行了空中采样。我们的初步结果表明，这些地区的蚊子也参与高空飞行。确定标本物种和感染状态的分子工作将于明年开始。作为我们盖茨基金会GCE奖的一部分，向赤道的其他航空采样将在加纳开始。 Covid19仍然阻止了加纳队的训练。我们正在整理一个在线培训计划。 4）我们已经在马里评估了一种新型的蚊子标记和跟踪方法，我们在LMVR/NIAID中开发了荧光标记物的结合，用于快速现场检测标记个体的快速现场检测和用于多功能标记的合成DNA TAG，从而扩展了蚊子跟踪蚊子的复杂性，使其在时间和空间上扩展了复杂性。我们的结果表明，这种技术最小化影响蚊子的生存，标记在整个蚊子生命中持续，并且在田间很容易被检测到（Faiman等，2020：预印本；正在审查中）。 5）一个新的流行病学项目，名为“评估基于血液喂养蚊子的马里群岛之间以及在西非的农村社区之间和内部共同传播的决定因素”，在项目AI001328-01中分别描述了。 铁的可用性对马里儿童疾病动力学的影响 为了解决铁的可用性对马里儿童疾病动力学的影响，我们的具体目的是：评估alpha globin基因拷贝数和铁生物利用度；检查细胞内血红蛋白浓度（平均红细胞血红蛋白浓度，MCHC）和相关RBC参数的分布；测量血红蛋白组成和氧亲和力：使用自动显微镜量化新鲜RBC的寒假动力学；并确定体内溶血和红细胞更新的速率。总之，这些测量结果将对红细胞中血红蛋白组成的自然异质性进行首次全面评估及其对疾病动力学的影响。 2020年，我们开始在马里巴里（Mali）巴马科（Bamako）的镰状细胞研究中心的一项新实验室中建立这些研究所需的专业设备。 对恶性疟原虫RH5的马里抗体的研究，这是一种主要的血阶段疫苗候选者 网状细胞结合蛋白同源物5（RH5）是恶性疟原虫血液阶段候选疫苗的候选者。另一个可能的候选膜抗原1（AMA1）在疟疾流行种群中没有有效，这可能是由于先前存在的抗疟疾抗体，这些抗疟疾抗体会干扰疫苗诱导的AMA1抗体的活性，以判定为生长抑制分析（GIA）所判断的。为了确定现有的抗体如何与疫苗诱导的RH5抗体相互作用，我们从暴露于疟疾的马里人和疟疾的RH5疫苗中纯化了总和RH5特异性IgG。感染引起的RH5抗体滴度远低于疫苗接种诱导的抗体，而RH5特异性IgGs在两个群体之间显示出结合位点和亲和力的差异。在GIA中，耗尽的Malian RH5 IgGs与RH5单克隆抗体以及与疫苗诱导的多克隆RH5 IgGs的添加剂或协同相互作用。这些结果表明，与AMA1抗体相比，预先存在的抗体将与疫苗诱导的RH5抗体相互作用。这项研究支持疟疾中流区域的RH5疫苗试验的持续试验。 马里的蚊子蚊子中天然发生的沃尔巴氏菌 沃尔巴奇（Wolbachia）是一种在节肢动物中发现的细菌，已知可降低库氏蚊对几种弧菌感染的敏感性。我们确定了An中的wolbachia自然菌株。冈比亚S.L. Kenieroba和Dangassa的马里村中的蚊子与以前在Burkina Faso中发现的菌株不同。现场和实验室数据表明，沃尔巴氏菌感染降低了孢子岩感染的患病率和强度。我们进行了实验性恶性疟原虫感染，发现沃尔巴奇降低了孢子岩感染的患病率和强度。 最近，我们培训了一名马里研究者，从现场捕获的干燥蚊子进行基因组DNA提取，并优化了一种新的基因组DNA提取方案和QRT-PCR测定法，以检测沃尔巴西亚。我们将研究Kenieroba和Dangassa感染的季节性变化，并调查该地区的其他村庄，以确定该地区Wolbachia的分布范围，以及不同的幼虫栖息地，以确定Wolbachia感染是广泛的还是限于特定幼虫繁殖地。 利什曼尼亚在马里 利什曼原虫是马里特有的另一种寄生疾病。我们已经检查了疟疾控制措施的影响，例如长寿命为网和室内残留喷涂，表明这些干预措施还影响了沙蝇和利什曼原虫感染。我们还研究了马里不同环境中丝状和利什曼原虫感染的共同性。蚊子和沙氟传播的两种感染的存在使整合的载体控制在此类地区非常重要。