Mali International Center for Excellence in Research: Malaria and Vectors

马里国际卓越研究中心：疟疾和媒介

• 批准号: 8555974
• 负责人: Carole Long
• 金额: $ 59.78万
• 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/8555974
• 关键词: ABO blood group system; Address; Adult; Africa; African; Aftercare; Age; Animal Model; Antibodies; Antigens; Area; Artemisinins; Asia; Behavioral; Binding; Biological Assay; Biology; Bite; Blood; Blood specimen; Body Size; Canis familiaris; Cell surface; Cells; Cellular Immunity; Centers of Research Excellence; Child; Collaborations; Collection; Culicidae; Cutaneous Leishmaniasis; Data; Delayed Hypersensitivity; Developing Countries; Development; Diagnosis; Disease; Disease Vectors; Drug Kinetics; Ecology; Endothelial Cells; Enrollment; Epidemiologic Studies; Epidemiology; Erythrocytes; Estivation; Europe; Event; Exhibits; Expeditions; Faculty; Falciparum Malaria; Female; Flow Cytometry; Genetic; Genetic Polymorphism; Glucosephosphate Dehydrogenase Deficiency; Goals; Hemoglobinopathies; Hour; Housing; Human; Human Volunteers; Hydrocarbons; Hypersensitivity skin testing; Immune response; Immunity; Immunoglobulin G; Immunology; In Vitro; Incidence; Increased Uric Acid Level; Individual; Infection; Investigation; Knowledge; Laboratories; Leishmania; Leishmania major; Leishmaniasis; Life; Location; Longitudinal Studies; Malaria; Mali; Mammals; Measures; Medical Entomology; Metabolic; Metabolic Clearance Rate; Metabolism; Methods; Modeling; Monitor; National Institute of Allergy and Infectious Disease; Nature; Nutritional; Oral; Oral Medicine; Order Spirochaetales; Ornithodoros; Oviposition; Parasitemia; Parasites; Pathogenesis; Pathology; Patients; Pharmaceutical Preparations; Pharmacy facility; Phenotype; Phlebotominae; Phlebotomus; Physiological; Plasma; Plasmodium falciparum; Population; Population Study; Predisposition; Pregnancy; Prevalence; Proteins; Protocols documentation; Rain; Relapsing Fever; Relative (related person); Reporting; Research; Research Personnel; Research Training; Resistance; Rodent; Role; Saliva; Salivary Proteins; Sand Flies; Science; Scientist; Seasons; Series; Serum; Shelter facility; Sickle Cell Trait; Sickle Hemoglobin; Site; Staging; Symptoms; Technology; Testing; Th2 Cells; Ticks; Time; Training; Training Programs; Tropical Medicine; Universities; Uric Acid; Water; Work; abstracting; acquired immunity; alpha-Thalassemia; artemisinine; artesunate; base; cohort; design; egg; enzootic; feeding; fly; hemoglobin AA; in vivo; interest; international center; leishmanin; male; medical schools; meetings; member; novel strategies; peripheral blood; posters; programs; protective effect; research study; response; vector; vector control; vector mosquito

Malaria Immunology and Pathogenesis The goals of the malaria pathogenesis/immunology program are: 1) To understand how Malian children with hemoglobin S, alpha-thalassemia, G6PD deficiency, and ABO blood group polymorphisms are protected from Plasmodium falciparum malaria.2) To develop a profile of the acquisition of malaria immunity in Malian children.3) To examine various aspects of pathogenesis due to malaria in Malian children and adults.4) To characterize the pharmacokinetics of artemisinin (ART) in this population. These goals are being accomplished through a 4-year longitudinal study of 1500 children ranging in age from 6 months to 18 years living in 3 villages in Mali (the Kenieroba study). One major effort is to determine the relative protection against malaria conferred by different red blood cell (RBC) polymorphisms, and all the enrolled children have been typed for a series of these polymorphisms. In the past 4 years, we have diagnosed and treated 4207 episodes of uncomplicated and severe falciparum malaria. Analysis of our data shows that sickle cell trait (HbAS) confers significantly greater protection against malaria than other RBC polymorphisms, and that age, a surrogate of naturally acquired immunity, is also associated with reduced malaria incidence. We are now investigating the mechanistic basis for this protection in a number of ways: 1)We identified a sub-cohort of children, selecting those with sickle cell trait (HbAS) and pairing them with age-matched HbAA controls. These children have been followed for development of humoral and cellular responses to blood-stage malaria antigens and we have found that antibodies to a variety of merozoite proteins are lower in HbAS children.2) We have developed a plasma reactivity assay using flow cytometry to measure antibody binding to infected red cells and shown that HbAS children do not display increased reactivity to the red cell surface. 3) We have followed 300 HbA, HbS, and HbC children weekly for parasitemia and malaria symptoms to compare asymptomatic parasite infections. 4) We are testing the effects of HbAS and naturally-acquired IgG on the binding of parasitized RBCs to microvascular endothelial cells (MVECs), a critical event in malaria pathogenesis.5) We are determining whether sera from HbAS children display reactivity to selected PfEMP1 molecules or domains. Some children with malaria display severe pathology, but it has been unclear as to whether certain P. falciparum strains elicit more pathology or whether aspects of the host genetics or responses contribute to susceptibility. We are conducting a series of studies related to pathology during malaria including:1) Reactivity of sera from adult males and females from Mali to various domains of a particular PfEMP1 protein, VAR2CSA, which has been implicated in pregnancy associated malaria. 2) Finding that uric acid levels increase during a malaria infection and correlate with disease severity.3)Obtaining evidence that uric acid can promote endothelial cell pathology.4)Demonstrating that the concentration of microparticles in the plasma is elevated in children with malaria.5) Collaborating with Dr. Michael Walther(LMIV) in examining the role of Tregulatory cells in severe malaria using data and peripheral blood samples from our cohort. We have continued a major initiative begun in 2010 to assess the in vitro and in vivo responses of Malian children to artesunate (ART), an effort prompted by reports from Asia of slow clearance of P. falciparum infections. In the past two years we have determined the clearance times of parasites in 215 Malian children with uncomplicated malaria by obtaining parasite counts of blood smears every 6 hours after treatment until clearance is complete. Fortunately, parasites from all children cleared quickly, indicating that the ART resistance phenotype is not present in our study population. Importantly, we have also observed that older children exhibit more rapid clearance times than younger children. We are testing the hypothesis that plasma IgG accelerates the parasite clearance rate in response to ART. Our studies supported the oral or poster presentation of 10 abstracts to the 2011 ASTMH meeting. All members of Dr. Fairhursts laboratory, many members of Dr. Longs laboratory, Dr. Michael Walther (LMIV) and several other LMVR trainees are presently using data, parasites, and/or patient blood samples from our Kenieroba protocol. Mosquito Vectors We continued to address a major issue in vector biology related to the dry season ecology of mosquitoes in the Sahel, viz., does An. gambiae persist during the dry season by aestivation? Continuous collection of mosquitoes throughout four years in a Malian village revealed that (i) mosquitoes are highly clustered during the dry season; (ii) these hot zones are located in the periphery of the village unlike the situation in the wet season; and (iii) mosquitoes shelter outside houses. We evaluated a novel approach to find aestivation shelters by using a trained sniffing dog to locate mosquitoes tagged with a foreign scent. During the dry season, we find 4 mosquitoes/day and we can scent-tag and release them. We have obtained promising results in a preliminary experiment with a trained dog and will move this to the field. We have also continued our analysis of physiological and behavioral changes that underlie aestivation in mosquitoes. To understand the mechanisms facilitating aestivation, mosquitoes were subjected to a sequence of experiments to measure their individual metabolism, flight activity, body size, egg development and oviposition, feeding response, nutritional reserves, and cuticular hydrocarbons. Sand fly / Leishmaniasis Program The LMVR program on leishmaniasis and its sandfly vectors is designed to describe the unexamined epidemiology of cutaneous leishmaniasis (CL) in Mali. Phlebotomus duboscqi is the principal vector of Leishmania major, the causative agent of cutaneous leishmaniasis (CL) and is the suspected vector in Mali. We conducted a three-year study in two neighboring villages, Kemena and Sougoula, in Central Mali, an area with a leishmanin skin test positivity of up to 45%. Initially we evaluated the overall diversity of sand flies and found that P. duboscqi represented 99% of the collected Phlebotomus species, and was the primary sand fly inside dwellings. The seasonality and infection prevalence of P. duboscqi was monitored over two consecutive years. Using a quasi-Poisson model we observed a significant annual, seasonal, and village effect on the number of collected P. duboscqi. The infection status of pooled P. duboscqi females was determined by PCR, and the infection prevalence was 2.7%, incriminating P. duboscqi as the vector of CL. Based on PCR, L. major was identified as the only species found in the flies. Importantly, there is no previous data characterizing cellular immune responses to sand fly salivary proteins in leishmania endemic areas. In animal models sand fly salivary proteins which induce a Th1 response or delayed-type hypersensitivity (DTH) confer protection against leishmaniasis. DTH to sand fly bites is also observed in human volunteers, and we are investigating the duration and nature (Th1 versus Th2) of cell-mediated immunity to sand fly salivary proteins in the two villages. Tick-borne relapsing fever In collaboration with RML, we have continued a study of tick-borne relapsing fever (TBRF) in Mali. TBRF is caused by spirochetes maintained in enzootic foci that involve various small mammals and argasid ticks. Through multiple field expeditions, we investigated 20 villages in Mali. By inspection of small rodents and ticks (Ornithodoros sonrai), we found 11.3% of rodents and 18% of ticks were seropositive for TBRF, with a smaller percentage actively infected.

疟疾免疫学和发病机理 疟疾发病机理/免疫学计划的目标是： 1）了解马里亚儿童如何患有血红蛋白儿童，α-甲基疾病，G6PD缺乏症和ABO血型多态性受到保护不受恶性疟疾疟疾的保护。2）发展了马里亚儿童的疟疾免疫的良好性，以促进疟疾的各种疟疾症状和成年儿童的特征。在该人群中的青蒿素（ART）药代动力学。 这些目标是通过一项为期4年的纵向研究来实现的，该研究对1500名儿童的年龄从6个月到18岁，居住在马里的3个村庄中（Kenieroba研究）。一项主要的努力是确定不同红细胞（RBC）多态性赋予的疟疾的相对保护，并且所有注册的儿童都被输入了一系列这些多态性。在过去的四年中，我们诊断出并处理了4207次简单且严重的恶性疟疾发作。对我们数据的分析表明，镰状细胞性状（HBAS）比其他RBC多态性更大的保护措施更大，并且该年龄（自然获得免疫力的替代）也与疟疾发病率降低有关。 现在，我们正在以多种方式研究这种保护的机械基础：1）我们确定了一系列儿童，选择了患有镰状细胞性状（HBA）的儿童，并将其与年龄匹配的HBAA对照配对。遵循这些儿童是为了发展出对血液阶段疟疾抗原的体液和细胞反应的发展，我们发现，HBAS儿童中对各种Merozoite蛋白的抗体较低。2）我们使用流式细胞术进行了血浆反应性测定，以测量对感染红细胞的抗体结合并显示出HBAS儿童的抗体，并且表现出了HBAS的表面表面增强了反应性。 3）我们每周都追踪300 hbA，HBS和HBC儿童，以降低寄生虫和疟疾症状，以比较无症状的寄生虫感染。 4）我们正在测试HBA和自然获得的IgG对寄生的RBC与微血管内皮细胞的结合（MVEC）的结合，这是疟疾发病机理中的关键事件。5）我们正在确定来自HBAS儿童的Sera是否表现出对所选PFEMP1分子的反应性。 一些疟疾的儿童表现出严重的病理学，但尚不清楚某些恶性疟原虫菌株是否会引起更多的病理学，或者宿主遗传学或反应的方面是否有助于易感性。我们正在进行与疟疾期间病理学有关的一系列研究，包括：1）成年男性和女性的血清反应性，从马里到特定PFEMP1蛋白的各个领域VAR2CSA，VAR2CSA，这与妊娠相关的疟疾与疟疾有关。 2）发现在疟疾感染期间尿酸水平升高并与疾病的严重程度相关。3）获得证据表明尿酸可以促进内皮细胞病理学。4）证明，血浆中微粒的浓度升高是疟疾儿童的升高。5）5）与我们在研究中与我们在较严重的细胞中合作的疟疾及其在使用Tregulia的作用中进行的较低型疟疾的作用，从而升高。队列。 我们一直在2010年启动了一项重大倡议，以评估马里儿童对临时运动（ART）的体外和体内反应，这是亚洲报道缓慢清除恶性疟原虫感染的努力。在过去的两年中，我们通过每6小时后每6小时获得寄生虫的寄生虫计数，直到清除完成后，我们确定了215名单独疟疾的马利亚儿童的寄生虫清除时间。幸运的是，所有儿童的寄生虫迅速清除，表明我们的研究人群中不存在艺术抗性表型。重要的是，我们还观察到，年龄较大的孩子比年幼的孩子表现出更快的清理时间。我们正在检验以下假设：血浆IgG响应于ART，寄生虫清除率加速了。 我们的研究支持了2011年ASTMH会议的10个摘要的口头或海报介绍。 Fairhursts实验室博士的所有成员，Longs Labs博士的许多成员Michael Walther博士（LMIV）和其他几位LMVR学员目前都使用我们的Kenieroba协议中的数据，寄生虫和/或患者血液样本。 蚊子向量 我们继续解决与萨赫尔蚊子干旱季节生态有关的媒介生物学的一个主要问题。冈比亚在干旱季节被审核持续吗？在马里亚一个村庄中，整个四年的蚊子连续收集表明（i）蚊子在干旱季节被高度聚集； （ii）这些热区位于村庄的外围，与潮湿季节的情况不同； （iii）蚊子庇护所在房屋外。我们通过使用训练有素的嗅探狗来定位用外国气味标记的蚊子来评估一种新的方法来找到美化庇护所。在干旱季节，我们每天发现4次蚊子，我们可以闻到标签并释放它们。我们在与训练有素的狗的初步实验中获得了有希望的结果，并将将其移至田野。 我们还继续分析蚊子中审核的生理和行为变化。为了了解促进美化的机制，对蚊子进行了一系列实验，以测量其单独的代谢，飞行活动，身体大小，卵发育和产卵，喂养反应，营养储备和表皮碳氢化合物。 沙蝇 /利什曼病计划 LMVR关于利什曼病及其Sandfly载体的计划旨在描述马里皮肤利什曼病（CL）的未见流行病学。 Phlebotomus duboscqi是利什曼原虫大满贯的主要载体，是皮肤利什曼病（CL）的病因，是马里的可疑载体。我们在马里中部的两个邻近村庄Kemena和Sougoula进行了为期三年的研究，该地区的阳性测试阳性高达45％。最初，我们评估了沙蝇的总体多样性，发现杜波斯基（P. duboscqi）代表99％的收集的静脉植物物种，并且是住宅内的主要沙子。连续两年监测了Duboscqi的季节性和感染率。使用准辉煌的模型，我们观察到了年度，季节性和乡村对收集的duboscqi数量的影响。通过PCR确定了合并的Duboscqi女性的感染状态，感染率为2.7％，将Duboscqi罪名成Cl的载体。基于PCR，L。Major被确定为果蝇中唯一的物种。 重要的是，没有以前的数据表征利什曼尼亚地方性地区的砂蝇唾液蛋白的细胞免疫反应。在动物模型中，沙蝇唾液蛋白会诱导Th1反应或延迟型超敏反应（DTH）赋予对利什曼病的保护。在人类志愿者中也观察到了dth蝇咬伤，我们正在研究两个村庄的细胞介导的免疫力的持续时间和性质（Th1与Th2）。 tick传播的发烧 与RML合作，我们继续研究了马里的tick传播发烧（TBRF）。 TBRF是由涉及各种小型哺乳动物和Argasid Tick的Enzootic Foci中维持的螺旋体引起的。通过多次实地考察，我们调查了马里的20个村庄。通过检查小啮齿动物和壁虱（Ornithodoros sonrai），我们发现啮齿动物的11.3％和18％的trick虫对TBRF具有血清阳性，而较小的百分比积极感染。