Eradication of a Primary Filariasis Vector Population at an Endemic Field Site

消灭流行现场的原发性丝虫病媒介种群

• 批准号: 7485109
• 负责人: Stephen Leonard Dobson
• 金额: $ 31.07万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-15 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7485109
• 关键词: Address; Adult; Aedes; Affect; Area; Attitude; Bacteria; Biology; Blood; Communities; Compatible; Condition; Country; Culicidae; Data; Decision Making; Development; Disease Vectors; Elephantiasis; Embryo; Environmental Risk Factor; Event; Failure; Female; Female Sterilization; Filaria bancrofti; Filarial Elephantiases; Filariasis; French Polynesia; Frequencies; Genetic Structures; Genetic Variation; Genetically Modified Organisms; Geography; Horizontal Disease Transmission; Human; Immigration; Infection; Island; Laboratories; Measures; Microfilaria; Microinjections; Microsatellite Repeats; Modeling; Monitor; Ownership; Partner in relationship; Pharmaceutical Preparations; Polynesia; Population; Population Dynamics; Population Sizes; Populations at Risk; Rate; Recording of previous events; Relative (related person); Research; Research Personnel; Risk; Risk Assessment; Sampling; Site; Study Section; Techniques; Testing; Transfection; Wolbachia; cost; design; disability; disease transmission; feeding; filaria; fitness; improved; islet; male; novel strategies; programs; research study; transmission process; vector; vector control; vector mosquito

DESCRIPTION (provided by applicant): Lymphatic filariasis (Elephantiasis) affects over 120 million people in 80 countries, with 1.2 billion people at risk worldwide. Over 90% of infections are caused by Wuchereria bancrofti, for which humans are the exclusive host. The absence of a nonhuman reservoir suggests that transmission can be interrupted by elimination of the microfilariae reservoir via community-wide treatment (Mass Drug Administration, MDA), which is the current focus of the Global Programme for the Elimination of Lymphatic Filariasis. While MDA strategies can be effective, history suggests that elimination of lymphatic filariasis in Polynesia is unachievable without vector control. An example is provided by Maupiti in French Polynesia, where filariasis persists despite five decades of constant MDA. The biology of the primary mosquito vector, Aedes polynesiensis, has been blamed for MDA failure. Since mosquitoes are obligate vectors of W. bancrofti, this suggests an additional approach for filariasis elimination: eradication of the mosquito vectors will break the disease transmission cycle. Unfortunately Ae. polynesiensis currently cannot be controlled, much less eradicated. Here, we propose a novel strategy in which releases of male Ae. polynesiensis mosquitoes infected with Wolbachia bacteria result in the sterilization of female mosquitoes at a field site endemic for filariasis transmission. Repeated male releases will permit the eradication of the targeted Ae. polynesiensis population. We emphasize that male mosquitoes do not blood feed and therefore are not disease vectors. Furthermore, the proposed strategy employs a naturally occurring bacteria infection and does NOT include genetically modified organisms. The preliminary studies section describes how a l/Vo/bac/7/a-infected Ae. polynesiensis strain has been generated and shown to sterilize female mosquitoes from Maupiti. The research plan describes laboratory and field cage tests of the eradication strategy, followed by field trials in which the Ae. polynesiensis population is eradicated from an endemic focus of filariasis. Additional experiments describe the characterization of the targeted field site (an uninhabited islet in Maupiti) prior to, during, and following the field trial. Prior to the field trial, experiments will compare the release strain and field population in their fitness, population dynamics and genetic structure, mating competitiveness, and vector competency. Recently developed techniques for generating new Wolbachia infection types in mosquitoes via microinjection will be used to generate additional mosquito strains for use in vector eradication strategies. We discuss the development of a model for the transitioning from field trials to a vector eradication campaign. We emphasize that a vector eradication strategy is more feasible economically relative to ongoing vector control in Polynesia. Furthermore, the geography of Polynesia will simplify an eradication approach by reducing problems of vector reinfestation via immigration. Relevance: History demonstrates that the current global effort to eliminate lymphatic filariasis can fail in the Pacific if it continues to rely solely upon a mass drug administration (MDA) strategy. The proposed research will demonstrate a strategy for eradicating the primary mosquito vector of filariasis at an endemic field site. Integration of the vector eradication strategy and the MDA approach will facilitate filariasis elimination in areas where MDA alone has failed.

描述（由申请人提供）：淋巴丝虫病（象皮病）影响80个国家的1.2亿多人，全球有12亿人处于危险之中。超过90%的感染是由班氏吴策线虫引起的，人类是其唯一宿主。非人类宿主的缺乏表明，通过社区范围内的治疗（大众药物管理局，MDA）消除微丝蚴宿主可以中断传播，这是消除淋巴丝虫病全球方案目前的重点。虽然MDA策略可能是有效的，但历史表明，如果不控制病媒，波利尼西亚的淋巴丝虫病就无法消除。法属波利尼西亚的Maupiti提供了一个例子，尽管持续了50年的MDA，但丝虫病仍然存在。主要蚊子媒介波利尼西亚伊蚊的生物学被认为是导致MDA失败的原因。由于蚊虫是W. bancrofti的研究表明，这是消除丝虫病的另一种方法：消灭蚊子媒介将打破疾病的传播周期。不幸的是，波利尼西亚人目前无法控制，更不用说根除了。在这里，我们提出了一种新的策略，其中男性AE的释放。感染沃尔巴克氏体细菌的波利尼西亚蚊子导致在丝虫病传播流行的现场雌蚊绝育。反复释放雄性将允许根除目标Ae。波利尼西亚种群我们强调，雄蚊不吸血，因此不是疾病媒介。此外，拟议的策略采用自然发生的细菌感染，不包括转基因生物。初步研究部分描述了l/Vo/bac/7/a感染的Ae.波利尼西亚菌株已经产生并显示出使来自Maupiti的雌性蚊子绝育。该研究计划描述了根除策略的实验室和田间笼试验，然后进行田间试验，其中Ae。波利尼西亚人从丝虫病的地方性疫源地被消灭。其他实验描述了田间试验之前、期间和之后的目标田间部位（毛皮蒂的无人居住小岛）的表征。在田间试验之前，实验将比较释放菌株和田间种群的适应性、种群动态和遗传结构、交配竞争力和媒介能力。最近开发的通过显微注射在蚊子中产生新的沃尔巴克氏体感染类型的技术将用于产生用于媒介根除战略的其他蚊子品系。我们讨论了从田间试验过渡到病媒根除运动的模型的开发。我们强调，相对于波利尼西亚正在进行的病媒控制，病媒根除战略在经济上更可行。此外，波利尼西亚的地理位置将简化根除方法，减少病媒通过移民再侵染的问题。相关性：历史表明，如果继续仅仅依靠大规模药物管理（MDA）战略，目前在太平洋地区消除淋巴丝虫病的全球努力可能会失败。拟议的研究将展示一个战略，消除丝虫病的主要蚊子媒介在地方性现场。将媒介消灭战略与MDA方法相结合，将有助于在仅MDA方法无效的地区消灭丝虫病。