Plasmodium vivax in a mobile population in northwestern Kenya

肯尼亚西北部流动人口中的间日疟原虫

• 批准号: 10574870
• 负责人: Wendy PrudhommeOMeara
• 金额: $ 6.48万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-11-03 至 2024-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10574870
• 关键词: Address; Africa; Africa South of the Sahara; Alleles; Animals; Antigen Receptors; Antigens; Area; Authorization documentation; Binding; Blood; Blood typing procedure; COVID-19 pandemic; Camping; Characteristics; Circulation; Collaborations; Communities; Community Health Aides; Contracts; County Government; Coupled; Data; Dryness; Erythrocytes; Ethiopia; Family; Genotype; Geographic Locations; Goals; Health Status; Health care facility; Home; Household; Human; Individual; Infection; Invaded; Investments; Kenya; Malaria; Maps; Measures; Monitor; Movement; Nature; Parents; Participant; Pathogen detection; Pathway interactions; Phenotype; Plasmodium falciparum; Plasmodium vivax; Point Mutation; Population; Population Surveillance; Predisposition; Prevalence; Public Health; Recommendation; Reporting; Research; Research Personnel; Return Migrations; Risk; Risk Assessment; Role; Route; Sampling; Seasons; Sentinel; Sentinel Surveillance; Signal Transduction; Southeastern Asia; Spottings; Surface; Testing; Time; Travel; Work; blood group; cohort; epidemic potential; high risk; high risk population; human DNA; interest; member; migration; prevent; programs; promoter; receptor; transmission process; vector-borne pathogen

ABSTRACT Plasmodium vivax has not traditionally been considered in malaria elimination strategies across Africa, due to the assumption that its transmission cannot be supported in the predominantly Duffy-negative population. Nevertheless, there is growing evidence that P.vivax is present across the continent and Duffy-negative individuals can contribute to onward transmission. Data from other elimination settings in Southeast Asia show that P.vivax becomes more prominent as P.falciparum (the dominant malaria species in Africa) declines. This poses a major threat to malaria elimination in Africa, particularly since surveillance and control strategies across the continent are almost exclusively focused on P.falciparum. Mobile pastoralist communities in northwestern Kenya may be especially susceptible to P.vivax infection due to their proximity to and seasonal contact with neighboring Ethiopia, where both P.vivax and Duffy-positive populations are present. They have been moving to and from Ethiopia with their herds for hundreds of years, thus it is possible that 1) these northwestern Kenyan communities harbor higher levels of Duffy antigen than most Kenyan populations and 2) their regular movements represent opportunities for importing P.vivax. Therefore, the pastoralist communities in northwestern Kenya represent a high-value surveillance population for monitoring and mitigating the threat of P.vivax transmission in the region. However, they remain largely outside of routine public health activities due to their isolated and remote nature, and little is known about their health status or malaria risk. We propose to leverage samples and data from a recently completed study in nomadic pastoralists in order to quantify the threat of P.vivax in this specific group and in the region more broadly. The parent study confirmed elevated risk of P.falciparum infection in those traveling with the herds compared to those who remain in the settlement. In addition, we have already identified several P.vivax infections, but the extent and relationship to Duffy antigen are still unknown. In the proposed work, we will first screen >1500 samples for P.vivax infection and describe the prevalence of P.vivax for the first time in this unique population. Then, we will work with Community Health Workers to obtain permission to test participant samples for expression of the Duffy receptor. This new information, coupled with the rich data associated with each sample, will allow us to assess the risk of emerging P.vivax in this group, determine the value of enhanced surveillance and targeted control, and recommend criteria for identifying critical surveillance populations as Kenya moves towards malaria elimination. The findings from this study would have broad application, informing malaria surveillance and control strategies in Turkana, Kenya, and areas across SSA where P.vivax may have an increasing impact as P.falciparum is controlled.

抽象的 由于在非洲各地的疟疾消除策略中，疟原虫在非洲的消除策略中尚未考虑 假设其传播在主要是达菲阴性人群中不能支持的假设。 然而，越来越多的证据表明，整个大陆和达菲阴性存在于p.vivax 个人可以为继续传播做出贡献。东南亚其他淘汰设置的数据显示 随着非洲的falciparum（非洲的主要疟疾物种）的下降，这种斑vax变得更加突出。这 对非洲消除疟疾的主要威胁，特别是因为监视和控制策略 整个非洲大陆几乎完全专注于菲尔卡里木马。移动牧民社区 肯尼亚西北部可能特别容易受到维瓦克斯感染的影响，因为它们靠近和季节性 与邻近的埃塞俄比亚接触，那里存在P.Vivax和Duffy阳性人群。他们有 多年来一直往返埃塞俄比亚，他们的牛群已经有数百年了，因此1） 肯尼亚西北部社区拥有比大多数肯尼亚人口更高的达菲抗原和2） 他们的常规运动代表了进口p.vivax的机会。因此，牧民社区 在西北部，肯尼亚代表了高价值监视人口，用于监测和减轻威胁 该地区的维瓦克斯传播。但是，它们在很大程度上仍在常规公共卫生活动之外 由于它们孤立而遥远的性质，并且对其健康状况或疟疾风险知之甚少。我们建议 利用最近完成的游牧牧民研究中的样本和数据，以量化 在该特定群体和该地区的威胁。家长研究证实了风险升高 与留在定居点的人相比，与牛群一起旅行的人中的falciparum感染。在 此外，我们已经确定了几种维瓦克斯感染，但与达菲抗原的关系和关系 仍然未知。在拟议的工作中，我们将首先筛选> 1500个样品，以进行维瓦克斯感染并描述 在这个独特的人群中，p.vivax的流行率第一次。然后，我们将与社区健康合作 工人获得了测试参与者样品表达达菲受体的许可。这个新 信息，再加上与每个样本相关的丰富数据，将使我们能够评估 在该组中的新兴p.vivax，确定增强监视和靶向控制的价值，以及 建议在肯尼亚朝疟疾的情况下识别关键监视人群的标准 消除。这项研究的发现将有广泛的应用，告知疟疾监测和 在图尔卡纳，肯尼亚和SSA地区的控制策略可能会产生越来越大的影响 P.Falciparum受到控制。