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 传统上，间日疟原虫并未被纳入整个非洲的疟疾消除战略中，因为 其传播在以达菲阴性为主的人群中不能得到支持的假设。 尽管如此，越来越多的证据表明间日疟原虫存在于整个非洲大陆并且达菲阴性 个人可以为进一步传播做出贡献。东南亚其他消除环境的数据显示 随着恶性疟原虫（非洲主要疟疾种类）的减少，间日疟原虫变得更加突出。这 对非洲消除疟疾构成重大威胁，特别是因为监测和控制战略 整个非洲大陆几乎只关注恶性疟原虫。流动牧民社区 肯尼亚西北部可能特别容易受到间日疟原虫感染，因为它们靠近且具有季节性。 与邻国埃塞俄比亚的接触，那里存在间日疟原虫和达菲阳性种群。他们有 数百年来一直带着牛群往返于埃塞俄比亚，因此有可能 1）这些 肯尼亚西北部社区的达菲抗原水平高于大多数肯尼亚人口，并且 2) 它们的定期活动为输入间日疟原虫提供了机会。因此，牧民社区 肯尼亚西北部的人口是监测和减轻威胁的高价值监测人群 间日疟原虫在该地区的传播。然而，它们在很大程度上仍然处于常规公共卫生活动之外 由于其偏僻和偏远的性质，人们对其健康状况或疟疾风险知之甚少。我们建议 利用最近完成的一项游牧牧民研究的样本和数据来量化 间日疟原虫对该特定群体和更广泛的地区的威胁。母公司研究证实风险升高 与留在定居点的人相比，与牛群一起旅行的人感染恶性疟原虫的情况。在 此外，我们已经鉴定了几种间日疟原虫感染，但其程度及其与达菲抗原的关系 仍然未知。在拟议的工作中，我们将首先筛查 > 1500 个样本的间日疟原虫感染并描述 间日疟原虫首次在这一独特人群中流行。然后，我们将与社区卫生部门合作 工作人员获得测试参与者样本达菲受体表达的许可。这个新的 信息，加上与每个样本相关的丰富数据，将使我们能够评估以下风险： 该群体中出现的间日疟原虫，确定加强监测和有针对性控制的价值，以及 随着肯尼亚走向疟疾，建议确定关键监测人群的标准 消除。这项研究的结果将具有广泛的应用，为疟疾监测和 肯尼亚图尔卡纳和撒哈拉以南非洲地区的控制策略，间日疟原虫可能会产生越来越大的影响 恶性疟原虫得到控制。