Plasmodium vivax in a mobile population in northwestern Kenya

摘要 在整个非洲，间日疟原虫传统上不被考虑在消除疟疾的战略中，因为 假设它的传播不能在以Duffy阴性为主的人群中得到支持。 然而，越来越多的证据表明，间日疟原虫在整个非洲大陆都存在，达菲阴性。 个人可以促进病毒的进一步传播。来自东南亚其他淘汰赛的数据显示 随着恶性疟原虫(非洲的主要疟疾物种)的减少，这种间日疟变得更加突出。这 对非洲消除疟疾构成重大威胁，特别是在监测和控制战略 整个非洲大陆几乎都只关注恶性疟原虫。中国的流动牧民社区 肯尼亚西北部可能特别容易感染间日疟原虫，因为他们靠近和季节性 与邻国埃塞俄比亚接触，那里同时存在间日疟原虫和达菲阳性人群。他们有 几百年来一直带着他们的牛群往返埃塞俄比亚，因此有可能这些 肯尼亚西北部社区的Duffy抗原水平高于大多数肯尼亚人，2) 它们的定期移动代表着输入间日疟原虫的机会。因此，牧民社区 在肯尼亚西北部，代表着监测和减轻威胁的高价值监测人口 间日疟原虫在该地区的传播。然而，它们在很大程度上仍处于常规公共卫生活动之外。 由于其与世隔绝和偏远的性质，人们对他们的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 间日疟原虫在这一特定群体和更广泛的区域中的威胁。母公司的研究证实了高风险 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可能性更大。在……里面 此外，我们已经确认了几种间日疟原虫感染，但感染的程度和与达菲抗原的关系 仍然是未知的。在拟议的工作中，我们将首先筛选&gt；1500个样本以检测间日疟原虫感染，并描述 间日疟原虫在这一独特人群中的首次流行。然后，我们将与社区卫生部门合作 工作人员必须获得许可，才能测试参与者样本中Duffy受体的表达。这是一项新的 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 在这一群体中出现间日疟原虫，确定加强监测和定向控制的价值，以及 在肯尼亚迈向疟疾之际，推荐识别关键监测人群的标准 淘汰赛。这项研究的发现将有广泛的应用，为疟疾监测和 图尔卡纳、肯尼亚和整个SSA地区的控制战略，在这些地区，间日疟原虫可能会产生越来越大的影响，因为 恶性疟原虫已得到控制。

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.