BACKGROUND Northern Senegal is a zone of very low malaria transmission, with an annual incidence of < 5/1000 inhabitants. This area, where the Senegal National Malaria Control Programme has initiated elimination activities, hosts Fulani, nomadic, pastoralists that spend the dry season in the south where malaria incidence is higher (150-450/1000 inhabitants) and return to the north with the first rains. Previous research demonstrated parasite prevalence of < 1% in this Fulani population upon return from the south, similar to that documented in the north in cross-sectional surveys. METHODS A modified snowball sampling survey of nomadic pastoralists was conducted in five districts in northern Senegal during September and October 2014. Demographic information and dried blood spots were collected. Multiplex bead-based assays were used to assess antibody responses to merozoite surface protein (MSP-119) antigen of the four primary Plasmodium species, as well as circumsporozoite protein (CSP) and liver stage antigen (LSA-1) of Plasmodium falciparum. RESULTS In the five study districts, 1472 individuals were enrolled, with a median age of 22 years (range 1 to 80 years). Thirty-two percent of subjects were under 14 years and 57% were male. The overall seroprevalence of P. falciparum MSP-119, CSP and LSA-1 antibodies were 45, 12 and 5%, respectively. Plasmodium falciparum MSP-119 antibody responses increased significantly with age in all study areas, and were significantly higher among males. The highest seroprevalence to P. falciparum antigens was observed in the Kanel district (63%) and the lowest observed in Podor (28%). Low seroprevalence was observed for non-falciparum species in all the study sites: 0.4, 0.7 and 1.8%, respectively, for Plasmodium ovale, Plasmodium vivax and Plasmodium malariae MSP-1. Antibody responses to P. vivax were observed in all study sites except Kanel. CONCLUSION Prevalence of P. falciparum MSP-119 antibodies and increases by study participant age provided data for low levels of exposure among this transient nomadic population. In addition, antibody responses to P. falciparum short half-life markers (CSP and LSA-1) and non-falciparum species were low. Further investigations are needed to understand the exposure of the Fulani population to P. vivax.

中文翻译：

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分析塞内加尔北部富拉尼游牧牧民的抗疟原虫IgG谱，以评估疟疾暴露情况。

背景技术塞内加尔北部是疟疾传播极低的地区，居民年发病率<5/1000。塞内加尔国家疟疾控制计划已在该地区发起了消除活动，该地区收容富拉尼，游牧，牧民，他们在南部的旱季度过，疟疾发病率较高（150-450 / 1000居民），并在北部首次出现。下雨。先前的研究表明，该富拉尼人从南部返回后，其寄生虫患病率＜1％，与北部在横断面调查中记录的相似。方法2014年9月至2014年10月，在塞内加尔北部的五个地区进行了游牧民改良雪球抽样调查，收集了人口统计学信息和干血斑。基于多重珠的分析用于评估对四种主要疟原虫物种的裂殖子表面蛋白（MSP-119）抗原以及恶性疟原虫的环子孢子蛋白（CSP）和肝阶段抗原（LSA-1）的抗体反应。结果在五个研究区中，共有1472人入组，中位年龄为22岁（范围为1至80岁）。32％的受试者年龄在14岁以下，而57％是男性。恶性疟原虫MSP-119，CSP和LSA-1抗体的总体血清阳性率分别为45％，12％和5％。在所有研究区域中，恶性疟原虫MSP-119抗体反应均随年龄显着增加，而男性中则明显更高。在坎内尔地区，恶性疟原虫抗原的血清阳性率最高（63％），在波多尔（Podor）最低（28％）。在所有研究地点，非恶性疟原虫的血清阳性率均较低：卵圆形疟原虫，间日疟原虫和疟疾疟原虫MSP-1分别为0.4％，0.7％和1.8％。除Kanel以外的所有研究部位均观察到了对间日疟原虫的抗体反应。结论恶性疟原虫MSP-119抗体的患病率以及研究参与者年龄的增加提供了有关这一短暂游牧人群低暴露水平的数据。此外，对恶性疟原虫短半衰期标志物（CSP和LSA-1）和非恶性疟原虫的抗体应答较低。需要进一步的调查，以了解富拉尼种群对间日疟原虫的暴露。在除Kanel之外的所有研究部位均观察到间日间病毒。结论恶性疟原虫MSP-119抗体的患病率以及研究参与者年龄的增加提供了有关这一短暂游牧人群低暴露水平的数据。此外，对恶性疟原虫短半衰期标志物（CSP和LSA-1）和非恶性疟原虫的抗体应答较低。需要进一步的调查，以了解富拉尼种群对间日疟原虫的暴露。在除Kanel之外的所有研究部位均观察到间日间病毒。结论恶性疟原虫MSP-119抗体的患病率以及研究参与者年龄的增加提供了有关这一短暂游牧人群低暴露水平的数据。此外，对恶性疟原虫短半衰期标志物（CSP和LSA-1）和非恶性疟原虫的抗体应答较低。需要进一步的调查，以了解富拉尼种群对间日疟原虫的暴露。