Laboratorio ICEMR-Amazonia, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofa, Universidad Peruana Cayetano Heredia, Lima, Perú.
Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Perú.
PLoS Negl Trop Dis. 2019 Nov 11;13(11):e0007876. doi: 10.1371/journal.pntd.0007876. eCollection 2019 Nov.
Despite efforts made over decades by the Peruvian government to eliminate malaria, Plasmodium vivax remains a challenge for public health decision-makers in the country. The uneven distribution of its incidence, plus its complex pattern of dispersion, has made ineffective control measures based on global information that lack the necessary detail to understand transmission fully. In this sense, population genetic tools can complement current surveillance. This study describes the genetic diversity and population structure from September 2012 to March 2015 in three geographically distant settlements, Cahuide (CAH), Lupuna (LUP) and Santa Emilia (STE), located in the Peruvian Amazon. A total 777 P. vivax mono-infections, out of 3264, were genotyped. Among study areas, LUP showed 19.7% of polyclonal infections, and its genetic diversity (Hexp) was 0.544. Temporal analysis showed a significant increment of polyclonal infections and Hexp, and the introduction and persistence of a new parasite population since March 2013. In STE, 40.1% of infections were polyclonal, with Hexp = 0.596. The presence of four genetic clusters without signals of clonal expansion and infections with lower parasite densities compared against the other two areas were also found. At least four parasite populations were present in CAH in 2012, where, after June 2014, malaria cases decreased from 213 to 61, concomitant with a decrease in polyclonal infections (from 0.286 to 0.18), and expectedly variable Hexp. Strong signals of gene flow were present in the study areas and wide geographic distribution of highly diverse parasite populations were found. This study suggests that movement of malaria parasites by human reservoirs connects geographically distant malaria transmission areas in the Peruvian Amazon. The maintenance of high levels of parasite genetic diversity through human mobility is a critical barrier to malaria elimination in this region.
尽管秘鲁政府数十年来一直致力于消除疟疾，但间日疟原虫仍然是该国公共卫生决策者面临的挑战。该病的发病率分布不均，且其传播模式复杂，这使得基于全球信息的无效控制措施缺乏充分了解传播情况所需的细节。在这种情况下，人口遗传工具可以补充当前的监测。本研究描述了 2012 年 9 月至 2015 年 3 月在秘鲁亚马逊地区三个地理位置不同的定居点（Cahuide[CAH]、Lupuna[LUP]和 Santa Emilia[STE]）的遗传多样性和种群结构。在 3264 例单感染中，共对 777 例进行了基因分型。在所研究的地区中，LUP 的多克隆感染率为 19.7%，其遗传多样性（Hexp）为 0.544。时间分析显示，自 2013 年 3 月以来，多克隆感染和 Hexp 显著增加，以及新寄生虫种群的引入和持续存在。在 STE，40.1%的感染为多克隆，Hexp=0.596。还发现了四个没有克隆扩张信号的遗传群集，以及感染寄生虫密度较低的情况，与其他两个地区相比。2012 年 CAH 至少存在四个寄生虫种群，2014 年 6 月后，疟疾病例从 213 例减少到 61 例，多克隆感染（从 0.286 减少到 0.18）和预期的 Hexp 变量减少。在研究地区存在强烈的基因流动信号，发现了广泛分布的高度多样化寄生虫种群。本研究表明，人类宿主携带疟原虫的运动将秘鲁亚马逊地区地理位置不同的疟疾传播区连接起来。人类流动维持高水平的寄生虫遗传多样性是该地区消除疟疾的一个关键障碍。
