Over 892 million people in 48 countries are at risk of infection by nematodes that cause lymphatic filariasis. As part of the Global Programme to Eliminate Lymphatic Filariasis, mass drug administration is distributed to communities until surveillance indicates infection rates are below target prevalence thresholds. In some countries, including American Samoa, lymphatic filariasis transmission persists despite years of mass drug administration and/or has resurged after cessation. Nothing is known about the population genetics of Wuchereria bancrofti worms in Polynesia, or whether local transmission is persisting and/or increasing due to inadequate mass drug administration coverage, expansion from residual hotspots, reintroduction from elsewhere, or a combination. We extracted DNA from microfilariae on blood slides collected during prevalence surveys in 2014 and 2016, comprising 31 pools of five microfilariae from 22 persons living in eight villages. We sequenced 1104 bp across three mitochondrial markers (ND4, COI, CYTB). We quantified parasite genetic differentiation using variant calls and estimated haplotypes using principal components analysis, F-statistics, and haplotype networks. Of the variants called, all but eight were shared across the main island of Tutuila, and three of those were from a previously described hotspot village, Fagali’i. Genotypic data did not support population genetic structure among regions or villages in 2016, although differences were observed between worms collected in Fagali’i in 2014 and those from 2016. Because estimated haplotype frequency varied between villages, these statistics suggested genetic differentiation, but were not consistent among villages. Finally, haplotype networks demonstrated American Samoan sequence clusters were related to previously published sequences from Papua New Guinea. These are, to our knowledge, the first reports of W. bancrofti genetic variation in Polynesia. The resurgent parasites circulating on the main island of American Samoa represent a single population. This study is the first step towards investigating how parasite population structure might inform strategies to manage resurgence and elimination of lymphatic filariasis.

48 个国家的超过 8.92 亿人面临感染导致淋巴丝虫病的线虫的风险。作为消除淋巴丝虫病全球计划的一部分，在监测表明感染率低于目标流行阈值之前，向社区分发大量药物。在包括美属萨摩亚在内的一些国家，尽管进行了多年大规模给药，淋巴丝虫病传播仍然存在和/或在停药后再次流行。Wuchereria bancrofti的群体遗传学一无所知波利尼西亚的蠕虫，或是否由于大规模给药覆盖率不足、残留热点的扩张、其他地方的重新引入或组合而导致局部传播持续存在和/或增加。我们从 2014 年和 2016 年流行率调查期间收集的血液载玻片上的微丝蚴中提取了 DNA，其中包括来自居住在 8 个村庄的 22 个人的 5 种微丝蚴的 31 个池。我们对三个线粒体标记（ND4、COI、CYTB）进行了 1104 bp 的测序。我们使用变异调用量化了寄生虫的遗传分化，并使用主成分分析、F 统计量和单倍型网络估计了单倍型。在被调用的变体中，除 8 个外，其余所有变种都在图图伊拉主岛上共享，其中 3 个来自之前描述的热点村庄 Fagali'i。基因型数据不支持 2016 年地区或村庄之间的种群遗传结构，尽管 2014 年在 Fagali'i 收集的蠕虫与 2016 年收集的蠕虫之间存在差异。由于估计的单倍型频率因村庄而异，这些统计数据表明遗传分化，但并非如此村间一致。最后，单倍型网络证明美属萨摩亚序列簇与先前公布的巴布亚新几内亚序列相关。据我们所知，这些是关于 单倍型网络证明美属萨摩亚的序列簇与先前公布的巴布亚新几内亚序列有关。据我们所知，这些是关于 单倍型网络证明美属萨摩亚的序列簇与先前公布的巴布亚新几内亚序列有关。据我们所知，这些是关于波利尼西亚的W. bancrofti遗传变异。在美属萨摩亚主岛上流行的复活寄生虫代表了一个群体。这项研究是调查寄生虫种群结构如何为控制淋巴丝虫病复发和消除策略提供信息的第一步。