Monitoring the genetic structure of pathogen populations may be an economical and sensitive approach to quantify the impact of control on transmission dynamics, highlighting the need for a better understanding of changes in population genetic parameters as transmission declines. Here we describe the first population genetic analysis of two major human malaria parasites, Plasmodium falciparum (Pf) and Plasmodium vivax (Pv), following nationwide distribution of long‐lasting insecticide‐treated nets (LLINs) in Papua New Guinea (PNG). Parasite isolates from pre‐ (2005–2006) and post‐LLIN (2010–2014) were genotyped using microsatellite markers. Despite parasite prevalence declining substantially (East Sepik Province: Pf = 54.9%–8.5%, Pv = 35.7%–5.6%, Madang Province: Pf = 38.0%–9.0%, Pv: 31.8%–19.7%), genetically diverse and intermixing parasite populations remained. Pf diversity declined modestly post‐LLIN relative to pre‐LLIN (East Sepik: R_s = 7.1–6.4, H_E = 0.77–0.71; Madang: R_s = 8.2–6.1, H_E = 0.79–0.71). Unexpectedly, population structure present in pre‐LLIN populations was lost post‐LLIN, suggesting that more frequent human movement between provinces may have contributed to higher gene flow. Pv prevalence initially declined but increased again in one province, yet diversity remained high throughout the study period (East Sepik: R_s = 11.4–9.3, H_E = 0.83–0.80; Madang: R_s = 12.2–14.5, H_E = 0.85–0.88). Although genetic differentiation values increased between provinces over time, no significant population structure was observed at any time point. For both species, a decline in multiple infections and increasing clonal transmission and significant multilocus linkage disequilibrium post‐LLIN were positive indicators of impact on the parasite population using microsatellite markers. These parameters may be useful adjuncts to traditional epidemiological tools in the early stages of transmission reduction.

中文翻译：

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使用微卫星标记监测恶性疟原虫和间日疟原虫表明在巴布亚新几内亚的传播大幅下降后人口结构变化有限

监测病原体种群的遗传结构可能是一种经济且敏感的方法，可以量化控制对传播动态的影响，突出表明需要更好地了解随着传播减少而发生的种群遗传参数变化。在这里，我们描述了在巴布亚新几内亚 (PNG) 全国范围内分发长效杀虫剂处理的蚊帐 (LLIN) 之后，对两种主要人类疟疾寄生虫恶性疟原虫( Pf ) 和间日疟原虫( Pv ) 进行的首次种群遗传分析。使用微卫星标记对 LLIN 前（2005-2006 年）和 LLIN 后（2010-2014 年）的寄生虫分离株进行基因分型。尽管寄生虫流行率大幅下降（东塞皮克省：Pf = 54.9%–8.5%，Pv  = 35.7%–5.6%，马当省：Pf  = 38.0%–9.0%，Pv：31.8%–19.7%），遗传多样性和混合寄生虫种群仍然存在。相对于 LLIN 之前，PF多样性在 LLIN 之后适度下降（East Sepik： R _s  = 7.1-6.4，H _E  = 0.77-0.71；Madang：R _s  = 8.2-6.1，H _E  = 0.79-0.71）。出乎意料的是，LLIN 前种群中存在的种群结构在 LLIN 后丢失，这表明各省之间更频繁的人类流动可能导致了更高的基因流动。光伏流行率最初下降但在一个省再次上升，但在整个研究期间多样性仍然很高（东塞皮克：R _s  = 11.4-9.3，H _E  = 0.83-0.80；马当：R _s  = 12.2-14.5，H _E = 0.85–0.88）。尽管各省之间的遗传分化值随着时间的推移而增加，但在任何时间点都没有观察到显着的种群结构。对于这两个物种，多重感染的减少和克隆传播的增加以及 LLIN 后显着的多位点连锁不平衡是使用微卫星标记对寄生虫种群产生影响的积极指标。在减少传播的早期阶段，这些参数可能是传统流行病学工具的有用辅助手段。