High Genetic Diversity of Plasmodium falciparum in the Low-Transmission Setting of the Kingdom of Eswatini
High Genetic Diversity of Plasmodium falciparum in the Low-Transmission Setting of the Kingdom of Eswatini
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DOI：
10.1093/infdis/jiz305
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发表时间：
2019-10-15
影响因子：
6.4
通讯作者：
Greenhouse, Bryan
中科院分区：
文献类型：
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作者：
Roh, Michelle E.;Tessema, Sofonias K.;Greenhouse, Bryan
背景为了更好地了解传播动力学，我们的特点恶性疟原虫遗传多样性在斯威士兰，那里的传播是低的，并持续输入。在66%的确诊病例中对26个恶性疟原虫微卫星进行了基因分型（2014-2016; N = 582）。人口和宿主内的多样性被用来描述输入性和本地获得性感染之间的差异。Logistic回归被用来评估多样性指标的附加值，以区分输入性和本地感染，而不仅仅是流行病学数据。斯威士兰的寄生虫种群高度多样（预期杂合性[H-E] = 0.75）和复杂：67%的多克隆感染，平均感染复数（MOI）2.2，平均宿主内感染固定指数（F-WS）0.84。输入性病例的多样性与本地病例相当，但MOI较高（2.4 vs 2.0; P =.004），平均F-WS较低（0.82 vs 0.85; P = .03）。在多变量分析中加入MOI和F-WS并没有增加输入性和本地感染之间的区别。与恶性疟原虫多样性随传播强度降低而下降的普遍看法相反，斯威士兰分离株表现出高寄生虫多样性，这与疟疾输入率高和局部传播有限一致。根据基因数据估计疟疾传播强度需要考虑输入的影响，特别是在接近消灭疟疾的国家。
Background. To better understand transmission dynamics, we characterized Plasmodium falciparum genetic diversity in Eswatini, where transmission is low and sustained by importation.Methods. Twenty-six P. falciparum microsatellites were genotyped in 66% of confirmed cases (2014-2016; N = 582). Population and within-host diversity were used to characterize differences between imported and locally acquired infections. Logistic regression was used to assess the added value of diversity metrics to classify imported and local infections beyond epidemiology data alone.Results. Parasite population in Eswatini was highly diverse (expected heterozygosity [H-E] = 0.75) and complex: 67% polyclonal infections, mean multiplicity of infection (MOI) 2.2, and mean within-host infection fixation index (F-WS) 0.84. Imported cases had comparable diversity to local cases but exhibited higher MOI (2.4 vs 2.0; P =.004) and lower mean F-WS (0.82 vs 0.85; P = .03). Addition of MOI and F-WS to multivariate analyses did not increase discrimination between imported and local infections.Conclusions. In contrast to the common perception that P. falciparum diversity declines with decreasing transmission intensity, Eswatini isolates exhibited high parasite diversity consistent with high rates of malaria importation and limited local transmission. Estimates of malaria transmission intensity from genetic data need to consider the effect of importation, especially as countries near elimination.