Long-distance transmission patterns modelled from SNP barcodes of Plasmodium falciparum infections in The Gambia
Long-distance transmission patterns modelled from SNP barcodes of Plasmodium falciparum infections in The Gambia
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DOI：
10.1038/s41598-019-49991-4
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发表时间：
2019-09-18
影响因子：
4.6
通讯作者：
D'Alessandro, Umberto
中科院分区：
文献类型：
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作者：
Amambua-Ngwa, Alfred;Jeffries, David;D'Alessandro, Umberto
冈比亚的疟疾已显着下降，确定恶性疟原虫的传播动态有助于有针对性地采取控制措施以消灭疟疾。这可以从来自不同地点和时间点的寄生虫分离株之间的遗传相似性来推断。在这里，我们将恶性疟原虫的生命周期强加于遗传距离似然模型，以确定由355个分离株组成的54个SNP条形码的传播路径。在2013年疟疾季节，从冈比亚西部到东部横跨300公里的6对村庄每月收集样本。在成对遗传关系中存在空间和时间层次，来自同一家庭和村庄内的分离株的条形码最相似。受出行数据约束，该模型检测到60个定向传播事件，27%的路径连接不同地区的人。我们确定了13名感染者(占基因分型者的4.2%)，对他们所在社区内的2至8起后续感染负有责任。这些超级感染者大多来自高传播村。在考虑来自最远地区(西部与东部)的分离株之间的路径和传播史时，从冈比亚东部到西部有3条传播路径，均在疟疾传播季节的高峰期(10月)。已知的旅行路径没有从最西向东发源的路径。尽管一半以上的路径是村内的，但寄生虫从东到西的流动可能有助于维持冈比亚西部的传播，那里的疟疾传播率已经很低。因此，阻断冈比亚西部的疟疾传播需要以冈比亚东部为目标，那里的疟疾流行率要高得多，并加强疟疾干预措施。
Malaria has declined significantly in The Gambia and determining transmission dynamics of Plasmodium falciparum can help targeting control interventions towards elimination. This can be inferred from genetic similarity between parasite isolates from different sites and timepoints. Here, we imposed a P. falciparum life cycle time on a genetic distance likelihood model to determine transmission paths from a 54 SNP barcode of 355 isolates. Samples were collected monthly during the 2013 malaria season from six pairs of villages spanning 300 km from western to eastern Gambia. There was spatial and temporal hierarchy in pairwise genetic relatedness, with the most similar barcodes from isolates within the same households and village. Constrained by travel data, the model detected 60 directional transmission events, with 27% paths linking persons from different regions. We identified 13 infected individuals (4.2% of those genotyped) responsible for 2 to 8 subsequent infections within their communities. These super-infectors were mostly from high transmission villages. When considering paths between isolates from the most distant regions (west vs east) and travel history, there were 3 transmission paths from eastern to western Gambia, all at the peak (October) of the malaria transmission season. No paths with known travel originated from the extreme west to east. Although more than half of all paths were within-village, parasite flow from east to west may contribute to maintain transmission in western Gambia, where malaria transmission is already low. Therefore, interrupting malaria transmission in western Gambia would require targeting eastern Gambia, where malaria prevalence is substantially higher, with intensified malaria interventions.