Strong isolation by distance and evidence of population microstructure reflect ongoing Plasmodium falciparum transmission in Zanzibar.
Strong isolation by distance and evidence of population microstructure reflect ongoing Plasmodium falciparum transmission in Zanzibar.
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距离的强烈隔离和种群微观结构的证据反映了桑给巴尔正在发生的恶性疟原虫传播。
DOI：
10.1101/2023.02.15.23285960
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发表时间：
2024
期刊：
影响因子：
--
通讯作者：
Verity,R
中科院分区：
文献类型：
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作者：
Connelly,SeanV;Brazeau,NicholasF;Msellem,Mwinyi;Ngasala,BillyE;Aydemir,Özkan;Goel,Varun;Niaré,Karamoko;Giesbrecht,DavidJ;Popkin-Hall,ZacharyR;Hennelly,ChristopherM;Park,Zackary;Moormann,AnnM;Ong'echa,JohnMichael;Verity,R
背景：坦桑尼亚的桑给巴尔群岛已成为恶性疟原虫的低传播区。尽管多年来一直被认为是一个预先消除的领域，但实现消除一直是困难的，可能是由于来自坦桑尼亚大陆的输入感染和当地持续传播的共同作用。方法：为了阐明这些传播源，我们应用分子倒置探针的高度多重基因分型方法，对2016-2018年间在桑给巴尔和沿海大陆Bagamoyo地区收集的282株恶性疟原虫分离株的遗传亲缘关系进行了表征。结果：总体上，沿海大陆和桑给巴尔群岛的寄生虫种群仍然具有高度的相关性。然而，来自桑给巴尔的寄生虫分离株由于寄生虫相关性在非常短的距离内迅速衰退而显示出种群微观结构。这一点，连同鞘内高度相关的对，表明正在进行低水平的局部传播。我们还发现了横跨Shehias的高度相关的寄生虫，这些寄生虫反映了温加岛主岛上的人类流动性，并在彭巴岛的Micheweni区发现了一群高度相关的寄生虫，这表明可能发生了疫情。无症状感染的寄生虫比有症状的感染表现出更高的感染复杂性，但具有相似的核心基因组。结论：我们的数据支持输入是桑给巴尔寄生虫种群遗传多样性和贡献的主要来源，但也显示了局部暴发集群，有针对性的干预对于阻断本地传播至关重要。这些结果突出表明，需要对输入性疟疾采取预防措施，并在由于易受感染的宿主和有能力的病媒而仍然容易再次出现疟疾的地区加强控制措施。
Background:The Zanzibar archipelago of Tanzania has become a low-transmission area for Plasmodium falciparum. Despite being considered an area of pre-elimination for years, achieving elimination has been difficult, likely due to a combination of imported infections from mainland Tanzania and continued local transmission.Methods:To shed light on these sources of transmission, we applied highly multiplexed genotyping utilizing molecular inversion probes to characterize the genetic relatedness of 282 P. falciparum isolates collected across Zanzibar and in Bagamoyo district on the coastal mainland from 2016 to 2018.Results:Overall, parasite populations on the coastal mainland and Zanzibar archipelago remain highly related. However, parasite isolates from Zanzibar exhibit population microstructure due to the rapid decay of parasite relatedness over very short distances. This, along with highly related pairs within shehias, suggests ongoing low-level local transmission. We also identified highly related parasites across shehias that reflect human mobility on the main island of Unguja and identified a cluster of highly related parasites, suggestive of an outbreak, in the Micheweni district on Pemba island. Parasites in asymptomatic infections demonstrated higher complexity of infection than those in symptomatic infections, but have similar core genomes.Conclusions:Our data support importation as a main source of genetic diversity and contribution to the parasite population in Zanzibar, but they also show local outbreak clusters where targeted interventions are essential to block local transmission. These results highlight the need for preventive measures against imported malaria and enhanced control measures in areas that remain receptive to malaria reemergence due to susceptible hosts and competent vectors.