Sekine Sho, Chan Chim W, Kalkoa Morris, Yamar Sam, Iata Harry, Taleo George, Kc Achyut, Kagaya Wataru, Kido Yasutoshi, Kaneko Akira
Department of Virology, Graduate School of Medicine, and Osaka International Research Center for Infectious Diseases, Osaka Metropolitan University, Osaka, Japan.
Department of Medical Technology, Morinomiya University of Medical Sciences, Osaka, Japan.
Commun Med (Lond). 2024 May 18;4(1):91. doi: 10.1038/s43856-024-00524-9.
Five years after successful malaria elimination, Aneityum Island in Vanuatu experienced an outbreak of Plasmodium vivax of unknown origin in 2002. Epidemiological investigations revealed several potential sources of P. vivax. We aimed to identify the genetic origin of P. vivax responsible for the resurgence.
Five P. vivax microsatellite markers were genotyped using DNA extracted from archived blood samples. A total of 69 samples from four P. vivax populations was included: 29 from the outbreak in 2002, seven from Aneityum in 1999 and 2000, 18 from visitors to Aneityum in 2000, and 15 from nearby Tanna Island in 2002. A neighbour-joining phylogenetic tree was constructed to elucidate the relationships among P. vivax isolates. STRUCTURE and principal component analysis were used to assess patterns of genetic structure.
Here we show distinct genetic origins of P. vivax during the outbreak on Aneityum. While the origin of most P. vivax lineages found during the outbreak remains unidentified, limited genetic diversity among these lineages is consistent with a rapid expansion from a recent common ancestor. Contemporaneous P. vivax from neighboring Tanna and potential relapse of P. vivax acquired from other islands in 1999 and 2000 are also identified as minor contributors to the outbreak.
Multiple reintroductions of P. vivax after elimination highlight the high receptivity and vulnerability to malaria resurgence in island settings of Vanuatu, despite robust surveillance and high community compliance to control measures.
在成功消除疟疾五年后，瓦努阿图的阿内蒂乌姆岛于2002年爆发了来源不明的间日疟原虫疫情。流行病学调查揭示了间日疟原虫的几个潜在来源。我们旨在确定导致疫情复发的间日疟原虫的基因来源。
使用从存档血液样本中提取的DNA对五个间日疟原虫微卫星标记进行基因分型。共纳入了来自四个间日疟原虫群体的69个样本：29个来自2002年的疫情，7个来自1999年和2000年的阿内蒂乌姆岛，18个来自2000年访问阿内蒂乌姆岛的游客，以及15个来自2002年附近的塔纳岛。构建邻接法系统发育树以阐明间日疟原虫分离株之间的关系。使用STRUCTURE和主成分分析来评估遗传结构模式。
我们在此展示了阿内蒂乌姆岛疫情期间间日疟原虫不同的基因来源。虽然疫情期间发现的大多数间日疟原虫谱系的来源仍未确定，但这些谱系中有限的遗传多样性与近期共同祖先的快速扩张一致。同时，来自邻近塔纳岛的间日疟原虫以及1999年和2000年从其他岛屿获得的间日疟原虫潜在复发也被确定为疫情的次要促成因素。
消除疟疾后间日疟原虫的多次重新引入凸显了瓦努阿图岛屿环境对疟疾复发的高易感性和脆弱性，尽管有强有力的监测以及社区对控制措施的高度依从性。
