Phylogeography of recently emerged DENV-2 in southern Viet Nam.
Phylogeography of recently emerged DENV-2 in southern Viet Nam.
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DOI：
10.1371/journal.pntd.0000766
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发表时间：
2010-07-27
影响因子：
3.8
通讯作者：
Holmes EC
中科院分区：
文献类型：
--
作者：
Rabaa MA;Ty Hang VT;Wills B;Farrar J;Simmons CP;Holmes EC
揭示登革病毒（DENV）在时间和空间上的传播对于了解其流行病学至关重要。然而，在当地人口规模上形成DENV传播模式的过程还没有得到很好的理解，特别是人口流动和城市化等因素的影响。在此，我们调查了越南南部高度流行环境中DENV-2传播的空间动态趋势。通过对来自越南南部10个省的住院登革热病例的168个全长DENV-2基因组序列的地理分布分析，我们揭示了城市和农村地区的大量遗传多样性，在单个季节内在个别省份确定了多个谱系，并表明社区之间的频繁病毒迁移。关注最近引入的亚洲I基因型，我们观察到相邻地理区域之间以及该地区主要城市中心胡志明市与越南南部人群之间的病毒交换率特别高。在胡志明市，DENV的运动模式似乎与病毒传播的重力模型一致，病毒穿过人口密度梯度。总的来说，我们的分析表明，胡志明市可能作为一个源人口的分布在越南南部的DENV，并提供了进一步的证据，东南亚的城市地区发挥主要作用，DENV的传播。然而，这些数据也表明，更多的农村地区也能够维持病毒种群，从而在多个季节中促进DENV的进化。登革病毒（DENV）是人类最常见的媒介传播病毒性疾病的原因，在东南亚部分地区的流行率特别高。大多数关于登革病毒传播的研究都集中在非常局部或国际的移动模式上，而没有探讨登革病毒如何在流行地区移动。为了解决这个问题，我们采用了新开发的地理学方法来研究在越南南部的一项基于医院的研究中收集的168个全长DENV-2基因组序列的空间传播模式，重点是最近在该地区出现的亚洲I型基因型。该分析表明，胡志明市的城市人口在病毒的传播中起着核心作用，并且DENV在该城市倾向于沿着人口密度梯度移动。此外，城市和农村地区之间的人员流动是DENV在越南南部传入胡志明市后迅速扩散的最可能解释。在到达更多的农村地区后，一些病毒谱系在那里维持了数年。因此，这些结果表明，病毒学监测是必要的，在城市和农村人口。
Revealing the dispersal of dengue viruses (DENV) in time and space is central to understanding their epidemiology. However, the processes that shape DENV transmission patterns at the scale of local populations are not well understood, particularly the impact of such factors as human population movement and urbanization. Herein, we investigated trends in the spatial dynamics of DENV-2 transmission in the highly endemic setting of southern Viet Nam. Through a phylogeographic analysis of 168 full-length DENV-2 genome sequences obtained from hospitalized dengue cases from 10 provinces in southern Viet Nam, we reveal substantial genetic diversity in both urban and rural areas, with multiple lineages identified in individual provinces within a single season, and indicative of frequent viral migration among communities. Focusing on the recently introduced Asian I genotype, we observed particularly high rates of viral exchange between adjacent geographic areas, and between Ho Chi Minh City, the primary urban center of this region, and populations across southern Viet Nam. Within Ho Chi Minh City, patterns of DENV movement appear consistent with a gravity model of virus dispersal, with viruses traveling across a gradient of population density. Overall, our analysis suggests that Ho Chi Minh City may act as a source population for the dispersal of DENV across southern Viet Nam, and provides further evidence that urban areas of Southeast Asia play a primary role in DENV transmission. However, these data also indicate that more rural areas are also capable of maintaining virus populations and hence fueling DENV evolution over multiple seasons. Dengue virus (DENV) is the cause of the most common vector-borne viral disease of humans, and is at particularly high prevalence in parts of Southeast Asia. Most studies of DENV transmission have focused on very local or international movement patterns, and have not explored how DENV moves through an endemic region. To address this issue, we employed newly developed phylogeographic methods to study patterns of spatial spread in 168 full-length DENV-2 genome sequences collected during a hospital-based study in southern Viet Nam, focusing on the Asian I genotype that recently emerged in this region. This analysis revealed that the urban population of Ho Chi Minh City plays a central role in the dispersal of the virus, and that DENV in this city tends to move along a gradient of population density. In addition, human movement between urban and rural areas was the most likely explanation for the rapid diffusion of DENV across southern Viet Nam following its introduction into Ho Chi Minh City. After reaching more rural areas, some virus lineages were maintained there for a number of years. These results therefore indicate that virological surveillance is necessary in both urban and rural populations.