Mode of transmission and the evolution of arbovirus virulence in mosquito vectors
Mode of transmission and the evolution of arbovirus virulence in mosquito vectors
复制标题
DOI：
10.1098/rspb.2008.1709
复制
发表时间：
2009-04-07
影响因子：
4.7
通讯作者：
Scott, Thomas W.
中科院分区：
文献类型：
--
作者：
Lambrechts, Louis;Scott, Thomas W.
传统的假设认为病媒传播的病原体应该进化成与其节肢动物病媒的良性关系，这一假设在理论依据和经验证据上受到了挑战。然而，在虫媒病毒(节肢动物传播的病毒)的情况下，尽管一些研究人员报告了病毒诱导媒介死亡的实验证据，但其他人没有检测到任何重大影响。观察到的虫媒病毒毒力水平的这种变化是否取决于生物学特性或实验设计尚不清楚。在这里，我们对一系列蚊子病毒系统的研究进行荟萃分析，以表明总的来说，虫媒病毒确实会降低蚊子媒介的存活率，但影响的大小取决于媒介/病毒分类群体和病毒传播方式。甲型病毒与蚊子的最高毒力水平有关。水平传播(胸腔接种或口腔感染)与显著的病毒诱导死亡率相关，而经感染布尼亚病毒的伊蚊没有发现不良影响。布尼亚病毒是一组病毒，其地方性媒介中的垂直传播率很高。我们的发现与一般预测一致，即垂直传播的病原体应该比水平传播的病原体毒性小。我们的结论是，在媒介病毒系统中观察到的不同程度的毒力可能反映了施加在主要水平传播而不是垂直传播的虫媒病毒上的不同选择压力。
The traditional assumption that vector-borne pathogens should evolve towards a benign relationship with their arthropod vectors has been challenged on theoretical grounds and empirical evidence. However, in the case of arboviruses (arthropod-borne viruses), although a number of investigators have reported experimental evidence for virus-induced vector mortality, others have failed to detect any significant impact. Whether this variation in the observed level of arbovirus virulence depends on biological traits or experimental design is unclear. Here, we perform a meta-analysis of studies across a range of mosquito virus systems to show that, overall, arboviruses do reduce the survival of their mosquito vectors, but that the magnitude of the effect depends on the vector/virus taxonomic groups and the mode of virus transmission. Alphaviruses were associated with highest virulence levels in mosquitoes. Horizontal transmission (intrathoracic inoculation or oral infection) was correlated with significant virus-induced mortality, whereas a lack of adverse effect was found for Aedes mosquitoes infected transovarially by bunyaviruses-a group of viruses characterized by high natural rates of vertical transmission in their enzootic vectors. Our findings are consistent with the general prediction that vertically transmitted pathogens should be less virulent than those transmitted horizontally. We conclude that varying degrees of virulence observed among vector-virus systems probably reflect different selective pressures imposed on arboviruses that are primarily transmitted horizontally versus vertically.