近日刊登在国际杂志Science上的一篇研究报告中，研究人员报告说，在整个夏威夷蜜蜂群中的一种寄生螨的传播使得一种曾经无害的病毒能够在这些有价值的昆虫群落中大肆生长。在世界的其它地方，这种螨和病毒的同时出现与大批蜂群的死亡时间一致，尽管这种情况迄今还没有在夏威夷发生。这种螨到达那里是相对近来的事件，它们仅在某些岛屿上传播。
Stephen Martin及其同事在该螨侵袭的时候利用这一不同寻常的机会来监测夏威夷的蜜蜂并了解该病毒是如何传播和演化的。DWV自身可以感染蜜蜂，但瓦螨可通过作为一种宿主和孵化器而一路给予其帮助。这种螨的摄食行为还能使该病毒被直接传输到蜜蜂的循环系统。文章的作者报告说，瓦螨的介入使得DWV在蜜蜂群落中的流行情况从大约10%增加至100%。
在蜜蜂体内的病毒量也出现直线上升的情况，而病毒株的多样性则出现相反的情况。实际上，只有一个DWV株现在在瓦螨感染的蜂群中占主导地位。文章的作者得出结论，瓦螨的普遍蔓延选择了那些已经出现了的DWV变异株并使其成为地球上分布最广泛且传染性最强的昆虫病毒之一
Emerging diseases are among the greatest threats to honey bees. Unfortunately, where and when an emerging disease will appear are almost impossible to predict. The arrival of the parasitic Varroa mite into the Hawaiian honey bee population allowed us to investigate changes in the prevalence, load, and strain diversity of honey bee viruses. The mite increased the prevalence of a single viral species, deformed wing virus (DWV), from ~10 to 100% within honey bee populations, which was accompanied by a millionfold increase in viral titer and a massive reduction in DWV diversity, leading to the predominance of a single DWV strain. Therefore, the global spread of Varroa has selected DWV variants that have emerged to allow it to become one of the most widely distributed and contagious insect viruses on the planet.
