来自亚洲起源的外寄生虫螨Varroa破坏因子在全球范围内的传播从根本上改变了蜜蜂(Apismellifera)与其几种病毒的关系,通过传播和/或宿主免疫抑制的变化。对于大多数病毒来说,瓦螨入侵后蜜蜂与病毒关系的变化程度知之甚少。部分原因是世界上很少有几个地理上接近但完全孤立的蜜蜂种群,或者没有,长期接触瓦罗亚,允许单独的生态,流行病学,蜜蜂和它们的病毒之间的适应性关系,与螨虫的存在或不存在有关。亚速尔群岛就是这样一个地方,因为它包含有和没有螨的岛屿。这里,我们将qPCR与meta扩增子深度测序相结合,以揭示瓦细菌存在之间的关系,和患病率,负载,多样性,以及在群岛上筛选的八种蜜蜂病毒的系统地理结构。在任何岛上均未检测到四种病毒(ABPV-急性蜜蜂麻痹病毒,KBV-克什米尔蜜蜂病毒,IAPV-以色列急性蜜蜂麻痹病毒,BeeMLV-蜜蜂黄斑样病毒);仅在受螨感染的岛屿上检测到一种(SBV-Sacbrood病毒);一种(CBPV-慢性蜜蜂麻痹病毒)发生在某些岛屿上,和两个(BQCV-BlackQueen细胞病毒,LSV-西奈湖病毒,)出现在每个岛上。这种多病毒筛选建立在对变形机翼病毒(DWV)毒株的平行调查的基础上,该毒株发现了一种非常异质的病毒景观,其特征是瓦螨感染的岛屿以DWV-A和-B为主,无巴罗亚群岛天真到DWV,和罕见的DWV-C的避难所,统治着最东端的无Varroa群岛。虽然这里调查的所有四种检测到的病毒都受到瓦螨的一个或两个参数(通常是流行率和/或ASV多样性的丰富性成分)的影响,对于多菌株LSV观察到最强的效果。Varroa明确导致患病率升高,负载,和LSV的多样性(丰富度和香农指数),这些结果主要由LSV-2(一种主要的LSV菌株)形成。通过实施系统地理学方法,进一步获得了对螨病毒关系的前所未有的见解。除了能够鉴定一种新的LSV菌株,它主导了最东端岛屿的独特病毒景观,这种方法,结合恢复的多样性模式,有力地表明瓦螨正在推动亚速尔群岛LSV的进化变化。这项研究极大地促进了目前对瓦螨对这些研究较少的病毒的流行病学和适应性进化的影响的理解,到目前为止,他与瓦罗亚的关系还没有得到很好的界定。
The worldwide dispersal of the ectoparasitic mite Varroa destructor from its Asian origins has fundamentally transformed the relationship of the honey bee (Apis mellifera) with several of its viruses, via changes in transmission and/or host immunosuppression. The extent to which honey bee-virus relationships change after Varroa invasion is poorly understood for most viruses, in part because there are few places in the world with several geographically close but completely isolated honey bee populations that either have, or have not, been exposed long-term to Varroa, allowing for separate ecological, epidemiological, and adaptive relationships to develop between honey bees and their viruses, in relation to the mite\'s presence or absence. The
Azores is one such place, as it contains islands with and without the mite. Here, we combined qPCR with meta-amplicon deep sequencing to uncover the relationship between Varroa presence, and the prevalence, load, diversity, and phylogeographic structure of eight honey bee viruses screened across the archipelago. Four viruses were not detected on any island (ABPV-Acute bee paralysis virus, KBV-Kashmir bee virus, IAPV-Israeli acute bee paralysis virus, BeeMLV-Bee macula-like virus); one (SBV-Sacbrood virus) was detected only on mite-infested islands; one (CBPV-Chronic bee paralysis virus) occurred on some islands, and two (BQCV-Black queen cell virus, LSV-Lake Sinai virus,) were present on every single island. This multi-virus screening builds upon a parallel survey of Deformed wing virus (DWV) strains that uncovered a remarkably heterogeneous viral landscape featuring Varroa-infested islands dominated by DWV-A and -B, Varroa-free islands naïve to DWV, and a refuge of the rare DWV-C dominating the easternmost Varroa-free islands. While all four detected viruses investigated here were affected by Varroa for one or two parameters (usually prevalence and/or the Richness component of ASV diversity), the strongest effect was observed for the multi-strain LSV. Varroa unambiguously led to elevated prevalence, load, and diversity (Richness and Shannon Index) of LSV, with these results largely shaped by LSV-2, a major LSV strain. Unprecedented insights into the mite-virus relationship were further gained from implementing a phylogeographic approach. In addition to enabling the identification of a novel LSV strain that dominated the unique viral landscape of the easternmost islands, this approach, in combination with the recovered diversity patterns, strongly suggests that Varroa is driving the evolutionary change of LSV in the
Azores. This study greatly advances the current understanding of the effect of Varroa on the epidemiology and adaptive evolution of these less-studied viruses, whose relationship with Varroa has thus far been poorly defined.