Evaluating the Ability of the Invasive Asian Longhorned Tick, Haemaphysalis longicornis, to Maintain and Transmit North American Tick-borne Viruses

项目总结与摘要 侵袭性亚洲长角硬蜱，长角血蜱，原产于东亚，但最近 在美国有固定的人口，并继续扩大其地理范围。这是一个公共的 对健康的威胁，因为在其固有的范围内，长角嗜血杆菌是一种既定的病毒媒介，与 心脏地带病毒(HRTV)和鹿虱病毒(DTV)，这是两种主要的北美壁虱传播病毒。 长角嗜血杆菌传播北美森林病毒(HRTV)和黄病毒的能力 (DTV)是未知的，这让我们不知道这种入侵的扁虱物种的流行病学影响。整体而言 此应用程序的目的是评估长角毛虫获取、维持和传播北极星的能力 美洲扁虱传播的静脉病毒和黄病毒。中心假设是，长角兽是一种称职的 HRTV和DTV的媒介，以及HRTV或DTV在受感染的本地硬蜱和 在没有宿主病毒血症的情况下，可能会发生未感染的长角线虫。这个项目的基本原理是，如果 长角血吸虫能够在硬蜱种群中维持HRTV和DTV，并将这些病毒传播到 哺乳动物宿主，我们可以开始预测这些病毒的演变流行病学和传播动态 在北美。中心假设将通过追求两个具体目标来检验：1)评估向量 长角血吸虫对HRTV和DTV的能力；以及，2)调查非病毒传播 HRTV或DTV发生在感染的本地硬蜱(美洲Amblyomma americanum或Ixodes shosularis)共食之间 与未感染的长角隐杆线虫在同一宿主上。在第一个目标下，长角毛虫将感染HRTV或 DTV，以及扁虱体内的病毒复制动力学。评估高分辨率电视的水平传输和 DTV，感染的长角兽将接受血餐，暴露的宿主将接受血清学和病毒血症 放映。在蜕皮进入下一个生命阶段后，扁虱将接受病毒检测，以评估垂直 变速箱。对于第二个目的，未受感染的长角隐翅虫将与HRTV在同一宿主上共同饲养。 感染美洲钩端螺旋体或DTV感染的肩周炎成虫。将对长角隐翅虫的若虫进行检测 在寄主的不同取食附近存在病毒。拟议的研究在概念上是创新的。 因为它是第一个评估长角毛虫对北美病毒、HRTV和 DTV，它在入侵的长角兽种群最近建立的地区传播。这一贡献 将具有重大意义，因为它勾勒出这种入侵的扁虱物种与北美相关的基本生物学 壁虱传播的病毒，这在我们试图了解H. 在这些病毒流行的北美地区建立的天角兽。

PROJECT SUMMARY & ABSTRACT The invasive Asian Longhorned tick, Haemaphysalis longicornis, is native to eastern Asia but recently established populations in the United States and continues to expand its geographic range. This is a public health threat, because in its native range, H. longicornis is an established vector of viruses closely related to Heartland virus (HRTV) and Deer tick virus (DTV), which are the two main North American tick-borne viruses. The capacity of H. longicornis to transmit North American tick-borne phleboviruses (HRTV) and flaviviruses (DTV) is unknown, leaving us unaware of the epidemiologic impact of this invasive tick species. The overall objective for this application is to assess the ability of H. longicornis to acquire, maintain, and transmit North American tick-borne phleboviruses and flaviviruses. The central hypothesis is that H. longicornis is a competent vector for HRTV and DTV, and co-feeding transmission of HRTV or DTV between infected native ticks and uninfected H. longicornis ticks can occur in the absence of host viremia. The rationale for this project is that if H. longicornis is capable of maintaining HRTV and DTV in tick populations and transmitting these viruses to mammalian hosts, we can begin to forecast evolving epidemiologic and transmission dynamics of these viruses in North America. The central hypothesis will be tested by pursuing two specific aims: 1) Assess the vector competence of H. longicornis ticks for HRTV and DTV; and, 2) Investigate whether non-viremic transmission of HRTV or DTV occurs between infected native ticks (Amblyomma americanum or Ixodes scapularis) co-feeding on the same host with uninfected H. longicornis. Under the first aim, H. longicornis will be infected with HRTV or DTV, and viral replication kinetics in the tick will be examined. To assess horizontal transmission of HRTV and DTV, infected H. longicornis will receive a bloodmeal and exposed hosts will undergo serology and viremia screening. After molting to the next life stage, ticks will be tested for the presence of virus to evaluate vertical transmission. For the second aim, uninfected H. longicornis nymphs will be co-fed on the same host with HRTV- infected A. americanum or DTV-infected I. scapularis adults. The H. longicornis nymphs will be tested for the presence of virus at different feeding proximities on the host. The proposed research is conceptually innovative because it is the first to evaluate H. longicornis’ vector competency for the North American viruses, HRTV and DTV, which circulate in regions where invasive H. longicornis populations recently established. This contribution will be significant because it frames the basic biology of this invasive tick species in relation to North American tick-borne viruses, which is extremely important as we seek to understand the public health implications of H. longicornis establishment in regions of North America where these viruses are endemic.