Transmission of Rickettsia africae by Amblyomma americanum and Amblyomma maculatum

项目摘要/摘要 由非洲立克次体引起的非洲扁虱咬伤热可能是最常见的人类斑点 发热组立克次体病。它发生在整个非洲，无论它的主要媒介Amblyomma在哪里 Variegatum，被发现。其他Amblyomma物种也可以传播非洲R。 该病毒通过印度洋和太平洋的候鸟传播于房间钝线虫 岛屿。非洲立克次体也发生在中美洲的卵形立克次体和加勒比地区。 这些岛屿是19世纪从非洲进口的牛。受感染的扁虱 广泛分布在加勒比海岛屿上的牛鹭身上，这是一种候鸟 它们可以很容易地在两个岛屿之间移动，并远至佛罗里达群岛。 附近的加勒比海岛屿和中美洲以及非洲、 扩大这些地区与美国之间的旅游和贸易，进入美国的旅行者 来自非洲、加勒比海和中美洲，感染了非洲R。 候鸟的存在增加了变色拟青霉和/或非洲锥虫被传入的风险 进入美国并逐渐确立地位。如果美国特有的Amblyomma物种能够 感染并维持和传播非洲乳杆菌，非洲扁虱叮咬热可能成为 在美国建立，导致广泛的发病率，就像在非洲一样。此外，这一点 将使本已困难的美国斑点热群的诊断变得更加复杂 立克次体感染，特别是落基山斑疹热。非洲狂犬病对人类健康的影响 美国的野生动物是不为人知的。 建立最相关的美国Amblyomma种A. Americanum和a.maculata，我们打算用几内亚进行传播实验。 猪和小牛作为宿主。花纹夜蛾幼虫和成虫感染R. 非洲病毒将在未感染的同时分别喂养豚鼠或小牛。 未成熟和成年的美国Amblyomma物种以确定感染是否可以传播 水平方向。如果可以证明在美国Amblyomma物种中有感染，那么进一步 将进行实验，以确定非洲锥体病毒是否可以在 饲喂阶段(经腹)，经卵途径，以及从每个饲喂阶段到 主持人。 这些实验产生的数据将使美国卫生工作者能够更准确地 确定非洲扁虱叮咬热在美国确立的风险，并适当地 有待制定的预防和应对战略。

Project Summary/ Abstract African tick-bite fever caused by Rickettsia africae is probably the most common human spotted fever group rickettsiosis. It occurs throughout Africa, wherever its major vector, Amblyomma variegatum, is found. Other Amblyomma species can also transmit R. africae and the organism has spread in Amblyomma loculosum on migratory birds through the Indian and Pacific Ocean islands. Rickettsia africae also occurs in Central America in A. ovale, and in the Caribbean islands in A. variegatum which were imported on cattle from Africa in the 1800s. Infected ticks were spread widely around the Caribbean islands on cattle egrets, which are migratory birds that move readily between the islands and as far as the Florida Keys. The presence of R. africae in the nearby Caribbean islands and Central America, and Africa, the expanding tourism and trade between these areas and the USA, the travelers entering the USA from Africa, the Caribbean, and Central America that are infected with R. africae, and the presence of migratory birds raises the risks of A. variegatum and/or R. africae being introduced into the USA and becoming established. If Amblyomma species endemic in the USA could then become infected with and maintain and transmit R. africae, African tick-bite fever could become established in the USA causing widespread morbidity as it does in Africa. Additionally, this would further complicate the already difficult diagnosis of American spotted fever group Rickettsia infections, in particular Rocky Mountain spotted fever. The effects of R. africae on American wildlife are unknown. To establish the reservoir and vector capacity of the most relevant US Amblyomma species, A. americanum and A. maculatum, we intend to conduct transmission experiments with guinea pigs and calves as hosts. Amblyomma variegatum larvae/ nymphs and adults infected with R. africae will be fed on guinea pigs or calves, respectively, at the same time as uninfected immature and adult US Amblyomma species to determine if infections can be transferred horizontally. If infections can be demonstrated in the US Amblyomma species, further experiments will be performed to establish if R. africae can be transmitted vertically between feeding stages (transtadially), transovarially through the eggs, and from each feeding stage to the host. Data generated from these experiments will enable American health workers to more precisely determine the risk of African tick-bite fever becoming established in the USA and for appropriate prevention and response strategies to be developed.