Transmission of Rickettsia africae by Amblyomma americanum and Amblyomma maculatum

美洲钝眼虫和斑钝眼虫传播非洲立克次体

• 批准号: 9894993
• 负责人: Patrick Kelly
• 金额: $ 5.3万
• 依托单位: ROSS UNIVERSITY SCH/VETERINARY MEDICINE
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-10 至 2022-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9894993
• 关键词: Adult; Africa; African; Amblyomma; Ambylomma americanum; American; Animals; Area; Caribbean region; Cattle; Cavia; Central America; Data; Diagnosis; Disease; Fever; Florida; Generations; Health; High Prevalence; Holidays; Human; Indian Ocean; Indian Ocean Islands; Infection; Intervention; Island; Knowledge; Larva; Mexico; Monitor; Morbidity - disease rate; Nymph; Organism; Pacific Islands; Pacific Ocean; Pathology; Policy Maker; Prevention; Prevention strategy; Protocols documentation; Rickettsia; Rickettsia Infections; Risk; Rocky Mountain Spotted Fever; Testing; Tick-Borne Diseases; Ticks; Time; Travel; Vectorial capacity; West Indies; egg; experimental study; feeding; flu; human disease; migratory bird; response; spotted fever; tick bite; transmission process; vector

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.

项目摘要/摘要 人力车引起的非洲tick虫发烧可能是最常见的人类 发烧组立克氏病。它发生在整个非洲，无论其主要矢量，Amblyomma 发现Variegatum。其他amblyomma物种也可以传播R. Africae和生物体 已经通过印度和太平洋在迁徙鸟类的Amblyomma loculosum中传播 岛屿。里克西亚非洲也发生在ovale的中美洲和加勒比海地区 1800年代从非洲从非洲进口的牛群中，瓦里加图特的岛屿。感染的壁虱 被广泛散布在加勒比海岛上的牛真皮岛，它们是候鸟 这很容易在岛屿和佛罗里达钥匙之间移动。 非洲河在附近的加勒比海群岛和中美洲以及非洲的存在， 扩大这些地区与美国之间的旅游业和贸易，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， 候鸟的存在增加了瓦里加图特和/或R.非洲的风险 进入美国并建立。如果在美国特有的高等种类，那么 被非洲tick虫发烧感染并维护和传播。 在美国建立，与非洲一样引起广泛的发病率。另外，这个 会进一步使美国斑点发烧组的诊断已经很困难 人力病感染，特别是落基山斑点发烧。非洲河对 美国野生动植物是未知的。 建立最相关的美国弱略物种的储层和矢量能力。 Americanum和A. maculatum，我们打算用几内亚进行传输实验 猪和小牛作为宿主。 Amblyomma variegatum幼虫/若虫和感染R的成年人 非洲将分别与未感染的同时，分别以豚鼠或犊牛喂食 未成熟和成人美国浓度症，以确定是否可以转移感染 水平。如果在美国庞然大物物种中可以证明感染， 将进行实验，以确定是否可以在 通过鸡蛋进行了循环的饲料阶段（三角体），从每个进食阶段到 主人。 这些实验产生的数据将使美国卫生工作者更精确 确定在美国建立非洲tick虫发烧的风险 预防和响应策略要制定。