Incongruent effects of two isolates of Rickettsia conorii on the survival of Rhipicephalus sanguineus ticks
Incongruent effects of two isolates of Rickettsia conorii on the survival of Rhipicephalus sanguineus ticks
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DOI：
10.1007/s10493-009-9268-9
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发表时间：
2009-12-01
影响因子：
2.2
通讯作者：
Dasch, G. A.
中科院分区：
文献类型：
--
作者：
Levin, M. L.;Killmaster, L.;Dasch, G. A.
康氏立克次体是地中海斑疹热的病原体，广泛分布于南欧、中东、非洲、印度和里海地区。在地中海地区，棕色狗蜱（Rhipicephalus sanguineus）是公认的 R. conorii 媒介。为了研究蜱与病原体的关系以及模型动物因被感染蜱叮咬而引起的感染的发病机制，我们试图建立一个实验室的 Rh 菌落。 sanguineus 持续感染 R. conorii。将北美和地中海来源的血扇头蜱蜱暴露于非洲（R. conorii conorii 株 Malish）和地中海（R. conorii israelensis 株 ISTT）来源的 R. conorii 分离株。将蜱喂给感染的小鼠和狗、血腔内接种以及浸没在纯化的立克次体悬浮液中，将病原体引入未感染的蜱中。测量摄食成功率、蜕皮成功率和蜕皮蜱的寿命，以评估 R. conorii 对 Rh 存活的影响。血气方刚。根据之前发表的结果，Rh。来自北美和地中海殖民地的血红幼虫和若虫接触 R. conorii conorii Malish 在摄食和蜕皮期间或之后立即经历了很高的死亡率。幸存蜱虫的感染率不超过5%。另一方面，暴露于 ISTT 菌株对蜱存活的影响较小，导致感染率为 35-66%。 RH。地中海起源的血红菌比北美的血红菌更容易感染 R. conorii 菌株。先前的实验研究已证明 R. conorii 在 Rh 中的跨卵巢和跨体传播。血性；然而，我们的数据表明，不同的 R. conorii 菌株在自然界中可能采用不同的维护方式。脊椎动物宿主可能是比以前认为的更重要的储存库，或者不同代蜱之间的共同进食传播可能会消除或减少 R. conorii 经卵巢维持的需要。
Rickettsia conorii, the etiologic agent of Mediterranean spotted fever is widely distributed in Southern Europe, the Middle East, Africa, India and the Caspian region. In the Mediterranean region, the brown dog tick, Rhipicephalus sanguineus, is the recognized vector of R. conorii. To study tick-pathogen relationships and pathogenesis of infection caused in model animals by the bite of an infected tick, we attempted to establish a laboratory colony of Rh. sanguineus persistently infected with R. conorii. Rhipicephalus sanguineus ticks of North American and Mediterranean origin were exposed to R. conorii isolates of African (R. conorii conorii strain Malish) and Mediterranean (R. conorii israelensis strain ISTT) origin. Feeding of ticks upon infected mice and dogs, intra-hemocoel inoculation, and submersion in suspensions of purified rickettsiae were used to introduce the pathogen into uninfected ticks. Feeding success, molting success and the longevity of molted ticks were measured to assess the effects of R. conorii on the survival of Rh. sanguineus. In concordance with previously published results, Rh. sanguineus larvae and nymphs from both North American and Mediterranean colonies exposed to R. conorii conorii Malish experienced high mortality during feeding and molting or immediately after. The prevalence of infection in surviving ticks did not exceed 5%. On the other hand, exposure to ISTT strain had lesser effect on tick survival and resulted in 35-66% prevalence of infection. Rh. sanguineus of Mediterranean origin were more susceptible to infection with either strain of R. conorii than those from North America. Previous experimental studies had demonstrated transovarial and transstadial transmission of R. conorii in Rh. sanguineus; however, our data suggest that different strains of R. conorii may employ different means of maintenance in nature. The vertebrate host may be a more important reservoir than previously thought, or co-feeding transmission between different generations of ticks may obviate or lessen the requirement for transovarial maintenance of R. conorii.