Abstract:
Theileria orientalis Ikeda has caused an epidemic of bovine anemia and abortion across several U.S. states. This apicomplexan hemoparasite is transmitted by Haemaphysalis longicornis ticks; however, it is unknown if other North American ticks are competent vectors. Since the disease movement is largely determined by the host tick range(s), the prediction of the T. orientalis spread among U.S. cattle populations requires determination of additional competent tick vectors. Although Rhipicephalus microplus has mostly been eradicated from the U.S., outbreaks in populations occur frequently, and the U.S. remains at risk for reintroduction. Since R. microplus is a vector of Theileria equi and T. orientalis DNA has been detected in R. microplus, the goal of this study was to determine whether R. microplus is a competent vector of T. orientalis. Larval R. microplus were applied to a splenectomized, T. orientalis Ikeda-infected calf for parasite acquisition, removed as molted adults, and applied to two T. orientalis naïve, splenectomized calves for transmission. After 60 days, the naïve calves remained negative for T. orientalis by PCR and cytology. Additionally, T. orientalis was not detected in the salivary glands or larval progeny of acquisition-fed adults. These data suggest that R. microplus is not a competent vector of the U.S. T. orientalis Ikeda isolate.
摘要:
Ikeda在美国多个州引起了牛贫血和流产的流行。这种顶复性血液寄生虫是由长角角蜱传播的;然而,未知其他北美蜱是否有能力。由于疾病运动在很大程度上是由宿主蜱范围决定的,在美国牛种群中传播的T.orientalis的预测需要确定其他称职的tick矢量。尽管在美国已经根除了微小的血脂症,人群中的疫情经常发生,美国仍然面临重新引入的风险。由于R.microplus是马氏Theileria的载体,并且已在R.microplus中检测到定向T.OrientalisDNA,这项研究的目的是确定R.microplus是否为东方T.幼虫R.microplus被应用于脾切除,鱼田方向感染的小牛用于获取寄生虫,作为蜕皮的成年人被移除,并应用于两个T.Orientalisnaive,用于传播的脾切除的小牛。60天后,通过PCR和细胞学检查,初生小牛的东方毛虫保持阴性。此外,在以采集为食的成虫的唾液腺或幼虫后代中未检测到东方毛虫。这些数据表明,R.microplus不是美国定向T.Ikeda分离株的有效载体。