Keirans J E, Hutcheson H J, Durden L A, Klompen J S
Institute of Arthropodology and Parasitology, Georgia Southern University, Statesboro 30460-8056, USA.
J Med Entomol. 1996 May;33(3):297-318. doi: 10.1093/jmedent/33.3.297.
The blacklegged tick, Ixodes (Ixodes) scapularis Say, 1821, is redescribed, based on laboratory reared specimens originating in Bulloch County, Georgia. Information on distribution, host associations, morphological variation, and medical/veterinary importance is also presented. A great deal of recent work has focused on this species because it is the principal vector of the agent of Lyme disease (Borrelia burgdorferi Johnson, Schmidt, Hyde, Steigerwaldt & Brenner) in eastern North America. Its distribution appears to be expanding, and includes the state of Florida in the southeastern United States north to the provinces of Nova Scotia and Prince Edward Island, Canada, west to North and South Dakota, United States, and south to the state of Coahuila, Mexico. Although I. scapularis feeds on at least 125 species of North American vertebrates (54 mammalian, 57 avian, and 14 lizard species), analysis of the U.S. National Tick Collection holdings show that white-tailed deer, Odocoileus virginianus (Zimmermann), cattle, Bos taurus L., dogs, Canis lupus L., and other medium-to-large sized mammals are important hosts for adults as are native mice and other small mammals, certain ground-frequenting birds, skinks, and glass lizards for nymphs and larvae. This tick is a polytypic species exhibiting north-south and east-west morphological clines. Analysis of variance and Student-Newman-Keuls multiple comparisons revealed significant interpopulational variation that is expressed most significantly in the nymphal stage. Nymphs from northern (Minnesota, Massachusetts, Maryland) populations had relatively larger basis capituli with shorter cornua (except Maryland) than southern (North Carolina, Georgia) populations. Midwestern populations (Minnesota, Missouri) differed from eastern populations (Massachusetts, Maryland, North Carolina, Georgia) in idiosomal characters (broader scuta, larger coxae III, and IV). In addition to Lyme disease, this tick is also a primary vector of the agent of human and rodent babesiosis, Babesia microti Franca. Under laboratory conditions it has transmitted the agents of deer babesiosis, Babesia odocoilei Emerson & Wright, tularemia, Francisella tularensis McCoy & Chapin, and anaplasmosis, Anaplasma marginale Theiler. Moreover, I. scapularis can reach pest proportions on livestock, and females can cause tick paralysis in dogs.
基于源自佐治亚州布洛奇县的实验室饲养标本，对黑脚硬蜱（Ixodes (Ixodes) scapularis Say，1821）进行了重新描述。文中还介绍了其分布、宿主关联、形态变异以及医学/兽医重要性等信息。近期大量研究聚焦于该物种，因为它是北美东部莱姆病病原体（伯氏疏螺旋体Borrelia burgdorferi Johnson, Schmidt, Hyde, Steigerwaldt & Brenner）的主要传播媒介。其分布范围似乎正在扩大，包括美国东南部的佛罗里达州，北至加拿大的新斯科舍省和爱德华王子岛省，西至美国的北达科他州和南达科他州，南至墨西哥的科阿韦拉州。尽管肩突硬蜱以至少125种北美脊椎动物为食（54种哺乳动物、57种鸟类和14种蜥蜴），但对美国国家蜱类收藏的分析表明，白尾鹿（Odocoileus virginianus (Zimmermann)）、牛（Bos taurus L.）、狗（Canis lupus L.）以及其他中大型哺乳动物是成虫的重要宿主，而本地小鼠和其他小型哺乳动物、某些常出没于地面的鸟类、石龙子和玻璃蜥蜴则是若虫和幼虫的重要宿主。这种蜱是一个多型物种，呈现出南北和东西方向的形态渐变群。方差分析和Student - Newman - Keuls多重比较显示出显著的种群间变异，在若虫阶段表现最为明显。来自北方（明尼苏达州、马萨诸塞州、马里兰州）种群的若虫，其头基部相对较大，角较短（马里兰州除外），而南方（北卡罗来纳州、佐治亚州）种群的则不然。中西部种群（明尼苏达州、密苏里州）在虫体特征（盾板更宽、第三和第四基节更大）方面与东部种群（马萨诸塞州、马里兰州、北卡罗来纳州、佐治亚州）不同。除了莱姆病，这种蜱还是人类和啮齿动物巴贝斯虫病病原体微小巴贝斯虫（Babesia microti Franca）的主要传播媒介。在实验室条件下，它还传播了鹿巴贝斯虫病病原体奥氏巴贝斯虫（Babesia odocoilei Emerson & Wright）、兔热病病原体土拉弗朗西斯菌（Francisella tularensis McCoy & Chapin）以及边缘无形体病病原体边缘无形体（Anaplasma marginale Theiler）。此外，肩突硬蜱在牲畜身上可能达到害虫比例，雌性蜱可导致犬类蜱瘫痪。
