Klich M, Lankester M W, Wu K W
Department of Biology, Lakehead University, Thunder Bay, ON, Canada.
J Med Entomol. 1996 Jul;33(4):581-5. doi: 10.1093/jmedent/33.4.581.
Birds that had migrated northward across Lake Superior were captured upon reaching landfall at Thunder Cape (48 degrees 18' N, 88 degrees 56' W) at the southwestern tip of the Sibley Peninsula, northwestern Ontario, from 9 May to 9 June 1995. Twenty-one of 530 birds examined (6 of 55 species) had a total of 34 ticks; 1 blue jay, Cyanocitta cristata, had a northern fowl mite, Ornithonyssus sylviarum (Canestrini & Fanzago). Four blacklegged tick, Ixodes scapularis Say, larvae were found on an American robin, Turdus migratorius, and 2 on a chipping sparrow, Spizella passerina. This tick was not found on small mammals at Thunder Cape. Twenty-six larvae and a nymph of the rabbit tick, Haemaphysalis leporispalustris (Packard) were found on 1 American robin, 2 Swainson's thrushes, Catharus ustulatus, 1 white-throated sparrow, Zonotrichia albicollis, 1 common yellowthroat, Geothlypis trichas, 1 blue jay, and 12 chipping sparrows. A nymph of H. chordeilis (Packard) occurred on 1 chipping sparrow. Results demonstrate that northward migrating birds transport larvae of I. scapularis to areas of Ontario where the tick does not appear to have become established in small mammal populations. Spring migrants may be more involved in the dispersal of I. scapularis larvae than previously thought. Cooler temperatures and shorter seasons experienced in the more northerly, continental parts of the established distribution of this tick may extend the life cycle, resulting in a predominance of larvae rather than nymphs being acquired by northward-bound birds in early spring. Consequently, the role of spring migrating birds in the northward spread of I. scapularis and of borreliosis should be reevaluated.
1995年5月9日至6月9日，向北飞越苏必利尔湖的鸟类在安大略省西北部锡布利半岛西南端的桑德角（北纬48度18分，西经88度56分）登陆时被捕获。在检查的530只鸟（55个物种中的6种）中有21只身上共有34只蜱虫；1只冠蓝鸦（学名：Cyanocitta cristata）身上有北方禽螨（学名：Ornithonyssus sylviarum，Canestrini & Fanzago）。在1只美洲知更鸟（学名：Turdus migratorius）身上发现了4只肩突硬蜱（学名：Ixodes scapularis Say）幼虫，在1只栗胁雀鹀（学名：Spizella passerina）身上发现了2只。在桑德角的小型哺乳动物身上未发现这种蜱虫。在1只美洲知更鸟、2只斯氏夜鸫（学名：Catharus ustulatus）、1只白喉带鹀（学名：Zonotrichia albicollis）、1只普通黄喉地莺（学名：Geothlypis trichas）、1只冠蓝鸦和12只栗胁雀鹀身上发现了26只兔蜱（学名：Haemaphysalis leporispalustris，Packard）幼虫和1只若虫。在1只栗胁雀鹀身上发现了1只哈氏血蜱（学名：H. chordeilis，Packard）若虫。结果表明，向北迁徙的鸟类将肩突硬蜱幼虫带到了安大略省的一些地区，而在这些地区，这种蜱虫似乎尚未在小型哺乳动物种群中定殖。春季迁徙鸟类在肩突硬蜱幼虫传播中所起的作用可能比之前认为的更大。在这种蜱虫既定分布区更靠北的大陆部分，温度较低且季节较短，这可能会延长其生命周期，导致在早春向北迁徙的鸟类身上获取的主要是幼虫而非若虫。因此，应重新评估春季迁徙鸟类在肩突硬蜱向北传播以及莱姆病传播中的作用。
