Role of migratory birds in introduction and range expansion of Ixodes scapularis ticks and of Borrelia burgdorferi and Anaplasma phagocytophilum in Canada
Role of migratory birds in introduction and range expansion of Ixodes scapularis ticks and of Borrelia burgdorferi and Anaplasma phagocytophilum in Canada
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DOI：
10.1128/aem.01982-07
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发表时间：
2008-03-01
影响因子：
4.4
通讯作者：
Thompson, R. A.
中科院分区：
文献类型：
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作者：
Ogden, N. H.;Lindsay, L. R.;Thompson, R. A.
2005年和2006年春季，在加拿大东部的12个鸟类观测站捕获了39,095只北迁陆鸟，以调查候鸟在莱姆疏螺旋体病、人类粒细胞无形体病及其扁虱媒介肩隆硬蜱向北传播过程中所起的作用。有经验的观察者进行的一项嵌套研究表明，鸟类携带肩虱(主要是若虫)的流行率为0.35%(95%可信区间[CI]=0.30至0.42)，但更现实的感染流行率为2.2%(95%CI=1.18至3.73)。平均危害强度为1.66只/只。总体而言，15.4%的肩胛若虫(95%CI=10.7~20.9)对伯氏疏螺旋体呈阳性，但如果不包括在伯氏疏螺旋体流行的安大略省朗波特市采集的若虫，只有8%(95%CI=3.8~15.1)呈阳性。伯氏杆菌的OspC和RRS-RRL基因间隔区等位基因在感染的硬蜱中被发现，包括那些与播散性莱姆病相关的等位基因和在美国东北部罕见的等位基因。总体而言，0.4%(95%CI=0.03~0.41)的华支睾吸虫若虫对噬细胞无浆体的PCR检测呈阳性。我们估计，每年春天，候鸟在加拿大各地散布5,000万至1.75亿只一肩伊蚊，这意味着候鸟可能对加拿大一肩伊蚊活动范围的扩大具有重要意义。然而，不常见的幼虫和鸟类携带的硬蜱的低感染率提出了问题，即伯氏杆菌和吞噬细胞性嗜血杆菌是如何在由鸟类运输的硬蜱建立的任何硬蜱种群中成为地方性的。
During the spring in 2005 and 2006, 39,095 northward-migrating land birds were captured at 12 bird observatories in eastern Canada to investigate the role of migratory birds in northward range expansion of Lyme borreliosis, human granulocytic anaplasmosis, and their tick vector, Ixodes scapularis. The prevalence of birds carrying I. scapularis ticks (mostly nymphs) was 0.35% (95% confidence interval [CI] = 0.30 to 0.42), but a nested study by experienced observers suggested a more realistic infestation prevalence of 2.2% (95% CI = 1.18 to 3.73). The mean infestation intensity was 1.66 per bird. Overall, 15.4% of I. scapularis nymphs (95% CI = 10.7 to 20.9) were PCR positive for Borrelia burgdorferi, but only 8% (95% CI = 3.8 to 15.1) were positive when excluding nymphs collected at Long Point, Ontario, where B. burgdorferi is endemic. A wide range of ospC and rrs-rrl intergenic spacer alleles of B. burgdorferi were identified in infected ticks, including those associated with disseminated Lyme disease and alleles that are rare in the northeastern United States. Overall, 0.4% (95% CI = 0.03 to 0.41) of I. scapularis nymphs were PCR positive for Anaplasma phagocytophilum. We estimate that migratory birds disperse 50 million to 175 million I. scapularis ticks across Canada each spring, implicating migratory birds as possibly significant in I. scapularis range expansion in Canada. However, infrequent larvae and the low infection prevalence in ticks carried by the birds raise questions as to how B. burgdorferi and A. phagocytophilum become endemic in any tick populations established by bird-transported ticks.