Ramey Andrew M, Schmutz Joel A, Reed John A, Fujita Go, Scotton Bradley D, Casler Bruce, Fleskes Joseph P, Konishi Kan, Uchida Kiyoshi, Yabsley Michael J
US Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, Alaska 99508, USA ; Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, The University of Georgia, 589 D. W. Brooks Drive, Athens, Georgia 30602, USA.
US Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, Alaska 99508, USA.
Int J Parasitol Parasites Wildl. 2014 Dec 30;4(1):11-21. doi: 10.1016/j.ijppaw.2014.12.004. eCollection 2015 Apr.
Empirical evidence supports wild birds as playing a role in the interhemispheric exchange of bacteria and viruses; however, data supporting the redistribution of parasites among continents are limited. In this study, the hypothesis that migratory birds contribute to the redistribution of parasites between continents was tested by sampling northern pintails (Anas acuta) at locations throughout the North Pacific Basin in North America and East Asia for haemosporidian infections and assessing the genetic evidence for parasite exchange. Of 878 samples collected from birds in Alaska (USA), California (USA), and Hokkaido (Japan) during August 2011-May 2012 and screened for parasitic infections using molecular techniques, Leucocytozoon, Haemoproteus, and Plasmodium parasites were detected in 555 (63%), 44 (5%), and 52 (6%) samples, respectively. Using an occupancy modeling approach, the probability of detecting parasites via replicate genetic tests was estimated to be high (ρ > 0.95). Multi-model inference supported variation of Leucocytozoon parasite prevalence by northern pintail age class and geographic location of sampling in contrast to Haemoproteus and Plasmodium parasites for which there was only support for variation in parasite prevalence by sampling location. Thirty-one unique mitochondrial DNA haplotypes were detected among haematozoa infecting northern pintails including seven lineages shared between samples from North America and Japan. The finding of identical parasite haplotypes at widely distributed geographic locations and general lack of genetic structuring by continent in phylogenies for Leucocytozoon and Plasmodium provides evidence for intercontinental genetic exchange of haemosporidian parasites. Results suggest that migratory birds, including waterfowl, could therefore facilitate the introduction of avian malaria and other haemosporidia to novel hosts and spatially distant regions.
实证证据支持野生鸟类在细菌和病毒的半球间传播中发挥作用；然而，支持寄生虫在各大洲重新分布的数据有限。在本研究中，通过对北美和东亚北太平洋盆地各地的针尾鸭（Anas acuta）进行采样以检测血孢子虫感染，并评估寄生虫交换的遗传证据，来检验候鸟促成寄生虫在各大洲之间重新分布这一假设。在2011年8月至2012年5月期间，从美国阿拉斯加、美国加利福尼亚和日本北海道的鸟类中采集了878份样本，并使用分子技术筛查寄生虫感染，分别在555份（63%）、44份（5%）和52份（6%）样本中检测到了白细胞原虫、血变原虫和疟原虫寄生虫。使用占有率建模方法，通过重复基因检测检测到寄生虫的概率估计很高（ρ > 0.95）。多模型推断支持白细胞原虫寄生虫患病率因针尾鸭年龄组和采样地理位置而异，与之形成对比的是血变原虫和疟原虫寄生虫，仅支持患病率因采样位置而异。在感染针尾鸭的血孢子虫中检测到31种独特的线粒体DNA单倍型，其中包括北美和日本样本之间共有的7个谱系。在广泛分布的地理位置发现相同的寄生虫单倍型，以及白细胞原虫和疟原虫系统发育中普遍缺乏按大陆划分的遗传结构，为血孢子虫寄生虫的洲际遗传交换提供了证据。结果表明，包括水禽在内的候鸟可能因此促进禽疟疾和其他血孢子虫传播到新宿主和空间遥远的地区。
