Vestbo Stine, Hindberg Claus, Forbes Mark R, Mallory Mark L, Merkel Flemming, Steenweg Rolanda J, Funch Peter, Gilchrist H Grant, Robertson Gregory J, Provencher Jennifer F
Department of Bioscience, Aarhus University, Aarhus C, Denmark.
Department of Biology, Carleton University, Ottawa, Ontario, Canada.
Int J Parasitol Parasites Wildl. 2019 May 17;9:184-194. doi: 10.1016/j.ijppaw.2019.05.004. eCollection 2019 Aug.
In birds, parasites cause detrimental effects to the individual host, including reduced survival and reproductive output. The level of parasitic infection can vary with a range of factors, including migratory status, body size, sex, and age of hosts, or season. Understanding this baseline variation is important in order to identify the effects of external changes such as climate change on the parasitic load and potential impacts to individuals and populations. In this study, we compared the infection level (prevalence, intensity, and abundance) of gastrointestinal parasites in a total of 457 common eiders () from four different sampling locations (Belcher Islands, Cape Dorset, West Greenland and Newfoundland), and explored the effects of migration, sex and age on levels of parasitism. Across all samples, eiders were infected with one nematode genus, two acanthocephalan genera, three genera of cestodes, and three trematode genera. Migratory phase and status alone did not explain the observed variation in infection levels; the expectation that post-migratory eiders would be more parasitized than pre-migratory eiders, due to the energetic cost of migration, did not fit our results. No effect of age was detected, whereas effects of sex and body size were only detected for certain parasitic taxa and was inconsistent with location. Since gastrointestinal helminths are trophically-transmitted, future studies of the regional and temporal variation in the diet of eiders and the associated variation and infestation level of intermediate hosts might further explain the observed variation of the parasitic load in eiders in different regions.
在鸟类中，寄生虫会对个体宿主造成有害影响，包括降低存活率和繁殖产出。寄生虫感染水平会因一系列因素而有所不同，这些因素包括宿主的迁徙状态、体型、性别、年龄或季节。了解这种基线变化对于识别气候变化等外部变化对寄生虫负荷的影响以及对个体和种群的潜在影响至关重要。在本研究中，我们比较了来自四个不同采样地点（贝尔彻群岛、多塞特角、西格陵兰和纽芬兰）的总共457只普通绒鸭（）的胃肠道寄生虫感染水平（患病率、感染强度和丰度），并探讨了迁徙、性别和年龄对寄生虫感染水平的影响。在所有样本中，绒鸭感染了一个线虫属、两个棘头虫属、三个绦虫属和三个吸虫属。仅迁徙阶段和状态并不能解释观察到的感染水平差异；由于迁徙的能量消耗，预计迁徙后的绒鸭比迁徙前的绒鸭更容易感染寄生虫，但这与我们的结果不符。未检测到年龄的影响，而性别和体型的影响仅在某些寄生虫类群中检测到，并且与地点不一致。由于胃肠道蠕虫是通过营养方式传播的，未来对绒鸭饮食的区域和时间变化以及中间宿主的相关变化和感染水平的研究可能会进一步解释在不同地区观察到的绒鸭寄生虫负荷变化。
