Akima Systems Engineering, Herndon, VA, USA.
Contractor to U.S. Geological Survey Eastern Ecological Science Center, Laurel, MD, USA.
Proc Biol Sci. 2022 Sep 14;289(1982):20221312. doi: 10.1098/rspb.2022.1312. Epub 2022 Sep 7.
Environmental contamination is widespread and can negatively impact wildlife health. Some contaminants, including heavy metals, have immunosuppressive effects, but prior studies have rarely measured contamination and disease simultaneously, which limits our understanding of how contaminants and pathogens interact to influence wildlife health. Here, we measured mercury concentrations, influenza infection, influenza antibodies and body condition in 749 individuals from 11 species of wild ducks overwintering in California. We found that the odds of prior influenza infection increased more than fivefold across the observed range of blood mercury concentrations, while accounting for species, age, sex and date. Influenza infection prevalence was also higher in species with higher average mercury concentrations. We detected no relationship between influenza infection and body fat content. This positive relationship between influenza prevalence and mercury concentrations in migratory waterfowl suggests that immunotoxic effects of mercury contamination could promote the spread of avian influenza along migratory flyways, especially if influenza has minimal effects on bird health and mobility. More generally, these results show that the effects of environmental contamination could extend beyond the geographical area of contamination itself by altering the prevalence of infectious diseases in highly mobile hosts.
环境污染广泛存在，并可能对野生动物的健康产生负面影响。一些污染物，包括重金属，具有免疫抑制作用，但先前的研究很少同时测量污染和疾病，这限制了我们对污染物和病原体如何相互作用影响野生动物健康的理解。在这里，我们测量了加利福尼亚州越冬的 11 种野鸭子 749 只个体的汞浓度、流感感染、流感抗体和身体状况。我们发现，在观察到的血液汞浓度范围内，流感感染的几率增加了五倍以上，同时考虑了物种、年龄、性别和日期。平均汞浓度较高的物种中，流感感染的流行率也更高。我们没有发现流感感染与体脂含量之间的关系。在候鸟中，流感流行率与汞浓度之间的这种正相关关系表明，汞污染的免疫毒性作用可能会促进禽流感沿迁徙飞行路线的传播，特别是如果流感对鸟类的健康和活动性影响很小的话。更一般地说，这些结果表明，通过改变高度移动宿主传染病的流行率，环境污染的影响可能会超出污染本身的地理区域。
