U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, United States of America.
U.S. Fish and Wildlife Service, Marine Mammals Management, Anchorage, Alaska, United States of America.
PLoS One. 2024 Oct 23;19(10):e0310973. doi: 10.1371/journal.pone.0310973. eCollection 2024.
Environmental changes associated with global warming create new opportunities for pathogen and parasite transmission in Arctic wildlife. As an apex predator ranging over large, remote areas, changes in pathogens and parasites in polar bears are a useful indicator of changing transmission dynamics in Arctic ecosystems. We examined prevalence and risk factors associated with exposure to parasites and viral and bacterial pathogens in Chukchi Sea polar bears. Serum antibodies to six pathogens were detected and prevalence increased between 1987-1994 and 2008-2017 for five: Toxoplasma gondii, Neospora caninum, Francisella tularensis, Brucella abortus/suis, and canine distemper virus. Although bears have increased summer land use, this behavior was not associated with increased exposure. Higher prevalence of F. tularensis, Coxiella burnetii, and B. abortus/suis antibodies in females compared to males, however, could be associated with terrestrial denning. Exposure was related to diet for several pathogens indicating increased exposure in the food web. Elevated white blood cell counts suggest a possible immune response to some pathogens. Given that polar bears face multiple stressors in association with climate change and are a subsistence food, further work is warranted to screen for signs of disease.
与全球变暖相关的环境变化为北极野生动物中的病原体和寄生虫传播创造了新的机会。作为一种在广阔、偏远地区活动的顶级掠食者，北极熊中病原体和寄生虫的变化是北极生态系统中传播动态变化的有用指标。我们研究了楚科奇海北极熊中寄生虫以及病毒和细菌病原体暴露的流行率和相关风险因素。检测到针对六种病原体的血清抗体，其中五种的流行率在 1987-1994 年和 2008-2017 年之间有所增加：刚地弓形虫、新孢子虫、土拉弗朗西斯菌、流产布鲁氏菌/猪布鲁氏菌和犬瘟热病毒。尽管北极熊增加了夏季的陆地利用，但这种行为与暴露增加无关。然而，与雄性相比，雌性中土拉弗朗西斯菌、考克斯氏体和流产布鲁氏菌/猪布鲁氏菌抗体的更高流行率可能与陆地巢穴有关。暴露与几种病原体的饮食有关，表明食物网中的暴露增加。白细胞计数升高表明可能对某些病原体产生了免疫反应。鉴于北极熊在气候变化的背景下面临多种压力，并且是一种维持生计的食物，因此需要进一步开展工作来筛查疾病迹象。
