Ebers Smith Jessica H, Cristol Daniel A, Swaddle John P
Department of Biology, College of William and Mary, Institute for Integrative Bird Behavior Studies, Williamsburg, VA, 23187, USA.
Bull Environ Contam Toxicol. 2018 Jan;100(1):89-94. doi: 10.1007/s00128-017-2246-8. Epub 2017 Dec 13.
Mercury is a globally distributed, persistent environmental contaminant that affects the health of many taxa. It can suppress the immune system, which often plays a role in defense against parasites. However, there have been few investigations of whether mercury affects the abilities of animals to resist parasitic infection. Here, we exposed zebra finches to a lifetime dietary exposure of methylmercury (1.2 μg/g wet weight) and experimentally infected them with coccidian parasites to examine the effect of methylmercury exposure on parasitic infection. The mercury-exposed birds did not have an altered immune response (heterophil:lymphocyte ratio) nor a reduced ability to clear the infection. However, mercury-exposed birds tended to have higher parasite loads at the time when we expected the greatest immune response (2-3 weeks post-infection). Although mercury did not greatly influence the infection-course of this parasite in captivity, responses may be more accentuated in the wild where birds face additional immune challenges.
汞是一种全球分布的持久性环境污染物，会影响许多生物分类群的健康。它会抑制免疫系统，而免疫系统通常在抵御寄生虫方面发挥作用。然而，关于汞是否会影响动物抵抗寄生虫感染的能力，此前鲜有研究。在此，我们让斑胸草雀终生通过饮食接触甲基汞（湿重1.2微克/克），并通过实验用球虫寄生虫感染它们，以研究甲基汞暴露对寄生虫感染的影响。接触汞的鸟类免疫反应（嗜异性白细胞：淋巴细胞比例）并未改变，清除感染的能力也未降低。然而，在我们预期会出现最强免疫反应时（感染后2至3周），接触汞的鸟类体内的寄生虫负荷往往更高。虽然在圈养环境中汞对这种寄生虫的感染过程影响不大，但在野外，鸟类面临额外的免疫挑战，反应可能会更加明显。
