Abstract

Mercury (Hg) is a ubiquitous environmental contaminant known to bioaccumulate in biota and biomagnify in food webs. Parasites occur in nearly every ecosystem and often interact in complex ways with other stressors that their hosts experience. Hepatozoon spp. are intraerythrocytic parasites common in snakes. The Florida green watersnake (Nerodia floridana) and the banded watersnake (Nerodia fasciata) occur syntopically in certain aquatic habitats in the Southeastern United States. The purpose of this study was to investigate relationships among total mercury (THg) concentrations, body size, species, habitat type and prevalence and parasitemia of Hepatozoon spp. infections in snakes. In the present study, we sampled N. floridana and N. fasciata from former nuclear cooling reservoirs and isolated wetlands of the Savannah River Site in South Carolina. We used snake tail clips to quantify THg and collected blood samples for hemoparasite counts. Our results indicate a significant, positive relationship between THg and snake body size in N. floridana and N. fasciata in both habitats. Average THg was significantly higher for N. fasciata compared to N. floridana in bays (0.22 ± 0.02 and 0.08 ± 0.006 mg/kg, respectively; p < 0.01), but not in reservoirs (0.17 ± 0.02 and 0.17 ± 0.03 mg/kg, respectively; p = 0.29). Sex did not appear to be related to THg concentration or Hepatozoon spp. infections in either species. We found no association between Hg and Hepatozoon spp. prevalence or parasitemia; however, our results suggest that species and habitat type play a role in susceptibility to Hepatozoon spp. infection.

中文翻译：

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汞的生物累积和肝虫属。南卡罗来纳州两条同位水蛇感染

摘要

汞 (Hg) 是一种普遍存在的环境污染物，已知会在生物群中生物富集并在食物网中生物放大。寄生虫几乎存在于每个生态系统中，并且经常以复杂的方式与其宿主经历的其他压力源相互作用。肝虫属是蛇中常见的红细胞内寄生虫。佛罗里达绿水蛇（Nerodia floriidana）和带状水蛇（Nerodia fasciata）普遍出现在美国东南部的某些水生栖息地。本研究的目的是调查肝虫属总汞 (THg) 浓度、体型、物种、栖息地类型以及患病率和寄生虫血症之间的关系。蛇的感染。在本研究中，我们从南卡罗来纳州萨凡纳河遗址的前核冷却水库和孤立的湿地中采集了佛罗里达猪笼草和带状猪笼草的样本。我们使用蛇尾夹来量化 THg 并收集血液样本进行血寄生虫计数。我们的结果表明，两个栖息地的佛罗里达猪笼草和带带猪笼草的 THg 和蛇体大小之间存在显着的正相关关系。与佛罗里达猪笼草相比，海湾中带状猪笼草的平均 THg 显着较高（分别为 0.22 ± 0.02 和 0.08 ± 0.006 mg/kg；p  < 0.01），但水库中的平均值则不然（0.17 ± 0.02 和 0.17 ± 0.03 mg/kg）分别；p  = 0.29）。性别似乎与 THg 浓度或肝原虫属无关。任一物种的感染。我们发现汞和肝虫属之间没有关联。流行或寄生虫血症；然而，我们的结果表明物种和栖息地类型在肝虫属的易感性中发挥作用。感染。