This study examined the impact of sertraline, an antidepressant common in treated wastewater, on the host-parasite dynamics between parasitic freshwater mussel (Unio tumidus, Unionidae) larvae (glochidia) and their host fish (Squalius cephalus, Cyprinidae). Employing a full-factorial design, both fish and glochidia were subjected to sertraline at the combinations of 0 µg L−1 (control), 0.2 µg L−1 (environmentally relevant concentration), and 4 µg L−1 (elevated concentration, short-term exposure of the parasite). The results showed that long-term host exposure (involving intensive sertraline accumulation in the fish brain) marginally increased subsequent glochidia attachment success by 2 %, while parasite exposure at the same environmentally relevant concentrations had no detectable effect. There was also no effect of exposure of glochidia to 0.2 µg L−1 of sertraline on their viability and encapsulation success during the initial parasitic stage. However, a significant alteration in attachment behavior, marked by a 3.3 % increase in attachment success and changes in the glochidia spatial distribution on the host body, was noted after 24 h of glochidia exposure to 4 µg L−1 of sertraline. Importantly, this study provides the first evidence of sertraline transfer from exposed glochidia to nonexposed host fish, as indicated by elevated levels of sertraline (12.8 ng g−1) in the brain tissue of nonexposed hosts. These findings highlight the subtle yet significant effects of pharmaceutical pollutants on freshwater ecosystems but also underscore the importance of understanding the unexpected dynamics of such contamination to predict and address future ecological changes.

中文翻译：

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抗抑郁药舍曲林在肾球鱼相互作用中的不同影响，涉及药物从寄生虫到宿主的转移


本研究检查了舍曲林（一种处理过的废水中常见的抗抑郁药）对寄生淡水贻贝 （Unio tumidus， Unionidae） 幼虫 （glochidia） 与其寄主鱼 （Squalius cephalus， Cyprinidae） 之间寄主-寄生虫动态的影响。采用全因子设计，鱼和 glochidia 均以 0 μg L-1（对照）、0.2 μg L-1（环境相关浓度）和 4 μg L-1（高浓度，寄生虫短期暴露）的组合进行舍曲林处理。结果表明，长期宿主暴露（涉及鱼脑中强烈的舍曲林积累）略微增加了随后的 glochidia 附着成功率 2%，而相同环境相关浓度的寄生虫暴露没有可检测的影响。在初始寄生阶段，glochidia 暴露于 0.2 μg L-1 舍曲林对其活力和包封成功也没有影响。然而，在将 glochidia 暴露于 4 μg L-1 舍曲林 24 小时后，注意到附着行为的显着改变，其特征是附着成功率增加 3.3% 和 glochidia 空间分布的变化。重要的是，这项研究提供了舍曲林从暴露的 glochidia 转移到未暴露的宿主鱼的第一个证据，如未暴露宿主脑组织中舍曲林水平升高 （12.8 ng g-1） 所示。这些发现突出了药物污染物对淡水生态系统的微妙而重大的影响，但也强调了了解此类污染的意外动态以预测和应对未来生态变化的重要性。