BACKGROUND Sanitary quality of recreational waters worldwide is assessed using fecal indicator bacteria (FIB), such as Escherichia coli and enterococci. However, fate and transport characteristics of FIB in aquatic habitats can differ from those of viral pathogens which have been identified as main etiologic agents of recreational waterborne illness. Coliphages (bacteriophages infecting E. coli) are an attractive alternative to FIB because of their many morphological and structural similarities to viral pathogens. METHODS In this in situ field study, we used a submersible aquatic mesocosm to compare decay characteristics of somatic and F+ coliphages to those of infectious human adenovirus 2 in a freshwater lake. In addition, we also evaluated the effect of ambient sunlight (and associated UV irradiation) and indigenous protozoan communities on decay of somatic and F+ coliphage, as well as infectious adenovirus. RESULTS Our results show that decay of coliphages and adenovirus was similar (p = 0.0794), indicating that both of these bacteriophage groups are adequate surrogates for decay of human adenoviruses. Overall, after 8 days the greatest log10 reductions were observed when viruses were exposed to a combination of biotic and abiotic factors (2.92 ± 0.39, 4.48 ± 0.38, 3.40 ± 0.19 for somatic coliphages, F+ coliphages and adenovirus, respectively). Both, indigenous protozoa and ambient sunlight, were important contributors to decay of all three viruses, although the magnitude of that effect differed over time and across viral targets. CONCLUSIONS While all viruses studied decayed significantly faster (p < 0.0001) when exposed to ambient sunlight, somatic coliphages were particularly susceptible to sunlight irradiation suggesting a potentially different mechanism of UV damage compared to F+ coliphages and adenoviruses. Presence of indigenous protozoan communities was also a significant contributor (p value range: 0.0016 to < 0.0001) to decay of coliphages and adenovirus suggesting that this rarely studied biotic factor is an important driver of viral reductions in freshwater aquatic habitats.

中文翻译：

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淡水栖息地中传染性腺病毒和大肠杆菌噬菌体的衰变受到环境阳光和本地原生动物群落存在的不同影响。

背景技术世界范围内的娱乐用水的卫生质量是使用粪便指示细菌（FIB）（例如大肠杆菌和肠球菌）来评估的。然而，FIB 在水生生境中的命运和运输特征可能与病毒病原体不同，病毒病原体已被确定为娱乐性水传播疾病的主要病原体。大肠杆菌噬菌体（感染大肠杆菌的噬菌体）是 FIB 的有吸引力的替代品，因为它们在形态和结构上与病毒病原体有许多相似之处。方法 在这项原位实地研究中，我们使用潜水式水生中生态系统来比较淡水湖中体细胞和 F+ 大肠杆菌噬菌体与传染性人类腺病毒 2 型的腐烂特性。此外，我们还评估了环境阳光（以及相关的紫外线照射）和本土原生动物群落对体细胞和 F+ 大肠杆菌噬菌体以及传染性腺病毒腐烂的影响。结果我们的结果表明，大肠杆菌噬菌体和腺病毒的腐烂相似（p = 0.0794），表明这两个噬菌体组都是人类腺病毒腐烂的充分替代品。总体而言，8天后，当病毒暴露于生物和非生物因素的组合时，观察到最大的log10减少（体细胞大肠杆菌噬菌体、F+大肠杆菌噬菌体和腺病毒分别为2.92±0.39、4.48±0.38、3.40±0.19）。本土原生动物和环境阳光都是导致所有三种病毒衰变的重要因素，尽管这种影响的程度随着时间的推移和病毒目标的不同而有所不同。结论 虽然所有研究的病毒在暴露于环境阳光下时腐烂速度都显着加快 (p < 0.0001)，但体细胞大肠杆菌噬菌体特别容易受到阳光照射，这表明与 F+ 大肠杆菌噬菌体和腺病毒相比，紫外线损伤的机制可能不同。本土原生动物群落的存在也是大肠杆菌噬菌体和腺病毒腐烂的重要贡献者（p值范围：0.0016至<0.0001），这表明这种很少研究的生物因素是淡水水生生境中病毒减少的重要驱动因素。