Martins David Tavares, Alegria Oscar Victor Cardenas, Dantas Carlos Willian Dias, De Los Santos Edian Franklin Franco, Pontes Paulo Rógenes Monteiro, Cavalcante Rosane Barbosa Lopes, Ramos Rommel Thiago Jucá
Laboratory of Bioinformatics and Genomics of Microorganisms, Federal University of Pará-UFPA, Belém, Pará, Brazil.
Institute of Biological Sciences, Federal University of Pará-UFPA, Belem, Pará, Brazil.
Appl Environ Microbiol. 2025 May 21;91(5):e0147024. doi: 10.1128/aem.01470-24. Epub 2025 Apr 25.
Viruses are the most abundant biological entities in all ecosystems of the world. Their ubiquity makes them suitable candidates for indicating fecal contamination in rivers. Recently, a group of Bacteroidetes bacteriophages named CrAssphages, which are highly abundant, sensitive, and specific to human feces, were studied as potential viral biomarkers for human fecal pollution in water bodies. In this study, we evaluated the presence, diversity, and abundance of viruses with a focus on crAssphages via metagenomic analysis in an Amazonian river and conducted correlation analyses on the basis of physicochemical and georeferencing data. Several significant differences in viral alpha diversity indexes were observed among the sample points, suggesting an accumulation of viral organisms in the river mouth, whereas beta diversity analysis revealed a significant divergence between replicates of the most downstream point (IT4) when compared to the rest of the samples, possibly due to increased human impact at this point. In terms of the presence of crAssphage, the analysis identified 61 crAssphage contigs distributed along the Itacaiúnas River. Moreover, our analysis revealed significant correlations between 19 crAssphage contigs and human population density, substantiating the use of these viruses as possible markers for human fecal pollution in the Itacaiúnas River. This study is the first to assess the presence of crAssphages in an Amazonian river, with results suggesting the potential use of these viruses as markers for human fecal pollution in the Amazon.
The Amazon biome is one of the most diverse ecosystems in the world and contains the most vast river network; however, the continuous advance of urban centers toward aquatic bodies exacerbates the discharge of pollutants into these water bodies. Fecal contamination contributes significantly to water pollution, and the application of an improved fecal indicator is essential for evaluating water quality. In this study, we evaluated the presence, diversity, and abundance of crAssphages in an Amazonian river and performed correlation analysis on the basis of physicochemical and georeferencing data to test whether crAssphages are viable fecal pollution markers. Our analysis revealed both the presence of crAssphages and their correlation with physicochemical data and showed significant correlations between the relative abundance of crAssphages and human density. These results suggest the potential use of these viruses as markers for water quality assessment in Amazonian rivers.
病毒是世界上所有生态系统中数量最多的生物实体。它们的无处不在使其成为指示河流粪便污染的合适候选者。最近，一组名为CrAssphages的拟杆菌噬菌体被研究作为水体中人类粪便污染的潜在病毒生物标志物，它们在人类粪便中含量极高、敏感且具有特异性。在本研究中，我们通过宏基因组分析评估了亚马逊河病毒的存在、多样性和丰度，重点关注CrAssphages，并基于理化和地理参考数据进行了相关性分析。在各采样点观察到病毒α多样性指数存在若干显著差异，表明河口处病毒生物量有所积累，而β多样性分析显示，与其他样本相比，最下游点（IT4）的重复样本之间存在显著差异，这可能是由于该点受到的人类影响增加所致。就CrAssphage的存在而言，分析确定了沿伊塔卡尤纳斯河分布的61个CrAssphage重叠群。此外，我们的分析揭示了19个CrAssphage重叠群与人口密度之间存在显著相关性，证实了这些病毒可作为伊塔卡尤纳斯河人类粪便污染的可能标志物。本研究首次评估了亚马逊河中的CrAssphages的存在情况，结果表明这些病毒有可能作为亚马逊河人类粪便污染的标志物。
亚马逊生物群落是世界上最多样化的生态系统之一，拥有最庞大的河网；然而，城市中心不断向水体推进加剧了污染物向这些水体的排放。粪便污染对水污染有重大影响，应用改进的粪便指标对于评估水质至关重要。在本研究中，我们评估了亚马逊河中CrAssphages的存在、多样性和丰度，并基于理化和地理参考数据进行了相关性分析，以测试CrAssphages是否是可行的粪便污染标志物。我们的分析揭示了CrAssphages的存在及其与理化数据的相关性，并显示CrAssphages的相对丰度与人类密度之间存在显著相关性。这些结果表明这些病毒有可能作为亚马逊河水质评估的标志物。
