Presence of Human Enteric Viruses, Protozoa, and Indicators of Pathogens in the Bagmati River, Nepal

Tandukar, Sarmila; Sherchand, Jeevan Bahadur; Bhandari, Dinesh; Sherchan, Samendra P.; Malla, Bikash; Shrestha, Rajani Ghaju; Haramoto, Eiji

doi:10.3390/pathogens7020038

Cited by 39 publications

(56 citation statements)

References 52 publications

(67 reference statements)

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“…A study that was conducted in three sites of the Bagmati River (Sundarijal (upstream), Thapathali (midstream), and Chovar (downstream)) reported that the microbiological quality of the river water upstream was less degraded when compared to those at the other two sites [9]. Indicator bacteria, potential index viruses, and human-fecal markers were more frequently detected than protozoa and human enteric viruses at all three Bagmati River sites.…”

Section: Introductionmentioning

confidence: 90%

“…As previously described [9], the Bagmati River water samples were collected every two months from the upstream, midstream, and downstream regions during a one-year period between November 2015 and September 2016, as shown in Figure 1. The sampling sites were selected based on population density in three regions of the Bagmati River basin, where the population density is lower in the upstream region when compared to the midstream and downstream regions, and also to observe the difference in bacterial community in start and end point of the Bagmati River flowing through the urban area of the Kathmandu Valley.…”

Section: Collection Of River Water Samples and Extraction Of Bacteriamentioning

confidence: 99%

“…Industrial pollution load, poor sewage and wastewater treatment facilities, inadequate water pollution control laws, and rapid urbanization have all contributed to the increased degradation of the river water environment in developing countries [1,2]. The Bagmati River, which flows from the northern boundary southwards across the urban areas of the Kathmandu Valley in Nepal, is suffering from chemical, biological, and solid waste pollution [1,[3][4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

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Prevalence of Arcobacter and Other Pathogenic Bacteria in River Water in Nepal

Shrestha

Tandukar

Bhandari

et al. 2019

Water

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This study aims to determine the diversity of pathogenic bacteria in the Bagmati River, Nepal, during a one-year period. A total of 18 river water samples were collected from three sites (n = 6 per site) along the river. Bacterial DNA, which were extracted from the water samples, were analyzed for bacterial 16S rRNA genes by next-generation sequencing for 13 of 18 samples, and by quantitative PCR targeting Arcobacter for all 18 samples. The 16S rRNA sequencing identified an average of 97,412 ± 35,909 sequences/sample, which were then categorized into 28 phyla, 61 classes, and 709 bacterial genera. Eighteen (16%) genera of 111 potential pathogenic bacteria were detected with abundance ratios of >1%; Arcobacter, Acinetobacter, and Prevotella were the dominant genera. The Arcobacter abundance ratios were 28.6% (n = 1), 31.3 ± 15.8% (n = 6), and 31.8 ± 17.2% (n = 6) at the upstream, midstream, and downstream sites, respectively. Arcobacter was detected in 14 (78%) of 18 samples tested, with concentrations ranging from 6.7 to 10.7 log10 copies/100 mL, based on quantitative PCR. Our results demonstrate the poor bacterial quality of the Bagmati River water, suggesting a need for implementing more measures to reduce fecal contamination in the river water.

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Section: Introductionmentioning

confidence: 90%

Section: Collection Of River Water Samples and Extraction Of Bacteriamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Prevalence of Arcobacter and Other Pathogenic Bacteria in River Water in Nepal

Shrestha

Tandukar

Bhandari

et al. 2019

Water

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“…74,76 Notably, HCoSV was recently detected using qPCR at relatively higher concentrations than observed in other environmental waters in the Bagmati River, Nepal, highlighting the importance of geographic variability in marker evaluation. 77 HCoSV may be a causative agent of waterborne viral disease; however, its variable specificity to wastewater (25-71%) across studies and presence in animal sources (pig) may limit its application for viral water quality monitoring. Notably, the recent detection of elevated HCoSV concentrations in environmental waters in Nepal points to a greater potential for application in specific geographic regions.…”

Section: Cosavirusmentioning

confidence: 99%

Metagenomics and the development of viral water quality tools

et al. 2019

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Human exposure to pathogenic viruses in environmental waters results in a significant global disease burden. Current microbial water quality monitoring approaches, mainly based on fecal indicator bacteria, insufficiently capture human health impacts posed by pathogenic viruses in water. The emergence of the 'microbiome era' and high-throughput metagenome sequencing has led to the discovery of novel human-associated viruses, including both pathogenic and commensal viruses in the human microbiome. The discovery of novel human-associated viruses is often followed by their detection in wastewater, highlighting the great diversity of human-associated viruses potentially present in the water environment. Novel human-associated viruses provide a rich reservoir to develop viral water quality management tools with diverse applications, such as regulating wastewater reuse and monitoring agricultural and recreational waters. Here, we review the pathway from viral discovery to water quality monitoring tool, and highlight select human-associated viruses identified by metagenomics and subsequently detected in the water environment (namely Bocavirus, Cosavirus, CrAssphage, Klassevirus, and Pepper Mild Mottle Virus). We also discuss research needs to enable the application of recently discovered human-associated viruses in water quality monitoring, including investigating the geographic distribution, environmental fate, and viability of potential indicator viruses. Examples suggest that recently discovered human pathogens are likely to be less abundant in sewage, while other human-associated viruses (e.g., bacteriophages or viruses from food) are more abundant but less human-specific. The improved resolution of human-associated viral diversity enabled by metagenomic tools provides a significant opportunity for improved viral water quality management tools.

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“…Studies showed that PMMoV and tobacco mosaic virus (TMV) are the most abundant and frequently detected viruses in sewage [15][16][17] . They are distributed globally and more abundant in environmental samples than human entric viruses, without any pronounced seasonal variation 18,19 . It may thus be beneficial to use PMMoV to evaluate the performance of drinking water and wastewater treatment processes 15,20 , although no studies have been conducted to date to evaluate the efficiency of reduction of TMV during wastewater treatment.…”

mentioning

confidence: 99%

Applicability of crAssphage, pepper mild mottle virus, and tobacco mosaic virus as indicators of reduction of enteric viruses during wastewater treatment

Tandukar

Sherchan

Haramoto

2020

Sci Rep

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this study was conducted to evaluate the applicability of crAssphage, pepper mild mottle virus (pMMoV), and tobacco mosaic virus (tMV) as indicators of the reduction of human enteric viruses during wastewater treatment. thirty-nine samples were collected from three steps at a wastewater treatment plant (raw sewage, secondary-treated sewage, and final effluent) monthly for a 13-month period. in addition to the three indicator viruses, eight human enteric viruses [human adenoviruses, Jc and BK polyomaviruses, Aichi virus 1 (AiV-1), enteroviruses, and noroviruses of genogroups I, II, and IV] were tested by quantitative pcR. indicator viruses were consistently detected in the tested samples, except for a few final effluents for crAssphage and TMV. The mean concentrations of crAssphage were significantly higher than those of most tested viruses. The concentrations of crAssphage in raw sewage were positively correlated with the concentrations of all tested human enteric viruses (p <0.05), suggesting the applicability of crAssphage as a suitable indicator to estimate the concentrations of human enteric viruses in raw sewage. The reduction ratios of AiV-1 (1.8 ± 0.7 log 10) were the lowest among the tested viruses, followed by TMV (2.0 ± 0.3 log 10) and PMMoV (2.0 ± 0.4 log 10). Our findings suggested that the use of not only AiV-1 and PMMoV but also TMV as indicators of reductions in viral levels can be applicable during wastewater treatment. Wastewater treatment plants (WWTPs) are currently facing numerous issues regarding insufficient treatment of human enteric viruses during the treatment process 1. Although a number of treatment procedures to remove physical, chemical, and microbiological waste from sewage are performed, these processess still need to be improved to reduce the viral content of water 2. The advanced multiple-barrier concept has been proposed for wastewater reclamation and reuse; however, it is insufficient to achieve complete reduction of human enteric viruses 3,4. In fact, advanced wastewater treatment has been developed to achieve reduction of viruses by facilitating chemical clarification, ultrafiltration, reverse osmosis, and advanced oxidation at different levels of regulatory control 5. However, despite implementing these modifications, the efficiency with which treatment can reduce viral levels in wastewater is still unsatisfactory. Moreover, no authorized regulatory standard for the reduction of viruses in wastewater treatment has yet been established 6. Human enteric viruses are the leading cause of waterborne illnesses and usually transmitted via the fecal-oral route 5-7. Infected individuals discharge millions of viral particles that ultimately enter sewage systems 7. In this context, it is important to study the efficiency of virus reduction at WWTPs to ascertain whether all viruses are removed from effluent samples or not. Fecal indicator bacteria, such as total coliforms and Escherichia coli, are not reliable indicators of the presence and removal of human enteric viruses during wastewa...

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Presence of Human Enteric Viruses, Protozoa, and Indicators of Pathogens in the Bagmati River, Nepal

Cited by 39 publications

References 52 publications

Prevalence of Arcobacter and Other Pathogenic Bacteria in River Water in Nepal

Prevalence of Arcobacter and Other Pathogenic Bacteria in River Water in Nepal

Metagenomics and the development of viral water quality tools

Applicability of crAssphage, pepper mild mottle virus, and tobacco mosaic virus as indicators of reduction of enteric viruses during wastewater treatment

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