Publications by authors named "Sunayana Raya"

Wastewater surveillance for pathogens is important to monitor disease trends within communities and maintain public health; thus, a quick and reliable protocol is needed to quantify pathogens present in wastewater. In this study, a method using a commercially available magnetic carbon bead-based kit, i.e.

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Wastewater-based epidemiology (WBE) is an effective, non-invasive method for monitoring the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by tracking viral prevalence in water. This study aimed to investigate the presence of SARS-CoV-2 in surface water in Vietnam over two years. One-step quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays were employed to quantify SARS-CoV-2 and its variant-specific mutation sites (G339D/E484A) and pepper mild mottle virus (PMMoV) from a total of 315 samples (105 samples per site) to compare with reported Coronavirus disease 2019 (COVID-19) cases and environmental factors.

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The target viral and bacterial concentrations in river water are essential for environmental monitoring and public health studies. Filtration-based methods are commonly employed, yet challenges arise due to recoverability and filter pore size. This study aimed to compare the performance of electronegative membrane filtration (EMF) and automated Concentrating Pipette (CP) Select (InnovaPrep) methods for quantifying antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and bacterial and viral markers in river water samples.

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Hepatitis A and E viruses (HAV and HEV, respectively) remain a significant global health concern despite advancements in healthcare and vaccination programs. Regular monitoring and vaccine efficacy of HAV are still lacking in different countries. This study aimed to investigate HAV and HEV prevalence in developed, developing, and least-developed Asian countries using wastewater as a surveillance tool.

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Wastewater-based epidemiology (WBE) is a critical tool for monitoring community health. Although much attention has focused on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a causative agent of coronavirus disease 2019 (COVID-19), other pathogens also pose significant health risks. This study quantified the presence of SARS-CoV-2, influenza A virus (Inf-A), and noroviruses of genogroups I (NoV-GI) and II (NoV-GII) in wastewater samples collected weekly (n = 170) from July 2023 to February 2024 from five wastewater treatment plants (WWTPs) in Yamanashi Prefecture, Japan, by quantitative PCR.

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No single microbial source tracking (MST) marker can be applied to determine the sources of fecal pollution in all water types. This study aimed to validate a high-throughput quantitative polymerase chain reaction (HT-qPCR) method for the simultaneous detection of multiple MST markers. A total of 26 fecal-source samples that had been previously collected from human sewage (n = 6) and ruminant (n = 3), dog (n = 6), pig (n = 6), chicken (n = 3), and duck (n = 2) feces in the Kathmandu Valley, Nepal, were used to validate 10 host-specific MST markers, i.

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Manila, a highly urbanized city, is listed as one of the top cities with the highest recorded number of coronavirus disease 2019 (COVID-19) cases in the Philippines. This study aimed to detect and quantify the RNA of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the Omicron variant in 51 wastewater samples collected from three locations in Manila, namely Estero de Santa Clara, Estero de Pandacan, which are open drainages, and a sewage treatment plant (STP) at De La Salle University-Manila, between July 2022 and February 2023. Using one-step reverse transcription-quantitative polymerase chain reaction, SARS-CoV-2 and Omicron variant RNA were detected in 78 % (40/51; 4.

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Despite being the major cause of death, clinical surveillance of respiratory viruses at the community level is very passive, especially in developing countries. This study focused on the surveillance of three respiratory viruses [severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza A virus (IFV-A), and respiratory syncytial virus (RSV)] in the Kathmandu Valley, Nepal, by implication of wastewater-based epidemiology (WBE). Fifty-one untreated wastewater samples were from two wastewater treatment plants (WWTPs) between April and October 2022.

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The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants is a major public health concern that has highlighted the need to monitor circulating strains to better understand the coronavirus disease 2019 (COVID-19) pandemic. This study was carried out to monitor SARS-CoV-2 RNA and its variant-specific mutations in wastewater using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). One-step RT-qPCR using the SARS-CoV-2 Detection RT-qPCR Kit for Wastewater (Takara Bio), which amplified two N-gene regions simultaneously using CDC N1 and N2 assays with a single fluorescence dye, demonstrated better performance in detecting SARS-CoV-2 RNA (positive ratio, 66 %) compared to two-step RT-qPCR using CDC N1 or N2 assay (40 % each, and 52 % when combined), with significantly lower Ct values.

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The role of wastewater-based epidemiology (WBE), a powerful tool to complement clinical surveillance, has increased as many grassroots-level facilities, such as municipalities and cities, are actively involved in wastewater monitoring, and the clinical testing of coronavirus disease 2019 (COVID-19) is downscaled widely. This study aimed to conduct long-term wastewater surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Yamanashi Prefecture, Japan, using one-step reverse transcription-quantitative polymerase chain reaction (RT-qPCR) assay and estimate COVID-19 cases using a cubic regression model that is simple to implement. Influent wastewater samples (n = 132) from a wastewater treatment plant were collected normally once weekly between September 2020 and January 2022 and twice weekly between February and August 2022.

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A rapid virus concentration method is needed to get high throughput. Reliable results of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) detection in wastewater are necessary for applications in wastewater-based epidemiology. In this study, an automated filtration method using a concentrating pipette (CP Select; Innovaprep) was applied to detect SARS-CoV-2 in wastewater samples with several modifications to increase its sensitivity and throughput.

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Escherichia coli has been used as an indicator of fecal pollution in environmental waters. However, its presence in environmental waters does not provide information on the source of water pollution. Identifying the source of water pollution is paramount to be able to effectively reduce contamination.

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Several virus concentration methods have been developed to increase the detection sensitivity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in wastewater, as part of applying wastewater-based epidemiology. Polyethylene glycol (PEG) precipitation method, a method widely used for concentrating viruses in wastewater, has some limitations, such as long processing time. In this study, Pegcision, a PEG-based method using magnetic nanoparticles (MNPs), was applied to detect SARS-CoV-2 in wastewater, with several modifications to increase its sensitivity and throughput.

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Background: In Nepal, it is estimated that about 3 million children under 5 years of age are prone to diarrhea and previous studies have shown rotavirus as the major etiological agent. Given the high burden of rotavirus, Rotarix® vaccine was introduced in the national immunization schedule in July 2020. This study was carried out in a tertiary health center from January- September 2018 to determine the burden of rotavirus diarrhea as well as genotypic variations in the circulating virus prior to vaccine introduction in Kathmandu, Nepal.

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Background: The emergence of multidrug-resistant (MDR) and extended-spectrum beta-lactamase (ESBL)-producing uropathogens has complicated the treatment of urinary tract infections (UTI). Paediatric UTI is a common illness, which if not treated properly, may lead to acute and long-term complications, such as renal abscess, septicaemia, and renal scarring. This study aimed to determine the prevalence of MDR and ESBL-producing uropathogens among children.

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Background: Diabetic patients are more susceptible to urinary tract infection compared to nondiabetic patients, being the most common uropathogen causing UTI. Unreasonable and incorrect antibiotic prescription for UTI in these patients may induce the development of antibiotic-resistant urinary pathogens resulting in delayed recovery and longer hospitalization. In addition to these, biofilm forming capacity of the pathogen may worsen the problem.

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Background: Rotavirus gastroenteritis is a major public health problem in Nepal. This study was conducted to obtain information associated with Rotavirus gastroenteritis and to perform genotyping of Rotavirus A.

Methods: Hospital based cross sectional study was conducted from January to December 2017 among children less than 5 years of age attending Kanti Children's Hospital and Tribhuvan University Teaching Hospital.

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