Food and Environmental Virology最新文献

The atypical arrival of Sargassum spp. along the Mexican Caribbean coast has raised environmental and public health concerns. This study assessed the occurrence of enteric viruses—Human adenovirus (HAdV), Norovirus genogroups I and II (NoV GI, GII), Aichi virus (AiV)—and the viral indicator Pepper mild mottle virus (PMMoV) in seawater during Sargassum tides (2020–2021) and in Sargassum-free conditions (2022). Seawater samples (15 L) were collected seasonally and processed using ultrafiltration and adsorption-elution methods, followed by nucleic acid extraction and quantification via qPCR/RT-qPCR. Enterococci were detected in all samples collected during Sargassum tides, where 87% (7/8) of the samples met recreational water quality standards (< 200 MPN/100 mL). NoV GI and GII were detected in all Sargassum-associated samples (10²–10³ and 10¹–10³ genome copies/L, respectively), while HAdV and AiV were found in 50% of samples (10¹–10² GC/L). In contrast, in Sargassum-free seawater, HAdV and NoV GII were detected in 66% of the samples (10² to 10⁴ GC/L, respectively), NoV GI was detected only in 33% of the samples (10² GC/L), and AiV was not detected. PMMoV was consistently present, with higher concentrations during Sargassum tides (10²–10⁴GC/L) compared to Sargassum-free periods (up to 10² GC/L). A significant difference was observed in the viral concentration profile detected in Sargassum tides compared to Sargassum-free seawater. These findings suggest that Sargassum tides may influence the occurrence and concentration of fecal-associated viruses in coastal waters. The detection of enteric virus genomes in recreational seawater highlights potential public health risks and underscores the need for integrated coastal monitoring strategies in regions affected by macroalgal influxes.

Wastewater-based epidemiology (WBE) represents a valuable tool for assessing viral circulation at the community level. Human bocavirus (HBoV), a member of the Parvoviridae family with four genotypes (HBoV1–4), has been detected in respiratory and enteric samples, although its environmental epidemiology remains poorly characterized. This study aimed to investigate the presence and diversity of HBoV in wastewater samples from Córdoba, Argentina, during 2020–2021. A total of 84 raw sewage samples collected at the city’s wastewater treatment plant were analyzed by nested PCR and sequencing of the VP1/VP2 and NP1 regions. HBoV DNA was detected in 44% of samples, with higher circulation in 2020 (69.7%) compared to 2021 (27.4%), and a seasonal trend peaking in winter and spring. Phylogenetic analyses revealed 15 sequences clustering with HBoV2 and 11 with HBoV3, while three HBoV1-positive samples were confirmed by NP1 sequencing. To our knowledge, this is the first report of HBoV detection in environmental samples from Argentina, documenting the co-circulation of three genotypes (HBoV1–3) in a single urban setting. These findings underscore the usefulness of WBE for monitoring bocavirus diversity and circulation in the community.

Enteroviruses (EVs), including those linked with hand, foot, and mouth disease (HFMD), are commonly transmitted via the fecal-oral route. Considering the underreporting of HFMD-associated EVs and Nepal’s significant burden of enteric disease, wastewater surveillance presents a vital tool for monitoring community-level viral transmission. Through this study, we intended to detect EVs, including EVA serotypes that are often associated with HFMD, in wastewater to support public health surveillance. Raw influent wastewater samples (n = 25) collected previously during April–October 2022 from a wastewater treatment plant in Kathmandu, Nepal, were tested for the presence of EVs and four serotypes of EV type A (EVA), namely EVA71, Coxsackievirus A types 6 (CVA6), 10 (CVA10), and 16 (CVA16), by reverse transcription-quantitative polymerase chain reaction. In all samples, EVs were detected with concentrations of 7.4 ± 0.4 log₁₀ copies/L. In addition, EVA71 was detected in 64% (16/25) of the samples, with concentrations of 5.3 ± 0.5 log₁₀ copies/L, suggesting frequent detection with more prominent peaks around the pre-monsoon (75%, April and May) and monsoon seasons (71%, June–September). CVA6, CVA10, and CVA16 were not detected in any of the tested samples. The present findings demonstrated the high prevalence of EVs in wastewater in Kathmandu. This study is the first to indicate the presence of EVA71 in the wastewater of Nepal. The co-detection of EVs and EVA71, along with respiratory viruses (severe acute respiratory syndrome coronavirus 2, influenza A virus, and respiratory syncytial virus) and hepatitis virus, detected in our previous studies, was also explored in the present study. Except for respiratory syncytial virus, all tested viruses were more frequently co-detected in 36% (9/25) of the samples, especially during the monsoon (43%, 6/14) and pre-monsoon (38%, 3/8) seasons. The co-detection of multiple viruses underscores the necessity for integrated viral surveillance and calls for further investigation into the clinical implications of co-infections.

This study assessed the presence and concentration of crAssphage, pepper mild mottle virus (PMMoV) and human mastadenovirus (HAdV) as potential indicators of human fecal contamination in different aquatic matrices. A total of 75 stream and seawater samples were collected between 2020 and 2021 across four watersheds displaying varying urbanization degrees in Brazil. Viral particles were concentrated employing the adsorption-elution method followed by ultrafiltration and quantified by qPCR/RT-qPCR. The findings indicate that crAssphage was the most frequently detected (65.33%), followed by PMMoV (45.33%) and HAdV (44.00%). CrAssphage also exhibited the highest viral loads in stream water (median of 6.49 log₁₀ GC L⁻¹), reflecting a strong association with domestic sewage. Comparatively, PMMoV showed similar detection rates in both matrices, whereas HAdV exhibited higher detection rates in stream water. Higher crAssphage and PMMoV concentrations were observed in watersheds located in higher population density areas when compared to lower density areas. No viruses were detected upstream of the urbanized regions, confirming the specificity of the selected viral indicators. In this sense, crAssphage and HAdV are more suitable for monitoring stream water bodies affected by human activities, while PMMoV is suited for both matrices. The findings suggest that the three viruses emerged as promising indicators for tracking human fecal contamination in aquatic matrices with different characteristics.

The presence of multiple viral genotypes of rotavirus A (RAV) and norovirus (NV) circulating among human population and environment is of particular concern to global public health. Hence, the viral prevalence and genetic diversity presented in influent wastewater from Bangkok wastewater treatment plants (WWTPs) was investigated. A total of 89 influent wastewater samples were collected by composite sampling from 10 Bangkok WWTPs between January and May 2023. The wastewater samples were concentrated and extracted for the total nucleic acid. Purified total viral RNA was subjected for cDNA synthesis, conventional PCR for detecting RAV, NV GI and GII, and DNA sequencing. The detection rate of RAV, NV GI and GII was 13.5% (12/89), 94.4% (84/89) and 89.9% (80/89), respectively. Co-detection was observed accounting 74.2% (66/89) and 13.5% (12/89) for NV GI + GII and NV GI + GII + RAV, respectively. A total of 76 viral sequences including 11 RAV, 33 NV GI, and 32 NV GII, were obtained and phylogenetically analyzed for viral genotyping. All RAV belonged to genotype G3 (100.0%). The 33 NV GI were identified in four distinct genotypes comprising GI.5 (72.7%), GI.3 (9.1%), GI.4 (9.1%), and GI.6 (9.1%). For NV GII, the genotype GII.17 was the most prevalent, accounting 87.5% followed by GII.2 (6.25%), GII.3 (3.13%), and GII.9 (3.13%). This study demonstrated the presence of RAV and multiple genotypes of NV GI and GII contaminating and co-circulating in community wastewater during COVID-19 situation in Bangkok. Viral dynamics between human population and environment raised potentially concerns for epidemiological patterns, affecting human health and safety.

Human norovirus (HuNoV) is the leading cause of acute gastroenteritis globally, with frozen berries frequently implicated in foodborne outbreaks. Current surveillance relies on quantitative reverse transcription PCR (qRT-PCR), which cannot differentiate between infectious and non-infectious viral particles, complicating risk assessment. This study is aimed to establish the minimum viral load on frozen berries detectable by qRT-PCR that corresponds to infectious virus, using murine norovirus (MNV) as a surrogate for HuNoV. Frozen raspberries were artificially inoculated with serial dilutions of MNV (7.1–1.0 log PFU/25 g) and processed using the ISO 15216:2017 method. Infectious virus was quantified by plaque assay, and viral RNA was detected by qRT-PCR. The limit of detection (LOD) for cell culture was 3.1 log PFU/25 g, whereas qRT-PCR extended sensitivity to 1.0 log PFU/25 g (Ct value at 36.7 ± 0.6), representing a 2-log difference. Recovery rates for infectious virus exceeded the ISO 15,216 minimum threshold (1%), and PCR inhibition was negligible. We next examined the extraction efficiency for both infectious MNV and its genetic material from frozen strawberries at inoculation levels higher than the LOD, and observed that the viral recovery from frozen strawberries is very similar to viral recovery from frozen raspberries with no significant differences between them. The disparity between LODs indicates that a substantial proportion of MNV genomes detected by qRT-PCR do not represent infectious particles, aligning with previous findings that one PFU may correspond to multiple genome copies. Given that many surveillance studies report high Ct values (> 35), our data suggest that such detections may not indicate viable virus, underscoring the importance of contextualizing qRT-PCR results with epidemiological evidence. These findings highlight the need for cautious interpretation of surveillance data, particularly for public health decision-making.

Monitoring SARS-CoV-2 RNA in industrial wastewater has emerged as a potential approach to indirectly identify infected individuals within workplace populations. However, wastewater-based surveillance of SARS-CoV-2 in industrial settings has not previously been conducted in Thailand. This study aimed to qualitatively and quantitatively detect SARS-CoV-2 RNA in wastewater discharged from onsite wastewater treatment plants (WWTPs) and to estimate the number of infected individuals. A total of 120 wastewater samples were consecutively collected from 40 onsite WWTPs comprising 38 factories and two non-factory buildings with over a three-month period (April to June 2023), after the Songkran festival, Thailand’s traditional new year celebration. Wastewater samples were concentrated, and the total nucleic acids were extracted. SARS-CoV-2 RNA concentrations were determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR) targeting the N gene. SARS-CoV-2 RNA was detected in 42.5%, 62.5%, and 40.0% of samples collected in April, May, and June, respectively. The concentrations ranged from 3.5 × 10²–1.1 × 10⁴ copies/L in April, 4 × 10²–1.7 × 10⁵ copies/L in May, and 1.1 × 10³–1.4 × 10⁵ copies/L in June. A higher frequency of SARS-CoV-2 RNA detection was observed in factories having more than 1000 employees. Based on our modified estimation model, the estimated infected individuals were 219, 3145, and 2711 for April, May, and June, respectively. The numbers of estimated infected population closely aligned with the official COVID-19 case trending reported in Pathum Thani province and at the national level during the same period. These findings suggest that wastewater-based epidemiology (WBE) is a reliable tool for measuring, estimating, and assessing COVID-19 dynamics in industrial setting.

Human norovirus (HuNoV) is the leading cause of acute nonbacterial gastroenteritis globally. Histo-blood group antigens (HBGAs) have been recognized as attachment factors for HuNoV. However, the receptors or other potential attachment factors for HuNoV have not been fully elucidated. A bacterial cell surface-displayed system was used to express GII.4 HuNoV protruding domain (GII.4 P) to capture attachment factors from a diarrheal sample of a patient infected with GII.4 HuNoV. A library of candidate HuNoV proteinaceous attachment factors was constructed. Through a database comparison, a literature review, the predicted protein subcellular localization, the protein–protein interactions (PPIs) network analysis, the molecular simulation and the protein docking analysis, four candidate attachment factors were selected for further investigation from the initial 118 candidates. Finally, two proteins, namely myelin-oligodendrocyte glycoprotein (MOG) and leucine-rich repeat-containing protein 15 (LRRC15), were demonstrated strongly binding to GII.4 P by both in vivo and in vitro assays. The binding between MOG/LRRC15 and GII.4 P can be blocked by GII.4 HuNoV antibody. Immunofluorescence showed that MOG/LRRC15 and GII.4 HuNoV co-localized in the cytoplasm in transfected cells. However, GII.4 HuNoV did not proliferate in the newly constructed MOG/LRRC15 overexpressing cells. This study describes attempts to identify HuNoV proteinaceous attachment factors from the diarrheal sample. Findings from this study will aid in understanding of HuNoV infection in humans, enrichment of GII.4 HuNoV from various environments and construction of cell lines for HuNoV cultivation in vitro.

The global emergence of SARS-CoV-2 has highlighted the urgent need for effective disinfection strategies to mitigate virus transmission. Electrolyzed water (EW), an eco-friendly and cost-effective biocidal agent, has garnered attention for its broad-spectrum antimicrobial activity. This study evaluates the virucidal, bactericidal, and fungicidal capacities of EW with diverse pH, with a focus on its effectiveness against SARS-CoV-2 and other pathogens. EW was generated under controlled conditions with adjustable pH (4.5 and 6.1) and free available chlorine (FAC) concentrations (300–1000 ppm). The biocidal activity was tested on surfaces and in solution following standardized protocols. Results demonstrated that oxidized EW at optimized concentrations achieved a ≥ 4 log reduction in bacterial populations and effectively inactivated enveloped and non-enveloped viruses, but this effect depends on FAC, pH, and contact time. Notably, EW reduced SARS-CoV-2 by > 4 log in solution and surfaces, in only 2 and 5 min, respectively. These findings highlight the potential of EW as a sustainable, multi-application disinfectant to combat emerging pathogens like SARS-CoV-2, ensuring public health safety.

Noroviruses are the leading cause of gastroenteritis outbreaks in humans worldwide. Their unique properties ensure stability over extended periods under adverse conditions, which enhances their risk as food and water contaminants. In recent years, intensive research has focused on the natural antimicrobial potential of plant metabolites as disinfectants against environmental pathogens. The oregano essential oil (OEO) has gained attention due to its valuable properties, including antimicrobial, antioxidant, antiviral, and antifungal activities. However, the susceptibility of OEO to degradation and oxidation under environmental or storage conditions, coupled with its low water solubility, has limited its practical applications. Nanoencapsulation has emerged as a promising strategy to overcome these limitations by prolonging shelf life, improving stability, enabling controlled release, and expanding its potential uses. In this study, we evaluated the virucidal potential of chitosan-based polymeric nanoparticles incorporating Origanum vulgare essential oil against murine norovirus 1 (MNV-1) for food and environmental applications. To assess the virucidal effect of the OEO nanoparticles, the reduction in viral infectivity was determined by comparing the TCID₅₀/mL values of untreated viral suspensions with those treated with the tested compounds at varying concentrations. The results demonstrated effective viral inactivation at all tested concentrations, with the undiluted formulation (40 mg/mL incorporated OEO) achieving the highest inactivation rate (99.72%). The blank formulation showed no significant virucidal activity, while the pure OEO exhibited cytotoxicity at most tested concentrations. These findings support the development of a biotechnological disinfectant with potential applications in both environmental and controlled conditions.