Preliminary Study on Norovirus, Hepatitis A Virus, Escherichia coli and their Potential Seasonality in Shellfish from Different Growing and Harvesting Areas in Sardinia Region

Hepatitis A and E Viruses in Mussels from Cherrat Estuary in Morocco: Detection by Real-Time Reverse Transcription PCR Analysis

The aim of the present study was to evaluate hepatitis A virus (HAV) and hepatitis E virus (HEV) contamination in mussels (Mytilus galloprovincialis) from Cherrat estuary (Moroccan Atlantic Coast), Morocco. In total, 52 samples (n = 12 mussels/each) were collected at four sites in the estuary, monthly, between March 2019 and March 2020. HAV and HEV were detected by real-time reverse transcription polymerase chain reaction (RT-PCR) according to the ISO/TS 15216 method. HAV was detected in 46.15% of analyzed samples. Conversely, HEV was not detected in any sample. Moreover, the HAV detection rate was significantly associated with seasonal rainfall variations. This qualitative study on HAV and HEV contamination highlights the interest of studying mussel samples from wild areas. As HAV presence in mussels represents a potential health risk, viral contamination surveillance of mussels is necessary to protect consumers. HAV shellfish contamination must be monitored at Cherrat estuary because of the role played by shellfish as HAV reservoirs and/or vehicles in fecal-oral HAV transmission.

Plasmonic Metasurfaces Based on Pyramidal Nanoholes for High-Efficiency SERS Biosensing

An inverted pyramidal metasurface was designed, fabricated, and studied at the nanoscale level for the development of a label-free pathogen detection on a chip platform that merges nanotechnology and surface-enhanced Raman scattering (SERS). Based on the integration and synergy of these ingredients, a virus immunoassay was proposed as a relevant proof of concept for very sensitive detection of hepatitis A virus, for the first time to our best knowledge, in a very small volume (2 μL), without complex signal amplification, allowing to detect a minimal virus concentration of 13 pg/mL. The proposed work aims to develop a high-flux and high-accuracy surface-enhanced Raman spectroscopy (SERS) nanobiosensor for the detection of pathogens to provide an effective method for early and easy water monitoring, which can be fast and convenient.

Evaluating the impact of hydrometeorological conditions on E. coli concentration in farmed mussels and clams: experience in Central Italy

Highly populated coastal environments receive large quantities of treated and untreated wastewater from human and industrial sources. Bivalve molluscs accumulate and retain contaminants, and their analysis provides evidence of past contamination. Rivers and precipitation are major routes of bacteriological pollution from surface or sub-surface runoff flowing into coastal areas. However, relationships between runoff, precipitation, and bacterial contamination are site-specific and dependent on the physiographical characteristics of each catchment. In this work, we evaluated the influence of precipitation and river discharge on molluscs' Escherichia coli concentrations at three sites in Central Italy, aiming at quantifying how hydrometeorological conditions affect bacteriological contamination of selected bivalve production areas. Rank-order correlation analysis indicated a stronger association between E. coli concentrations and the modelled Pescara River discharge maxima (r = 0.69) than between E. coli concentration and rainfall maxima (r = 0.35). Discharge peaks from the Pescara River caused an increase in E. coli concentration in bivalves in 87% of cases, provided that the runoff peak occurred 1-6 days prior to the sampling date. Precipitation in coastal area was linked to almost 60% of cases of E. coli high concentrations and may enhance bacterial transportation offshore, when associated with a larger-scale weather system, which causes overflow occurrence.

Hepatitis A Virus Strains Circulating in the Campania Region (2015-2018) Assessed through Bivalve Biomonitoring and Environmental Surveillance

The genetic diversity of Hepatitis A Virus (HAV) circulating in the Campania Region in years 2015–2018 was investigated through the monitoring of sentinel bivalve shellfish and water matrices. Overall, 463 water samples (71 sewage samples, 353 coastal discharge waters, and 39 seawaters samples), and 746 bivalve shellfish samples were analyzed. Positivity for HAV was detected in 20/71 sewage samples, 14/353 coastal discharge waters, 5/39 seawaters, and 102/746 bivalve shellfish. Sixty-one of the positive samples were successfully sequenced and were characterized as genotype IA (n = 50) and IB (n = 11). The prevalent strain circulating in 2015 in both bivalves and waters was the IA strain responsible for the outbreak occurring around the same time in the Naples area. This variant was no longer identified in subsequent years (2017–2018) when, instead, appeared two of the IA variants of the multistate outbreak affecting men who have sex with men (MSM), VRD_521_2016, and RIVM-HAV16–090, with the former prevailing in both shellfish and water environments. HAV IB isolates were detected over the years in shellfish and in water matrices, but not in clinical samples, suggesting that this genotype had been circulating silently. An integrated surveillance system (environment/food/clinical cases) can be a useful tool to monitor changes in viral variants in the population, as well as an early warning system.

Enumeration of Escherichia coli and determination of Salmonella spp. and verotoxigenic Escherichia coli in shellfish (Mytilus galloprovincialis and Ruditapes decussatus) harvested in Sardinia, Italy

The aim of the present study was to evaluate the occurrence of Salmonella spp., Verotoxigenic E. Coli (VTEC) and enumerate E. coli in shellfish (Mytilus galloprovincialis and Ruditapes decussatus) collected before and after depuration from two class B harvesting areas located in Sardinia (Italy). All the samples were analyzed for Salmonella spp. detection according to European Commission Regulation (EC) 2073/2005 and examined using the five tube Most-Probable-Number (MPN) method for enumeration of E. coli in accordance with the European Union reference method ISO 16649-3:2015. E. coli VTEC was investigated following a direct multiplex Polymerase Chain Reaction (PCR) screening test. The enumeration of E. coli met the European law limit for Class A areas of 230 MPN/100g. The averaged enumeration of E. coli in samples of M. galloprovincialis and R. decussatus collected at the harvesting time was 39 and 37 MPN/100 g respectively. The average contamination levels in samples collected after purification were 58 MPN/100g (M. galloprovincialis) and 32 MPN/100 g (R. decussatus). E. coli VTEC was not detected, on the contrary, Salmonella ser. Typhimurium was detected in one sample of M. galloprovincialis and in one sample of R. decussatus collected at the harvesting time. No significant associations were observed between E. coli levels in shellfish and environmental parameters of water or with the detection of Salmonella ser. Typhimurium in M. galloprovincialis and R. decussatus samples. Nevertheless, the occurrence of Salmonella ser. Typhimurium, involved in human infection outbreaks, should be considered a potential risk for consumers.

Analysis of the sanitary survey 2015-2017 conducted in the gulf of La Spezia (Italy): Reclassification of the areas of production of live bivalve molluscs

The sanitary survey is aimed at classifying and monitoring the production areas of live bivalve molluscs (LBM) and it is performed using standards that are provided by the Centre for Environment, Fisheries and Aquaculture Science's Guide to Good Practice. In this study, data from the sanitary survey carried out by the Asl5 Spezzino on the production areas of the gulf of La Spezia during the period 2015-2017 were analysed. The number and type of the analysis performed both on the total sampling and on the individual target species, as well as the number and type of found non-compliance (assessed on both mandatory parameters and on parameters fixed by the local monitoring plan) were considered. Data were also compared with those from the sanitary survey 2012-2014. Appropriate statistic tests were used to evaluate data from E. coli and Norovirus monitoring. Overall, 4306 analysis were performed, especially on the species M. galloprovincialis (89%) and they were mostly focused on to the search of biological agents. 160 NC were detected. Most of the NC concerns the Norovirus's positivity (93.75%) in M. galloprovincialis and C. gigas. A correlation between the levels of E. coli and rainfall/ seasonality (higher levels in the colder months) was proved, especially in the sampling points located in the inner part of the dam and in the Portovenere Bay. Class B was reconfirmed for M. galloprovincialis, the production areas of C. gigas were reclassified as A and those of V. verrucosa were definitively closed. The sanitary survey was therefore confirmed as a useful tool for reclassification and for monitoring LBM production areas.

Risk factors for seasonal influenza virus detection in stools of patients consulting in general practice for acute respiratory infections in France, 2014-2016

Background

Previous studies reported detection of influenza RNA in stools of patients with seasonal influenza infection. While this detection may have a clinical significance, other factors may influence the stool positivity for influenza viruses.

Objectives

The objective of this study was to investigate demographical, clinical, and microbiological factors which could favor the presence of influenza viral RNA in the stools of patients with laboratory‐confirmed influenza infection.

Methods

Acute respiratory infection (ARI) patients were enrolled by general practitioners (GP) during two winter seasons (2014‐2016). Nasopharyngeal swabs, stool specimens, and clinical data were collected. Samples were tested for 12 respiratory pathogen groups (nasopharyngeal and stool specimens) and for 12 enteric pathogens (stool specimens).

Results

Among the 331 patients with ARI enrolled by GP, 114 (34.4%) presented influenza infection. Influenza RNA was detected in stool samples of 21% (24/114) of the 114 stool specimens analyzed. Hospitalization (adjusted odds ratio (aOR) = 7.8 (95% confidence interval (CI)) [1.7‐33.7], P = .02), age between 45 and 64 years (aOR = 4.8 [1.7‐14.5], P = .01), consumption of raw shellfish and/or mollusks (aOR = 16.7 [3.6‐90.9], P = .00), and use of antibiotics (aOR = 6.4 [2.1‐19.8], P = .006) or antiviral treatment (aOR = 7.4 [1.9‐29], P = .01) were significantly associated with an increased odds of the detection of influenza RNA in stools. Among the 24 stool samples subjected to viral isolation, no one showed virus growth.

Conclusions

These findings will be useful to studies investigating the dissemination route of influenza viruses to gastrointestinal tract.

Influence of Environmental Conditions on Norovirus Presence in Mussels Harvested in Montenegro

This study comprises the first systematic survey of the occurrence of Norovirus in Mediterranean mussels from harvesting areas in Montenegro coast of Adriatic Sea. Mussels may accumulate contaminants of public health concern, including pathogenic bacteria and viruses. Microbiological monitoring of harvesting areas is based on count of Escherichia coli in bivalve molluscs in the European Union. It is assumed that E. coli does not reflect contamination with enteric viruses. A structured field study was undertaken at six locations in Bay of Kotor, Montenegro, in order to investigate plausible influence of environmental factors on the variability of E. coli and norovirus (NoV). From July 2015 to July 2016, a total of 72 samples of mussels were collected in coastal harvesting areas of the Montenegro. The samples were screened for NoV of genogroups GI and GII using reverse transcription-qPCR (RT-qPCR). There were 43% NoV positive samples with higher presence of genogroup GII (74.2%). With regard to influence of environmental conditions on Norovirus presence, we have proved seasonal pattern of virus occurrence i.e., the largest number of positive samples was noticed during winter, while other physico-chemical factors were not of great significance. It was found that count of E. coli did not correlate with Norovirus prevalence. From the aspect of food safety, an upgrade of monitoring plans could lead to obtaining safer products.