David Polo

University of Santiago de Compostela | USC · Department of Microbiology and Parasitology

Oysters, being filter feeders, can accumulate some human pathogens such as norovirus, a highly infectious calicivirus, most common cause of acute gastroenteritis worldwide. Accumulated virus decays over a period of days to weeks, possibly rendering contaminated oysters safe again. Sensitive molecular methods have been set up for shellfish analysis...

The presence of SARS-CoV-2 in the feces of infected patients and wastewater has drawn attention, not only to the possibility of fecal-oral transmission but also to the use of wastewater as an epidemiological tool. The COVID-19 pandemic has highlighted problems in evaluating the epidemiological scope of the disease using classical surveillance appro...

The presence of SARS-CoV-2 in wastewater pose the question of whether this new pandemic virus could be released into watercourses and potentially continue to finally reach coastal waters. In this study, we employed two bivalve molluscan species from the genus Ruditapes as sentinel organisms to investigate the presence of SARS-CoV-2 signals in the m...

Since its first identification in the United Kingdom in late 2020, the highly transmissible B.1.1.7 variant of SARS-CoV-2 has become dominant in several countries raising great concern. We developed a duplex real-time RT-qPCR assay to detect, discriminate, and quantitate SARS-CoV-2 variants containing one of its mutation signatures, the ΔHV69/70 de...

Little data on the persistence of human norovirus infectivity are available to predict its transmissibility. Using human intestinal enteroids, we demonstrate that 2 human norovirus strains can remain infectious for several weeks in seawater. Such experiments can improve understanding of factors associated with norovirus survival in coastal waters a...

Human pathogenic viruses can be introduced into sewage sludge and soils via fecal material from a variety of human activities. These contaminated matrices can play a substantial role in the dispersion of pathogenic viruses in the environment, constituting a potential public health problem if they enter the water cycle or the food chain. However, th...

Human bocaviruses (HBoVs) are recently described as human emergent viruses, especially in young children. In this study we undertook a systematic review and meta-analysis to estimate their prevalence in Europe. PubMed, Web of Science and Scopus databases were systematically screened for clinical studies, up to October 2020. Study eligibility criter...

Background: Since its first identification in the United Kingdom in late 2020, the highly transmissible B.1.1.7 variant of SARS-CoV-2, become dominant in several European countries raising great concern. Aim: The aim of this study was to develop a duplex real-time RT-qPCR assay to detect, discriminate and quantitate SARS-CoV-2 variants containing o...

This study evaluates and compares the effectiveness of solar photo-Fenton systems for the inactivation of hepatitis A virus (HAV) in water. The effect of solar irradiance, dark- Fenton reaction and three different reactant concentrations (2.5/5, 5/10 and 10/20 mg/L of Fe2+/H2O2) on the photo-Fenton process were tested in glass bottle reactors (200...

Supplementary Material

Pollution of coastal waters can result in contamination of bivalve shellfish with human enteric viruses, including norovirus (NoV), and oysters are commonly implicated in outbreaks. Depuration is a postharvest treatment involving placement of shellfish in tanks of clean seawater to reduce contaminant levels; this review focuses on the efficacy of...

Ensuring the safety and quality of drinking water is essential in the prevention of waterborne diseases, especially in developing countries where water scarcity and lack of access to sanitation is common. Noroviruses (NoV) are the leading cause of non-bacterial acute gastroenteritis worldwide, being the second most common cause of diarrheal death i...

Using samples from oysters clearly implicated in human disease, we quantified norovirus levels by using digital PCR. Concentrations varied from 43 to 1,170 RNA cop-ies/oyster. The analysis of frozen samples from the production area showed the presence of norovirus 2 weeks before consumption.

Prevalence of human Sapovirus, an emerging pathogen of human gastroenteritis, was investigated in an 18-month survey from class “B” mollusc harvesting areas in two Galician Rías (NW Spain). Detection and quantification of Sapovirus was performed by reverse transcription-real time PCR, according to the recently developed standard method ISO/TS 15216...

This study evaluates the effectiveness of solar water disinfection (SODIS) in the reduction and inactivation of hepatitis A virus (HAV) and of the human Norovirus surrogate, murine Norovirus (MNV-1), under natural solar conditions. Experiments were performed in 330 ml polyethylene terephthalate (PET) bottles containing HAV or MNV-1 contaminated wat...

Enteric virus depuration from shellfish is a complex biological process that may be influenced by biological properties of the mollusc and/or virus species. On the basis of previous experimental data, a mathematical model was developed to characterize the kinetics of viral elimination during the depuration process. The experimental data consisted o...

An 18-month survey was conducted in ten class “B” harvesting areas from two Galician Rias (NW of Spain), the most important bivalve production area in Europe, to determine the prevalence of hepatitis A virus (HAV) and human norovirus (NoV), including genogroups I (GI) and II (GII). Quantification was performed by reverse tran- scription real-time P...

This study evaluates and compares the uptake rates and depuration kinetics of murine norovirus (MNV-1), as a human norovirus surrogate, in Manila clams (Venerupis philippinarum) and Mediterranean mussels (Mytilus galloprovincialis). Ten trials of 70 kg/trial (five with each mollusk) were performed. Mollusks were subjected to a controlled bioaccumul...

The effectiveness of depuration for the removal of hepatitis A virus (HAV), norovirus (NoV) genogroups I (GI) and II (GII), and F+RNA bacteriophage (F+RNA) was evaluated for pullet carpet shell clams (Venerupis pullastra) and Mediterranean mussels (Mytilus galloprovincialis). The objective was to compare the behaviour of the different pathogens und...

From a virological standpoint, shellfish safety continues to be a sanitary challenge. Bivalves are one of the most common vehicles of viral illness and the adoption of viral standards into European Union legislation is being considered. In this study, a 18-months survey were conducted in ten harvesting areas from two estuaries in Galicia (NW of Spa...

Sapovirus (SaV), etiologic agent of human gastroenteritis, is a RNA virus from the Caliciviridae family, mostly detected in Asia. It has been classified by the U.S. Environmental Protection Agency as an emergent human pathogen with risk for public health in aquatic environments. Bivalves, due to their filtrating feeding, concentrate viral particles...

The efficacy and kinetic of depuration of hepatitis A virus (HAV) were evaluated under experimental conditions with Mediterranean mussels (Mytilus galloprovincialis) subjected previously to bioaccumulation processes. Seven independent trials (70kg of mussels each) were performed in a closed experimental system using two different water temperatures...

This study evaluates and compares the effectiveness of depuration in clams and mussels subjected to bioaccumulation with murine norovirus (MNV-1), as a surrogate for human norovirus. Ten experiments with artificially contaminated shellfish were performed with clams and mussels (five with each species) using 102 pfu of MNV-1/ml seawater. After 24 h...

Hepatitis A virus (HAV) represents a significant public health problem due to its high persistence in the environment and its transmission through contaminated water and food. Bivalve shellfish are filter feeders that can bioaccumulate human pathogens found in contaminated waters, their consumption being a potential cause of hepatitis A outbreaks....

Standard and real-time reverse transcription-PCR (rRT-PCR) procedures were used to monitor cultured and wild bivalve molluscs from the Ría de Vigo (NW Spain) for the main human enteric RNA viruses, specifically, norovirus (NoV), hepatitis A virus (HAV), astrovirus (AsV), rotavirus (RT), enterovirus (EV), and Aichi virus (AiV). The results showed th...

Standard and real-time reverse transcription-PCR (rRT-PCR) procedures were used to monitor cultured and wild bivalve molluscs from the Ria de Vigo (NW Spain) for the main human enteric RNA viruses, specifically, norovirus (NoV), hepatitis A virus (HAV), astrovirus (AsV), rotavirus (RT), enterovirus (EV), and Aichi virus (AiV). The results showed th...