Viral uptake and stability in Crassostrea gigas oysters during depuration, storage and steaming

Pilotto, Mariana Rangel; Souza, Dóris Sobral Marques; Barardi, Célia Regina Monte

doi:10.1016/j.marpolbul.2019.110524

Cited by 16 publications

(10 citation statements)

References 39 publications

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“…The results of the laboratory depuration trials indicate that norovirus, whilst not completely removed, was significantly reduced when the water temperature used for depuration was increased to > 11 °C, but not at lower temperatures. Other studies have previously reported similar findings where norovirus was reduced, but not eliminated from contaminated shellfish, including clams, mussels and oysters (Ueki et al 2007;Neish 2013;Polo et al 2014a;Pilotto et al 2019) using a variety of time and temperature combinations. The initial temporary increase in norovirus concentrations observed here at Day 1, and by others at Day 1-2 (McLeod et al 2009;Polo et al 2014c), could be explained by transient capture and subsequent release of norovirus particles from animal tissue outside of DT, such as gills and mantle (Maalouf et al 2010).…”

Section: Discussionsupporting

confidence: 58%

“…Artificial contamination of shellfish with viral pathogens is a common approach to studying depuration processes and has been described previously (Muniain-Mujika et al 2002 ; Choi and Jiang 2005 ; Nappier et al 2008 ; McLeod et al 2009 ; Polo et al 2014b ). As shellfish are known to efficiently bioaccumulate viruses in as little as several hours (Flannery et al 2012 ; Souza et al 2013 , 2018 ; Pilotto et al 2019 ), this approach allows for a rapid generation of animals contaminated with one or multiple viral strains. Concentrations as high as 10 11 genome copies per gram (gcg −1 ) of murine norovirus (MNV1) were achieved during 24h bioaccumulation in C. gigas by Pilotto et al ( 2019 ), whereas both GI and GII human norovirus genogroups, simultaneously bioaccumulated in C. gigas oysters to 10 6 gcg −1 (Maalouf et al 2011 ).…”

Section: Introductionmentioning

confidence: 99%

“…As shellfish are known to efficiently bioaccumulate viruses in as little as several hours (Flannery et al 2012 ; Souza et al 2013 , 2018 ; Pilotto et al 2019 ), this approach allows for a rapid generation of animals contaminated with one or multiple viral strains. Concentrations as high as 10 11 genome copies per gram (gcg −1 ) of murine norovirus (MNV1) were achieved during 24h bioaccumulation in C. gigas by Pilotto et al ( 2019 ), whereas both GI and GII human norovirus genogroups, simultaneously bioaccumulated in C. gigas oysters to 10 6 gcg −1 (Maalouf et al 2011 ). Maximum reductions of the norovirus concentrations in such artificially contaminated shellfish were previously reported in the region of 1–1.2 log 10 unit (equivalent to 90–94% reduction) and based on that evidence the process was deemed ineffective (McLeod et al 2017 ).…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of Norovirus Reduction in Environmentally Contaminated Pacific Oysters During Laboratory Controlled and Commercial Depuration

et al. 2021

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Norovirus contamination of oysters is the lead cause of non-bacterial gastroenteritis and a significant food safety concern for the oyster industry. Here, norovirus reduction from Pacific oysters (Crassostrea gigas), contaminated in the marine environment, was studied in laboratory depuration trials and in two commercial settings. Norovirus concentrations were measured in oyster digestive tissue before, during and post-depuration using the ISO 15216-1 quantitative real-time RT-PCR method. Results of the laboratory-based studies demonstrate that statistically significant reductions of up to 74% of the initial norovirus GII concentration was achieved after 3 days at 17–21 °C and after 4 days at 11–15 °C, compared to 44% reduction at 7–9 °C. In many trials norovirus GII concentrations were reduced to levels below 100 genome copies per gram (gcg−1; limit of quantitation; LOQ). Virus reduction was also assessed in commercial depuration systems, routinely used by two Irish oyster producers. Up to 68% reduction was recorded for norovirus GI and up to 90% for norovirus GII reducing the geometric mean virus concentration close to or below the LOQ. In both commercial settings there was a significant difference between the levels of reduction of norovirus GI compared to GII (p < 0.05). Additionally, the ability to reduce the norovirus concentration in oysters to < LOQ differed when contaminated with concentrations below and above 1000 gcg−1. These results indicate that depuration, carried out at elevated (> 11 °C) water temperatures for at least 3 days, can reduce the concentration of norovirus in oysters and therefore consumer exposure providing a practical risk management tool for the shellfish industry.

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Section: Discussionsupporting

confidence: 58%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Evaluation of Norovirus Reduction in Environmentally Contaminated Pacific Oysters During Laboratory Controlled and Commercial Depuration

et al. 2021

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“…(LEE et al, 2008). Bivalve depuration experiments conducted in SC involved studies on the pathogens Salmonella Typhimurium (CORRêA et al, 2007), Vibrio parahaemolyticus and Vibrio vulnificus (RAMOS et al, 2012), norovirus, hepatitis A virus (HAV) and human mastadenovirus (HAdV) (CORRêA et al, 2012;SOUZA et al, 2013, PILOTTO et al, 2019, murine norovirus (MNoV) (SOUZA et al, 2013), and the Protozoa Cryptosporidium and Giardia (SOUZA et al, 2013 2012) investigated the reduction of HAV and HAdV-5 in artificially contaminated oysters using an apparently similar system to the one used in the previous study. Dimensions (tank volume), water temperature, number of animals, and pumping rate were the same as those in the 2007 study.…”

Section: Bivalve Depurationmentioning

confidence: 99%

Depuração e tratamento térmico para redução dos níveis de patógenos em moluscos bivalves produzidos em Santa Catarina, Brasil

Souza

Moresco

Miotto

et al. 2022

RAC

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Esta revisão resume os achados de estudos realizados em Santa Catarina (SC) sobre redução de patógenos em moluscos por meio de tratamentos pós-colheita. Estudos indicam que os níveis de Salmonella e Vibrio spp. de ocorrência natural podem ser eficientemente reduzidos em ostras por meio de ciclos de depuração de 48h, enquanto vírus (hepatite A e norovírus murino) requerem mais de 48 horas para serem completamente inativados. Protozoários (Cryptosporidium e Giardia) não foram eliminados pelos protocolos de depuração testados. O protocolo de tratamento térmico adotado nas indústrias locais (cozimento a vapor durante 6 min a 100ºC) é capaz de eliminar Vibrio spp. de mexilhões e norovírus murino de ostras. Apesar de algumas limitações, a adoção desses tratamentos pós-colheita é uma estratégia importante para melhorar a segurança dos moluscos em SC.

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“…For example, an assessment of 121 market-ready oysters in Vietnam showed 81% of samples were found to be contaminated with norovirus (Suffredini et al 2020). Largely this occurs at safe consumption levels, but in cases can cause mass shellfish poisoning events (Pilotto et al 2019). The largest ever shellfish poisoning event was in Shanghai and involved 300,000 people contracting Hepatitis A and 47 deaths within 2 months (Chiang & Chuang 2003, Xu et al 1992.…”

Section: Implications and Further Researchmentioning

confidence: 99%

Morphological, histological and behavioural change in two species of marine bivalves in response to environmental stress

Damodaran¹

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<p>Mass mortality events (MMEs) occur when a disproportionate part of a population dies in a single event. The frequency of MMEs is increasing globally. In the past, MMEs have been linked to starvation, changes in environmental conditions and disease outbreaks. However, it is often unclear what the underlying cause of these events are. In New Zealand several MMEs have occurred in the bivalve species Austrovenus stutchburyi (Wood 1828) and Paphies subtriangulata (Wood 1828) with little known about the cause. Both of these species are recreationally harvested for consumption in New Zealand and have cultural significance. In order to better understand MMEs in these species we must first gain a better understanding of stress expression. Bivalves have few observable features and it is difficult to classify them as healthy or stressed without investigating immune change which can be quite costly. Some research has looked into how different cell types change in response to pollutants but few studies have researched how cell types change in response to environmental conditions. The aim of this research was to find novel ways of assessing if shellfish were healthy or stressed. Little is known about how shellfish respond to environmental stressors and this is the first study to look at several novel stress expressions simultaneously, in New Zealand shellfish. Histological, morphological and behavioural responses were measured in both A. stutchburyi and P. subtriangulata after treatment with increased temperature, lowered salinity and increased fine sediment input for up to 5 weeks. Temperature stress was the main stressor for P. subtriangulata (85% of overall mortality occurred in the heat treatment), salinity was the main stressor for A. stutchburyi (46% of overall mortality occurred in the salinity treatment), and fine sediment stress did not seem to have an effect on either species in this study. Overall, A. stutchburyi were more robust to the treatments, but low mortality occurred in both species (≤8%). Mortality correlated with time of year and was believed to be related to spawning in P. subtriangulata (48% of overall mortality occurred from October-November). Both species had a single histological marker, in A. stutchburyi this was change in gill morphology, and in P. subtriangulata this was change in digestive gland morphology. Several individual morphological features were identified as potential stress markers in A. stutchburyi and P. subtriangulata. Additionally, when removed from aquaria P. subtriangulata had impeded foot retraction time in the salinity treatment. The differences in stress markers shows the diversity of reactions to stressors even within New Zealand bivalves. This study provides a useful baseline in investigating how P. subtriangulata and A. stutchburyi respond to environmental stress. The histological slides produced during this investigation are an invaluable resource that can be used in future studies and in comparisons with archived specimens from known MMEs. Knowing how to detect signs of stress in these bivalves will help to predict MMEs in the future and aid in implementing processes to combat these events.</p>

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Viral uptake and stability in Crassostrea gigas oysters during depuration, storage and steaming

Cited by 16 publications

References 39 publications

Evaluation of Norovirus Reduction in Environmentally Contaminated Pacific Oysters During Laboratory Controlled and Commercial Depuration

Evaluation of Norovirus Reduction in Environmentally Contaminated Pacific Oysters During Laboratory Controlled and Commercial Depuration

Depuração e tratamento térmico para redução dos níveis de patógenos em moluscos bivalves produzidos em Santa Catarina, Brasil

Morphological, histological and behavioural change in two species of marine bivalves in response to environmental stress

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