Determination of Norovirus Contamination in Oysters from Two Commercial Harvesting Areas over an Extended Period, Using Semiquantitative Real-Time Reverse Transcription PCR

2008 ◽  
Vol 71 (7) ◽  
pp. 1427-1433 ◽  
Author(s):  
JAMES A. LOWTHER ◽  
KATHLEEN HENSHILWOOD ◽  
DAVID N. LEES
Keyword(s):  
Human Health Risk ◽  
Extended Period ◽  
Epidemiological Data ◽  
Indicator Organisms ◽  
Fecal Indicator ◽  
E Coli ◽  
Reverse Transcription Pcr ◽  
The United Kingdom ◽  
Male Specific ◽  
Production Areas

The human health risk associated with the consumption of molluscan shellfish grown in sewage-contaminated waters is well established. Noroviruses, which cause gastroenteritis, are the principal agents of shellfish-related illness. Fecal-indicator quality standards based on Escherichia coli are well established in Europe and elsewhere. However, norovirus outbreaks after consumption of shellfish meeting these standards still occur, and the need to improve consumer health protection is well recognized. Alternative approaches proposed include direct monitoring of viral pathogens and the use of alternative indicator organisms capable of providing a better indication of virus risk. This study applies a recently developed TaqMan PCR assay to assess norovirus contamination in shellfish. Comparison was made with E. coli as the existing sanitary standard and a male-specific RNA bacteriophage as a possible alternative. Two commercial pacific oyster (Crassostrea gigas) harvesting areas were monitored over a 31-month period. The results show peaks of norovirus contamination in both areas during winter months, with average levels approximately 17 times higher in oysters sampled October to March than during the remainder of the year, consistent with epidemiological data for the United Kingdom showing oyster-associated illness is confined to winter months. While there was no apparent association with E. coli, an association between levels of norovirus contamination and the male-specific RNA bacteriophage was noted, with average norovirus levels over 40 times higher in samples with male-specific RNA bacteriophage counts of >1,000 PFU/100 g than in samples with <100 PFU/100 g. Overall, these results suggest that norovirus monitoring in shellfish production areas could be an effective strategy for reduction of virus risk.

scholarly journals Microbial water quality at contrasting recreational areas in a mixed-use watershed in eastern Canada

2021 ◽  
Author(s):  
Ainslie J. Butler ◽  
Katarina Pintar ◽  
Janis L. Thomas ◽  
Manon Fleury ◽  
Stefanie Kadykalo ◽  
...  
Keyword(s):  
Human Health ◽  
Health Risks ◽  
Human Health Risk ◽  
Indicator Organisms ◽  
Eastern Canada ◽  
Recreational Waters ◽  
Fecal Indicator ◽  
E Coli ◽  
Main River ◽  
Pathogen Testing

Abstract Recreational water use is an important source of human enteric illness. Enhanced (episodic) surveillance of natural recreational waters as a supplement to beach monitoring can enrich our understanding of human health risks. From 2011 to 2013, water sampling was undertaken at recreational sites on a watershed in eastern Canada. This study compared the prevalence and associations of human enteric pathogens and fecal indicator organisms. Beach water samples had lower pathogen presence than those along the main river, due to different pollution sources and the hydrological disposition. Pathogen profiles identified from the beach sites suggested a more narrow range of sources, including birds, indicating that wild bird management could help reduce public health risks at these sites. The presence and concentration of indicator organisms did not differ significantly between beaches and the river. However, higher concentrations of generic Escherichia coli were observed when Salmonella and Cryptosporidium were present at beach sites, when Salmonella was present at the river recreational site, and when verotoxigenic E. coli were present among all sites sampled. In this watershed, generic E. coli concentrations were good indicators of potential contamination, pathogen load, and elevated human health risk, supporting their use for routine monitoring where enhanced pathogen testing is not possible.

scholarly journals Thermotolerant Coliforms Are Not a Good Surrogate for Campylobacter spp. in Environmental Water

2009 ◽  
Vol 75 (21) ◽  
pp. 6736-6744 ◽  
Author(s):  
Karen St-Pierre ◽  
Simon Lévesque ◽  
Eric Frost ◽  
Nathalie Carrier ◽  
Robert D. Arbeit ◽  
...  
Keyword(s):  
Environmental Water ◽  
Indicator Organisms ◽  
Fecal Indicator ◽  
E Coli ◽  
Microbial Monitoring ◽  
Environmental Surface ◽  
Thermotolerant Coliforms ◽  
Eastern Townships ◽  
Campylobacter Spp

ABSTRACT This study aimed to assess the importance of quantitatively detecting Campylobacter spp. in environmental surface water. The prevalence and the quantity of Campylobacter spp., thermotolerant coliforms, and Escherichia coli in 2,471 samples collected weekly, over a 2-year period, from 13 rivers and 12 streams in the Eastern Townships, Québec, Canada, were determined. Overall, 1,071 (43%), 1,481 (60%), and 1,463 (59%) samples were positive for Campylobacter spp., thermotolerant coliforms, and E. coli, respectively. There were weak correlations between the weekly distributions of Campylobacter spp. and thermotolerant coliforms (Spearman's ρ coefficient = 0.27; P = 0.008) and between the quantitative levels of the two classes of organisms (Kendall tau-b correlation coefficient = 0.233; P < 0.0001). Well water samples from the Eastern Townships were also tested. Five (10%) of 53 samples from private surface wells were positive for Campylobacter jejuni, of which only 2 were positive for thermotolerant coliforms. These findings suggest that microbial monitoring of raw water by using only fecal indicator organisms is not sufficient for assessing the occurrence or the load of thermophilic Campylobacter spp. Insights into the role of environmental water as sources for sporadic Campylobacter infection will require genus-specific monitoring techniques.

scholarly journals Salmonella enterica Serovar Typhimurium and Escherichia coli Survival in Estuarine Bank Sediments

2018 ◽  
Vol 15 (11) ◽  
pp. 2597 ◽  
Author(s):  
Mahbubul Siddiqee ◽  
Rebekah Henry ◽  
Rebecca Coulthard ◽  
Christelle Schang ◽  
Richard Williamson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Growth Patterns ◽  
Estuarine Sediments ◽  
Human Pathogens ◽  
Indicator Organisms ◽  
Fecal Indicator ◽  
E Coli ◽  
Serovar Typhimurium

Estuarine bank sediments have the potential to support the survival and growth of fecal indicator organisms, including Escherichia coli. However, survival of fecal pathogens in estuarine sediments is not well researched and therefore remains a significant knowledge gap regarding public health risks in estuaries. In this study, simultaneous survival of Escherichia coli and a fecal pathogen, Salmonella enterica serovar Typhimurium, was studied for 21 days in estuarine bank sediment microcosms. Observed growth patterns for both organisms were comparable under four simulated scenarios; for continuous-desiccation, extended-desiccation, periodic-inundation, and continuous-inundation systems, logarithmic decay coefficients were 1.54/day, 1.51/day, 0.14/day, and 0.20/day, respectively, for E. coli, and 1.72/day, 1.64/day, 0.21/day, and 0.24/day for S. Typhimurium. Re-wetting of continuous-desiccated systems resulted in potential re-growth, suggesting survival under moisture-limited conditions. Key findings from this study include: (i) Bank sediments can potentially support human pathogens (S. Typhimurium), (ii) inundation levels influence the survival of fecal bacteria in estuarine bank sediments, and (iii) comparable survival rates of S. Typhimurium and E. coli implies the latter could be a reliable fecal indicator in urban estuaries. The results from this study will help select suitable monitoring and management strategies for safer recreational activities in urban estuaries.

scholarly journals Two-Year Systematic Study To Assess Norovirus Contamination in Oysters from Commercial Harvesting Areas in the United Kingdom

2012 ◽  
Vol 78 (16) ◽  
pp. 5812-5817 ◽  
Author(s):  
James A. Lowther ◽  
Nicole E. Gustar ◽  
Andrew L. Powell ◽  
Rachel E. Hartnell ◽  
David N. Lees
Keyword(s):  
United Kingdom ◽  
Systematic Study ◽  
Quantitative Methods ◽  
Human Health Risk ◽  
Risk Indicators ◽  
The European Union ◽  
Systematic Analysis ◽  
The United Kingdom ◽  
Production Areas ◽  
The Impact

ABSTRACTThe contamination of bivalve shellfish with norovirus from human fecal sources is recognized as an important human health risk. Standardized quantitative methods for the detection of norovirus in molluscan shellfish are now available, and viral standards are being considered in the European Union and internationally. This 2-year systematic study aimed to investigate the impact of the application of these methods to the monitoring of norovirus contamination in oyster production areas in the United Kingdom. Twenty-four monthly samples of oysters from 39 United Kingdom production areas, chosen to represent a range of potential contamination risk, were tested for norovirus genogroups I and II by using a quantitative real-time reverse transcription (RT)-PCR method. Norovirus was detected in 76.2% (643/844) of samples, with all sites returning at least one positive result. Both prevalences (presence or absence) and norovirus levels varied markedly between sites. However, overall, a marked winter seasonality of contamination by both prevalence and quantity was observed. Correlations were found between norovirus contamination and potential risk indicators, including harvesting area classifications,Escherichia coliscores, and environmental temperatures. A predictive risk score for norovirus contamination was developed by using a combination of these factors. In summary, this study, the largest of its type undertaken to date, provides a systematic analysis of norovirus contamination in commercial oyster production areas in the United Kingdom. The data should assist risk managers to develop control strategies to reduce the risk of human illness resulting from norovirus contamination of bivalve molluscs.

scholarly journals Evaluation of F-Specific RNA Bacteriophage as a Candidate Human Enteric Virus Indicator for Bivalve Molluscan Shellfish

2000 ◽  
Vol 66 (4) ◽  
pp. 1280-1285 ◽  
Author(s):  
William J. Doré ◽  
Kathleen Henshilwood ◽  
David N. Lees
Keyword(s):  
Disease Outbreaks ◽  
Enteric Virus ◽  
Seasonal Trend ◽  
Human Consumption ◽  
Point Of Sale ◽  
E Coli ◽  
Reverse Transcription Pcr ◽  
The United Kingdom ◽  
Viral Indicators ◽  
A Site

ABSTRACT Escherichia coli is a widely utilized indicator of the sanitary quality of bivalve molluscan shellfish sold for human consumption. However, it is now well documented that shellfish that meet the E. coli standards for human consumption may contain human enteric viruses that cause gastroenteritis and hepatitis. In this study we investigated using F-specific RNA bacteriophage (FRNA bacteriophage) to indicate the likely presence of such viruses in shellfish sold for consumption. FRNA bacteriophage and E. coli levels were determined over a 2-year period for oysters (Crassostrea gigas) harvested from four commercial sites chosen to represent various degrees of sewage pollution. Three sites were classified as category B sites under the relevant European Community (EC) Directive (91/492), which required purification (depuration) of oysters from these sites before sale. One site was classified as a category A site, and oysters from this site could be sold directly without further processing. Samples were tested at the point of sale following commercial processing and packaging. All of the shellfish complied with the mandatory EC E. coli standard (less than 230 per 100 g of shellfish flesh), and the levels of contamination for more than 90% of the shellfish were at or below the level of sensitivity of the assay (20 E. coli MPN per 100 g), which indicated good quality based on this criterion. In contrast, FRNA bacteriophage were frequently detected at levels that exceeded 1,000 PFU per 100 g. High levels of FRNA bacteriophage contamination were strongly associated with harvest area fecal pollution and with shellfish-associated disease outbreaks. Interestingly, FRNA bacteriophage contamination exhibited a marked seasonal trend that was consistent with the trend of oyster-associated gastroenteritis in the United Kingdom. The correlation between FRNA bacteriophage contamination and health risk was investigated further by using a reverse transcription-PCR assay for Norwalk-like virus (NLV). NLV contamination of oysters was detected only at the most polluted site and also exhibited a seasonal trend that was consistent with the trend of FRNA bacteriophage contamination and with the incidence of disease. The results of this study suggest that FRNA bacteriophage could be used as viral indicators for market-ready oysters.

Male-Specific Coliphages as an Additional Fecal Contamination Indicator for Screening Fresh Carrots

2003 ◽  
Vol 66 (1) ◽  
pp. 88-93 ◽  
Author(s):  
SEEMA ENDLEY ◽  
LINGENG LU ◽  
EVERARDO VEGA ◽  
MICHAEL E. HUME ◽  
SURESH D. PILLAI
Keyword(s):  
Fecal Contamination ◽  
Microbiological Quality ◽  
Indicator Organisms ◽  
Viral Pathogens ◽  
E Coli ◽  
Bacterial Contaminants ◽  
Viral Indicators ◽  
Additional Level ◽  
Male Specific

The objective of this study was to evaluate the efficacy of male-specific (F+) coliphages as a fecal-contaminationindicator for fresh carrots. The prevalence of specific pathogens and indicator organisms on the surface of carrots obtained from a farm, truck, and processing shed was studied. Twenty-five carrot samples collected from each of these locations were washed, and aliquots of the wash were analyzed for the presence of F+ coliphages, Escherichia coli, Salmonella, and Shigella. Additionally, the Salmonella isolates were genotyped using pulsed-field gel electrophoresis (PFGE). Our studies detected the presence of F+ coliphages, E. coli, and Salmonella on carrots. All samples, however, tested negative for Shigella. Although none of the carrot samples from the field were positive for E. coli, one sample was positive for Salmonella, and another was positive for F+ coliphages. From the truck, two carrot samples (8%) were positive for Salmonella, four (16%) were positive for F+ coliphages, and four (16%) were positive for E. coli. None of the carrot samples from the processing shed were positive for Salmonella. However, 2 carrot samples (8%) were positive for E. coli, and 14 carrot samples (56%) were positive for F+ coliphages. The PFGE results suggest that there were three distinct Salmonella genotypes among the carrot samples from the truck and that the Salmonella isolates identified on carrot samples from the field and truck locations were different. Microbiological screening of fresh produce such as carrots (which can be exposed to fecal contaminants in soils and water) should ensure the detection of both viral and bacterial contaminants. Overall, in this study, F+ coliphages were detected in 25% of the carrot samples, compared to E. coli (8%), Salmonella (4%), and Shigella (0%). The results suggest F+ coliphages can serve as a conservative indicator of fecally associated viruses on carrots. This suggests that in addition to E. coli screening, F+ coliphages should be included when produce such as carrots that are vulnerable to fecal contaminants are screened. Since the detection of specific enteric viral pathogens is expensive, screening for viral indicators of fecal contamination using F+ coliphages can be an economical approach to providing an additional level of assurance about the microbiological quality of fresh carrots.

scholarly journals Quantification of human norovirus GII, human adenovirus, and fecal indicator organisms in wastewater used for irrigation in Accra, Ghana

2013 ◽  
Vol 11 (3) ◽  
pp. 473-488 ◽  
Author(s):  
Andrea I. Silverman ◽  
Mark O. Akrong ◽  
Philip Amoah ◽  
Pay Drechsel ◽  
Kara L. Nelson
Keyword(s):  
Water Reuse ◽  
Wastewater Irrigation ◽  
World Health ◽  
Quantitative Microbial Risk Assessment ◽  
Human Pathogens ◽  
Indicator Organisms ◽  
Fecal Indicator ◽  
E Coli ◽  
Human Viruses ◽  
Human Specific

Quantitative microbial risk assessment (QMRA) is frequently used to estimate health risks associated with wastewater irrigation and requires pathogen concentration estimates as inputs. However, human pathogens, such as viruses, are rarely quantified in water samples, and simple relationships between fecal indicator bacteria and pathogen concentrations are used instead. To provide data that can be used to refine QMRA models of wastewater-fed agriculture in Accra, stream, drain, and waste stabilization pond waters used for irrigation were sampled and analyzed for concentrations of fecal indicator microorganisms (human-specific Bacteroidales, Escherichia coli, enterococci, thermotolerant coliform, and somatic and F+ coliphages) and two human viruses (adenovirus and norovirus genogroup II). E. coli concentrations in all samples exceeded limits suggested by the World Health Organization, and human-specific Bacteroidales was found in all but one sample, suggesting human fecal contamination. Human viruses were detected in 16 out of 20 samples, were quantified in 12, and contained 2–3 orders of magnitude more norovirus than predicted by norovirus to E. coli concentration ratios assumed in recent publications employing indicator-based QMRA. As wastewater irrigation can be beneficial for farmers and municipalities, these results should not discourage water reuse in agriculture, but provide motivation and targets for wastewater treatment before use on farms.

scholarly journals Evaluation of Potential Indicators of Viral Contamination in Shellfish and Their Applicability to Diverse Geographical Areas

2003 ◽  
Vol 69 (3) ◽  
pp. 1556-1563 ◽  
Author(s):  
M. Formiga-Cruz ◽  
A. K. Allard ◽  
A.-C. Conden-Hansson ◽  
K. Henshilwood ◽  
B. E. Hernroth ◽  
...  
Keyword(s):  
Hepatitis A Virus ◽  
Human Adenovirus ◽  
Fecal Indicator ◽  
Viral Contamination ◽  
E Coli ◽  
The North ◽  
The United Kingdom ◽  
Before And After ◽  
Microbiological Parameters ◽  
Human Viruses

ABSTRACT The distribution of the concentration of potential indicators of fecal viral pollution in shellfish was analyzed under diverse conditions over 18 months in diverse geographical areas. These microorganisms have been evaluated in relation to contamination by human viral pathogens detected in parallel in the analyzed shellfish samples. Thus, significant shellfish-growing areas from diverse countries in the north and south of Europe (Greece, Spain, Sweden, and the United Kingdom) were defined and studied by analyzing different physicochemical parameters in the water and the levels of Escherichia coli, F-specific RNA bacteriophages, and phages infecting Bacteroides fragilis strain RYC2056 in the shellfish produced, before and after depuration treatments. A total of 475 shellfish samples were studied, and the results were statistically analyzed. According to statistical analysis, the presence of human viruses seems to be related to the presence of all potential indicators in the heavily contaminated areas, where E. coli would probably be suitable as a fecal indicator. The F-RNA phages, which are present in higher numbers in Northern Europe, seem to be significantly related to the presence of viral contamination in shellfish, with a very weak predictive value for hepatitis A virus, human adenovirus, and enterovirus and a stronger one for Norwalk-like virus. However, it is important to note that shellfish produced in A or clean B areas can sporadically contain human viruses even in the absence of E. coli or F-RNA phages. The data presented here will be useful in defining microbiological parameters for improving the sanitary control of shellfish consumed raw or barely cooked.

Soil Textural Inactivation of Residual Faecal Indicator Organisms in Bio Slurry Used for Carrot Production

2021 ◽  
Vol 7 (3) ◽  
pp. 30-35
Author(s):  
J Nakamya ◽  
◽  
J.B Tumuhairwe ◽  
E.N Sabiiti ◽  
J Nakanwagi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Agricultural Research ◽  
Sandy Loam ◽  
Loamy Sand ◽  
Indicator Organisms ◽  
Fecal Indicator ◽  
Makerere University ◽  
E Coli ◽  
Randomized Design ◽  
Screen House

A screen house pot study using bio-slurry at the rate of 7.8 t N / ha was conducted at Makerere University Agricultural Research Institute (MAURIK) Kabanyolo, Uganda. This was monitored using fecal indicator organisms (coliforms, Escherichia coli and Enterococci) in loamy sand, sandy loam and sandy clay loam texture obtained at the study site within 5litres pots under a Complete Randomized Design under a screenhouse. The different textures significantly (p<0.05) reduced the fecal indicator organisms. Conditions within the loamy sand texture reduced the pathogenic microorganisms within 90 days due to its high sand content. In this soil texture, E. coli and enterococci were reduced to undetectable levels within 90 days unlike the coliforms. Fecal, Bio slurry, coliforms, Escherichia. coli, Enterococci

scholarly journals Influence of Soil on Fecal Indicator Organisms in a Tidally Influenced Subtropical Environment

2002 ◽  
Vol 68 (3) ◽  
pp. 1165-1172 ◽  
Author(s):  
Timothy R. Desmarais ◽  
Helena M. Solo-Gabriele ◽  
Carol J. Palmer
Keyword(s):  
River Water ◽  
Laboratory Experiments ◽  
Sediment Accumulation ◽  
Soil Core ◽  
Indicator Organisms ◽  
Field Sampling ◽  
Deep Soil ◽  
Fecal Indicator ◽  
E Coli

ABSTRACT The potential regrowth of fecal indicator bacteria released into coastal environments in recreational water bodies has been of concern, especially in tropical and subtropical areas where the number of these bacteria can be artificially elevated beyond that from fecal impacts alone. The task of determining the factors that influence indicator bacterial regrowth was addressed though a series of field sampling and laboratory experiments using in situ densities of Escherichia coli, enterococci, and Clostridium perfringens in river water, sediment, and soil. Field sampling efforts included the collection of surface sediments along the cross section of a riverbank, a 20-cm-deep soil core, and additional surface soils from remote locations. In addition to field sampling, two types of laboratory experiments were conducted. The first experiment investigated the survival of bacteria already present in river water with the addition of sterile and unsterile sediment. The second experiment was designed to simulate the wetting and drying effects due to tidal cycles. The results from the sampling study found elevated numbers of E. coli and C. perfringens in surficial sediments along the riverbank near the edge of the water. C. perfringens was found in high numbers in the subsurface samples obtained from the soil core. Results from laboratory experiments revealed a significant amount of regrowth for enterococci and E. coli with the simulation of tides and addition of sterile sediment. Regrowth was not observed for C. perfringens. This study demonstrates the need to further evaluate the characteristics of indicator microbes within tropical and subtropical water systems where natural vegetation, soil embankments, and long-term sediment accumulation are present. In such areas, the use of traditional indicator microbes to regulate recreational uses of a water body may not be appropriate.

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