Quantitative Microbial Risk Assessment of Pathogenic Vibrios in Marine Recreational Waters of Southern California

ABSTRACTThis study investigated the occurrence of three types of vibrios in Southern California recreational beach waters during the peak marine bathing season in 2007. Over 160 water samples were concentrated and enriched for the detection of vibrios. Four sets of PCR primers, specific forVibrio cholerae,V. parahaemolyticus, andV. vulnificusspecies and theV. parahaemolyticustoxin gene, respectively, were used for the amplification of bacterial genomic DNA. Of 66 samples from Doheny State Beach, CA, 40.1% were positive forV. choleraeand 27.3% were positive forV. parahaemolyticus, and 1 sample (1.5%) was positive for theV. parahaemolyticustoxin gene. Of the 96 samples from Avalon Harbor, CA, 18.7% were positive forV. cholerae, 69.8% were positive forV. parahaemolyticus, and 5.2% were positive for theV. parahaemolyticustoxin gene. The detection of theV. choleraegenetic marker was significantly more frequent at Doheny State Beach, while the detection of theV. parahaemolyticusgenetic marker was significantly more frequent at Avalon Harbor. A probability-of-illness model forV. parahaemolyticuswas applied to the data. The risk for bathers exposed to recreational waters at two beaches was evaluated through Monte Carlo simulation techniques. The results suggest that the microbial risk from vibrios during beach recreation was below the illness benchmark set by the U.S. EPA. However, the risk varied with location and the type of water recreation activities. Surfers and children were exposed to a higher risk of vibrio diseases. Microbial risk assessment can serve as a useful tool for the management of risk related to opportunistic marine pathogens.

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The application of quantitative microbial risk assessment to natural recreational waters: A review

Marine Pollution Bulletin ◽

10.1016/j.marpolbul.2019.04.073 ◽

2019 ◽

Vol 144 ◽

pp. 334-350 ◽

Cited By ~ 10

Author(s):

Ileana Federigi ◽

Marco Verani ◽

Gabriele Donzelli ◽

Lorenzo Cioni ◽

Annalaura Carducci

Keyword(s):

Risk Assessment ◽

Quantitative Microbial Risk Assessment ◽

Recreational Waters ◽

Microbial Risk Assessment ◽

Microbial Risk

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Sapovirus in Wastewater Treatment Plants in Tunisia: Prevalence, Removal, and Genetic Characterization

Applied and Environmental Microbiology ◽

10.1128/aem.02093-17 ◽

2018 ◽

Vol 84 (6) ◽

pp. e02093-17 ◽

Cited By ~ 11

Author(s):

Miguel F. Varela ◽

Imen Ouardani ◽

Tsuyoshi Kato ◽

Syunsuke Kadoya ◽

Mahjoub Aouni ◽

...

Keyword(s):

Risk Assessment ◽

Wastewater Treatment ◽

Bayesian Estimation ◽

Quantitative Pcr ◽

Censored Data ◽

Wastewater Treatment Plants ◽

Quantitative Microbial Risk Assessment ◽

Content Type ◽

Microbial Risk Assessment ◽

Microbial Risk

ABSTRACTSapovirus(SaV), from theCaliciviridaefamily, is a genus of enteric viruses that cause acute gastroenteritis. SaV is shed at high concentrations with feces into wastewater, which is usually discharged into aquatic environments or reused for irrigation without efficient treatments. This study analyzed the incidence of human SaV in four wastewater treatment plants from Tunisia during a period of 13 months (December 2009 to December 2010). Detection and quantification were carried out using reverse transcription-quantitative PCR (RT-qPCR) methods, obtaining a prevalence of 39.9% (87/218). Sixty-one positive samples were detected in untreated water and 26 positive samples in processed water. The Dekhila plant presented the highest contamination levels, with a 63.0% prevalence. A dominance of genotype I.2 was observed on 15 of the 24 positive samples that were genetically characterized. By a Bayesian estimation algorithm, the SaV density in wastewater was estimated using left-censored data sets. The mean value of log SaV concentration in untreated wastewater ranged between 2.7 and 4.5 logs. A virus removal efficiency of 0.2 log was calculated for the Dekhila plant as the log ratio posterior distributions between untreated and treated wastewater. Multiple quantitative values obtained in this study must be available in quantitative microbial risk assessment in Tunisia as parameter values reflecting local conditions.IMPORTANCEHuman sapovirus (SaV) is becoming more prevalent worldwide and organisms in this genus are recognized as emerging pathogens associated with human gastroenteritis. The present study describes novel findings on the prevalence, seasonality, and genotype distribution of SaV in Tunisia and Northern Africa. In addition, a statistical approximation using Bayesian estimation of the posterior predictive distribution (“left-censored” data) was employed to solve methodological problems related with the limit of quantification of the quantitative PCR (qPCR). This approach would be helpful for the future development of quantitative microbial risk assessment procedures for wastewater.

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Comparison of recreational health risks associated with surfing and swimming in dry weather and post-storm conditions at Southern California beaches using quantitative microbial risk assessment (QMRA)

Marine Pollution Bulletin ◽

10.1016/j.marpolbul.2012.03.009 ◽

2012 ◽

Vol 64 (5) ◽

pp. 912-918 ◽

Cited By ~ 31

Author(s):

Linda Y. Tseng ◽

Sunny C. Jiang

Keyword(s):

Risk Assessment ◽

Health Risks ◽

Southern California ◽

Quantitative Microbial Risk Assessment ◽

Microbial Risk Assessment ◽

Microbial Risk

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Human Health Risks Associated with Recreational Waters: Preliminary Approach of Integrating Quantitative Microbial Risk Assessment with Microbial Source Tracking

Water ◽

10.3390/w12020327 ◽

2020 ◽

Vol 12 (2) ◽

pp. 327 ◽

Cited By ~ 1

Author(s):

Anna Gitter ◽

Kristina Mena ◽

Kevin Wagner ◽

Diane Boellstorff ◽

Kyna Borel ◽

...

Keyword(s):

Risk Assessment ◽

Human Health ◽

Sampling Site ◽

Microbial Source Tracking ◽

Source Tracking ◽

Quantitative Microbial Risk Assessment ◽

Recreational Waters ◽

Microbial Risk Assessment ◽

Microbial Risk ◽

E Coli

Gastrointestinal (GI) illness risks associated with exposure to waters impacted by human and nonhuman fecal sources were estimated using quantitative microbial risk assessment (QMRA). Microbial source tracking (MST) results had identified Escherichia coli (E. coli) contributors to the waterbody as human and unidentified (10%), cattle and domestic animals (25%), and wildlife (65%) in a rural watershed. The illness risks associated with ingestion during recreation were calculated by assigning reference pathogens for each contributing source and using pathogen dose–response relationships. The risk of GI illness was calculated for a specific sampling site with a geometric mean of E. coli of 163 colony forming units (cfu) 100 mL−1, and the recreational standard of E. coli, 126 cfu 100 mL−1. While the most frequent sources of fecal indicator bacteria at the sampling site were nonhuman, the risk of illness from norovirus, the reference pathogen representing human waste, contributed the greatest risk to human health. This study serves as a preliminary review regarding the potential for incorporating results from library-dependent MST to inform a QMRA for recreational waters. The simulations indicated that identifying the sources contributing to the bacterial impairment is critical to estimate the human health risk associated with recreation in a waterbody.

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