scholarly journals Total and infectious Cryptosporidium oocyst and total Giardia cyst concentrations from distinct agricultural and urban contamination sources in Eastern Canada

2011 ◽  
Vol 10 (1) ◽  
pp. 147-160 ◽  
Author(s):  
Cindy Lalancette ◽  
Mylène Généreux ◽  
Jacinthe Mailly ◽  
Pierre Servais ◽  
Caroline Côté ◽  
...  
Keyword(s):  
Wastewater Treatment Plants ◽  
Cryptosporidium Oocyst ◽  
Human Health Risk ◽  
Giardia Cyst ◽  
Quantitative Microbial Risk Assessment ◽  
Water Safety ◽  
Eastern Canada ◽  
Microbial Risk Assessment ◽  
Discharge Point ◽  
Drinking Water Safety

Cryptosporidium and Giardia (oo)cyst concentrations are frequently used for assessing drinking water safety. The widely used USEPA Method 1623 provides total counts of (oo)cysts, but may not be accurate for human health risk characterization, since it does not provide infectivity information. The total counts and infectious fraction of Cryptosporidium oocysts and the total counts of Giardia cysts were assessed in major fecal pollution sources. Fresh calf and cow feces, their manure, and the discharge point were sampled in a small rural sub-watershed (n = 20, 21, 10, 10). Median concentrations for total (oo)cysts were higher in calves (333 oocysts g−1; 111 cysts g−1) than in cows (52 oocysts g−1; 7 cysts g−1). Infectious oocysts were found in 17 (7%) of the samples and none were found in manure or at the discharge point. Urban sources were sampled in the influent and effluent (n = 19, 18) of two wastewater treatment plants. Peak concentrations were 533 oocysts L−1 and 9,010 cysts L−1 for influents and 89 oocysts L−1 and 472 cysts L−1 for effluents. Infectious oocyst fractions varied from below the detection limit to 7–22% in the effluent and influent respectively. These infectious fractions are significantly lower than those currently used for quantitative microbial risk assessment estimates.

scholarly journals Quantitative microbial risk assessment of SARS-CoV-2 for workers in wastewater treatment plants

2021 ◽  
Vol 754 ◽  
pp. 142163 ◽  
Author(s):  
Rafael Newton Zaneti ◽  
Viviane Girardi ◽  
Fernando Rosado Spilki ◽  
Kristina Mena ◽  
Ana Paula Campos Westphalen ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Quantitative Microbial Risk Assessment ◽  
Microbial Risk Assessment ◽  
Microbial Risk

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

2018 ◽  
Vol 84 (6) ◽  
pp. e02093-17 ◽  
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.

scholarly journals Risk of diarrhoea from shallow groundwater contaminated with enteropathogens in the Kathmandu Valley, Nepal

2014 ◽  
Vol 13 (1) ◽  
pp. 259-269 ◽  
Author(s):  
Sadhana Shrestha ◽  
Eiji Haramoto ◽  
Rabin Malla ◽  
Kei Nishida
Keyword(s):  
Water Treatment ◽  
Cryptosporidium Oocyst ◽  
Shallow Groundwater ◽  
Kathmandu Valley ◽  
Giardia Cyst ◽  
Quantitative Microbial Risk Assessment ◽  
Total Risk ◽  
E Coli ◽  
Tube Wells ◽  
Increased Risk

Shallow groundwater is the main water source among many alternatives in the Kathmandu Valley, Nepal, which has a rapidly growing population and intermittent piped water supply. Although human pathogens are detected in groundwater, its health effects are unclear. We estimated risk of diarrhoea from shallow groundwater use using quantitative microbial risk assessment. Escherichia coli, Giardia cyst and Cryptosporidium oocyst levels were analysed in dug and tube wells samples. E. coli concentrations were converted to those of enteropathogenic E. coli (EPEC). Risks from EPEC in dug wells and from Cryptosporidium and Giardia in both dug and tube wells were higher than the acceptable limit (<10−4 infections/person-year) for both drinking and bathing exposures. Risk from protozoan enteropathogens increased the total risk 10,000 times, indicating that ignoring protozoans could lead to serious risk underestimation. Bathing exposure considerably increased risk, indicating that it is an important pathway. Point-of-use (POU) water treatment decreased the risk six-fold and decreased risk overestimation. Because removal efficiency of POU water treatment has the largest impact on total risk, increasing the coverage and efficiency of POU water treatment could be a practical risk management strategy in the Kathmandu Valley and similar settings.

scholarly journals Molecular characterization of the waterborne pathogens Cryptosporidium spp., Giardia duodenalis, Enterocytozoon bieneusi, Cyclospora cayetanensis and Eimeria spp. in wastewater and sewage in Guangzhou, China

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yingying Fan ◽  
Xinrui Wang ◽  
Ruohong Yang ◽  
Wentao Zhao ◽  
Na Li ◽  
...  
Keyword(s):  
Wastewater Treatment Plants ◽  
Giardia Duodenalis ◽  
Enterocytozoon Bieneusi ◽  
Quantitative Microbial Risk Assessment ◽  
Waterborne Pathogens ◽  
Microbial Risk Assessment ◽  
Cyclospora Cayetanensis ◽  
Type Iv ◽  
Eimeria Spp ◽  
Wastewater Samples

Abstract Background The waterborne pathogens Cryptosporidium spp., Giardia duodenalis, Enterocytozoon bieneusi and Cyclospora cayetanensis can cause intestinal diseases in humans. An understanding of their occurrence and transport in the environment is essential for accurate quantitative microbial risk assessment. Methods A total of 238 influent samples were collected from four wastewater treatment plants (WWTPs) and 88 samples from eight sewer locations in Guangzhou, China. PCR-based tools were used to detect and genetically characterize Cryptosporidium spp., G. duodenalis and E. bieneusi. Eimeria spp. and Cyclospora spp. were also analyzed to assess the sources of Cryptosporidium spp., G. duodenalis and E. bieneusi in wastewater. Results The overall occurrence rates in the WWTP and sewer samples were 14.3% (34/238) and 13.6% (12/88) for Cryptosporidium spp., 55.5% (132/238) and 33.0% (29/88) for G. duodenalis, 56.3% (134/238) and 26.1% (23/88) for E. bieneusi and 45.4% (108/238) and 47.7% (42/88) for Eimeria spp., respectively. Altogether, 11 Cryptosporidium species and genotypes, six G. duodenalis genotypes, 11 E. bieneusi genotypes and four C. cayetanensis were found, together with the presence of nine Eimeria species. The common occurrence of Cryptosporidium rat genotype IV, C. muris and Eimeria papillata and E. nieschulzi suggested that rodents were significant sources of the enteric pathogens detected in the wastewater samples. Conclusions While the dominant Cryptosporidium spp. detected in the raw wastewater sampled in this study are not pathogenic to humans, the widely detected G. duodenalis assemblage A and E. bieneusi genotypes D and Type IV are well-known zoonotic pathogens. Further studies are needed to monitor the occurrence of these waterborne pathogens in WWTPs to better understand their transmission and environmental transport in China.

scholarly journals QMRA of SARS-CoV-2 for workers in wastewater treatment plants

2020 ◽  
Author(s):  
Rafael Newton Zaneti ◽  
Viviane Girardi ◽  
Fernando Rosado Spilki ◽  
Kristina Mena ◽  
Ana Paula Campos Westphalen ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Management Strategies ◽  
Quantitative Microbial Risk Assessment ◽  
Potential Health ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Risk Management Strategies ◽  
Novel Coronavirus ◽  
Sanitation Systems

AbstractFaecal-oral transmission of SARS-CoV-2 is a hot topic and additional research is needed to elucidate the risks of the novel coronavirus in sanitation systems. This is the first article that investigates the potential health risks of SARS-CoV-2 in sewage to wastewater treatment plants (WWTPs) workers. A quantitative microbial risk assessment (QMRA) is applied for three COVID-19 scenarios (moderate, aggressive and extreme) to study the effect of different stages of the pandemic, in terms of percentage of infected population, on the probability of infection. Results reveal that estimates of viral loads in sewage at the entrance of WWTPs ranged from 1.03×102 to 1.31×104 GC.mL−1 (0.1 to 13.06 PFU.mL−1, respectively) and that estimated risks for the aggressive and extreme scenarios (6.5×10−3 and 3.1×10−2, respectively) were likely to be above a WHO benchmark of tolerable risk used for virus infection of 10−3 and higher than the risk of infection of E. coli, used herein as common pathogen indicator for a relative comparison, thus reinforcing the concern of sewage systems as a transmission pathway of SARS-CoV-2. These findings are helpful as an early-warning tool and in prioritizing upcoming risk management strategies in the sanitation sector during COVID-19 pandemic.

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