Fecal Contamination Of Water Research Articles

Risk of Faecal Contamination of Water Used by Food Vendors in Owerri Munipality, Imo State Nigeria

Assessment of faecal contamination of water is a key factor in assessing the quality and safety of food. It also reveals the level of hygiene adopted by food handlers in the course of preparation and serving of such foods. This study assessed the risk of microbial contamination of water used by food vendors in Owerri munipality, Imo State Nigeria between January-December 2019 with an emphasis on total coliforms and the faecal coliforms/ faecal indicator bacteria (FIB) – Escherichia coli (E. coli) and thermotolerant coliforms (TTC). One hundred and thirty water samples collected across three vending types (street vendors, high level and low level restaurants) were evaluated for microbial contamination using standard methods. Data obtained was statistically analyzed with p-value set at 0.05 significance level. The result identified Enterobacter spp. and Klebsiella spp. The result showed that 48.46% (63) of the 130 water samples examined were contaminated with coliform bacteria, of which 20 (22.22%) samples had faecal coliform bacteria, representing 10.77% of the entire water samples examined. Of the 64 samples from water used for food preparation, 12.50% (8) had faecal coliform bacteria as against 9.09% (6) of 66 samples collected from water offered to customers for drinking. The result showed that 116 (89.23%) of the 130 water samples recorded no faecal coliform contamination, hence they were considered excellent based on the guidelines for determination of faecal contamination of water. Two samples had faecal coliform counts of 1-3 per 100 ml of water accounting for 1.54% of water samples, which is considered Satisfactory. The result revealed suspicious (4-9 per 100 ml) coliform count in 9 (6.92%) water samples, while three water samples (2.31%) had ≥10 count and are classified as unsatisfactory. The result revealed that 89.23% (116) of the examined water samples were of ‘no risk’ to the public, which was significantly higher than 8.46% (11) and 2.31% (3) recognized as being of low and intermediate risk respectively (p <0.05). High and very high risk water samples were not encountered in the study. This trend in qualification of risk of water samples reflected in the two types of water usages, and the observed differences was however not statistically significant (p>0.05).

Microbial Source Tracking: An Emerging Technology for Microbial Water Quality Assessment: A Review

Microbial Source Tracking is a scientific approach that primarily aims to identify the sources of faecal contamination in water bodies. Microbial Source Tracking (MST) is a set of techniques employed to identify the origins of faecal contamination in water. The capacity to track faecal bacteria to their source is a crucial aspect of both public health and water quality management. The utilisation of information obtained from the method of MST would provide water quality managers with an enhanced comprehension of the origins of contamination, thus facilitating the implementation of remedial measures to impede transmission. Numerous studies have demonstrated that the gut-associated bacteria of the order Bacteroidales, specifically the Bacteroides genus, has a tendency to undergo co-evolution with the host, making it a highly viable option for MST applications. However, it is noteworthy that MST is also facilitating the scientific community with effective techniques for tracing faecal bacteria and pathogens in water sources. The methodologies utilised in MST are frequently categorised as either Library-Dependent Methods (LDMs) or Library-Independent Methods (LIMs). Microbial source tracking has been employed for diverse objectives, such as ensuring adherence to regulations, remediating pollution, and evaluating risk. The implementation of MST is expected to mitigate the prevalence of waterborne illnesses resulting from contamination. The implementation of MST has facilitated the ability to anticipate the probable origins of faecal contamination and the associated health hazards linked to compromised water systems. In addition to conventional faecal indicators, these methodologies are suggested as means to furnish supplementary insights into the origins of pollution, as well as the ecological and public health ramifications of animal-derived water contamination. 

Drinking water contamination potential and associated factors among households with under-five children in rural areas of Dessie Zuria District, Northeast Ethiopia.

More than half of the 700 million people worldwide who lack access to a safe water supply live in sub-Saharan Africa, including Ethiopia. Globally, approximately 2 billion people use drinking water sources that are contaminated with fecal matter. However, little is known about the relationship between fecal coliforms and determinants in drinking water. Therefore, the objective of this study was to investigate the potential for contamination of drinking water and its associated factors in households with children under 5 years of age in Dessie Zuria district in northeastern Ethiopia. The water laboratory was conducted based on the American Public Health Association guidelines for water and wastewater assessment using a membrane filtration technique. A structured and pre-tested questionnaire was used to identify factors associated with the potential for contamination of drinking water in 412 selected households. A binary logistic regression analysis was performed to determine the factors associated with the presence or absence of fecal coliforms in drinking water, with a 95% confidence interval (CI) and a value of p ≤ 0.05. The overall goodness of the model was tested using the Hosmer-Lemeshow test, and the model was fit. A total of 241 (58.5%) households relied on unimproved water supply sources. In addition, approximately two-thirds 272 (66.0%) of the household water samples were positive for fecal coliform bacteria. Water storage duration ≥3 days (AOR = 4.632; 95% CI: 1.529-14.034), dipping method of water withdrawal from a water storage tank (AOR = 4.377; 95% CI: 1.382-7.171), uncovered water storage tank at control (AOR = 5.700; 95% CI: 2.017-31.189), lack of home-based water treatment (AOR = 4.822; 95% CI: 1.730-13.442), and unsafe household liquid waste disposal methods (AOR = 3.066; 95% CI: 1.706-8.735) were factors significantly associated with the presence of fecal contamination in drinking water. Fecal contamination of water was high. The duration of water storage, the method of water withdrawal from the storage container, covering of the water storage container, the presence of home-based water treatment, and the method of liquid waste disposal were factors for fecal contamination in drinking water. Therefore, health professionals should continuously educate the public on proper water use and water quality assessment.

Hand hygiene and water quality assessment in schools of Muthanna province, Southern Iraq.

The severe drought and prolonged heat waves in Iraq have adversely affected the water quality supplied to public facilities. Schools are among the most affected facilities by water scarcity. This work aims to evaluate the level of students' hand hygiene, and the quality of municipal (MW) and drinking water (DW) in some schools of Al-Muthanna Province, Iraq. Between October 2021 and June 2022, a total of 324 water samples from 162 schools and 2,430 hand swabs (HSs) from 1,620 students (1,080 males and 540 females) were collected. Some physicochemical standards of water were assessed besides investigating faecal contamination in water and students' hands using Escherichia coli as an indicator. All MW samples were faecally contaminated with poor standards of pH, turbidity, total dissolved solids, color, and chlorine. Despite the good physicochemical standards of all DW samples, E. coli was observed in 12% of samples. Hand hygiene levels dropped by 2.5-fold within a few hours after school entry compared to early-morning levels (before school entry). Male students were 1.5- and 1.7-fold more prone to hand contamination than female students either inside or outside school, respectively. An increasing chlorine tolerance by E. coli was observed in water samples with turbidity > 5 NTU and pH > 8. The students' hand hygiene level decreases within a few hours of entering school, particularly among male students. Residual-free chlorine < 0.5 mg/L with high turbidity and alkalinity in water is insufficient for 100% prevention of E. coli contamination.

Examining ecosystem (dis-)services on liver fluke infection in rural Northeast Thailand

BackgroundThe direct reliance of humans on and their interactions with freshwater ecosystems in the Lower Mekong Basin have given rise to parasitic infections, which is particularly prevalent in Northeast Thailand where raw fish consumption is practiced. This study examined the interactions between environments, ecosystem (dis-)services, human raw fish consumption habits, and raw fish dish sharing on liver fluke infection risk.MethodWater fecal contents and the first intermediate snail host were sampled between June and September of 2019. One hundred twenty questionnaires were surveyed in two villages of different environmental surroundings, one next to a river and the other located inland, in Northeast Thailand. Multivariate regression analyses using linear mixed effect models assessed the influence of social, behavioral and perceptual factors on raw fish consumption frequency, willingness to avoid consumption and liver fluke infection status. Social network analysis compared the degree of raw fish dish sharing between the villages and assessed the probable influence of connections to fish procurement locations and sharing activities on liver fluke infection risk.ResultsHigh abundance of the first intermediate snail host and presence of fecal contamination in water could endanger both villages to ecosystem disservices of parasitic transmission. The river-side village relied more on provisioning ecosystem services than the inland village (29.7% vs. 16.1% of villages) to consume raw fish as their main source of protein. Males in both villages (64.5 and 40.4 days/year for the respective villages) are also likely to consume koi pla and pla som, higher risk fish dishes, more frequently than females (4.1 and 4.3 days/year for the respective villages). The consumption habits of both villages were driven mostly by deriving cultural ecosystem services. Participation in raw fish dish sharing activities significantly reduced the odds of an individual being willing to avoid the consumption (Odds ratio = 0.19). Network analysis suggested that river-side villagers had a more direct raw fish dish sharing interaction and they procured fish from multiple locations; these characteristics might potentially account for more liver fluke infected households in the village.ConclusionVillagers’ raw fish consumption is driven by deriving cultural ecosystem services, and the geographic settings of the villages potentially affect villagers’ fish procurement locations and infection risk. The findings underscore the linkages between villagers and their surrounding ecosystem environments as pertinent determinants for foodborne parasitic disease risk.Graphical

Household drinking water quality and its predictors in flood-prone settings of Northwest Ethiopia: A cross-sectional community-based study

Globally, the deterioration of drinking water quality is a major public health problem that contributes to the spread of disease and causes death. Therefore, it is important to have regular quality control monitoring. This study aimed to assess the level of physicochemical and bacteriological quality of household drinking water and its contributing factors in flood-prone settlements of South Gondar Zone, Ethiopia. A community-based cross-sectional study was conducted in flood-prone settings of Northwest Ethiopia from January 17 to March 30, 2021. Structured questionnaires were used to gather the sociodemographic, environmental, and behavioral data. A total of 675 drinking water samples were collected from water storage containers of selected households. Logistic regression models were used for both univariate and multivariable studies. The survey included a total of 675 households. The mean values of pH (5.9 ± 1.03), turbidity (6.7 ± 2.21 NTU), and free residual chlorine (0.02 ± 0.01 mg/l) did not meet the WHO recommended limits for drinking water. The prevalence of fecal contamination of drinking water in the study area was 62.2% with [95% CI (53–60%)]. Family size [AOR = 2.205, 95% CI (1.375–3.536), absence of latrine [AOR = 3.449, 95% CI (1.349–8.823)], and lack of a separate container to draw water from its storage [AOR = 0.454, 95% CI (0.249–0.827)] were significant predictors for fecal contamination of household drinking water. In conclusion, the water quality in terms of pH, turbidity, residual chlorine, and bacteriological parameters was poor and not suitable for consumption. High prevalence of fecal contamination of water was found, and it was significantly associated with family size, the absence of a latrine, and the lack of a separate cap to take water from the storage. Therefore, continuous chlorination and monitoring its concentration, educating the community on how to use stored water, educating the advantage of having a latrine, and promoting point-of-use treatments such as filtration and boiling are needed.

Utilization of Tryptophan-like Fluorescence as a Proxy for E. coli Contamination in a Mixed-Land-Use Karst Basin

Karst aquifers are susceptible to contamination by pathogenic microorganisms, such as those found in human and animal waste, because the surface and subsurface drainage are well integrated through dissolution features. Fecal contamination of water is commonly assessed by the concentration of thermotolerant coliform bacteria, especially E. coli. This method is time-consuming, taking ≥18 h between the start of incubation and subsequent enumeration, as well as the time required to collect and transport samples. We examined the utility of continuous monitoring of tryptophan-like fluorescence (TLF) as a real-time proxy for E. coli in a mixed-land-use karst basin in the Inner Bluegrass region of central Kentucky (USA). Two logging fluorometers were sequentially deployed at the outlet spring. During storm flow, TLF typically peaked after discharge, which suggests that TLF transport in the phreatic conduit is likely related to sediment transport. The ability of TLF and other parameters (48 h antecedent precipitation, turbidity, and air temperature) to predict E. coli concentrations was assessed using the Akaike information criterion (AIC) applied to linear regression models. Because both the models and baseline concentrations of TLF differed between fluorometers, TLF and instrument interaction were accounted for in the AIC. TLF was positively correlated with E. coli and, in conjunction with antecedent precipitation, was the best predictor of E. coli. However, a model that included air temperature and antecedent precipitation but not TLF predicted E. coli concentrations similarly well. Given the expense of the fluorometers and the performance of the alternate model, TLF may not be a cost-effective proxy for E. coli in this karst basin.

Cholera outbreak in some communities in North-East Nigeria, 2019: an unmatched case–control study

BackgroundCholera, a diarrheal disease caused by the bacterium Vibrio cholerae, transmitted through fecal contamination of water or food remains an ever-present risk in many countries, especially where water supply, sanitation, food safety, and hygiene are inadequate. A cholera outbreak was reported in Bauchi State, North-eastern Nigeria. We investigated the outbreak to determine the extent and assess risk factors associated with the outbreak.MethodsWe conducted a descriptive analysis of suspected cholera cases to determine the fatality rate (CFR), attack rate (AR), and trends/patterns of the outbreak. We also conducted a 1:2 unmatched case–control study to assess risk factors amongst 110 confirmed cases and 220 uninfected individuals (controls). We defined a suspected case as any person > 5 years with acute watery diarrhea with/without vomiting; a confirmed case as any suspected case in which there was laboratory isolation of Vibrio cholerae O1 or O139 from the stool while control was any uninfected individual with close contact (same household) with a confirmed case. Children under 5 were not included in the case definition however, samples from this age group were collected where such symptoms had occurred and line-listed separately. Data were collected with an interviewer-administered questionnaire and analyzed using Epi-info and Microsoft excel for frequencies, proportions, bivariate and multivariate analysis at a 95% confidence interval.ResultsA total of 9725 cases were line-listed with a CFR of 0.3% in the state. Dass LGA had the highest CFR (14.3%) while Bauchi LGA recorded the highest AR of 1,830 cases per 100,000 persons. Factors significantly associated with cholera infection were attending social gatherings (aOR = 2.04, 95% CI = 1.16–3.59) and drinking unsafe water (aOR = 1.74, 95% CI = 1.07–2.83).ConclusionAttending social gatherings and drinking unsafe water were risk factors for cholera infection. Public health actions included chlorination of wells and distribution of water guard (1% chlorine solution) bottles to households and public education on cholera prevention. We recommend the provision of safe drinking water by the government as well as improved sanitary and hygienic conditions for citizens of the state.

SOLITARY INTRAMUSCULAR CYSTICERCOSIS OF RIGHT ELBOW REGION

Cysticercosis and Taeniasis are two conditions that tapeworms can transmit to humans. Cysticerci can be contracted by eating pork meat or eating eggs with tainted water. Cystocercosis of the muscles typically has no symptoms. Once the infection has been identified, it is critical to screen out intra-ocular and intra-cranial involvement since involuting cysticercus causes a strong inflammatory response that, if not discovered and treated promptly, can result in blindness. Controlling fecal contamination of water and food requires proper sanitation and personal hygiene. Food that is raw or inadequately cooked should be avoided, especially in endemic areas. A crucial component of treatment is conservative treatment with medicines. Surgical intervention is reserved for instances that do not react to conservative treatment and do not provide symptomatic relief. In our case, after establishing the diagnosis with ultrasound and magnetic resonance imaging, albendazole was administered as treatment and the definite diagnosis was made. In conclusion, although isolated soft tissue cysticercosis is difficult to identify most of the time, especially when it is not accompanied by central nervous system infection, if larvae can be demonstrated with any imaging modalities, cysticercosis can be easily diagnosed without further differential diagnosis.

Prevalence of diarrheal disease and associated factors among under-five children in flood-prone settlements of Northwest Ethiopia: A cross-sectional community-based study.

Diarrheal illnesses are a long-standing public health problem in developing countries due to numerous sanitation issues and a lack of safe drinking water. Floods exacerbate public health issues by spreading water-borne infectious diseases such as diarrhea through the destruction of sanitation facilities and contamination of drinking water. There has been a shortage of studies regarding the magnitude of diarrheal disease in flood-prone areas. Therefore, this research aimed to evaluate the prevalence of diarrheal disease and its predictors among under-five children living in flood-prone localities in the south Gondar zone of Northwest Ethiopia. A community-based cross-sectional research was carried out in flood-prone villages of the Fogera and Libokemkem districts from March 17 to March 30, 2021. Purposive and systematic sampling techniques were used to select six kebeles and 717 study units, respectively. Structured and pretested questionnaires were used to collect the data. A multivariable analysis was performed to determine the predictors of diarrheal disease, with P-value <0.05 used as the cut-off point to declare the association. The prevalence of a diarrheal disease among under-five children was 29.0%. The regular cleaning of the compound [AOR: 2.13; 95% CI (1.25, 3.62)], source of drinking water [AOR: 2.36; 95% CI: (1.26, 4.41)], animal access to water storage site [AOR: 3.04; 95% CI: (1.76, 5.24)], vector around food storage sites [AOR: 9.13; 95% CI: (4.06, 20.52)], use of leftover food [AOR: 4.31; 95% CI: (2.64, 7.04)], and fecal contamination of water [AOR: 12.56; 95% CI: (6.83, 23.20)] remained to have a significant association with diarrheal diseases. The present study found that the prevalence of the diarrheal disease among under-five children was high. Routine compound cleaning, the source of drinking water, animal access to a water storage site, vectors near food storage sites, consumption of leftover food, and fecal contamination of water were significant predictors of diarrheal disease. Therefore, it is advised to provide improved water sources, encourage routine cleaning of the living area, and offer health education about water, hygiene, and sanitation.

Viral Metagenomics as a Tool to Track Sources of Fecal Contamination: A One Health Approach.

The One Health framework recognizes that human, animal, and environmental health are linked and highly interdependent. Fecal contamination of water, soil, foodstuff, and air may impact many aspects of One Health, and culture, PCR-based, and sequencing methods are utilized in the detection of fecal contamination to determine source, load, and risk to inform targeted mitigation strategies. Viruses, particularly, have been considered as fecal contamination indicators given the narrow host range many exhibit and their association with other biological contaminants. Culture- and molecular-based methods are considered the gold-standards for virus detection and for determining specific sources of fecal contamination via viral indicators. However, viral metagenomics is also being considered as a tool for tracking sources of fecal contamination. In the present review, studies tracking potential sources of fecal contamination in freshwaters, marine waters, foodstuff, soil, and air using viral metagenomics are discussed to highlight the potential of viral metagenomics for optimizing fecal source tracking. Limitations of the use of viral metagenomics to track fecal contamination sources, including sample processing, nucleic acid recovery, sequencing depth, and bioinformatics are also discussed. Finally, the present review discusses the potential of viral metagenomics as part of the toolbox of methods in a One Health approach.

Endotoxin as a Marker for Water Quality

Water quality testing is vital to protect human health. Current testing relies mainly on culture-based detection of faecal indicator organisms such as Escherichia coli (E.coli). However, bacterial cultures are a slow process, taking 24-48 h and requiring specialised laboratories and trained personnel. Access to such laboratories is often sparse in developing countries and there are many fatalities deriving from poor water quality. Endotoxin is a molecular component of Gram-negative bacterial cell walls and can be used to detect their presence in drinking water. The current study used a novel assay (BacterisK) to rapidly detect endotoxin in various water samples and correlate the results with E. coli content measured by culture methods. The data generated by the BacterisK assay are presented as an 'endotoxin risk' (ER). The ER values correlate with E. coli and thus endotoxin can be used as a marker of faecal contamination in water. Moreover, the BacterisK assay provides data in near real-time and can be used in situ allowing water quality testing at different spatial and temporal locations. We suggest that BacterisK can be used as a convenient risk assessment tool to assess water quality where results are required quickly or access to laboratories is lacking.

Lessons from Vaccine-Related Poliovirus in Israel, UK and USA.

Genetic variants of vaccine poliovirus type 2, imported from an unknown source, were detected in waste waters in Jerusalem, London and New York in early 2022. Wild poliovirus type 2 was globally eradicated in 1999, but vaccine virus type 2 continued for 16 more years; routine use of the vaccine was discontinued in 2016 and reintroduced occasionally on purpose. As an unintended consequence, type 2 vaccine virus variants (circulating vaccine-derived polioviruses, cVDPVs) that mimic wild viruses' contagiousness and neurovirulence, have been emerging and spreading. To illustrate, in just the past four years (2018-2021), 2296 children developed cVDPV polio in 35 low-income countries. Many assume that virus transmission is via the faecal-oral route. Sustained virus transmission was documented in London and New York, in spite of high standards of sanitation and hygiene. Here, virus transmission cannot be attributed to faecal contamination of food or drinking water (for faecal-oral transmission). Hence, contagious transmission can only be explained by inhalation of droplets/aerosol containing virus shed in pharyngeal fluids (respiratory transmission), as was the classical teaching of polio epidemiology. If transmission efficiency of VDPV is via the respiratory route where hygiene is good, it stands to reason that it is the same case in countries with poor hygiene, since poor hygiene cannot be a barrier against respiratory transmission. By extrapolation, the extreme transmission efficiency of wild polioviruses must also have been due to their ability to exploit respiratory route transmission. These lessons have implications for global polio eradication. It was as a result of assuming faecal-oral transmission that eradication was attempted with live attenuated oral polio vaccine (OPV), ignoring its safety problems and very low efficacy in low-income countries. Inactivated poliovirus vaccine (IPV) is completely safe and highly efficacious in protecting children against polio, with just three routine doses. Protecting all children from polio must be the interim goal of eradication, until poliovirus circulation dies out under sustained immunisation pressure. OPV should be discontinued under cover of immunity induced by IPV to stop the emergence of new lineages of VDPVs, not only type 2, but also types 1 and 3, to expedite the completion of polio eradication.

Enumeration, Serotypes and Virulence Genes Associated with Shigatoxigenic (STEC) and Enterotoxigenic (ETEC) Escherichia coli from Beef and Chicken of Mizoram, India

Background: E. coli is one of the most important zoonotic pathogen and also an indicator of faecal contamination of food and water. There is paucity of data regarding the level of contamination of raw meat and characterization of pathogenic E. coli from slaughtered cattle and chicken in un-organized sector from Mizoram, India. Methods: Raw meat samples from traditionally slaughtered cattle and chicken were collected from Aizawl, Kolasib and Champhai districts of Mizoram and analyzed for E. coli count (ECC), serotypes and virulence genes of STEC and ETEC. Result: A proportion of 65.55 per cent beef and 58.89 per cent chicken had unacceptable level of ECC. The most predominant serotypes of E. coli were O118 (13.33%) in beef and O8 (13.89%) in chicken. Both STEC (8.00% and 6.94%) and ETEC (12.00% and 26.38%) pathotypes were detected in beef and chicken, respectively. Detection of serotype O121 in chicken and O26 and O111 in both beef and chicken along with virulence genes of STEC indicated the contamination of raw meat with highly pathogenic STEC strains.

Improving the Identification of Fecal Contamination in Recreational Water through the Standardization and Normalization of Microbial Source Tracking

Improving the Identification of Fecal Contamination in Recreational Water through the Standardization and Normalization of Microbial Source Tracking

The impact of anthropogenic and environmental factors on the variability of Escherichia coli in rivers in southwest Bangladesh

Faecal contamination of surface water sources is an important water quality issue worldwide. Although quite a few studies exist on surface water faecal contamination and variability of indicator bacteria, most of the studies have been based on larger river basins and in temperate region. The variability is relatively unknown in local scale and in tropical developing countries. In this study, we assess how anthropogenic and environmental factors affect faecal contamination and physicochemical parameters in Rupsha and Bhairab rivers around Khulna city, Bangladesh. Water samples were collected from six locations of the rivers during a wet and dry period in 2018 to measure Escherichia coli (E. coli) concentrations applying membrane filtration method. Of the physicochemical parameters examined, turbidity, biochemical oxygen demand, and chemical oxygen demand showed higher levels of spatial variability (variation over 30%). Higher concentrations of E. coli were found in the sampling sites located near the densely populated urban area compared to the downstream site, which receives fewer amounts of discharges from sewer drains. After rainfall events E. coli concentrations were increased by about one order of magnitude compared to dry weather conditions, this is in line with expectations that runoff from urban and agricultural areas brings pathogens into the rivers. All the E. coli samples violated bathing water quality standards. E. coli concentrations were found to be correlated positively with precipitation and turbidity. A linear regression model was applied, that explains large part of the variation in E. coli concentration (R2 = 0.42). Water quality index assessment also ranked the water quality as ‘poor’ category indicating high health risks involved with the water use. Therefore, the river water should not be used for domestic, recreational or bathing purposes. The study findings highlight the problem of untreated sewage discharge into the rivers. Implementation of sewage treatment plant with adequate capacity is highly recommended.

Influence of temperature and water quality on the persistence of human mitochondrial DNA, human Hf183 Bacteroidales, fecal coliforms and enterococci in surface water in human fecal source tracking context.

Mitochondrial DNA (mtDNA) is used as a genetic marker to track fecal contamination in surface water. Its potential to effectively discriminate between the nonpoint sources of fecal pollution (e.g. human, livestock) in water environments is relevant for water quality management. However, there is a lack of knowledge about the environmental persistence of mtDNA in relation to those of other microbial parameters, such as fecal indicator bacteria (FIB). In this study, mesocosms composed of water collected from four rivers and tap water were spiked with raw wastewater to mimic human fecal contamination. Mesocosms composed of raw wastewater were also studied. The mesocosms were incubated at 4 °C or at 22 °C for 189 days, from which the levels of human mtDNA (HumtDNA) and human Bacteroidales (Hf183) were measured by qPCR. The levels of FIB (fecal coliforms and enterococci) and heterotrophs were determined by culture methods along with the determination of physicochemical attributes. The decay rates of the genetic markers and FIB were determined with first-order decay rate models. The decay rates of HumtDNA (0.004-0.059 d-1), Hf183 (0.007-0.082 d-1), and the two FIBs (0.005-0.066 d-1) were similar at 4 °C, while the genetic markers both had higher decay rates (0.013-0.919 d-1) at 22 °C. Different HumtDNA decay rates were observed between the river mesocosms (0.043-0.919 d-1) and the wastewater and tap water mesocosms (0.004-0.095 d-1). Covariations of pH and conductivity among the HumtDNA, Hf183 and FIB decay rates were observed. HumtDNA and Hf183 had similar environmental persistence, whereas fecal coliforms and enterococci persisted longer at 22 °C. Finally, HumtDNA had the same trends of persistence in the four river mesocosms, suggesting a relative stability of this marker in different rivers. Our results suggest that HumtDNA could be more suitable for tracking the source of a recent fecal contamination in complement to FIB.

Occurrence of coliphage in effluent: A systematic literature review and meta-analysis

Studies have illustrated that wastewater treatment methods targeting bacteria do not remove all types of viruses and available epidemiological studies indicate bacteria concentrations may not always be predictive of viral illnesses associated with recreational water exposure. To address these challenges, coliphages have been proposed as an indicator of fecal contamination in recreational water. When compared to traditional fecal indicator bacteria, coliphages exhibit a longer persistence in the environment. The persistence of coliphages in the environment and through wastewater treatment more closely resembles that of pathogenic viruses. We conducted a systematic literature search of peer-reviewed publications to identify coliphage density data (somatic [SC] and male-specific [MSC]) in wastewater treatment plant (WWTP) effluent categorized as primary, secondary, tertiary treated, or disinfected. Scope, study quality, and data availability were included as literature review inclusion criteria. An analysis was conducted to estimate the coliphage densities for specific treatment types within each respective WWTP effluent category. Densities of MSC and SC in influent were significantly higher when compared to densities of MSC and SC in effluent subjected to secondary treatment using biological treatment processes both with and without nutrient removal, tertiary treatment using either a treatment pond or a phosphate removal process, or disinfection using either chlorine, UV, or a combination of both UV and chlorine. Distributions of coliphage in various wastewater effluents will be useful for evaluating the efficacy of treatment processes and disinfectants in future microbial risk assessments.

WASH and Health in Sindhupalchowk District of Nepal after the Gorkha Earthquake

An earthquake of magnitude 7.8 MW and 6.8 MW struck Nepal on 25 April and 12 May, 2015, respectively, which caused massive damage. In such crises, understanding the water, sanitation, and hygiene (WASH) situation is of paramount importance. Therefore, we aimed to assess the WASH situation and its impact on health, particularly in the Sindhupalchowk district. A questionnaire survey and microbial analysis of water samples were conducted. Descriptive statistics and parametric and non-parametric statistical tests were employed. The results revealed that 97.1% of water samples from the source during the pre-monsoon season and 98.5% during the monsoon season had fecal contamination. Similarly, 92.8% of water samples during the pre-monsoon season and 96.7% during the monsoon season at point of use (PoU) had fecal contamination. Furthermore, water consumption was comparatively less during the pre-monsoon season. The increase in water consumption improved hygiene behavior and lowered the prevalence of waterborne diseases. Similarly, less water consumption affected water handling behavior; for example, the cleaning interval of storage vessels was less frequent. An increase in cleaning interval resulted in fecal contamination of water at PoU. The findings of this study can be useful in the review of existing WASH policy and plans and integration with the disaster management plan for disaster risk reduction.

An Overview of Microbial Source Tracking Using Host-Specific Genetic Markers to Identify Origins of Fecal Contamination in Different Water Environments

Fecal contamination of water constitutes a serious health risk to humans and environmental ecosystems. This is mainly due to the fact that fecal material carries a variety of enteropathogens, which can enter and circulate in water bodies through fecal pollution. In this respect, the prompt identification of the polluting source(s) is pivotal to guiding appropriate target-specific remediation actions. Notably, microbial source tracking (MST) is widely applied to determine the host origin(s) contributing to fecal water pollution through the identification of zoogenic and/or anthropogenic sources of fecal environmental DNA (eDNA). A wide array of host-associated molecular markers have been developed and exploited for polluting source attribution in various aquatic ecosystems. This review is intended to provide the most up-to-date overview of genetic marker-based MST studies carried out in different water types, such as freshwaters (including surface and groundwaters) and seawaters (from coasts, beaches, lagoons, and estuaries), as well as drinking water systems. Focusing on the latest scientific progress/achievements, this work aims to gain updated knowledge on the applicability and robustness of using MST for water quality surveillance. Moreover, it also provides a future perspective on advancing MST applications for environmental research.