Microbial source tracking of private well water samples across at-risk regions in southern Ontario and analysis of traditional fecal indicator bacteria assays including culture and qPCR.

Many people living in rural areas rely on privately owned wells as their primary source of drinking water. These water sources are at risk for fecal contamination of human, wildlife, and livestock origin. While traditional bacteriological testing involves culture-based methods, microbial source tracking (MST) assays present an opportunity to additionally determine the source of fecal contamination. This study investigated the main host sources of contamination in private well water samples with high levels of Escherichia coli (E. coli), using MST with human and multi-species specific markers. Fecal contamination of human origin was detected in approximately 50% of samples, indicating that current contamination prevention strategies require reconsideration. The relationship between cattle density and fecal contamination of bovine origin was investigated using a Bovine Bacteroidales specific MST assay. Regional variations of microbial sources were examined, and may inform local primary prevention strategies. Additionally, in order to assess MST and E. coli quantitative real time polymerase chain reaction (qPCR) assays as indicators of fecal contamination, these were compared to E. coli culture methods. Variation in results was observed across all assay methods investigated, suggesting the most appropriate routine bacteriological testing methodology cannot be determined without comparison to a method that directly detects the presence of fecal contamination.

Bacteriological testing of private well water: a trends and guidelines assessment using five years of submissions data from southeastern Ontario.

OBJECTIVE: Rural populations are at an elevated risk of gastrointestinal illness, as they are dependent on private groundwater sources, and water quality remains the responsibility of the owner. Previous research suggests that only a minority of well water owners test their wells for bacteriological contamination. The aim of this study was to use testing records, in conjunction with current provincial guidelines, to assess submission rates and temporal trends in southeastern Ontario. METHODS: Using five years of data (2008-2012) from the Public Health Ontario Laboratory in Kingston, Ontario, submissions of well water samples from unique properties (identified through geocoding) were descriptively analyzed. Temporal trends in guideline compliance were tested using a Cochran Armitage test. Finally, correlations between time and submission numbers were investigated using a 10-year provincial dataset to identify long-term temporal trends. RESULTS: There were 107,547 submissions in the five years studied, 84% of which were geocoded, culminating in 30,687 unique properties. Although 11%-12% of owners met the guidelines in any given year, only 0.3% met them every year in the five-year study. Statistically significant decreases were found temporally both in the number of properties that met current guidelines and in all samples tested. CONCLUSIONS: This study is the first to use submission records, rather than surveys, to definitively demonstrate that private well water submission guidelines are not being met in Ontario. However, there are no consistent guidelines across the country or continent, and limited supporting scientific literature is available. Significant research is required to develop evidence-based policies.

Microbial source tracking and spatial analysis of E. coli contaminated private well waters in southeastern Ontario.

Private water supplies, which are the primary source of drinking water for rural communities in developed countries, are at risk of becoming fecally contaminated. It is important to identify the source of contamination in order to better understand and address this human health risk. Microbial source tracking methods using human, bovine and general Bacteroidales markers were performed on 716 well water samples from southeastern Ontario, which had previously tested positive for Escherichia coli. The results were then geospatially analyzed in order to elucidate contamination patterns. Markers for human feces were found in nearly half (49%) of all samples tested, and a statistically significant spatial cluster was observed. A quarter of the samples tested positive for only general Bacteroidales markers (25.7%) and relatively few bovine specific marker positives (12.6%) were found. These findings are fundamental to the understanding of pathogen dynamics and risk in the context of drinking well water and will inform future research regarding host-specific pathogens in private well water samples.

Triage and protocol recommendations for the parasitology laboratory based on an epidemiological investigation of parasite diagnostics in Ontario laboratories.

OBJECTIVES: A study was performed using a subset of Ontario laboratory parasitology data, with three objectives: to describe parasitic infections in Ontario; to identify risk factors for acquiring a parasitic infection using routinely collected information; and to use this information to assess current protocols for parasite testing in laboratories and, in turn, to propose alternatives to optimize the allocation of laboratory resources. METHODS: All parasitology records from January 4, 2010 to September 14, 2010 were reviewed descriptively and risk factor analyses were performed using information collected from requisitions. These results were used to develop preliminary alternative protocols, which considered high-throughput screening tests and inclusion/exclusion criteria for ova and parasite testing; these were then retrospectively analyzed with the dataset to determine appropriateness. RESULTS: Of the 29,260 records analyzed, 10% were multiple samples from single patients submitted on the same day, of which 98% had the same result. Three percent of all parasite tests were positive, with the most prevalent parasites being (in ascending order) Dientamoeba fragilis, Giardia lamblia, Cryptosporidium species and Entamoeba histolytica/dispar. Age and sex were found to be weak risk factors, while rural living was found to be a moderate risk factor for D fragilis, G lamblia and Cryptosporidium infections. The strongest risk factor was travel history, especially for nonendemic parasites. The retrospective analysis of six alternative protocols identified four that may be more efficient than current procedures. CONCLUSIONS: The present study demonstrated that current protocols may be redundant and can be optimized to target prevalent parasites and populations with high risk factors.

OBJECTIFS: Une étude a été menée d'après un sous-groupe de données des laboratoires de parasitologie de l'Ontario pour réaliser trois objectifs : décrire les infections parasitaires en Ontario, déterminer les facteurs de risque d'infection parasitaire d'après la collecte systématique d'information et utiliser l'information pour évaluer les protocoles actuels respectés dans les tests parasitaires en laboratoire, puis proposer des solutions pour optimiser l'affectation des ressources de laboratoire. MÉTHODOLOGIE: Les chercheurs ont effectué une recherche descriptive de tous les dossiers de parasitologie entre le 4 janvier et le 14 septembre 2010, ainsi que des analyses des facteurs de risque à l'aide de l'information figurant dans les réquisitions. Ils ont utilisé les résultats pour préparer de nouveaux protocoles préliminaires, qui tenaient compte des tests de dépistage à haut débit et des critères d'inclusion et d'exclusion des tests d'œufs et de parasites. Ils ont ensuite fait l'analyse rétrospective de l'ensemble des données pour en déterminer la pertinence. RÉSULTATS: Sur les 29 260 dossiers analysés, 10 % provenaient d'échantillons multiples du même patient soumis le même jour, dont 98 % donnaient les mêmes résultats. Par ailleurs, 3 % de tous les tests parasitaires étaient positifs, les parasites les plus prévalents étant (par ordre ascendant) le Dientamoeba fragilis, le Giardia lamblia, les espèces de Cryptosporidium et l'Entamoeba histolytica/dispar. L'âge et le sexe étaient des facteurs de risque faibles, tandis que la vie en milieu rural était un facteur de risque modéré d'infections à D fragilis, à G lamblia et à Cryptosporidium. Les antécédents de voyage étaient les principaux facteurs de risque, particulièrement pour les parasites non endémiques. L'analyse rétrospective des six nouveaux protocoles a établi que quatre d'entre eux seraient plus efficaces que les protocoles actuels. CONCLUSIONS: La présente étude a démontré que les protocoles actuels seraient redondants et pourraient être optimisés pour cibler les parasites prévalents et les populations présentant des facteurs de risque élevés.

A spatial analysis of private well water Escherichia coli contamination in southern Ontario.

Research to date has provided limited insight into the complexity of water-borne pathogen transmission. Private well water supplies have been identified as a significant pathway in infectious disease transmission in both the industrialised and the developing world. Using over 90,000 private well water submission records representing approximately 30,000 unique well locations in south-eastern Ontario, Canada, a spatial analysis was performed in order to delineate clusters with elevated risk of E. coli contamination using 5 years of data (2008-2012). Analyses were performed for all years independently and subsequently compared to each other. Numerous statistically significant clusters were identified and both geographic stability and variation over time were examined. Through the identification of spatial and temporal patterns, this study provides the basis for future investigations into the underlying causes of bacterial groundwater contamination, while identifying geographic regions that merit particular attention to public health interventions and improvement of water quality.