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

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.

Estimating the Relative Role of Various Subcategories of Food, Water, and Animal Contact Transmission of 28 Enteric Diseases in Canada.

OBJECTIVE: Enteric illness represents a significant burden of illness in Canada and internationally. Building on previous research, an expert elicitation was undertaken to explore the routes of transmission for 28 pathogens involved in enteric illness in Canada. This article considers the subcategories of foodborne, waterborne, and animal contact transmission. METHODS: As part of an expert elicitation, 31 experts were asked to provide estimates of source attribution for subcategories of foodborne (n = 15), waterborne (n = 10), and animal contact (n = 3) transmission. The results from an online survey were combined using triangular probability distributions, and median and 90% credible intervals were produced. The total proportion and estimated number of cases of enteric illness attributable to each type of food commodity, water source, and animal exposure route were calculated using results from the larger elicitation survey and from a recent Canadian foodborne burden of illness study (Thomas et al., 2013). RESULTS: Thirty experts provided foodborne subcategory estimates for 15/28 pathogens, waterborne subcategory estimates for 14/28 pathogens and animal contact subcategory estimates for 5/28. The elicitation identified raw produce, recreational water, and farm animal contact as important risk factors for enteric illness. These results also highlighted the complexity of transmission, with greater uncertainty for certain pathogens and routes of transmission. CONCLUSIONS: This study is the first of its kind to explore subcategories of foodborne, waterborne, and animal contact transmission across such a range of enteric pathogens. Despite inherent uncertainty, these estimates present an important quantitative synthesis of the roles of foodborne commodities, water sources, and pathways of animal contact in the transmission of enteric illness in Canada.

Expert elicitation as a means to attribute 28 enteric pathogens to foodborne, waterborne, animal contact, and person-to-person transmission routes in Canada.

Enteric illness contributes to a significant burden of illness in Canada and globally. Understanding its sources is a critical step in identifying and preventing health risks. Expert elicitation is a powerful tool, used previously, to obtain information about enteric illness source attribution where information is difficult or expensive to obtain. Thirty-one experts estimated transmission of 28 pathogens via major transmission routes (foodborne, waterborne, animal contact, person-to-person, and other) at the point of consumption. The elicitation consisted of a (snowball) recruitment phase; administration of a pre-survey to collect background information, an introductory webinar, an elicitation survey, a 1-day discussion, survey readministration, and a feedback exercise, and surveys were administered online. Experts were prompted to quantify changes in contamination at the point of entry into the kitchen versus point of consumption. Estimates were combined via triangular probability distributions, and medians and 90% credible-interval estimates were produced. Transmission was attributed primarily to food for Bacillus cereus, Clostridium perfringens, Cyclospora cayetanensis, Trichinella spp., all three Vibrio spp. categories explored, and Yersinia enterocolitica. Multisource pathogens (e.g., transmitted commonly through both water and food) such as Campylobacter spp., four Escherichia coli categories, Listeria monocytogenes, Salmonella spp., and Staphylococcus aureus were also estimated as mostly foodborne. Water was the primary pathway for Giardia spp. and Cryptosporidium spp., and person-to-person transmission dominated for six enteric viruses and Shigella spp. Consideration of the point of attribution highlighted the importance of food handling and cross-contamination in the transmission pathway. This study provides source attribution estimates of enteric illness for Canada, considering all possible transmission routes. Further research is necessary to improve our understanding of poorly characterized pathogens such as sapovirus and E. coli subgroups in Canada.

Systematic review of expert elicitation methods as a tool for source attribution of enteric illness.

Expert elicitation is a useful tool to explore sources of uncertainty and to answer questions where data are expensive or difficult to collect. It has been used across a variety of disciplines and represents an important method for estimating source attribution for enteric illness. A systematic review was undertaken to explore published expert elicitation studies, identify key considerations, and to make recommendations for designing an expert elicitation in the context of enteric illness source attribution. Fifty-nine studies were reviewed. Five key themes were identified: the expert panel including composition and recruitment; the pre-elicitation material, which clarifies the research question and provides training in uncertainty and probability; the choice of elicitation tool and method (e.g., questionnaires, surveys, and interviews); research design; and analysis of elicited data. Careful consideration of these themes is critical in designing and implementing an expert elicitation in order to reduce bias and produce the best possible results. While there are various epidemiological and microbiological methods available to explore source attribution of enteric illness, expert elicitation provides an opportunity to identify gaps in our understanding and where such studies are not feasible or available, represents the only possible method for synthesizing knowledge about transmission.

Near real-time determination of B.1.1.7 in proportion to total SARS-CoV-2 viral load in wastewater using an allele-specific primer extension PCR strategy.

The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has claimed millions of lives to date. Antigenic drift has resulted in viral variants with putatively greater transmissibility, virulence, or both. Early and near real-time detection of these variants of concern (VOC) and the ability to accurately follow their incidence and prevalence in communities is wanting. Wastewater-based epidemiology (WBE), which uses nucleic acid amplification tests to detect viral fragments, is a reliable proxy of COVID-19 incidence and prevalence, and thus offers the potential to monitor VOC viral load in a given population. Here, we describe and validate a primer extension PCR strategy targeting a signature mutation in the N gene of SARS-CoV-2. This allows quantification of B.1.1.7 versus non-B.1.1.7 allele frequency in wastewater without the need to employ quantitative RT-PCR standard curves. We show that the wastewater B.1.1.7 profile correlates with its clinical counterpart and benefits from a near real-time and facile data collection and reporting pipeline. This assay can be quickly implemented within a current SARS-CoV-2 WBE framework with minimal cost; allowing early and contemporaneous estimates of B.1.1.7 community transmission prior to, or in lieu of, clinical screening and identification. Our study demonstrates that this strategy can provide public health units with an additional and much needed tool to rapidly triangulate VOC incidence/prevalence with high sensitivity and lineage specificity.

Public health benefits of strategies to reduce greenhouse-gas emissions: food and agriculture.

Agricultural food production and agriculturally-related change in land use substantially contribute to greenhouse-gas emissions worldwide. Four-fifths of agricultural emissions arise from the livestock sector. Although livestock products are a source of some essential nutrients, they provide large amounts of saturated fat, which is a known risk factor for cardiovascular disease. We considered potential strategies for the agricultural sector to meet the target recommended by the UK Committee on Climate Change to reduce UK emissions from the concentrations recorded in 1990 by 80% by 2050, which would require a 50% reduction by 2030. With use of the UK as a case study, we identified that a combination of agricultural technological improvements and a 30% reduction in livestock production would be needed to meet this target; in the absence of good emissions data from Brazil, we assumed for illustrative purposes that the required reductions would be the same for our second case study in São Paulo city. We then used these data to model the potential benefits of reduced consumption of livestock products on the burden of ischaemic heart disease: disease burden would decrease by about 15% in the UK (equivalent to 2850 disability-adjusted life-years [DALYs] per million population in 1 year) and 16% in São Paulo city (equivalent to 2180 DALYs per million population in 1 year). Although likely to yield benefits to health, such a strategy will probably encounter cultural, political, and commercial resistance, and face technical challenges. Coordinated intersectoral action is needed across agricultural, nutritional, public health, and climate change communities worldwide to provide affordable, healthy, low-emission diets for all societies.

Development of a Climate Change Vulnerability Assessment Using a Public Health Lens to Determine Local Health Vulnerabilities: An Ontario Health Unit Experience.

Climate change is negatively impacting the health of Canadians and is accordingly expected to have a significant impact on public health agencies and their response to these health impacts throughout the twenty-first century. While national and international research and assessments have explored the potential human health impacts of climate change, few assessments have explored the implications of climate change from a local public health perspective. An applied research approach to expand local knowledge and action of health vulnerabilities through a climate change action plan and vulnerability assessment was utilized by a local public health agency. Adoption and adaptation of the approach used may be valuable for public health organizations to assist their communities. Through completing a vulnerability assessment, an evidentiary base was generated for public health to inform adaptation actions to reduce negative health impacts and increase resiliency. Challenges in completing vulnerability assessments at the local level include the framing and scoping of health impacts and associated indicators, as well as access to internal expertise surrounding the analysis of data. While access to quantitative data may be limiting at the local level, qualitative data can enhance knowledge of local impacts, while also supporting the creation of key partnerships with community stakeholders which can ensure climate action continues beyond the scope of the vulnerability assessment.

Health outcomes associated with crack-cocaine use: Systematic review and meta-analyses.

BACKGROUND: Crack-cocaine use is prevalent largely in socio-economically marginalized populations in the Americas. Its use has been associated with diverse health outcomes, yet no recent or systematic reviews of these exist. METHODS: A systematic review of health outcomes associated with crack-cocaine use was performed, using MEDLINE, Scopus, Web of Science, CINAHL, PsycINFO, and LILACS up to October 2016. Search terms included crack-cocaine and health outcome-related keywords, targeting peer-reviewed studies on quantified health outcomes associated with crack-cocaine use. Random effects meta-analyses produced pooled odds ratios. Levels of evidence for major results were assessed using the GRADE approach. A review protocol was registered with PROSPERO (CRD42016035486). RESULTS: Of 4700 articles returned, 302 met eligibility criteria, reporting on health outcomes for 14 of 22 ICD-10 chapters. Conclusive evidence and meta-analyses showed positive associations between crack-cocaine use and blood/sexually transmitted diseases (HIV and hepatitis C virus, others); moderate evidence and meta-analyses supported associations with neonatal health, and violence. There were mixed associations for mental and other health outcomes, yet insufficient evidence to perform meta-analyses for many categories (e.g., mortality). Most underlying research was of limited or poor quality, with crack-cocaine commonly assessed as a secondary covariate. CONCLUSIONS: Crack-cocaine use was associated with a range of health outcomes, although it was unclear if there was direct causal impact, interactions between risk factors, or external drivers of both crack-cocaine use and outcomes. Rigorous epidemiological studies are needed to systematically assess health outcomes of crack-cocaine use and underlying pathways, also to inform evidence-based interventions.

Public health impact of global heating due to climate change: potential effects on chronic non-communicable diseases.

OBJECTIVES: Several categories of ill health important at the global level are likely to be affected by climate change. To date the focus of this association has been on communicable diseases and injuries. This paper briefly analyzes potential impacts of global climate change on chronic non-communicable diseases (NCDs). METHOD: We reviewed the limited available evidence of the relationships between climate exposure and chronic and NCDs. We further reviewed likely mechanisms and pathways for climatic influences on chronic disease occurrence and impacts on pre-existing chronic diseases. RESULTS: There are negative impacts of climatic factors and climate change on some physiological functions and on cardio-vascular and kidney diseases. Chronic disease risks are likely to increase with climate change and related increase in air pollution, malnutrition, and extreme weather events. CONCLUSIONS: There are substantial research gaps in this arena. The health sector has a major role in facilitating further research and monitoring the health impacts of global climate change. Such work will also contribute to global efforts for the prevention and control of chronic NCDs in our ageing and urbanizing global population.