Author
Alex H.S. Chik
Other affiliations: Vienna University of Technology, Utrecht University, Canadian Water Network ...read more
Bio: Alex H.S. Chik is an academic researcher from University of Waterloo. The author has contributed to research in topics: Medicine & Public health. The author has an hindex of 5, co-authored 8 publications receiving 81 citations. Previous affiliations of Alex H.S. Chik include Vienna University of Technology & Utrecht University.
Papers
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Canadian Water Network1, Ontario Clean Water Agency2, BC Centre for Disease Control3, University of Waterloo4, Public Health Agency of Canada5, University of Alberta6, University of Ottawa7, École Polytechnique de Montréal8, University of Windsor9, University of Saskatchewan10, University of Manitoba11, University of British Columbia12
TL;DR: In this paper, a real wastewater sample was spiked with surrogates of SARS-CoV-2 and human coronavirus strain 229E [HCoV]-strains at low and high levels then provided to eight laboratories.
Abstract: Detection of SARS-CoV-2 RNA in wastewater is a promising tool for informing public health decisions during the COVID-19 pandemic. However, approaches for its analysis by use of reverse transcription quantitative polymerase chain reaction (RT-qPCR) are still far from standardized globally. To characterize inter- and intra-laboratory variability among results when using various methods deployed across Canada, aliquots from a real wastewater sample were spiked with surrogates of SARS-CoV-2 (gamma-radiation inactivated SARS-CoV-2 and human coronavirus strain 229E [HCoV-229E]) at low and high levels then provided “blind” to eight laboratories. Concentration estimates reported by individual laboratories were consistently within a 1.0-log10 range for aliquots of the same spiked condition. All laboratories distinguished between low- and high-spikes for both surrogates. As expected, greater variability was observed in the results amongst laboratories than within individual laboratories, but SARS-CoV-2 RNA concentration estimates for each spiked condition remained mostly within 1.0-log10 ranges. The no-spike wastewater aliquots provided yielded non-detects or trace levels (
84 citations
TL;DR: Habitual reporting of raw microbial observations and sample sizes is proposed to facilitate accurate estimation and analysis of microbial concentrations.
Abstract: Accurate estimation of microbial concentrations is necessary to inform many important environmental science and public health decisions and regulations. Critically, widespread misconceptions about laboratory-reported microbial non-detects have led to their erroneous description and handling as "censored" values. This ultimately compromises their interpretation and undermines efforts to describe and model microbial concentrations accurately. Herein, these misconceptions are dispelled by (1) discussing the critical differences between discrete microbial observations and continuous data acquired using analytical chemistry methodologies and (2) demonstrating the bias introduced by statistical approaches tailored for chemistry data and misapplied to discrete microbial data. Notably, these approaches especially preclude the accurate representation of low concentrations and those estimated using microbial methods with low or variable analytical recovery, which can be expected to result in non-detects. Techniques that account for the probabilistic relationship between observed data and underlying microbial concentrations have been widely demonstrated, and their necessity for handling non-detects (in a way which is consistent with the handling of positive observations) is underscored herein. Habitual reporting of raw microbial observations and sample sizes is proposed to facilitate accurate estimation and analysis of microbial concentrations.
29 citations
TL;DR: In this paper, a review of relevant ethical literature focused on ethics applicable to public health surveillance of wastewater has been conducted, which revealed that classical health bioethics governing clinical practice and general public health ethics guidance did not adequately address key issues in wastewater surveillance.
Abstract: The COVID-19 pandemic has given rise to rapid and widespread international pursuit of wastewater surveillance for genetic signals of SARS-CoV-2, the virus causing the pandemic. Environmental scientists and engineers familiar with the techniques required for this endeavor have responded. Many of the environmental scientists engaged in these investigations have not necessarily had experience with the ethical obligations associated with generating and handling human health data. The Canadian Water Network facilitated adoption of these surveillance methods by creating a national coalition, which included a public health advisory group that recognized a need for ethics guidance for the wastewater approach to public health surveillance. This Policy Analysis addresses that need and is based on a review of relevant ethics literature tightly focused on ethics applicable to public health surveillance. That review revealed that classical health bioethics governing clinical practice and general public health ethics guidance did not adequately address key issues in wastewater surveillance. The 2017 World Health Organization guidelines, directly based on a systematic literature review, specifically addressed ethical issues in public health surveillance. The application of relevant ethical guidance to wastewater surveillance is analyzed and summarized for environmental scientists.
26 citations
TL;DR: In the investigated RBF system, groundwater table changes exhibited striking dynamics even though flow velocities were rather low under regular discharge conditions, and the dynamics of the bacterial groundwater community was predominantly governed by the hydrogeological dynamics.
24 citations
TL;DR: The utility of 16S rRNA gene amplicon sequencing for contextualizing and complementing conventional microbial techniques, allowing for hypotheses about source and transport processes to be tested and refined, is demonstrated.
12 citations
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01 Jan 2020
TL;DR: The US Food and Drug Administration (FDA) regulates medical devices primarily through the law known as the Federal Food, Drug, and Cosmetic Act, as Amended (FD&C Act, or “the Act”) as discussed by the authors.
Abstract: The US Food and Drug Administration (FDA) regulates medical devices primarily through the law known as the Federal Food, Drug, and Cosmetic Act, as Amended (“the FD&C Act,” or “the Act”). Regulations promulgated by FDA in Title 21 of the Code of Federal Regulations (CFR) spell out the broad provisions contained in the Act.
701 citations
Commonwealth Scientific and Industrial Research Organisation1, University of Notre Dame2, University of Melbourne3, University of Barcelona4, Instituto Nacional de Saúde Dr. Ricardo Jorge5, University of Queensland6, Queensland Health7, University of North Carolina at Chapel Hill8, University of South Australia9, Michigan State University10, Vienna University of Technology11, University of Health Sciences Antigua12, Southern Nevada Water Authority13, Southern California Coastal Water Research Project14, Drexel University15, Arizona State University16, National Environment Agency17, University of South Florida18, International Centre for Diarrhoeal Disease Research, Bangladesh19, University of New South Wales20, Stellenbosch University21, Hokkaido University22, United States Environmental Protection Agency23, Istituto Superiore di Sanità24, University of Georgia25, University of Wisconsin–Milwaukee26, University College Dublin27, University of Guelph28, University of California, Merced29, Griffith University30, University of Helsinki31, National Institute for Health and Welfare32, National University of Salta33, Spanish National Research Council34, Tulane University35, Chulabhorn Research Institute36, National University of Singapore37, Tohoku University38, Nanyang Technological University39, University of Minnesota40
TL;DR: A technical review of factors that can lead to false-positive and -negative errors in the surveillance of SARS-CoV-2, culminating in recommendations and strategies that can be implemented to identify and mitigate these errors.
116 citations
TL;DR: In this paper , a technical review of factors that can cause false-positive and false-negative errors in the surveillance of SARS-CoV-2 RNA in wastewater, culminating in recommended strategies that can be implemented to identify and mitigate some of these errors.
105 citations
TL;DR: In this paper, the authors present a longitudinal analysis of SARS-CoV-2 RNA prevalence in sewage across six major urban centres in the UK (total population equivalent 3 million) by q(RT-)PCR and viral genome sequencing.
87 citations
TL;DR: In this article, the authors investigated how the dynamics of new COVID-19 infections estimated based on wastewater monitoring or confirmed cases compare to true COVID19 incidence dynamics, and they focused on the first pandemic wave in Switzerland (February to April, 2020), when test positivity ranged up to 26%.
84 citations