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Publications

Journal Article Research Support, Non-U.S. Gov't Ppublish 23 citations

PubMed: 37023782 DOI: 10.1016/S2666-5247(23)00010-1

Real-time sewage surveillance for SARS-CoV-2 in Dhaka, Bangladesh versus clinical COVID-19 surveillance: a longitudinal environmental surveillance study (December, 2019-December, 2021).

Lancet Microbe 4(6):e442-e451

Authors: Elizabeth T Rogawski McQuade, Isobel M Blake, Stephanie A Brennhofer, Md Ohedul Islam, Syed Shahnewaj Siraj Sony, Tonima Rahman, Md Hamim Bhuiyan, Sabrina Karim Resha, Erin G Wettstone, Lauren Hughlett, Claire Reagan, Sarah E Elwood, Yoann Mira, Ayesha S Mahmud, Kawsar Hosan, Md Raihanul Hoque, Md Masud Alam, Mahbubur Rahman, Tahmina Shirin, Rashidul Haque, Mami Taniuchi

Affiliations

  • Division of Infectious Diseases & International Health, University of Virginia, Charlottesville, VA, USA; Department of Epidemiology, Emory University, Atlanta, GA, USA.
  • MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, UK.
  • Division of Infectious Diseases & International Health, University of Virginia, Charlottesville, VA, USA.
  • icddr,b, Dhaka, Bangladesh.
  • Division of Infectious Diseases & International Health, University of Virginia, Charlottesville, VA, USA; Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA.
  • Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA.
  • Novel-T, Geneva, Switzerland.
  • Department of Demography, University of California at Berkeley, Berkeley, CA, USA.
  • a2i, Dhaka, Bangladesh; Department of Economics, Jahangirnagar University, Dhaka, Bangladesh.
  • a2i, Dhaka, Bangladesh.
  • Institute of Epidemiology, Disease Control and Research, Dhaka, Bangladesh.
  • Division of Infectious Diseases & International Health, University of Virginia, Charlottesville, VA, USA; Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA; Department of Civil and Environmental Engineering Systems and Environment, University of Virginia, Charlottesville, VA, USA.

Abstract

BACKGROUND

Clinical surveillance for COVID-19 has typically been challenging in low-income and middle-income settings. From December, 2019, to December, 2021, we implemented environmental surveillance in a converging informal sewage network in Dhaka, Bangladesh, to investigate SARS-CoV-2 transmission across different income levels of the city compared with clinical surveillance.

METHODS

All sewage lines were mapped, and sites were selected with estimated catchment populations of more than 1000 individuals. We analysed 2073 sewage samples, collected weekly from 37 sites, and 648 days of case data from eight wards with varying socioeconomic statuses. We assessed the correlations between the viral load in sewage samples and clinical cases.

FINDINGS

SARS-CoV-2 was consistently detected across all wards (low, middle, and high income) despite large differences in reported clinical cases and periods of no cases. The majority of COVID-19 cases (26 256 [55·1%] of 47 683) were reported from Ward 19, a high-income area with high levels of clinical testing (123 times the number of tests per 100 000 individuals compared with Ward 9 [middle-income] in November, 2020, and 70 times the number of tests per 100 000 individuals compared with Ward 5 [low-income] in November, 2021), despite containing only 19·4% of the study population (142 413 of 734 755 individuals). Conversely, a similar quantity of SARS-CoV-2 was detected in sewage across different income levels (median difference in high-income vs low-income areas: 0·23 log viral copies + 1). The correlation between the mean sewage viral load (log viral copies + 1) and the log clinical cases increased with time (r = 0·90 in July-December, 2021 and r=0·59 in July-December, 2020). Before major waves of infection, viral load quantity in sewage samples increased 1-2 weeks before the clinical cases.

INTERPRETATION

This study demonstrates the utility and importance of environmental surveillance for SARS-CoV-2 in a lower-middle-income country. We show that environmental surveillance provides an early warning of increases in transmission and reveals evidence of persistent circulation in poorer areas where access to clinical testing is limited.

FUNDING

Bill & Melinda Gates Foundation.

MeSH

Environmental Monitoring, Infections, Research Design, Income, Microbiological Phenomena, Sewage, Sars Virus, Viral Load, Covid-19, Sars-Cov-2

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