Early warning system for COVID-19 gets faster through wastewater detection and tracing
Math continues to be a powerful force against COVID-19.
Its latest contribution is a sophisticated algorithm, using municipal wastewater systems, for determining key locations in the detection and tracing of COVID-19 back to its human source, which may be a newly infected person or a hot spot of infected people. Timing is key, say the researchers who created the algorithm, especially when COVID-19 is getting better at transmitting itself, thanks to emerging variants.
“Being quick is what we want because in the meantime, a newly-infected person can infect others,” said Oded Berman, a professor of operations management and statistics at the University of Toronto’s Rotman School of Management.
This latest research builds on previous work Prof. Berman did with co-investigators Richard Larson of the Massachusetts Institute of Technology and Mehdi Nourinejad of York University. The trio initially developed two algorithms for identifying choice locations in a sewer system for manual COVID-19 testing and subsequent tracing back to the source. Sewers are a rich environment for detecting presence of the disease upstream because genetic remnants of its virus are shed in the stool of infected people up to a week before they may even know they are sick.
The investigators’ new research refines and optimizes that initial work by more accurately modelling a typical municipal sewer system’s treelike network of one-way pipes and manholes, and by speeding up the detection/tracing process through automatic sensors installed in specific manholes, chosen according to an easier-to-use algorithm.
Under this scenario, a sensor sends out an alert any time COVID-19 is detected. Manual testing is then done at a few manholes further upstream, also chosen according to the algorithm, until the final source is located, be that a small group of homes or a “hotspot” neighbourhood. Residents in that much smaller area can then be contacted for further testing and isolation as needed, limiting potential new outbreaks. More