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As well as shedding SARS-CoV-2 virus through nose and throat secretions, infected people can, even when asymptomatic, excrete the virus in their stool. Because of this, wastewater sampling has been under investigation since the beginning of the pandemic as a way to monitor levels of the novel coronavirus in whole populations.
Accumulating evidence suggests that such analyses can detect spikes in case numbers earlier than diagnostic testing can, and may therefore lead to swifter implementation of public health measures. However, methods for detecting SARS-CoV-2 in wastewater are slow and laborious, says microbiologist Smruthi Karthikeyan, a postdoc in the laboratory of computational microbiologist and engineer Rob Knight at the University of California, San Diego. Karthikeyan had been performing such analyses on a small scale, using traditional filtration to concentrate the viral RNA from wastewater samples. But when her university announced, early in the pandemic, that it would ...