Coronavirus answers: floating in the sewage

| Apr 14, 2020

At a time when excrement metaphors seem perfectly suited to certain aspects of the coronavirus response, it’s fitting that hope is now found in our sewage.

About a dozen wastewater facilities in Colorado are participating in a COVID-19 screening project run by Biobot, a Boston company that specializes in wastewater data, according to company press liaison Sarah Pugsley. Researchers at Harvard and MIT are collaborating in this pro bono project.

With coronavirus nasal-swab testing severely restricted in Colorado, other sources of information on the extent of the pathogen’s spread are crucial. Wastewater sampling shows promise of being an effective method of estimating the number of infected residents in a locale.

Dutch scientists go searching

A study in the Netherlands pioneered this approach in February. “In the current COVID-19 pandemic, a significant proportion of cases shed SARS-Coronavirus-2 with their feces,” the authors wrote. This encouraged the scientists to begin looking for the virus in the wastewater of seven cities and a major airport three weeks before the first case was reported in the Netherlands on February 27.

By March 5, fragments of the coronavirus gene were detected in samples from five of the sites. Testing for one of the fragments was sensitive enough to pick up a signal at one in 100,000 people, or even below that, according to calculations in the study. This means that analysis of a population’s feces may serve as an early-warning system.

Peter Mayer of Boulder-based Water Demand Management

Pugsley would not disclose which wastewater facilities in Colorado have signed up for sample testing, except to point to Gunnison County, which announced the project on its website. Chris Douville, Wastewater Treatment Manager for the City of Boulder, said in a phone conversation that Boulder is not currently participating in coronavirus sewage screening. Douville added that in the past, his team has collaborated on research to detect illicit drugs, anti-anxiety and antidepressant medications, and even caffeine in the city’s wastewater. “The premise has been very solid over the years,” Douville said. Testing wastewater for “the appearance of coronavirus in communities or to indicate hotspots may expose occurrences that otherwise might not be known,” he said.

Samples for future researchers

American scientists, including wastewater epidemiologists, are calling on water utilities to freeze one-liter sewage samples every week for future research. “Once activities resume at universities and other research agencies, there will be considerable demand for these samples,” they wrote in a paper on the website of the National Water Research Institute. Or, as Peter Mayer, an urban water expert and founder of Boulder-based Water Demand Management, wrote to me: “It (literally) provides a lot of shit for academics to sift through for years to come that will explain the actual extent [of the coronavirus].”

Meanwhile, some laboratories, such as Diagnostic Solutions Laboratory in Atlanta, Georgia, have begun offering RNA stool tests for the coronavirus. Part of the impetus for fecal testing comes from a study in China, published in the Lancet Gastroenterology & Hepatology, showing that fecal samples remained positive for almost 28 days after first onset of symptoms. However, 45% of patients never tested positive through their feces, while testing positive in their respiratory tract.

I suppose this means that while our excrement is part of the solution, we’ll ultimately have to dig ourselves out of this dung heap with lots of ingenuity.

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Leora Frankel

Author Leora Frankel has written previously for Boulder Reporter on topics that have included the air-quality effects of fracking and the profit potential for developers of Opportunity Zones.

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