Portland Water District employee Chris Cogan operates a machine that collected samples of wastewater for coronavirus testing last summer. Photo courtesy of Portland Water District

Communities and colleges across Maine are expanding testing of wastewater as an additional way to monitor for levels of coronavirus in the surrounding area.

Since summer, a handful of cities, towns and campuses have been regularly collecting samples of raw sewage from treatment plants to measure the amount of genetic “markers” of coronavirus that are shed by infected individuals. That information can then be used to monitor how virus levels are changing in the local population or, in the case of college campuses, target testing at certain areas of campus or even specific buildings to find infected individuals.

Results from those samples have mirrored the recent surge in cases across Maine, although more frequent analysis would likely be required for the tests to provide an early-warning system of COVID-19 spikes at the municipal level.

Levels of COVID-19 in waste collected at Portland Water District’s facility in Portland increased 20-fold between Nov. 17 and 24 and three-fold during that time at the Westbrook facility. While levels decreased somewhat a week later, they began increasing again in samples from both facilities throughout December and into January.

Total cases of COVID-19 in Maine have increased more than sixfold – from roughly 5,400 on Oct. 1 to nearly 35,000 cases Wednesday – and deaths tripled during that period.

In Yarmouth, levels of COVID-19 in wastewater were 10 times higher recently than they were just before Christmas, prompting the town’s coronavirus task force to issue a statement this week urging “extra vigilance” among residents.

“This rapid rise in both wastewater testing results and COVID-19 patient cases in town coupled with the number of COVID-19 cases and deaths at the state and national level suggest that Yarmouth is seeing a spike in cases that will continue to rise unless we all redouble our efforts to protect ourselves, our loved ones, and our community,” read the message to Yarmouth residents. “We feel that all of these measures will be higher next week (in fact our wastewater test results provide an early indication of what we’ll see for COVID-19 cases next week).”

Some wastewater monitoring programs are now expanding as the virus is surges across Maine.

Portland Water District, which has been sending wastewater samples to a lab at Saint Joseph’s College weekly for analysis since the summer, also began sending samples this month to a national laboratory. That lab, Arizona-based AquaVitas LLC, is analyzing samples from up to 100 treatment plants nationwide – representing 10 percent of the country’s population – as part of a new, federally funded national monitoring program.

“Since March, we try to follow local, regional and national events so we’ve been aware that there has been interest in creating a national wastewater surveillance program with a national database,” said Scott Firmin, director of wastewater services at the Portland Water District.

Firmin said the data collected is more useful to public health officials than to his staff. COVID-19 has not forced any operational changes at Portland Water District, whose employees already take health and safety precautions because of a host of pathogens and viruses in sewage before the waste goes through a two-step treatment process.

Saint Joseph’s College, which has successfully used wastewater monitoring to detect small outbreaks on the Standish campus, is beginning to test three times a week – up from twice weekly. Samples are collected from three wastewater “lift stations,” allowing the college’s testing lab to detect spikes in different sections of campus.

Last fall, that monitoring program allowed Saint Joseph’s to find and isolate members of campus infected with the virus even before they began experiencing symptoms. As students return to campus this week, residence halls and the entire campus will be tested three times a week.

“The more frequently we test, the easier it is to get a trend line,” said Yolanda Brooks, an assistant professor of biology at Saint Joseph’s College who leads the testing effort for the college and several municipalities. Brooks is currently working on a scientific paper for publication in an upcoming federal health journal detailing the college’s program.

“We do think this will help other colleges get a better understanding of the transmission of the virus on campus,” Brooks said.

At the University of Maine System, meanwhile, a campus testing lab is resuming a monitoring program of wastewater on the Orono and Fort Kent campuses as well as at the University of Southern Maine’s Gorham campus. The UMaine lab in Orono also plans to expand that monitoring to the University of Maine at Presque Isle and will continue testing municipal wastewater for the town of Orono.

The system said it plans to announce additional details on the expanded testing program soon.

Several other towns in Maine are either currently testing wastewater or have in the past.

The city of Augusta, for instance, sent samples to a laboratory in Massachusetts, Biobot, between July and October as part of a national program. The results showed significant fluctuations in virus levels during that time but the city stopped the sampling in October after grant funding expired.

Brian Tarbuck, general manager for the Greater Augusta Utility District, said the broad-scale testing was less useful for his district than in other settings, such as on college campuses.

“It tells you that a community has people that have COVID-19 but doesn’t give you that information on a granular level,” Tarbuck wrote in an email. “Universities have had some success with testing wastewater from individual dormitories. This allows them to target a smaller population and then start testing individuals.”

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