Elevated levels of COVID-19 viral particles have been detected in the sewer systems serving several locations in St. Mary’s County.
At Tuesday’s county commissioner meeting, commissioners convened as the board of health to discuss COVID-19 related updates with Dr. Meena Brewster, health officer for the county. She said the COVID-19 data dashboard on the health department’s website now includes results from the wastewater monitoring project.
The health officer reminded commissioners of the collaborative initiative by the St. Mary’s County Health Department, St. Mary’s College of Maryland and The St. Mary’s County Metropolitan Commission, where the groups work together to collect and test wastewater samples from several private, public and municipal wastewater treatment plants throughout the county. She said recent testing of the viral load, or the number of viral particles per liter of wastewater, has demonstrated an increase from prior amounts in several county locations.
She explained residents infected with COVID-19 pass skeletons of the virus through their stools, which in turn, end up in the wastewater systems.
Rising levels of viral particles in the wastewater from a particular wastewater treatment plant may indicate an increase in COVID-19 in the area that contributes wastewater to that plant, she said, mentioning sometimes the spike in wastewater can be seen before lab results indicate a spike in cases. She said since COVID-19 may be asymptomatic in some people, these results should encourage even asymptomatic residents to evaluate their exposure risk and seek COVID-19 testing if they have risk for infection.
She said of the eight wastewater systems being tested, a spike was seen in five of them, including St. Clements Shores, Wicomico Shores, Forrest Farms, the Charlotte Hall Veteran’s Home and St. Mary’s College.
“Can you guess why we have a spike of almost 800%?” Commissioner Todd Morgan (R) asked of recent results.
“So the confounding factor here is heavy rainfall,” Brewster replied. “Heavy rainfall will dilute out the samples while also collecting stormwater that is contributing to the treatment plants ... so you’re likely going to show much lower values of viral particles per liter of wastewater than what would otherwise be found.”
Regarding the spiked values from Oct. 8, Brewster said the period before may have been a more dry period, but it could also mean an actual increase in viral load. She noted previous dilution of samples could also make this spike seem more dramatic than it actually is.
According to a press release from the health department, community members living in areas with rising wastewater viral levels should self-monitor for signs and symptoms of COVID-19. It is recommended residents get tested for the virus within 48 hours of developing any symptoms and consider getting tested even without symptoms. Prevention measures should continue to be practiced, including washing hands often, avoiding close contact with people outside of one’s household and wearing a face covering in public settings.
As of Wednesday, St. Mary’s had seen a total of 1,445 confirmed cases, along with 59 deaths of county residents and an additional 27 deaths in the county of non-county residents, primarily people living at Charlotte Hall Veterans Home and other nursing homes, according to the health department’s website.
Earlier in the meeting, Brewster said over the past few weeks the county has seen “somewhat of a decrease” in the rate of new cases, as well as in the positivity rate. She noted 23% of the population has been tested at least once.
Halloween holiday not on hold
Regarding Halloween, she said the health department is referring residents to the Centers for Disease Control and Prevention guidelines online, which recommend different but safer ways people can enjoy Halloween. She encourages residents to use face coverings instead of costume masks if they do go out, as costume masks are “not built to obstruct from the nose and mouth.” She also said families should avoid trick-or-treating in large groups and suggested people put candy in bags to grab, rather than physically passing it out, to minimize physical contact.
Morgan said “it’s great to hear” Halloween isn’t “canceled … it’s good for little kids and it’s good for parents … people want to feel good right now.”