The prevalence of SARS-CoV-2, the virus that causes COVID-19, in municipal wastewater increased twentyfold in the last week within East Helena and doubled within Helena during that same time, Lewis and Clark Public Health announced in a news release Monday morning.
"The results point to a large amount of disease in the community, which correlates well with the current significant rise in local disease identified through diagnostic testing and could, more importantly, indicate many individuals are infected with the virus but have yet to be tested," agency officials stated in the news release.
Health officials called for residents of both cities to "be extremely careful when out in public and to closely follow established tenets to avoid transmission of the virus." Such "tenets" include practicing strict physical distancing, wearing masks when in public, avoiding gatherings of any size, staying home when sick and washing hands often.
“Now is the time to stay home,” said Drenda Niemann, health officer for Lewis and Clark Public Health. “If you must go out, make sure you’re practicing everything we’ve learned over the last seven months.”
Last week, virus concentrations in East Helena wastewater were measured by Carroll College researchers at approximately 5,000 genomic copies per liter (gc/l) of wastewater. Thursday’s report shows about 110,000 copies of the virus per liter of wastewater. Concentrations in Helena also spiked to 22,000 gc/l, doubling from last week.
“This report shows there’s a great deal of virus out there, and we need everyone to take personal responsibility to ensure the safety of the community," Niemann said in the news release. "With the numbers we are seeing this week, we’re extremely concerned.”
In early results, concentrations of the virus in wastewater have been followed by increases in cases in the cities of Helena and East Helena.
"The data could serve as an early predictor of an increase in cases in the respective communities," the news release stated.
Wastewater for testing is collected by Helena and East Helena wastewater treatment plants and delivered to Carroll College on a weekly basis. The college processes the samples and provides a report to the city of Helena, city of East Helena and Lewis and Clark Public Health.