Researchers found SARS-CoV-2, the virus that causes COVID-19, in the water on four beaches on Lake Superior in Duluth earlier this month.
A “visible level” of the virus was found in water samples on beaches in the area over the weekends of Sept. 11 and Sept. 18 on several beaches, according to the University of Minnesota Medical School in Duluth, which regularly tests lake water in eight beach areas.
The results show virus levels in the range of 100 to 1,000 copies per liter, 10,000 times lower than levels found in wastewater, the medical school said. The US Centers for Disease Control and Prevention “is not aware of any scientific reports showing that the virus can spread to humans through exposure to lake water,” the medical school added.
“The source or sources of the virus are currently unknown. Therefore, Minnesota Sea Grant will provide financial support to continue monitoring the Medical School on the eight beaches of Duluth, “said a statement from the medical school. “They will also work with lake experts and the Minnesota Department of Health to seek more information on possible sources.”
The medical school called on beachgoers to continue wearing masks and social distance.
Researchers from the Medical School at the University of Minnesota in Duluth regularly test the water on the beaches for the virus on weekends. Because the virus is excreted in a person’s stool, it is likely to be flushed from the swimmer’s body.
Researchers – assistants Richard Melvin and Glen Simmons Jr. – are also studying the presence of the virus in untreated wastewater in Minnesota, hoping to determine how many people in a community may have the disease based on the amount of virus in the sample.
The wastewater survey gave them early signs of outbreaks and reflected rising levels of cases across the country.
Samples are also taken from wastewater leaving dormitories at the universities of Minnesota – the twin cities and Duluth.