Researchers are monitoring water along Lake Superior beaches for signs of SARs-CoV-2, the virus that causes COVID-19.
After more than a month and a half of testing, however, there's been no sign of it — yet.
"I have not detected the genetic presence of the virus that causes COVID-19 in the water samples from the beach," Richard Melvin, an assistant professor at the University of Minnesota Medical School, Duluth Campus' Department of Biomedical Sciences, said. "The word 'yet' is OK because we are going to continue monitoring. ... We're just looking since there is a potential."
Since July 4, Melvin and a technician have been collecting water samples from eight Lake Superior beaches on Fridays, Saturdays and Sundays — when most people are there and in the water.
Because the virus is shed in an infected person's stool for a month, even after respiratory symptoms have gone away, it likely rinses off a person's body when they enter the water and would be found by testing the water for it.
Melvin said that while results so far could mean the it is "completely absent," it may also mean the virus is "at such a low concentration that we can't detect it."
But testing the water has shown signs of another virus: pepper mid mottle virus, or PMMoV, a plant virus with genetic evidence that stays in processed foods and our stool. While it infects plants, it doesn't infect humans, and when it shows up, it's an indicator of human presence, Melvin said.
"If people get into the water and dip their lower half in, it's highly likely that they will leave behind (PMMoV) ... and the virus is a way to say that 'yeah, people have been here,'" Melvin said.
In the lab, Melvin isolates viruses from the water using the same process he and fellow medical school assistant professor Glenn Simmons Jr. use when studying the virus' presence in raw sewage across Minnesota.
The duo hope that related study will use the amount of virus in a sample to determine how many people in that community have COVID-19. Four months in, they say levels of viral particles in the wastewater reflect increasing cases across the state and has even given them early signs of outbreaks.
"Dr. Simmons and I have kind of become experts on getting this virus out of water," Melvin said.
The virus does not enter the water from treated wastewater as it is destroyed by the treatment process before it is returned to the environment.
The testing of water at beaches is funded by the Minnesota Sea Grant, which also supports ongoing testing for bacteria along Lake Superior beaches and rip current warnings.
Jesse Schomberg, the associate director of extension for the Minnesota Sea Grant said idea for the project started after they heard "some interest in whether or not COVID was found at the beach."
He said a new section with SARs-CoV-2 water testing results will be added to parkpointbeach.org, which already has the beach bacteria and wave and current risks listed.
Ultimately, Schomberg hopes testing results that show no signs of the virus in water won't give people a false sense of security at the beach and urged visitors to keep taking social distancing seriously.
"We don't want the result to be that folks show up at the beach and throw big parties ... So that's kind of a line that we're hoping to walk: reassuring folks, but still making sue that the proper precautions are taken," Schomberg said.
Added Melvin, "Water is not known to be a major infectious route. The major infectious route is through respiratory droplets, which means that the biggest risk on a beach is being there in crowds of people."