Health

Coronavirus detected in lake water, researchers find. Experts say don't panic.

Korin Miller

Wed, September 30, 2020, 3:18 PM EDT

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A team of researchers at the University of Minnesota has found traces of SARS-CoV-2, the virus that causes COVID-19, in lake water.
The virus was detected by a group led by Richard Melvin, an assistant professor in the Department of Biomedical Sciences at the University of Minnesota Medical School, in mid-September. Melvin and his team have been sampling water from various beaches on Lake Superior since July 4 on a weekly basis as a partnership with Minnesota Sea Grant, an organization that works to enhance the state’s coastal environment. The team hadn’t found the virus during weekly tests, but, on Sept. 11, that changed.
The research team detected SARS-CoV-2 at 100 to 1,000 copies per liter, or 10,000 times lower than levels observed in wastewater. “I was surprised and not surprised,” Dr. Richard Melvin, assistant professor at the University of Minnesota Medical School, Duluth campus, tells Yahoo Life. “We were testing a hypothesis that beachgoers would bring this on their bodies into the water, but when you see it on the machine, there’s this sinking feeling.”

Researchers have been sampling water from various beaches on Lake Superior since July 4 on a weekly basis and detected SARS-CoV-2 at 100 to 1,000 copies per liter, or 10,000 times lower than levels observed in wastewater. (Photo by Alex Kormann/Star Tribune via Getty Images)

The source — or sources — of the virus are unknown at this point, Melvin says, but the research team plans to continue to monitor the water, as well as work with local health experts to try to pinpoint the source of the virus in the water.
The news sounds scary, but public health experts say people shouldn’t panic.
Dr. Richard Watkins, an infectious disease physician in Akron, Ohio, and a professor of internal medicine at the Northeast Ohio Medical University, tells Yahoo Life that, while research has shown that SARS-CoV-2 can show up in wastewater, there’s no data to suggest that the virus is actually transmitted through water. “However, there is a lot we don’t know about the virus, so nothing can be definitively ruled out at this point,” he says.
But finding the virus in water “doesn’t mean that they’re infection particles,” Dr. Thomas Russo, professor and chief of infectious disease at the University at Buffalo, tells Yahoo Life. “It’s highly unlikely that SARS-CoV-2 can survive in a body of water for very long,” he says.
Dr. Valerie Fitzhugh, an associate professor and interim chair of the Department of Pathology at the Rutgers New Jersey Medical School and Rutgers Robert Wood Johnson Medical School, agrees. “Lake water should not be a risk,” she tells Yahoo Life. “The bigger issue would be crowds at a beach near the lake than the water itself.”
Even if the virus were infectious in water, it’s likely to be diluted if it shows up in a larger body of water, like a lake, Russo says. “It would probably be so diluted that it wouldn’t be sufficient enough to cause an infection in an individual,” he says.
But how did the virus get there in the first place? There are a few different possibilities, Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security, tells Yahoo Life.
“People excrete the virus in their feces, and people deposit fecal matter in lakes,” he says. The virus could be shed into water after someone didn’t wipe well after using the bathroom, or it could actually end up in the water from someone using the area as a toilet. “People go to the bathroom in lakes,” Adalja points out.
There is also a risk of sewage contamination seeping into lakes, Adalja says. And, since SARS-CoV-2 has already been detected in sewage, it could end up in a lake that way. “This is not surprising to me,” Adalja says. Worth noting: Melvin says that the virus is “not likely” to come from local wastewater treatment plants. “They do a perfectly effective job of eliminating the virus,” he says. “However, it could be coming from sewer lines or septic tanks.”
Because of all this, Adalja says, SARS-CoV-2 is likely to also be found in other bodies of water elsewhere.
But, again, people shouldn’t panic. “I don’t think it’s a major mode of transmission,” Adalja says. “SARS-CoV-2 was just found in water — it’s not necessarily living in water. Any virus that gets excreted fecally can be found in water.” Melvin agrees, noting that the virus “rapidly degrades” in water. “In my research, I’ve never found a case of anyone recording an infection due to water,” he says.
Ultimately, Melvin says, his findings are more a signal of what’s happening around the lake. “It’s just an indication that the infection level is high in the city,” he says. “Anytime something like that happens on a high level, it spills into the environment in some way.”