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Lewis & Clark Public Health reports coronavirus spike in local wastewater

Posted at 6:32 PM, Oct 26, 2020
and last updated 2020-10-26 20:32:45-04

Public health leaders in Lewis and Clark County are warning the public to keep taking precautions against COVID-19, after they’ve seen more signs of the virus in local wastewater.

For weeks, Lewis and Clark Public Health, the cities of Helena and East Helena and Carroll College have been working together to test wastewater from both cities for signs that the coronavirus is spreading in the community. Last week, their results showed the amount of the virus in Helena’s wastewater had doubled since the previous measurement. In East Helena, the numbers were more than 20 times higher than the week before.

Eric Merchant, Lewis and Clark Public Health’s Disease Control and Prevention Division administrator, said they were so startled by the results that Carroll researchers repeated the tests to make sure there hadn’t been a mistake.

“Given these really high concentrations this week, we suspect that there are a significant number of folks out there that are infected but don’t know it or are choosing not to be tested,” he said. “It’s another indicator to say, ‘You know what, the virus is out there, we need to be really careful right now and practice what we’ve learned.’”

When someone has SARS-CoV-2, the virus that causes COVID-19, their body “sheds” some of the virus. Genetic markers characteristic of the virus can be found in what they flush.

Public Health believes testing wastewater can give them a fuller picture of how prevalent the virus is in the community.

“There could be folks out there, as it relates to the wastewater, that are shedding the virus, and they don’t even know that they’re infected,” Merchant said. “People make a choice to go and have a diagnostic test done to see if they have COVID. When you’re talking about wastewater, people are using the bathroom, and that results in those viral concentrations going up in that system. So that’s telling us about everybody.”

Merchant said it isn’t a perfect correlation yet, but they have previously seen increases in virus concentration several days before large spikes in the number of confirmed cases.

“If there’s a high concentration, which is what we saw this week, we anticipate an increase in cases moving forward in the next few days,” he said.

Merchant said Public Health took this wastewater data into account when making their decision last week to stop approving events with more than 50 people.

“Right now, it’s not a good time for that, because we understand how much community spread is occurring and how much virus, again, is in the wastewater,” he said. “It shows us that we really need to be careful.”

Merchant said Public Health has already had difficulty performing all the contact tracing they have to do on confirmed positive cases. He urged people to limit their contacts when possible and keep following the steps they have been taking – washing hands regularly, wearing masks in public and maintaining distancing.

Leaders say, in the coming weeks and months, Lewis and Clark County will begin contributing their wastewater testing results to a nationwide database. They hope that will help health professionals better understand the virus.

The federal government is currently paying for this testing through the end of the year, using money from the CARES Act. Merchant said, if that funding isn’t extended, Lewis and Clark Public Health will look for other ways to continue the tests.

“We think it’s in the best interest of our community and our jurisdiction,” he said.

You can find Lewis and Clark Public Health’s most recent information on COVID-19 on their website.