Wastewater samples signal potential spread of COVID-19 in Jasper County

May 18—Wastewater samples collected recently in Jasper County have shown an increase in viral load, signaling to health experts that more COVID-19 cases in the region could be on the horizon.

Treatment plants in Joplin and Carthage have samples showing the increase. One showed a 40% or more increase from last week, and the other recorded an increase of 25% or more over the past two weeks, according to data from the Sewershed Surveillance Project.

Tracking the coronavirus through wastewater has been a collaborative effort of the Missouri Department of Health and Senior Services, Missouri Department of Natural Resources and University of Missouri.

The group began testing wastewater samples in February 2021 to look for the presence of variants of the virus that causes COVID-19. Using a technique called high throughput sequencing, samples with enough COVID-19 genetic material are tested for genetic mutations, which are compared against mutations in known variants.

"What's nice is we are banking the samples, so if there is something new, we could go back and find out when it appears here," Marc Johnson, a professor of molecular microbiology and immunology at MU, said in an interview with the Missouri Independent in 2021. "If the variant is here, we should be able to find out when it arrived and perhaps where."

Some people infected with COVID-19 may not display symptoms for several days. The genetic material from the virus can be present in human waste even when individuals have no symptoms, which means sewershed surveillance can help paint a picture of possible infections for health experts.

Researchers have linked wastewater samples to the number of positive COVID-19 tests a week later, suggesting health officials could get an early glimpse at infection trends.

"It is not a big sort of advance warning but a couple of days," Johnson told the Missouri Independent in a previous interview.

Omicron spread

With subtypes of the omicron variant now spreading, the U.S. is averaging about 91,000 cases reported a day, compared with about 57,000 just two weeks ago. That's a small fraction of the infections seen during the winter surge — but experts also say it's a vast undercount as testing has dropped and at-home tests often aren't reported.

After holding steady for a couple months, the number of COVID-19 cases in the region is slowly rising but not to alarming levels, according to Tony Moehr, administrator of the Jasper County Health Department.

"We have been pretty steady, and numbers have been low," Moehr said. "We have seen a few more cases in the last week or two than we have been seeing. We had been averaging maybe a case per day, or maybe even fewer than that at times. There have been several days where we've had three or four cases per day, so it's not anything that's dramatic or urgent, but it is still floating around out there in the community."

Moehr said he's been monitoring the Sewershed Surveillance Project data, in which viral loads in Jasper County had remained below baseline over the last six weeks but just recently started rising.

"We have seen a pretty significant increase in those, but that significant increase is still way, way lower than the times when we were seeing a lot of infection throughout the community," he said.

Jasper County was averaging over 300 cases per day during its last peak in January.

Hospitalizations

With so many people using at-home tests and fewer cases being reported to the state, Moehr said hospital data can also be a good indicator of how many cases there are in the community.

"The No. 1 goal is to keep hospitals from being flooded and to keep illness and deaths down as much as possible," he said. "If they're not seeing a tremendous spike in hospitalizations or anything like that, then they can pretty well say, 'Based on the watershed data and the number of tests that we see coming in, we do have it spreading around the community, but what must be going on isn't severe enough to cause excessive hospitalizations.'"

Local hospitalizations rates among COVID-19 patients have remained low and stable over the last couple of months, according to officials with Mercy Hospital Joplin and Freeman Health System.

Mercy spokesman Jordan Larimore said Tuesday that the number of COVID-19 inpatients has remained low and that there hasn't been a significant increase in the past few weeks.

"We've stayed in single digits, often below five inpatients, although we have not yet hit zero," Larimore said. "Typically not more than one patient in ICU or on a ventilator at a time. We're hopeful that vaccines are helping prevent positive cases from becoming hospitalizations, etc."

Freeman Health System is also seeing low numbers and on Tuesday reported three COVID-19 patients at Freeman Hospital West.

"We are very lucky in our region to have continued stability in the low number of COVID-19 cases we are seeing," said Lisa Olliges, media specialist for Freeman Health System. "Unlike the coasts and other states, we have not seen a surge in cases where patients require hospitalization."

Data from the wastewater project can be found at https://storymaps. arcgis.com/stories/ f7f5492486114da6b5 d6fdc07f81aacf.

The Associated Press contributed to this report.