Missouri Covid-19 wastewater uses new technique to collect data after heavy rainfall
COLUMBIA, Mo. (KMIZ)
Wastewater testing for COVID at the University of Missouri is set to try a technique researchers have been developing over the past year to test diluted wastewater.
Marc Johnson, professor of medicine and head of MU's wastewater team, says his colleague Chung-Ho Lin led a project to find the best way to adjust wastewater data after heavy rainfall.
After numerous testing, the wastewater team found that the most reliable way to find human contribution amounts in diluted water is by testing a small molecule that only humans contribute-- caffeine.
Johnson says a solid piece of evidence for this in Columbia is the increased caffeine levels in the wastewater when there are more people during Homecoming weekend.
The team specifically looks for caffeine molecules that are metabolized, which look different from caffeine molecules before human consumption.
Johnson says that before this technique was developed, wastewater testing teams would use the rain flow rates from cities to predict how much the sewer system has been diluted. He says the method to measure rain flows into sewer systems is difficult in places that don't have those systems or when rainfall is so heavy that wastewater flows into rivers.
He says that because of the recent rainfall in Missouri, "It's actually exciting because this is a great stress test for this technique we've been developing."
The testing site at the University of Missouri is one of over 100 sites under the Sewershed Surveillance Project according to the Missouri Department of Health and Senior Services.
According to the project, one of the main benefits of sewershed surveillance is the early detection of new or worsening outbreaks.
Johnson says that recent sewershed testing found samples of the highly transmissible BA.5 variant, which accounts for most current cases in the state and the country according to PBS News. However, "right now it's not time to panic," Johnson says, because this lineage has not alarmed the team like the Delta and Omicron variants.
Wastewater data from the University of Missouri has shown a slow and gradual increase in viral load for the last 17 weeks, and although Johnson predicts the numbers will level off soon, he says they are prepared to see another "wave" from a new lineage in the future.
