Damakant Jayshi

COVID-19 cases in Marathon County appear to be in decline, according to last week’s wastewater data released by the Centers for Disease Control and Prevention (CDC).

Compared to the peak this year on Jan. 13 when the 7-day average COVID-19 case rate at the Wausau Water Works Wastewater Treatment Facility was 247.3 per 100,000 residents, the rate dropped to 28 per 100,000 residents by Feb. 16, the data show.

The CDC helped set up the National Wastewater Surveillance System (NWSS) to analyze sewershed data. fed by local health departments or state health agencies. The NWSS comprises 43 health departments funded by the CDC to provide data on presence of and trends in SARS-CoV-2 infections that are independent of clinical testing.

The Marathon County Health Department considers this a steep decline in cases.

“The wastewater surveillance data is confirming what we already know, that COVID-19 cases are rapidly decreasing in our area,” Health Department Spokesperson Aaron Ruff told Wausau Pilot & Review. “Data from the Wausau WTF clearly shows a steep decline in concentration of SARS-CoV-2 in wastewater as well.” Ruff was referring to the Wausau Wastewater Treatment Facility.

Wastewater data is used for early detection of COVID-19 within a community.

“For people with COVID-19, the virus can be detected in their feces shortly after they are infected with the virus, even before they experience symptoms or if they are infected but asymptomatic,” Ruff said. “By testing wastewater, we can measure the amount of the virus and see whether the levels are increasing or decreasing. This can be an early warning sign of increasing COVID-19 cases within a community.”