Virologist expects months-long battle with COVID-19 delta variant in Illinois Sewer testing shows the delta variant spread unusually fast and far in Missouri. It arrived in St. Louis just before Illinois reported its first delta cases. Author: Erin Richey (KSDK), PJ Randhawa Published: 6:34 PM CDT July 29, 2021 Updated: 6:34 PM CDT July 29, 2021 ST. LOUIS — The hunt for COVID-19 variants has lead some researchers to the gutters--literally. "It doesn't matter if you've been vaccinated, it doesn't matter whether you have health insurance, it doesn't matter whether you believe in COVID. If you use the toilet, we're sampling you," said Professor Marc Johnson. He's a virologist and wastewater researcher with the University of Missouri School of Medicine.