Sewer samples help gather coronavirus information

A study of wastewater samples across Missouri is showing researchers where COVID-19 hot spots are likely to occur.

As the Southeast Missourian reported in June, Cape Girardeau is one of several communities throughout the state participating in a “sewershed surveillance” study intended to help identify coronavirus case trends. Doing so can help health authorities and government officials forecast COVID-19 case trends, which can help them allocate supplies and human resources to meet community needs.

More than 1,400 sewer samples have been collected and analyzed since the study began in July.

“We have learned a lot about sewershed testing and monitoring since the project started,” said Jeff Wenzel, chief of the Bureau of Environmental Epidemiology at the Missouri Department of Health and Senior Services (DHSS), which is partnering in the study with the Missouri Department of Natural Resources (DNR) and researchers at the University of Missouri-Columbia.

“The CDC (Centers for Disease Control and Prevention) and other states have started conducting testing, as well, which is allowing us to have partners to collaborate with and advance the science faster,” he said.

Sally Zemmer, environmental program specialist with the DNR, said similar studies have helped track other diseases through community sewer systems.

“Wastewater testing has been used to track norovirus, hepatitis A and polio,” she said. “It could be a valuable tool for COVID-19 surveillance because people can be infected for up to 14 days before showing any symptoms, and individuals with mild symptoms may not get tested. Wastewater testing could provide early awareness of virus emergence — or reemergence — in a community.”

The Cape Girardeau area has shown a significant increase in coronavirus cases in recent days. That increase, Wenzel said, was foreshadowed by sewer water testing in early November.

“Our most recent lab result for Cape is from Nov. 2,” he said. “That viral load measurement was higher than it has been, which does seem to correspond with the increase in individual positive case results (in Cape Girardeau).”

The case correlation in the Cape Girardeau area is one example of the study’s success in tracking virus outbreaks.

“It is relatively easy to find COVID-19 viral particles in sewage in areas where there are active cases,” Wenzel said. “However, being able to go into a community with known active cases and confirming there are cases is not very informative and is not the intent of the project. What we hope to be able to do with this data is to be a tool to help detect new outbreaks in a community and monitor trends over time.”

“Many similar projects are underway nationwide and across the globe and have demonstrated success tracking the virus,” Zemmer said. “Additionally, federal agencies have now initiated a National Wastewater Surveillance System, or NWSS, in response to the pandemic. One of the goals of NWSS is to compile and analyze wastewater data from state and local studies, like Missouri’s, to help inform public health officials.”

Zemmer said Missouri’s sewershed surveillance project is one of the largest of its kind in the United States.

The project was initially funded with $850,000 in federal grants directed to DHSS, enough funding to test up to 80 sewer samples a week for a year.

“The project is currently seeking additional funding to increase the number of sampling locations and sampling frequency,” Wenzel said, adding the study “would not be possible without wastewater operators donating their time to collect these samples.”

Just more than 80 Missouri communities are providing sewer samples for the study. In addition to Cape Girardeau, other Southeast Missouri communities participating in the project are Charleston, Dexter, Farmington, Perryville and Sikeston.

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