University of Idaho

MOSCOW - Researchers at the University of Idaho have partnered with the City of Moscow to improve wastewater testing for the presence of SARS-CoV-2, the virus that causes COVID-19. The team hopes to develop an early warning system for spikes in local cases.

Testing wastewater for the presence of SARS-CoV-2 is being conducted in areas worldwide, and estimating cases within a community based on the concentration of viral RNA in wastewater samples is a science that is gaining ground.

“Our primary contribution would be toward a bit of an early warning test,” said Erik Coats, U of I civil and environmental engineering professor.

Test results with higher concentrations of the virus, especially in areas with low case numbers, could foretell of future spikes in diagnosed patients.

“We could help hospitals focus on clearing up beds, gathering more personal protective equipment and making sure people are well-rested in advance of a wave,” Coats said.

Coats is working with Research Assistant Cynthia Brinkman, Department of Biology Professor Eva Top and Research Support Scientist Thibault Stalder. Department of Mathematics Assistant Professor Benjamin Ridenhour will assist with sampling schemes, analysis and extrapolation of results.

Moscow participated in a subsidized testing program through Massachusetts-based startup Biobot Analytics. The city provided Biobot with 24-hour composite wastewater samples in May and July.

SARS-CoV-2 was not detected for the three tests in early May. Biobot estimated 190 cases of COVID-19 from a test later that month. Analysis of samples sent July 1 and July 13 indicated 1,400 and 1,800 cases respectively.

“It is important to note that the Biobot data provides estimates, not actual cases,” Moscow City Supervisor Gary Riedner said in a statement released from the city. “While we can’t rely on the accuracy of the case estimation, the thing that is certain is that we are seeing significantly increased concentrations of COVID-19 in our wastewater.”

U of I testing will start using the same sample submitted to Biobot on July 1. Samples from the City of Twin Falls also have been obtained for analysis, and Coats is reaching out to regional wastewater treatment plants that have also participated in testing.

By comparing test results from different sources, researchers can better confirm the accuracy of their method and learn more about how that could translate into estimated cases.

“We’re hoping to develop a baseline,” Moscow Water Reclamation Utility Manager Evan Timar said. “We’re trying to compare and contrast testing results from different sources to see where we’re at and relay that information. We’re still learning and using that information to be proactive about what’s going on and to do our part for the wellbeing of the community.”

The city will collect and provide samples to the U of I lab, where researchers will isolate the viral RNA within the sample, reverse transcribe it to DNA, and then quantify regions within this DNA that are specific to SARS-CoV-2. This process allows detection of the SARS-CoV-2 at low concentrations. The method is being validated and optimized.

“The importance is the increase we observed,” U of I Research Support Scientist Thibault Stalder said. “With more samples, we will see the trend. For now, the data mirrored with public health data will be a great complementary tool.”

Wastewater consists of suspended solids and water, and one of the biggest challenges is identifying where the virus is most present in the sample. Reports suggest all carriers of the disease, asymptomatic or not, shed the virus, although virus shedding may be more prominent upon a person’s early infection.