Carroll College scientist tests wastewater for COVID-19


HELENA, Mont. (AP) – When Carroll College neuroscientist Stefanie Otto-Hitt planned a sabbatical for this semester, testing wastewater for traces of COVID-19 was the last thing she expected to do.

Otto-Hitt said she had previously planned a different project for the sabbatical, but ended up doing this after local public health officials reached out in an effort to find a local partner for testing. Otto-Hitt said she ultimately feels the testing project is not only more timely, but significantly better than her originally planned sabbatical project.

“I’m a lover of techniques and new research,” Otto-Hitt told the Independent Record. “I felt very comfortable jumping in.”

Otto-Hitt is working alongside Dr. Ashley Beck, a geneticist, and Dr. Theresa McHugh, a microbiologist, on the testing. Their first data point was published on Aug. 10 and has essentially shown that there is more COVID-19 in the community than there are positive tests reported. The research received the green light around the end of July.

At the start of the research, Otto-Hitt spent time looking into what other scientists were doing for COVID-19 wastewater testing. She found that using polyethylene glycol (PEG) as an agent to concentrate viruses from large volumes of wastewater had been used previously for this type of research. This substance acts as a binding agent, essentially attracting the virus particles and making them heavy, allowing them to be separated from other parts of the wastewater.

Following virus concentration with PEG, the RNA genomes are extracted and then converted into viral DNA, which is a more stable molecule for the testing procedure. The viral DNA is then subjected to an amplification process called Polymerase Chain Reaction, or PCR. The PCR process specifically seeks out and amplifies two regions of the SARS-CoV-2 viral genome that are unique to that virus, namely the N1 and N2 genes. The results of the PCR process are compared to known concentrations of the SARS-CoV-2 genome; this final analysis lets the scientists determine just how much SARS-CoV-2 is in the wastewater sample.

This process is essentially a “community surveillance” technique in regards to potential overall COVID-19 infection rates. It bypasses the limitation of testing every individual person by testing their waste instead.

Otto-Hitt said they were essentially running blind during the first couple of tests, with around a 50% return rate on samples. Now every sample is testing positive for traces of the virus. In mid-October, the scientists saw a huge spike in the number of cases in the wastewater tests. Otto-Hitt at that time completed the entire process over again to see if the results replicated, which they did.

“The hope is that by doing this we can use the data retrospectively,” Otto-Hitt said.

During the week of Oct. 26, Otto-Hitt’s work showed more returns and a rising number of SARS-CoV-2 genomic copies in the city’s wastewater in Helena. The number of genomic copies is fairly close to the number of daily active cases and similar to the number of daily new cases, except for an enormous spike in daily new cases the week prior on Oct. 25.

However, East Helena’s wastewater tells a very different story. After an enormous spike the week prior, the number of genomic copies in the wastewater was more than halved the following week. This data show that East Helena is still at an elevated level of genomic copies in the wastewater when compared to two weeks ago, but is more in line with previous readings than the massive spike in genomic copies on Oct. 21.

Otto-Hitt said learning the safety precautions of working with wastewater was a new process for her. The wastewater itself is provided by local treatment facilities and is taken from the intake at that facility before any processing is done.

City engineer Ryan Leland said Helena’s drinking water is not affected by the presence of COVID-19 in wastewater.

Leland said Helena’s tap water comes from two different sources: Ten Mile Creek’s drainage around Rimini and the Regulating Reservoir. That raw water is treated through a sedimentation, filtration and disinfection process before entering the distribution system. Leland said the city maintains a chlorine residual in the distribution system to ensure the safety of the water from pathogens.

Both sources of the raw water are above the discharge of the city’s wastewater treatment plant, said Leland. The Ten Mile drainage, which is the primary source of drinking water, is collected at the headwaters of the drainage, mostly above Rimini.

Additionally, studies by both the Environmental Protection Agency and the Centers for Disease Control and Prevention have shown that COVID-19 is not present in drinking water and that the virus cannot survive the treatment and disinfection process.

For more information from the EPA, visit its website ( and search for “coronavirus and drinking water and wastewater.”

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