Coronavirus case numbers in communities are normally tracked by local health districts by testing people who show symptoms of the virus, but that’s an indicator that lags behind the actual spread of the disease, Patterson told the News-Sun.
“Unfortunately, that’s like using a canary in coal mine,” Patterson said. Years ago, coal miners would bring cages with canaries with them as they traveled deep into the mines. If the miners with in contact with methane gas while working, the canaries would die, alerting miners to the harmful gas exposure.
“Wouldn’t it be better to find out from a machine, a test that the levels are rising so that we don’t have to kill the canary?” Patterson said.
In Clark County, 14,366 cases of COVID-19 have been confirmed as of Wednesday, according to ODH. There has been 536 hospitalizations and 308 deaths reported.
Last week, the county saw 21 new, confirmed cases of the virus. On Monday morning, the health district was alerted to an additional 17.
“It appears that the data on the actual cases is following right along with what we would have expected from the precursor data from the wastewater treatment program,” Patterson said.
Wastewater monitoring is a method to estimate the disease’s impact on a community in earlier stages than simply waiting for symptoms to appear.
According to the Ohio Department of Health, which works with the state’s health departments and districts to monitor wastewater, national research has shown that non-infectious ribonucleic acid (RNA) from the virus that causes COVID-19 can be excreted from both symptomatic and asymptomatic infected people and can be detected in wastewater as many as three to seven days before those infections lead to increases in cases and hospitalizations.
Monitoring wastewater in sewage collection systems can serve as a warning sign to possible disease increase in a community, ODH noted on its website that tracks wastewater virus levels statewide. Wastewater entering treatment plants is sampled for fragments of the virus RNA protein segments. The wastewater comes from homes in the area serviced by the wastewater treatment plant and travels through pipes to the plant. A mixed wastewater sample (which consists of a 24-hour composite) is collected in an area where all the sewage enters the specific plant.
A laboratory analyzes this sample to determine the number of virus gene copies present in the water, related to the wastewater flow that occurred on the day the sample was collected and the number of people that contributed to the flow, ODH said.
In short, a significant increase in viral gene copies over time can serve as an indicator that cases may be increasing in a community.
Clark County’s health commissioner said that the monitoring of the Springfield Water Treatment Facility began late last year. Community and public health leaders can use this warning information to make decisions about ways to limit further spread of COVID-19 in their communities, Patterson said.
The last health alert from the state, prior to the alert that was communicated this week, occurred in late March of this year, Patterson said.
Several days after the alert, the county saw an uptick in COVID-19 cases, with a virus surge experienced in the beginning of April.
Although wastewater monitoring provides an early alert to health leaders, it is unclear what the status will be a month from now. Patterson noted the health district has received many questions from community members about the future of county under the pandemic, given the recent Clark County Fair and the oncoming school year. Nationally amid a change in guidance from the Centers for Disease Control, many businesses are opting to re-implement mask mandates.
“I think the one thing to remember is, although it doesn’t appear there’s going to be a mask mandate, I think even vaccinated people are going to have to start being a little more careful about where they go, or who they’re around, or whether or not they wear masks,” he said. “We’re starting to approach what I feel is a potential dangerous period for Clark County, over the next month or two.”
The state health department updates its statewide data about virus levels in wastewater across the state roughly two to three times per week.
By the Numbers:
6,893: The average viral gene copies per liter reported to the CCHD from a July 19 water sample.
17: The number of new cases of COVID-19 reported to the health department at the start of this week.
60,000: The number of residents serviced by the Springfield Water Treatment Plant.
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