Authorities at Cook County Jail are searching for coronavirus clues in the unlikeliest of places: the sewers.
"You know, I wanted to get as far out front of determining what the positivity rrate was in the jail," Cook County Sheriff Tom Dart told NBC5. "It's just a proactive thing that I really wanted to do."
The process is complex, but the premise is rather simple. After all, anyone infected with the virus sheds evidence of it in their waste.
And it just so happens that the output of the restrooms and cells at Cook County Jail run in defined sewers out of each division, isolated from storm water or melting snows. It's an ideal place to look for traces of the virus.
If you know how and where to look, that is (and if you don't mind staring down a torrent of sewage).
Enter the scientists from the University of Illinois at Chicago.
"It's much easier to test a couple of wastewater samples than to test hundreds of people," says UIC's Dr. Samuel Dorevitch. "If we tell them, that building where they thought they didn't have any COVID cases actually does, then they know what measures to put in place---to isolate people, move people out, so COVID isn't being transmitted in that building any more."
To be certain, the sheriff's office already tests the detainees---when they arrive, and on a random basis during their stay. But health officials say this can yield much faster results----and can give a global picture of virus concentrations in each of the jail's divisions.
"The time frame, which is so huge, this gives us about a five day heads up on anything that could be breaking out here, that we wouldn't get through normal testing," Dart said. "Because right now we test everyone---we've tested 55,000 people!"
On a recent morning, a UIC team, accompanied by doctors from the jail's Cermak Health Services and the Chicago Department of Health, showed NBC5 how they take samples from sewers at six different sites inside the jail complex.
Picture the water bottle from your fitness class, attached to a 10-foot chain. Scientists pop open the manhole covers of the sewers, and lower those bottles into the raw sewage flowing about ten feet below.
"So it's wastewater. Basically that they flush down the toilet, they shower, everything gets mixed up," says UIC's Dr. Abhilasha Shresta.
After each sample was taken, Dr. Shreshta made sure the top was screwed down tight, then sprayed the outside with disinfectant. Each was labeled with the date and the division where the sample was taken.
"So we are taking it in the lab," she said. "And then we'll start doing the processing right away."
If it sounds like a tedious process which is not for those with a weak constitution, you're right on both counts, but back in the UIC labs is where the real science kicks in.
There, defined amounts of sewage from each sample are poured through filters, which capture any traces of virus. Dr. Dorevich said the tests are so sensitive, they can reveal more than just the presence of the virus.
"We're able to know how much virus is in that sample," he said. "Certainly, the difference between none, a little, and a lot, is useful."
From the beginning, the virus presented an ominous challenge for jail officials. The complex houses thousands of pre-trial detainees, some for years, and new residents arrive every day.
A month into the pandemic, Dart and his team faced a single day in April with over 300 virus cases. But since then, the sheriff's office has spent millions on testing, PPE, and a new housing scheme separating detainees into previously mothballed areas of the jail complex.
And those procedures have paid off. On Wednesday morning, there were only eight positive cases.
To be sure, the numbers have waxed and waned with the same regularity seen on the outside. Just as the rest of Illinois saw a spike in the fall, the jail also saw some of its highest numbers---375 cases on Dec. 13 alone.
But now those numbers are back in the single digits, and officials say they are optimistic this process could become a new tool in the front lines of the fight.
Partners at Argonne National Laboratory will also be testing the samples for new strains of the virus, such as the South African variant which has proven more contagious.
"This can serve as an early warning system," says Dr. Wilnise Jasmin of the Chicago Department of Health. "Samples collected here will tell us a lot earlier than if we wait for someone to become symptomatic."
And if virus is found? Dr. Chad Zawitz of the jail's Cermak Health Services, says the results will help his department to be much more nimble.
"Knowing exactly where we need to target our resources, we can more effectively respond," he said. "We are particularly interested in learning what is circulating on the compound."