Students were just settling in on the campus of Mount St. Mary’s University in Western Maryland when researchers wearing protective gear began scooping up weekly samples from the pipes outside their dorms.
Without a single student getting a nose swab, public health officials knew that a student at the small, private university — potentially more than one — was carrying the virus. They just had to identify them.
Administrators quickly tested 221 students. Ten were positive. Nine had never shown symptoms and weren’t aware they were sick.
“It could have become quite a spreading event,” said Donna Klinger, a spokeswoman for the university. The coronavirus-positive students were put in isolation, and the college decided to increase its wastewater sampling to twice a week.
Mount St. Mary’s is one of a growing number of colleges and universities across the country that are testing wastewater to monitor and attack the spread of the coronavirus.
Now state and local governments are starting to follow suit, with Maryland launching a statewide wastewater testing program that will focus on nursing homes, prisons and low-income housing developments.
The District is joining a new federal initiative to identify coronavirus hot spots through wastewater testing. The initiative, run by the U.S. Department of Health and Human Services, will compile data from individual wastewater treatment plants and systems.
“It’s an unintrusive way to study what is circulating in the community,” said Rita Colwell, a microbiologist and president of CosmosID, a Rockville-based firm that will analyze Maryland’s specimens.
CosmosID has been testing collections from as far as California and Maine for months. In the greater Washington region, the company has worked on collections in Frederick County, including at Mount St. Mary’s. The University of Virginia also has used wastewater sampling as a tool to detect the novel coronavirus.
Maryland began a two-month pilot program in July, testing samples from five wastewater treatment plants in Baltimore, Montgomery, Prince George’s, Allegany and Wicomico counties. The program gave state public health officials an early sense of areas where community spread of the virus might be high.
Last month, Gov. Larry Hogan (R) announced the state will spend $1 million for the Maryland Department of the Environment to launch its statewide effort.
Jay Apperson, a spokesman for the agency, said the program began in mid-December in coordination with the Baltimore City housing authority. The state ultimately intends to have 50 testing sites across the state.
State environmental secretary Ben Grumbles said wastewater testing does not replace clinical testing but can be a great predictor of where the virus is and how rampantly it is spreading, detecting its presence in people who may never show symptoms. The tool allows the state to screen congregate settings for the virus without asking people to line up to take tests.
Researchers across the country and around the world have tested wastewater to study everything from polio to cholera and, more recently, opioids and heroin. Since the pandemic began this spring, scientists have learned that the ribonucleic acid, or RNA, of the coronavirus, which causes covid-19, can be detected in feces, and that infected individuals shed particles in their stool soon after being infected.
Biobot, a Boston-based wastewater epidemiology firm, was the first company in the United States to try this approach. Its scientists began working with MIT and the Harvard School of Public Health in February, collecting samples from wastewater treatment plants in Boston. Today the company is analyzing water from 400 communities across 42 states, including Stafford County in Virginia, Miami-Dade County in Florida and Chattanooga, Tenn.
“Individuals who contract [coronavirus], they are shedding the virus in stool within days of infection,” said Newsha Ghaeli, the co-founder and president of Biobot.
Barbara A. Brookmyer, the health officer in Frederick County, said there are a lot of questions about wastewater testing, particularly of large sewage plants.
“This is still in the early stages of understanding everything from the sample collection up through and including interpretation of what the data means,” she said. “There is nothing in a textbook right now that says if you take a look at a wastewater treatment plant that serves 30,000 people and you see this many copies of this gene particle, then that is equivalent to X number of people who are in Day 1 of infection, X number of people in Day 2 of infection, X number of people who are still shedding virus.”
When the county initially started collecting samples, said Mark Schweitzer, the director of the Frederick County Division of Water and Sewer Utilities, he found “a lot of difficulty matching up the wastewater collection system area with the case data.”
He said there were a number of variables that affect the collection, including rainwater and the time it takes for the waste to reach the treatment facility.
Now the county is doing more targeted testing of congregate facilities, Schweitzer said.
“It’s one of the tools in the toolbox,” said Manoj Dadlani, the CEO of CosmosID. “It can’t solve everything, but it’s a useful tool in terms of decisions, in terms of policy and ramping up testing.”