North Dakota is among states dipping a toe into wastewater surveillance methods for COVID-19, and Williston is among cities where samples for this developing method are being taken and analyzed.
The method hit the media spotlight a few weeks back when the University of Arizona employed the technique to find early signs of a COVID-19 outbreak and stop it in a dormitory as students were returning to campus. By testing wastewater, the university was able to direct testing resources to the dormitory in question and isolate two asymptomatic cases before anyone else could be infected.
John McEvoy, head of Microbiology Science at NDSU, said North Dakota is looking not only at using the technique on campuses, but it is exploring how to use the technique to monitor COVID-19 trends in communities.
“We started doing work on this back in probably early July, late June,” McEvoy said. “(It) was based on this idea that for the virus, when people are infected, even though it is a respiratory virus, they are shedding it in their stools. (And that) led to this idea that we could monitor wastewater to determine how much of the disease is present in a community.”
Using a small grant from the Department of Environmental Quality, a testing system was set up by a multidisciplinary team on thtree cities, Fargo, Bismarck and Grand Forks.
“As it became clear that this could be a useful approach for monitoring the virus in communities, we have begun expanding that,” McEvoy said. “The state is really interested in expanding to smaller municipalities around the state, and so we added Williston a couple of weeks ago, and we hope to add a lot more smaller municipalities across the state.”
So far Williston has just two or three data points McEvoy said. It will take more before trends can be established and analyzed for the community.
McEvoy said samples municipal samples in general could be taken at varying locations in a given community, perhaps even to approximate divisions like zip codes.
“The sewer shed is a collection of pipes that are like a tree that eventually work through to the wastewater facility,” McEvoy said. “We can sample at various branches of that. They don’t match perfectly to zip codes, but we can certainly sample areas of a city by sampling at various locations. And that is something we’re interested in doing, is breaking down cities to smaller areas to identify areas with higher numbers.”
McEvoy said they are also looking at institutions that might benefit from waste water surveillance for COVID-19, among them, correctional facilities and potentially university dormitories.
“If you look at the waste water coming out of a building, and monitor it to see if there’s virus present, that would indicate that someone in the building is infected,” McEvoy said. “That could help to drive decision making.”
To that end, the state has ordered a machine that can sit in a manhole collecting samples at regular intervals over a 24-hour period.
“The problem with a single grab sample is you are only testing whoever is contributing to the waste water at that time of day,” McEvoy explained. “If an infected person wasn’t present then, you are not testing them. So the better approach is a composite sample.”
Autosamplers like this are in high demand across the country, as other communities are looking to use the technology for COVID-19 surveillance as well.
“We are waiting for more of them to be delivered, and then we will start installing those on campuses like NDSU and UND to collect samples from dorms,” McEvoy said. “That will give us a much more accurate reflection of what is going on there.”
The samples are available quickly, McEvoy added. A sample collected in the morning can be available that afternoon.
“We’re looking at where our data can help in making decisions and can help with directing resources, so you are not having to test a population who maybe really doesn’t have any COVID or has very low levels,” he explained. “If you consider a community in North Dakota that doesn’t have many if any cases, and we start testing and their waste water levels are low or not detecting it, and then all of a sudden we start seeing it, then we’d say you need to direct resources at this community. It can be detected in wastewater before you see (COVID-19) cases emerge.”
McEvoy said the project is in the early phase of development, and they are actively seeking situations where the surveillance could be useful.
“We are at that phase in this project where we are really open to trying out a lot of different things to see what works best,” he said. “We are open to looking at any situation where someone feels like this could be a benefit to them.”
McEvoy said the system could also have benefits beyond the COVID-19 pandemic.
“This type of testing for communities for infectious diseases could be useful for other infectious diseases beyond COVID,” he said. “This could be used to track other diseases in communities as well. We have felt like we are building this plane as we fly it, but at the end of the day, we believe we will ultimately have tools to use for other things in public health.”