Samples could be collected from specific points in the national network of wastewater treatment plants.
A sewage-based coronavirus test could be an “easy win” that would detect spikes of infection up to 10 days earlier than existing medical tests.
Scientists led by the UK’s Center for Ecology and Hydrology are working on a standardized test to “count” the amount of coronavirus in a wastewater sample.
“The sooner you find [a signal]the sooner an intervention can occur, “says lead investigator Dr. Andrew Singer.
“That means that lives will be much more livable in the current crisis.”
Mapping infections through sewers
A network of scientists from universities such as Newcastle, Bangor and Edinburgh has already partnered with local water companies to collect samples of untreated wastewater from treatment plants; The first stage in mapping the outbreak through sewers.
Water treatment plants could provide sampling points to map the outbreak
Early in the Covid-19 pandemic, research revealed that people infected with the virus “dump” viral material into their stool. That idea sparked an interest in “epidemiology of wastewater.”
“By sampling wastewater from different parts of the sewer network, we can gradually reduce an outbreak to smaller geographic areas, allowing public health officials to quickly focus interventions on those areas most at risk of spreading infection, “said Dr. Singer.
“Our network already has six laboratories that are capable of doing that work, so a national surveillance system could occur tomorrow.”
So while the researchers say they already have a reliable test that can show the presence or absence of the coronavirus, they are now working on a way to measure infection levels regularly and reliably through the water treatment network.
“It is easy to say whether there is something with the genetic fingerprints or not,” explained Professor David Graham of Newcastle University, who is participating in the development of that test. “But for the sake of epidemiology, which has life and death impacts, we wanted to be more exact.”
Professor Graham and his colleagues have developed a way to quantify the genetic material of the coronavirus.
Genetic ‘signature’ of coronavirus can be detected in a wastewater sample
“We can count how much virus is in a sample,” he explained. And, because each sample comes from a water treatment plant that serves a specific community, we can also tell you an approximate number of humans that it comes from. ”
He noted that it currently took seven to 10 days to determine if a person had the disease, but said: “We can collect a sample of wastewater and give it an exact number per person within the next day, and that is for the community.
“We can tell him if anyone in the community has it at least a week before.”
Disordered epidemiology
The wastewater contains other contaminants that could affect viral material, making accurate measurements difficult.
The researchers want to adjust and reproduce this test before it can be implemented as part of a Covid-19 alert system.
While many countries, including Spain, have started monitoring their wastewater, there have been some initial problems: A result that suggested that the coronavirus was present in Barcelona in March 2019 may have been the result of laboratory contamination.
There are problems to solve to maximize the precision and value of a wastewater-based surveillance system: the propensity of the virus to break down when in the water, the effect on the outcome of other contaminants, and how many sampling points need to be included on a network across the UK in order to build a useful picture of the outbreak.
“It seems obvious that we should be doing this,” said Dr. Singer. “But it is an approach that has never been considered for an active outbreak.”
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