During the COVID-19 pandemic, sewage testing became a key way to track the spread of the virus, especially as free laboratory tests for people were phased out for all but a few in later waves. Dr Theresa Tam said experts at the National Microbiology Laboratory have now discovered a promising approach to detecting monkeypox in sewage and will use the infrastructure developed during the pandemic to look for it. “Moving forward, it could be part of our monitoring of disease activity going up and down across the country,” Tam said at a media briefing. Tam said the method is complicated, but they’ve landed on something that can “probably” be used more widely. How this monitoring fits into Public Health Canada’s monkeypox surveillance efforts is not yet clear. The monkeypox disease comes from the same family of viruses that cause smallpox, which the World Health Organization declared eradicated worldwide in 1980. Monkeypox outbreaks began to appear worldwide in non-endemic countries in May. Just this week the number of cases in Canada topped 1,000, although there are early signs that the virus may now be spreading at a slower rate, Tam said. Public Health Canada also plans to begin testing for polio as soon as possible after US health officials discovered the polio virus in New York sewage. The devastating virus was eradicated from Canada in 1994 and until very recently had not been found in the United States since 1993. Outbreaks have recently emerged in Western nations with traditionally high rates of vaccination. A positive case was discovered in New York last month. The presence of the polio virus in the city’s sewage suggests the virus may be circulating locally, city, New York state and U.S. federal health officials said Friday. “We’ve already started looking at what the options are,” Tam said of polio surveillance in Canada. Polio tests are just now coming online in Ontario, said Eric Arts, a professor of microbiology and immunology at Western University. The COVID-19 pandemic proved how useful waste can be compared to person-to-person testing, he said, especially when it comes to early detection. “Instead of testing hundreds of thousands of people at random to determine if they’re infected with a particular pathogen or one we don’t even know is circulating, you can just take a sample of sewage and test 100,000 people with one test. ,” he said. Wastewater surveillance can be adapted for other things as well, he said. Even before the pandemic, Tam said the public health agency was looking for ways to scan for antimicrobial-resistant microorganisms, or superbugs as they’re often called. However, sewage detection is still imperfect, Tam warned. “You’re dealing with a mush of a lot of stuff with a lot of DNA, RNA, all kinds of things,” Tam said, putting it politely. This pulp contains countless viruses and virus mutations. Some vaccines, such as the oral polio vaccine given in some countries, which contains a live, weakened virus, can also be confused with the real thing in a sewage sample. “It’s not terribly easy,” he said. Different countries use different methods, Tam said, and even in Canada there are many innovations. “I think one of the roles of our lab is to then look at the best methods and try to bring some standardization and guidance to those tests,” he said. Laura Osman, The Canadian Press Aqueous waste management
