A monitoring program is expected to start this fall.
As bird flu infections continue to rise among livestock and humans in the United States, surveillance is ramping up in Canada.
Wastewater testing for the H5N1 bird flu virus is set to begin in the coming weeks in Ontario communities considered at high risk, said Rob Delatolla, whose University of Ottawa lab will lead the wastewater surveillance as part of a research program based at the University of Guelph. That will likely mean testing wastewater in communities in agricultural regions of the province. It is unclear whether there will also be testing in larger cities.
Delatolla’s lab, which has been a leader in wastewater surveillance since early in the COVID-19 pandemic, has developed a test to detect Highly Pathogenic Avian Influenza, as it is known, in wastewater.
Testing of wild birds and poultry for avian influenza has been ongoing for several years since the current strain showed up in wild birds and poultry in Canada in 2021, but there is a new urgency since it unexpectedly began infecting dairy herds in the U.S. earlier this year and has since infected dozens of humans there as well as several pigs.
“The emergence of a H5N1 influenza virus in wild birds, dairy cattle, pigs and also humans in the U.S. has raised real concerns about our ability to identify, monitor and prevent human outbreaks of highly pathogenic avian influenza in humans in Canada,” Delatolla said.
“We know that wastewater monitoring is an effective, non-invasive, economical, early warning system for pathogen detection in communities in Canada, and hence this tool can also be implemented to give us an early warning of any potential H5N1 human cases and spread within our towns and cities.”
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Delatolla said he expected the testing to begin this fall.
Ontario developed Canada’s largest wastewater monitoring program during the early years of the COVID-19 pandemic, but the province stopped funding the program last summer, shutting down wastewater programs at most locations. Some communities, including Ottawa with Delatolla’s lab, continue to test wastewater for the virus that causes COVID-19, RSV (respiratory syncytial virus) and influenza, among other things.
There is currently no widespread wastewater testing program for H5N1 avian influenza in Canada, as there is in the U.S.
Claire Jardine, a professor in the department of pathobiology at University of Guelph, leads the HPAI risk factor study research team. The wastewater testing complements that research, Delatolla said. Their project is funded by the Ontario government and supported by the Canadian Food Inspection Agency, Jardine said, and their work began about a year ago.
“With the start of avian influenza outbreaks in Canada and detection in poultry, we thought there was a need to better understand wildlife and domestic poultry interactions,” Jardine said.
Avian influenza has been identified in thousands of wild birds in Canada in recent years, including several crows and a waterfowl in Ottawa earlier this year. It has also been identified in foxes in the Maritime provinces. There have been serious outbreaks in poultry farms across the country.
But its spread through cattle herds in the U.S. has raised alarm bells about the risk of the virus eventually changing enough to cause sustained spread in humans. The results could be catastrophic.
Global health officials have said avian flu has pandemic potential. So far, human cases in the U.S. have been limited mainly to mild cases in people working with infected livestock and poultry. The risk to people in Canada remains low, public health officials say.
Jardine said understanding and monitoring H5N1 bird flu had been an urgent issue since the current strain emerged in Canada in 2021. Detection of the virus in cattle is an added concern because the risk it poses for further adaptation to mammals.
The Public Health Agency of Canada monitors wastewater for influenza A and B, but is not conducting ongoing wastewater surveillance for Highly Pathogenic Avian Influenza, spokesperson Anna Maddison said. However, if “an unusual signal” was detected, PHAC would be able to test for H5 and other influenza subtypes in wastewater, she said. PHAC monitors wastewater in the GTA in Ontario and has says it has plans to expand.
Maddison said there were limitations to wastewater surveillance for avian influenza, though, since iut was widely spread in wildlife.
“Since the virus is already circulating in wildlife, determining the source of a wastewater-based detection is not possible at present, making it challenging to accurately interpret results to inform risk assessment and potential actions.”
She said PHAC would work with partners to determine the source if any “unusual respiratory virus activity is detected.”
Canada has been testing milk for traces of bird flu since last spring. None has been detected. Nor have any cases been reported among dairy cattle.
But the use of wastewater surveillance in the U.S. suggests bird flu in humans could be more widely spread than other testing shows. Wastewater surveillance can also provide advance warning of any outbreaks in humans or rapid increases in transmission.
U.S. agriculture officials have confirmed infection in at least 440 dairy herds in 15 states since March. The number of herds infected continues to grow, with most of the new infections identified in herds in California, according to the U.S. Centres for Disease Control. Since April, 22.37 million domestic birds in the U.S. have been infected.
At least 44 human cases have also been identified, including 20 in California dairy farmers and nine among poultry workers in Washington State. The source of a case in Missouri could not be determined, the CDC said.
According to the Public Health Agency of Canada, a number of countries, including Canada, have authorized influenza A(H5N1) vaccines,” however, there are no widely available vaccines for public use.”
More information is available online at www.canada.ca/en/public-health/services/publications/diseases-conditions/guidance-human-health-issues-avian-influenza.html
