Federal tests find no signs of bird flu virus in Canadian retail milk
UPDATE: Full results of the Canadian Food Inspection Agency's first round of milk testing, released on May 23, involved roughly 300 re‐ tail milk samples from across Canada and did not find any H5N1 viral frag‐ ments. The next steps will be decided "as part of fur‐ ther discussions with part‐ ners," the agency said.
Early tests on milk being sold in Canada found no signs of the virus that causes a dangerous form of bird flu, federal officials say.
Canadian Food Inspection Agency (CFIA) laboratories have tested 142 retail milk samples from across all 10 provinces, the agency said. To date, all samples in the CFIA's interim round of tests have been negative.
"Negative results mean that [virus] fragments are not present in milk. This supports current reports that the virus has not been detected in Canadian dairy cows," a Tues‐ day statement from the CFIA continued.
The current round of testing is expected to be fin‐ ished shortly, the agency told CBC News on Wednesday, but it's unclear whether addi‐ tional tests will occur.
Federal officials "will re‐ view the results of the testing and decide on next steps to support the surveillance and monitoring of [avian influen‐ za] in Canada, which could include further testing of milk in the future," the CFIA said in response to follow-up questions.
Canadian monitoring is underway as the U.S. grap‐ ples with an unprecedented outbreak of H5N1 bird flu in dairy cattle.
Cases have spread to 46 herds across nine states, and scientists south of the border suspect limited testing and surveillance could be mask‐ ing the true scope of the out‐ break - since U.S. Food and Drug Administration tests re‐ cently found H5N1 virus par‐ ticles in roughly one in five samples of milk being sold on store shelves.
Food safety specialists have been quick to note that pasteurization, a specialized heating process, works to kill a host of pathogens.
"There's no evidence showing that [H5N1] is threatening our milk supply," noted Siyun Wang, an asso‐ ciate professor of food, nutri‐ tion and health at the Univer‐ sity of British Columbia.
In late April, U.S. federal officials said testing con‐ firmed the pasteurization process worked for H5N1, ensuring pasteurized produc‐ ts remain safe to drink even if they contain viral fragmen‐ ts. (Health Canada made milk pasteurization mandatory in 1991.)
Though the sale of raw milk is allowed in many U.S. states, there have been no reports yet of anyone getting sick from drinking it. A single human case of bird flu in a farm worker has been linked to the dairy cattle outbreaks in Texas, but the transmis‐ sion route isn't yet clear, and the worker's only symptom was eye inflammation.
Multiple farm cats, how‐ ever, have died after drinking contaminated raw milk from H5N1-infected cows.
Research on some of the earliest samples, published in the Emerging Infectious Diseases journal, showed cats began showing symp‐ toms a day or so after dis‐ ease was found in cows - and roughly half the infected cats died.
WATCH | Human bird flu case linked to U.S. dairy cattle outbreaks:
Cattle testing also un‐ derway
In its latest statement, the CFIA said the agency under‐ stands that "Canadians may be concerned about the safety of milk and milk pro‐ ducts" in this country, as well.
Testing on milk samples to locate fragments of H5N1 is happening in collaboration with the CFIA, Public Health Agency of Canada and Health Canada, using highly sensi‐ tive polymerase chain reac‐ tion (PCR) tests.
Scott Weese, a veterinari‐ an and expert on infectious animal diseases at the Uni‐ versity of Guelph, said the CFIA's early results are hope‐ ful, suggesting there aren't widespread infections going unreported, but they also don't guarantee the virus hasn't hit any Canadian cat‐ tle.
"It's a good start," he ad‐ ded. "It's a relatively small number of samples."
Alongside milk testing, the CFIA is also requiring nega‐ tive test results for lactating dairy cattle being imported from the United States and "facilitating the voluntary testing of cows" that aren't presenting with any symp‐ toms.
Weese agreed it will be crucial to look at cattle move‐ ment and ensure no infected cows make it into Canada. But what's also important, he stressed, is wild bird surveil‐ lance alongside monitoring on Canadian farms, including financial support for farmers and clear communication on what happens if a farm does find a positive case.
That could mean the fed‐ eral government goes as far as buying up all the milk from an infected premise, to ensure there are no disincen‐ tives for farmers to test their herds, Weese said: "We really should be doubling down on our prevention methods."
Wang, from the University of British Columbia, agreed ongoing testing should con‐ tinue, both to ensure safety in the food supply chain and to generate more scientific data.
In the U.S., officials are ramping up surveillance, in‐ cluding wastewater monitor‐ ing efforts and nearly $200 million US in funding to test for H5N1, including payouts of $75 US for any farm worker who agrees to give blood or nasal swab samples to help track the spread of this virus.