Federal health and agriculture officials said at a press conference Wednesday that additional testing of retail dairy products from around the country has found no signs of live avian influenza virus, reinforcing the consensus that pasteurization protects consumers from the threat. said.
But scientists and other experts say the extent of avian influenza in cattle remains unclear because dairy cows are not routinely tested for infection.
Human infections have been mild, with only one case reported in Texas where a dairy cow worker had direct contact with sick cows. But scientists fear there may be many more undetected cases, especially among farm workers.
Only 24 people have been tested for bird flu, federal officials said at a news conference. The researchers added that there was no unusual increase in influenza cases across the country, even in areas with infected cattle.
However, Dr. Keith Paulsen, director of the Wisconsin Veterinary Diagnostic Laboratory, said farms are not required to test their employees, many of whom are migrant workers who are reluctant to cooperate with state health officials. Ta.
“How often do we ignore it because we're worried or afraid of what will happen if we don't get an answer that makes sense to us?” Dr. Paulsen said.
Until last week, potentially contaminated dairy products appeared to be the most immediate threat to the public. Federal regulators last week released initial test results for about 95 retail milk samples. Approximately one in five cases was found to contain genetic fragments of the virus, but health officials said this poses no threat to consumers.
More advanced testing later this week found no live virus in the samples, much to the relief of federal regulators.
On Wednesday, Dr. Donald A. Prater, acting director of the Food and Drug Administration's Center for Food Safety and Applied Nutrition, said federal scientists tested 201 additional samples of commercial dairy products, including milk, cottage cheese and sour cream.
So far, scientists have found no evidence of a potentially contagious virus. “Findings from our U.S. government partners and academic researchers do not change our assessment of the safety of milk,” Dr. Prater said.
Dr. Prater said the FDA still strongly recommends against consuming raw, unpasteurized dairy products. He added that federal scientists are reviewing data on whether the virus in raw milk can be infectious.
As of Wednesday, the infection had spread to 36 herds in nine states, according to the Department of Agriculture. Scientists have criticized the Biden administration for not conducting more animal testing to determine the extent of the spread.
Federal officials say some dairy farms are difficult to access and owners may be reluctant to allow government officials into production facilities.
“There are a lot of farms that aren't reporting,” says Dr. Poulsen, the Wisconsin expert. “The reason they're not reporting is because they're really afraid of what will happen if they don't come back negative.”
The Department of Agriculture has decided that lactating cows must test negative for influenza A viruses, a class that includes avian influenza, before they can be transported across state lines. The rule also requires owners of herds that test positive to provide data on the whereabouts of their cattle so investigators can track the disease.
However, further guidance released last week says farmers only need to test 30 cows in a group, meaning infected cows in large herds can move between states undetected. It became clear.
Dr. Rosemary Sifford, a senior USDA official, defended the scope of the order, saying 30 cows is a “statistically significant number that allows us to determine the status of the lot.” The ministry is now asking laboratories and state veterinarians to report any positive tests from cattle to authorities.
The USDA is also paying attention to meat. Last week, Colombia became the first country to ban beef and beef products from certain U.S. states due to an outbreak of bird flu.
Dr. Jose Emilio Esteban, the USDA's senior food safety official, said in a briefing that beef is safe to eat, but that the USDA is working to “strengthen the scientific knowledge to secure additional data points.” He said he is conducting three studies.
Dr. Esteban said the department is testing ground meat purchased at grocery stores and the remains of slaughtered animals in states where dairy cows are known to be infected. The agency is also investigating the effectiveness of cooking beef patties at three different temperatures to kill the virus.
Dr Sifford said the agency was also considering possible ways to compensate dairy farmers for their “cooperation and commitment to additional biosecurity practices”.
Underlying concerns about the cattle outbreak are scientists' concerns that avian influenza viruses may be adapting to mammals. Dr. Sifford told a news conference that federal scientists have not detected any changes that would make the virus more transmissible between humans.
Dr. Demetre Daskalakis, a senior official at the U.S. Centers for Disease Control and Prevention, acknowledged that only about 25 people have been tested for infection, about the same number reported last week.
More than 100 people are being monitored for symptoms. Dr Daskalakis said the number of people being tested and monitored is “fluctuating” as the monitoring period for people with symptoms ends as they recover.
Emily Anthes contributed reporting.
