Further testing of retail dairy products from across the country has found no signs of live avian influenza virus, reinforcing the consensus that pasteurization protects consumers from the threat, federal health and agriculture officials said at a news conference Wednesday.
But the extent of the avian flu outbreak in cattle remains unclear because dairy herds are not routinely tested for the infection, scientists and other experts have found.
Only one human infection was reported, which was mild, in a dairy worker in Texas who had direct contact with sick cows. But scientists fear there could be many more undetected infections, particularly among agricultural workers.
Barely two dozen people have been tested for bird flu, federal officials said at the news conference. There has been no unusual increase in flu cases across the country, even in areas with infected cows, they added.
But Dr. Keith Poulsen, director of the Wisconsin Veterinary Diagnostic Laboratory, said farms are not required to test employees, who are often migrant workers who are reluctant to cooperate with state health officials.
“How much do we ignore out of fear and anxiety about what will happen if you don’t get an answer you like?” said Dr. Poulsen.
Until last week, potentially contaminated dairy products appeared to pose the greatest threat to the public. Federal regulators last week announced initial test results from about 95 retail milk samples: About one in five samples contained genetic fragments of the virus, a fact that health officials said posed no threat to consumers.
Further testing later in the week showed there was no live virus in the samples, a relief to federal regulators.
On Wednesday, Dr. Donald A. Prater, the acting director of the Food and Drug Administration’s Center for Food Safety and Applied Nutrition, said federal scientists examined an additional 201 commercial milk samples, including milk, cottage cheese and sour cream.
So far, scientists have found no evidence of a potentially infectious virus. “The findings from U.S. government partners and academic researchers do not change our assessment of the safety of the milk,” said Dr. Prater.
Dr. Prater said the FDA still strongly discourages consumption of raw, unpasteurized dairy products. Federal scientists are still reviewing data on whether the virus could be contagious in raw milk, he added.
As of Wednesday, the outbreak had spread to 36 herds in nine states, according to the Agriculture Department. Scientists have criticized the Biden administration for not conducting more animal testing to determine the extent of the outbreak.
Some dairy farms have been difficult to gain access to, and owners have at times been reluctant to allow government employees into production facilities, federal officials said.
“There are a lot of farms out there that don’t report,” Dr. said. Poulsen, the Wisconsin expert. “They don’t report because they are very afraid of what would happen if they weren’t negative.”
The Agriculture Department has ruled that lactating cows must test negative for influenza A viruses, a class that includes bird flu, before being transported across state lines. The rule also requires owners of herds that test positive to provide data on the whereabouts of cattle to help investigators trace the disease.
However, further guidance released last week revealed that farmers only need to test 30 cows in a group, potentially leading to infected cows in larger herds moving undetected between states.
Dr. Rosemary Sifford, a senior USDA official, defended the size of the order, saying 30 cows was a “statistically significant number to determine the status of the lot.” The department now requires laboratories and state veterinarians to report all positive tests on cattle to the agency.
The USDA has also turned its attention to meat. Last week, Colombia became the first country to ban beef and beef products from certain U.S. states due to the bird flu outbreak.
Dr. Jose Emilio Esteban, a senior food safety official at the USDA, said at the news conference that beef is safe to eat but that the agency is conducting three studies to “improve our science and ensure we have additional data points.”
The department is testing ground meat from grocery stores as well as the remains of slaughtered animals in states known to have infected dairy cattle, Dr. Esteban. The agency is also studying the effectiveness of cooking in killing the virus by heating beef patties to three different temperatures.
Officials are also considering ways to compensate dairy farmers for “their cooperation and adoption of additional biosecurity practices,” Dr. Sifford.
Much of the concern over the cattle outbreak stems from scientists’ fears that the bird flu virus is adapting to mammals. Dr. Sifford said at the briefing that federal scientists have not identified changes to the virus that would allow it to spread more easily between people.
Dr. Demetre Daskalakis, a senior official at the Centers for Disease Control and Prevention, acknowledged that only about 25 people had been tested for infection, about the same number as reported last week.
More than 100 people are being monitored for symptoms. Dr. Daskalakis said the number of people being tested and monitored is “dynamic,” in part because the monitoring period for people with symptoms ends when they recover.
Emily Anthes contributed reporting.
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2024-05-02 12:15:45
www.nytimes.com
