The Biden administration said Wednesday it will begin requiring dairy cows moving across state lines to be tested for bird flu, which has been spreading through herds for months. The new policy is part of a growing effort to stem the spread of a virus that federal health officials have tried to reassure Americans poses little risk to humans so far.
The New order, issued by the Department of Agriculture, says that lactating cows must test negative for influenza A viruses, a category that includes bird flu, before being transported. Owners of herds with positive tests should provide data on cattle movements to help researchers trace the disease.
The tests will help protect the livestock industry, limit the spread of the virus and “understand this disease better,” Mike Watson, a senior Department of Agriculture official, told reporters at a news conference Wednesday morning.
Since a highly contagious form of bird flu was detected in the United States in 2022, federal officials sought to reassure Americans that the threat to the public remained low, even as the virus infected a growing number of mammals. Federal regulators announced Tuesday that inactive viral fragments were found in pasteurized milk, an indication that the virus is likely spreading much more widely among cattle than previously known.
Dr. Nirav Shah, the principal deputy director of the Centers for Disease Control and Prevention, told reporters on Wednesday that there were no changes in the genetic makeup of the virus that would allow it to spread easily between people. So far, Dr. Shah said, the states are tracking 44 people who were exposed to the virus and are being monitored for infection.
As of Wednesday, the outbreak had spread to 33 herds in eight states, according to the USDA, but only one human infection has been reported, in a dairy worker in Texas who had direct contact with sick cows. The case was mild.
Federal officials on Wednesday also sought to downplay the seriousness of the Food and Drug Administration’s findings in recent days that inactive virus fragments had been found in pasteurized milk, including some on grocery store shelves. Don Prater, an FDA official, told reporters Wednesday that regulators are conducting more advanced tests to determine whether any milk contained live virus. The agency will release data in the coming days on the milk tests, he said.
The USDA order will require laboratories and state veterinarians to report any positive tests from cattle to the agency. Mr Watson said the department would be able to process tens of thousands of tests each day, with results reported after one to three days. The agency will now reimburse dairies for testing asymptomatic cows as well as those that are moved.
Dr. Shah, the CDC official, said the federal government relied on local officials and health workers to reach out to dairy producers and their workers, including veterinarians who have close relationships with people who may be reluctant to open up to strangers.
“There may be owners who are reluctant to work with public health, to say nothing of individual workers who may be reluctant to sit down with someone who identifies themselves as a member of the government in some way,” Dr. Shah said.
It is not yet clear when the bird flu outbreak began, but an analysis of genetic data suggests that wild birds may have passed the pathogen to cows as early as December. Cows weren’t usually thought to be vulnerable to bird flu, and it wasn’t until late March that federal officials announced that the virus had been detected in sick cows in Texas and Kansas.
The USDA order came after public health experts and dairy farmers had criticized the Biden administration for the scope of its investigation into the cow outbreak and the lack of extensive testing.
While testing more cows is critical, so is reducing the risk of infection among dairy workers who are regularly exposed to fresh milk now thought to contain widespread virus, said Seema Lakdawala, a virologist at Emory University.
If a worker splashes the nose or eyes and becomes infected, that human infection would give the virus new opportunities to adapt and start spreading between people, he said.
Federal health officials said Wednesday they reminded states they could request protective equipment from the national stockpile.
But Dr Lakdawala said the risks of worker infections were already serious enough that farms would have to make face shields universal. He said other steps, such as a two-week “stay at home” order for cows, could also obviate the need for even more economic deterrents.
Troy Sutton, a virologist at Penn State University, said the emergence of bird flu in cattle has intensified efforts to understand the virus.
“Now it’s moved into a genre that people have more contact with,” he said.