By Tom Polansek and Julie Steenhuysen
CHICAGO (Reuters) -The U.S. government will require dairy cattle moving between states to be tested for bird flu from Monday, as federal officials step up their response to an outbreak that has bled into the U.S. milk supply.
Agriculture Secretary Tom Vilsack said Wednesday that all labs and state veterinarians in the country must report positive tests, and that the U.S. Department of Agriculture (USDA) would pay for more testing.
The measures are aimed at containing the spread of bird flu, which has been reported in eight states and 33 dairy farms since the disease was first detected in Texas in late March. A person exposed to livestock tested positive for the disease and developed conjunctivitis.
Dr. Michael Worobey, an evolutionary biologist at the University of Arizona, said based on new information it appears that infections with the H5N1 virus in dairy cattle occurred through a single transmission from a bird to a cow sometime in late 2023, probably in 2023. December .
Worobey and colleagues analyzed genetic sequences of the virus released by the USDA this weekend.
The U.S. Food and Drug Administration said Tuesday it has found bird flu virus particles in some pasteurized milk samples, but said it remains safe for human consumption because such milk has been heated to a high temperature to kill harmful bacteria and viruses.
Vilsack said the U.S. milk supply is safe “based on the information we currently have available,” adding that no live virus has been found.
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Milk containing bird flu particles entered commercial supplies from asymptomatic cows that were found to be infected through testing, he said.
USDA has conducted more than 2,000 tests on livestock samples in recent weeks, Vilsack said.
Dairy cows must test negative for the influenza A virus, which includes bird flu, at an accredited laboratory before being transported across state lines, the USDA said. Owners of cows that test positive will be required to provide epidemiological information, including tracking animal movements, the department said.
The agency plans to initially focus testing on lactating cows.
SPREAD BETWEEN COWS
Richard Webby, director of the World Health Organization’s Collaborating Center for Studies on the Ecology of Influenza in Animals and Birds at St. Jude’s Children’s Research Hospital in Memphis, said testing cows about to be shipped will help.
“If we can control the virus that’s moving with those cows, we’ll absolutely be better off,” Webby said.
Positive flu tests prohibit cows from being moved for 30 days and until they test negative, Vilsack added. Dairy cattle appear to be recovering from bird flu, a disease that is often fatal to chickens and turkeys.
“In recent weeks, USDA has noted spread between cows within the same herd; spread from cows to poultry; spread between dairies associated with livestock movements; and cows without clinical symptoms that have tested positive,” Vilsack said.
USDA estimates it will need about $500 million to continue addressing outbreaks among dairy cows, commercial poultry farms, wild birds and possibly other species.
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She is finalizing a request for a transfer of funds from the Commodity Credit Corporation, which provides funds from the U.S. Department of the Treasury to help stabilize agricultural prices and support farm incomes.
The Meat Institute, which represents U.S. meat processors, urged the USDA and the U.S. Centers for Disease Control and Prevention (CDC) to conduct additional testing to ensure beef remains safe to eat and to protect meatpacking workers. protect against infections. USDA said it is confident the meat supply is safe.
The CDC maintained its low risk assessment for the general public after USDA microbiologists on April 16 identified “a shift in an H5N1 sample from a cow in Kansas that could indicate the virus has adapted to mammals,” according to the USDA .
The finding had previously been seen in other mammals and does not affect virus transmission, according to the department.
The USDA said in a statement that it “found no changes in the virus that would make it more transmissible to humans and between humans.”
