Some milk from dairy cows in Texas and Kansas has tested positive for bird flu, U.S. health officials said Monday — but they added that the country’s commercial milk supply is safe and the risk to humans remains low.
This marks the first known time that bird flu, also known as bird flu, has been detected in livestock. And in response, dairy industry officials said producers have begun increased biosecurity efforts on U.S. farms, including limiting the amount of traffic on and off the property and limiting visits by employees and essential personnel.
However, although sporadic human infections with bird flu viruses have occurred, the US Centers for Disease Control and Prevention (CDC) has stated that such viruses “do not usually infect humans”.
Officials with the Texas Commission of Animal Health have confirmed that the flu virus is the type A H5N1 strain, which has been known for decades to cause outbreaks in birds and occasionally infect humans. The virus affects older dairy cows in those states and in New Mexico, causing symptoms such as “decrease in milk production, loss of appetite and changes in manure consistency.”
It comes a week after officials in Minnesota announced that goats on a farm where there was an outbreak of bird flu among poultry had been diagnosed with the virus.
American dairies are required to allow only milk from healthy animals to enter the food supply chain.
Meanwhile, milk from sick animals is diverted or destroyed.
And in rare cases, contaminated milk enters the food supply, pasteurization – process required for milk sold through interstate commerce – it also kills viruses and other bacteria, the US Department of Agriculture (USDA) said.
“At this stage, there are no concerns about the safety of the commercial supply of milk or that this circumstance poses a risk to the health of consumers,” the agency said in a statement.
The federal government said its tests on the cattle found no changes to the virus that would make it easier to spread to humans.
Although Texas agriculture officials believe cattle are expected to recover, the outbreak could have negative economic consequences for some dairies.
“Herds that are severely affected can lose up to 40 percent of their milk production in seven to 10 days until symptoms subside,” the Texas Department of Agriculture said.
For the general public, however, the USDA said any “milk loss from symptomatic cattle to date is too limited to have a large impact on supply.” And the price of milk and other dairy products will not be affected, the USDA said.
Dairy farmers in Texas — the nation’s fourth-largest milk producer — were initially alarmed three weeks ago when cattle began falling ill with what officials called a “mysterious dairy cow disease,” Sid Miller said. , Texas Commissioner of Agriculture. Milk production dropped sharply and the cows were lethargic and did not eat much.
“We hadn’t seen anything like this before,” he said. “Like they had a cold.”
But Miller emphasized that any contaminated milk is “all thrown away.”
The state Commission on Animal Health has launched an investigation that includes testing for bird flu, spokeswoman Erin Robinson said. Based on findings from Texas, USDA officials believe the cows got the virus from infected wild birds.
Experts say the animals seem to recover on their own within seven to 10 days. This is different from bird flu outbreaks in poultry, which require culling flocks to get rid of the virus. As of 2022, outbreaks have resulted in the loss of an estimated 80 million birds in US commercial flocks.
So far, the virus appears to be infecting about 10 percent of lactating dairy cows in affected herds, said Michael Payne, a food animal veterinarian and biosecurity expert at the University of California, Davis’ Western Institute for Food Safety and Security.
“This is not like the highly prevalent flu in bird flocks,” he said.
Avian influenza was detected in unpasteurized, clinical samples of milk from sick cattle collected from two dairy farms in Kansas and one in Texas. The virus was also found in a nose and throat swab from another dairy in Texas.
Officials called it a fast-moving situation. The Food and Drug Administration and CDC are involved, along with officials in the three states. Another dairy-heavy state, Iowa, said it was monitoring the situation.
Bird flu had previously been reported in 48 different mammal species, Payne noted, adding, “It was probably only a matter of time before bird flu reached ruminants.”
The Associated Press contributed to this report