Idaho monitors bird flu to protect dairy farms and human health

A month since Idaho first discovered bird flu in a dairy herd in Cassia County, scientists are still unraveling details about the nationwide outbreak.

As of Wednesday, federal officials had confirmed 36 affected herds in nine states. In Idaho, two herds have confirmed cases of the virus, and a third farm is awaiting confirmation from laboratory samples.

The first farm had imported cattle from an affected farm in Texas, but the other two dairy farms, also in Cassia County, had not recently received cows from outside the state.

Dr. Scott Leibsle, Idaho's state veterinarian, said the leading theory is that the cows contracted the virus from wild birds. While scientists believe the outbreak was likely caused by a single spillover event from birds to cattle early this year or late last year, there is evidence that the virus has since spread back to birds from infected cows.

“We're working with some state and federal agencies to test some of the wild birds in the area to see if they carry the virus and if they find one in the birds, whether the genetic makeup of the virus is with it which corresponds in the birds. “Cattle,” said Leibsle.

Federal officials suspect the virus spreads through cow's milk, but Leibsle pointed to uncertainties such as which species of birds could infect cattle, how long the disease lasts in animals and how long it takes for the virus to shed.

Leibsle's primary concern is agricultural production and possible financial impacts on farms. To prevent outbreaks, he recommends regularly disinfecting milking equipment, implementing biosecurity measures for workers and isolating symptomatic cattle.

“If a producer finds that their cattle are showing symptoms, call us and we will collect some samples and send them for testing,” he said, noting that the U.S. Department of Agriculture covers the cost of the testing.

Federal officials said some dairy farms are blocking authorities from testing their livestock, but Leibsle said that hasn't happened to him in Idaho.

“I don’t want dairy producers to be afraid of what could happen – that the government will step in and close their dairy. That is absolutely not the case,” he said.

The milk supply

Leibsle said testing of commercial milk shipments found genetic material from the virus in one in five retail samples, but also showed that the pasteurization process inactivates the virus.

“I don’t think consumers should be concerned about milk they buy in their grocery stores,” he said.

However, the risk of drinking raw milk during the outbreak is unclear. The Food and Drug Administration emphasizes that it never recommends the consumption of raw milk, but in Idaho producers can sell raw milk with a permit from the Idaho State Department of Agriculture.

“The burden is really on the producer to be very conscious of the health of their animals,” Leibsle said.

Occupational safety

The Centers for Disease Control and Prevention considers the risk of bird flu to the public to be low; Only two mild cases have been reported in the United States

“At the moment there is very little evidence of a risk to humans,” said Dr. Christine Hahn, Idaho state epidemiologist. “Nevertheless, we want to be ready; We don’t want to be complacent, so we talk a lot about how we can make sure we’re prepared if there are human cases.”

However, the risk may be higher for those who work directly with cows. About 25 people were tested for the virus and more than 100 workers who came into contact with sick cows were monitored for symptoms.

Hahn said the state was not informed about sick workers in Idaho. She said dairy operators were informed that the state lab could test any worker with symptoms for free.

The health department did not visit farms, Hahn said, but instead worked with the Idaho Dairymen's Association and the Idaho State Department of Agriculture to provide the latest CDC guidance in English and Spanish.

“They are trusted partners and know these dairy operators well,” she said.

This guidance states that workers should have access to protective equipment such as gloves, masks and eye protection.

Anna Harden

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