A dairy herd in northwestern Iowa is infected with the H5N1 avian flu virus, said state agriculture secretary Mike Naig on Wednesday. He called on dairy and poultry farmers to “harden their biosecurity defenses” against the virus. Iowa is the 10th state in the nation, and the first since April 25, to identify bird flu in dairy cattle.
The Iowa herd, the 83rd in the nation with H5N1, is in O’Brien County, next door to Sioux County, where a bird flu outbreak was reported on an egg farm with 4.3 million hens last week. Based on genomic sequencing, the virus that hit the egg farm is consistent with the variant that struck dairy farms in other states, said the Iowa Agriculture Department.
Three workers on dairy farms have contracted mild cases of bird flu from cattle; the most recent infection was the first to include respiratory symptoms. The risk to the general public is low, say public health officials, who advise people in contact with infected animals to wear gloves, masks, and other personal protective equipment.
“Poultry producers and dairy farmers should immediately take steps to harden their biosecurity defenses, limit unnecessary visitors, and report symptomatic birds or cattle to the department,” said Naig. He said new steps to protect Iowa livestock would be announced soon. “While lactating dairy cattle appear to recover with supportive care, we know this destructive virus continues to be deadly for poultry.”
Since February 2022, highly pathogenic avian influenza has killed more than 96.8 million birds in domestic flocks, mostly egg-laying hens and turkeys being raised for meat. It is the largest animal disease outbreak ever to hit the United States. The H5N1 virus jumped from birds to dairy cows in the Texas Panhandle in late 2023 or early this year, say researchers.