Wisconsin detects avian flu in cattle for first time

Yesterday the US Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) announced the first known case of highly pathogenic avian influenza (HPAI) in a dairy cattle herd in Wisconsin, noting that the detection does not does pose a risk to consumer health or affect the safety of the commercial milk supply.

In a press release, APHIS said H5 clade 2.3.4.4b avian flu virus had been detected via a routine national milk testing program. Avian influenza detections in dairy cattle have been quiet this year compared with 2024, when an outbreak that began in March of that year spread across the country, resulting in 18 states reporting infected cattle herds.

This detection does not pose a risk to consumer health or affect the safety of the commercial milk supply.

“This detection does not pose a risk to consumer health or affect the safety of the commercial milk supply. The U.S. Food and Drug Administration is confident that pasteurization is effective at inactivating HPAI virus, and that the commercial, pasteurized milk supply is safe,” APHIS said in the release.

“Dairies are required to send only milk from healthy animals into processing for human consumption; milk from impacted animals is being diverted from the commercial milk tank or destroyed so that it does not enter the human food supply.”

No signs of illness in cattle

According to Wisconsin Public Radio, the farm is in Dodge County and had been engaging in routine milk surveillance since May. Wisconsin State Veterinarian Darlene Konkle, DVM, said no cattle had recently been moved onto the farm, and the herd did not exhibit signs of flu.

“The farmer did not have a reason to suspect highly pathogenic avian influenza on the farm,” Konkle said. “There’s really no appreciable increase in morbidity, which is cow sickness, or mortality, which is death.”