Bird flu found in Wisconsin dairy herd for first time

Officials said they have found bird flu in a Wisconsin dairy herd for the first time.

Tests of cow’s milk from a Dodge County farm were positive for the highly contagious virus, officials with the Department of Agriculture, Trade and Consumer Protection announced Sunday.

The Wisconsin Veterinary Diagnostics Laboratory on Thursday found the first milk sample to test positive for the virus. That was followed by a second positive test on Friday in milk from the same farm. The National Veterinary Services Laboratory confirmed both results. 

The farm had previously been sampled five times with negative results. DATCP has been working with the farmers, industry partners and the state to test dairy farms since May.

Wisconsin State Veterinarian Dr. Darlene Konkle said no animals had moved onto the farm recently, and the herd was not showing signs of the illness.

“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.”

Bird flu or avian flu are names for the H5N1 virus. It is potentially deadly to humans and can be spread as a result of close contact with infected animals, but so far it has not been spread from human to human, according to the Centers for Disease Control and Prevention.

Pasteurization kills the virus, and DATCP’s protocols do not prevent a farm from shipping milk that meets existing quality standards and will be pasteurized.

Officials have notified the field representative and processor for the farm. It is using proper biosecurity protocols to help address concerns. DATCP and the USDA are also helping the farm review biosecurity practices. The cows at the Dodge County farm are quarantined in order to prevent further spread.

The Wisconsin Department of Health Services and local health partners are helping monitor farmers and employees for flu or fever-like symptoms. 

“Wisconsin is committed to protecting its dairy farms, its dairy workers, its dairy farmers, from … avian influenza and other animal diseases,” said DATCP Secretary Randy Romanski.

Humans and cattle are typically able to recover from avian flu, but it is highly contagious and deadly to poultry. Outbreaks have affected farms across the country. Millions of birds on Wisconsin farms have been culled so far this year. 

In early December, a backyard poultry flock in Marquette County succumbed to the illness. 

Early this year, the Louisiana Department of Health reported the first human death from avian flu in the U.S. In response, some Wisconsin researchers called for stricter hygiene practices on farms.