DHS confirms first human bird flu case in Wisconsin

Wisconsin health officials have detected the first human case of highly-contagious avian flu in the state.

The state Department of Health Services announced the presumptive positive case in Barron County on Wednesday. It was identified by state health officials and is pending confirmation from the Centers for Disease Control and Prevention.

Tom Haupt, DHS epidemiologist, said the affected person was an employee at an infected commercial turkey farm, which was identified by state agriculture officials last week. 

“She had relatively mild symptoms, but symptoms that would be consistent with influenza, including sore throat, slight fever, some fatigue, some eye discharge,” Haupt said on a call with reporters.

He said the young adult was treated with oseltamivir, a medication that reduces influenza symptoms, and is expected to make a full recovery.

Haupt said DHS continues to monitor 19 people who may have been exposed to the infected flock in Barron County and has so far tested two people.

There have been 61 confirmed human cases of avian flu across the U.S. this year, according to the CDC. Previously, only one case had been reported in a Colorado poultry worker in 2022.

Dr. Angie Maxted, public health veterinarian at DHS, said none of these human cases have had suspected human-to-human transmission. But she said DHS has done contact tracing to notify other people who may have been exposed to the Barron County worker and has directed them to monitor for any symptoms.

Maxted said health officials don’t fully understand why the virus is spreading to humans this year versus during previous outbreaks.

“We traditionally have always offered testing to people who’ve been in contact with ill poultry in previous outbreaks, and offered testing when they have become ill,” she said.

About a third of confirmed human cases in the U.S. have in poultry farm workers, while the majority have been workers on dairy farms. The virus was first found in cows in Texas and Kansas this March and has spread to 865 farms across 16 states. Wisconsin has not had a case of avian flu in dairy cows.

The state Department of Agriculture, Trade and Consumer Protection also announced Wednesday that a new case of avian flu was confirmed in a backyard poultry flock in Kenosha County. 

Before identifying the Barron County farm last week, Wisconsin had not had a case of avian flu since January. But state officials say the virus has continued to circulate in wild birds and in domestic flocks in other Midwest states.

Dr. Darlene Konkle, DATCP state veterinarian, pointed out that the genotype affecting dairy farms in other states is different from the one more commonly found in wild birds. She said state officials are still waiting for identification of the virus genotype on the Wisconsin farms.

“Our assumption is that it’s the genotype circulating in wild waterfowl, since we haven’t identified any connections with dairy with these latest two cases,” she said.

The CDC reported the first case of severe disease from the avian flu virus on Wednesday. The affected person is located in Louisiana and is the first to have been exposed by a backyard poultry flock. The agency confirmed the virus genotype was the kind found in wild birds and poultry.

Wisconsin officials urged people to avoid contact with dead or ill birds when possible. Poultry and dairy producers in the state are strongly encouraged to practice biosecurity measures like wearing protective equipment and limiting visitors to their farms.