Wisconsin reports first presumptive human case of H5N1 bird flu

Louisiana has reported its first presumptive human case of H5N1 bird flu, according to the state’s health department. The individual had exposure to poultry.

In a statement released on Wednesday, the Wisconsin Department of Health Services (DHS) announced the state’s first presumptive case. “The human case follows an infected flock of commercial poultry identified in Barron County,” said the statement. “The person had exposure to the infected flock.”

In the announcement, the DHS stated that the case was identified through testing conducted at the Wisconsin State Lab of Hygiene (WSLH) and is now pending confirmation from the Centers for Disease Control and Prevention (CDC). No details regarding the patient’s symptoms or current condition have been provided.

Wisconsin first case comes just days after the first cases in Arizona, Louisiana and Delaware, part of a larger trend of H5N1 infections being detected in people with close exposure to infected birds or dairy.

A newer strain of H5N1 bird flu – clade 2.3.4.4b – has raised concern due to its global spread and the rising number of cases in mammals, including hundreds of outbreaks among dairy cows in the U.S. This year has also seen a limited but growing number of human cases after contact with birds or cows.

LINK: A list of all human cases of H5N1 bird flu since 2021

There have been 69 confirmed human cases of H5N1 in the U.S., with most linked to poultry or dairy exposure. However, three cases—one in California and one in Missouri, as well as Canada’s first case—have no known connection to poultry or dairy, sparking concerns that the virus might be spreading through other mammals or alternate transmission methods.

Globally, 84 human cases of H5N1 bird flu have been reported this year, including 69 in the United States, 10 in Cambodia, two in Vietnam, and one each in Australia, Canada, and China. The newer clade 2.3.4.4b variant has been identified or suspected in the Canadian case and all U.S. cases, which include 35 in California, 14 in Washington, 10 in Colorado, 2 in Arizona, 2 in Michigan, and 1 each in Wisconsin, Delaware, Louisiana, Texas, Oregon, and Missouri.