Highly Pathogenic Avian Influenza Confirmed in Walworth County

MADISON, Wis. – The Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) has identified a case of highly pathogenic avian influenza (HPAI) in a commercial poultry flock in Walworth County.

DATCP and the U.S. Department of Agriculture (USDA) animal health officials are working together in a joint incident response. The affected premises has been quarantined to restrict movement of poultry and poultry products. Birds on the property will be depopulated to prevent the spread of the disease. Birds from the flock will not enter the food system.

The H5N1 HPAI virus has continued to circulate in both wild and domestic birds in North America since December 2021. H5N1 HPAI viruses are highly contagious and often fatal to domestic poultry. Caused by influenza type A viruses, the disease varies in severity depending on the strain and species affected. The disease can be spread by contact with infected birds, commingling with wild birds or their droppings, equipment, or clothing worn by anyone working with the animals.

DATCP continues to urge all livestock owners to implement strong biosecurity measures to protect their flocks and herds from the disease. This includes washing hands, disinfecting equipment, restricting access to animals, and separating new additions to the flock or herd for at least 30 days. Poultry owners are asked, when possible, to keep their birds indoors.

When HPAI is diagnosed in a Wisconsin poultry flock, a control area is established within a 10 kilometer area around the infected premises, restricting movement on or off any premises with poultry. To help producers determine if their poultry are located within an active control area or surveillance zone, poultry owners are encouraged to use DATCP’s mapping tool.

The Wisconsin Department of Health Services (DHS) and Walworth County Public Health are monitoring exposed farm workers for HPAI symptoms. The risk to the general public in Wisconsin remains low. Prevention information for farmworkers or others who have close contact with birds, dairy cows, or other relevant animals can be found under https://www.dhs.wisconsin.gov/occupational-health/farm-health.htm.

DATCP reminds Wisconsin livestock owners to register their premises. State law requires that all livestock owners register where their animals are kept. Registration helps animal health officials communicate with flock and herd owners during disease outbreaks.

To report increased mortality or signs of illness among domestic birds, dairy cattle, or other animals, contact a DATCP district veterinarian. For updates on how the virus is affecting domestic birds in Wisconsin, and to find resources on protecting Wisconsin poultry, visit DATCP’s HPAI in Poultry webpage: https://datcp.wi.gov/Pages/Programs_Services/HPAIWisconsin.aspx.

H5N1 in Other Species

The HPAI H5N1 virus has continued to circulate in both wild and domestic birds in North America since December 2021. Since that time, the H5N1 virus has also affected other species, including mammalian species. Wisconsin previously identified an H5N1 infection in one dairy herd in the state last year. The quarantine was released for that farm. DATCP continues to work with USDA to conduct testing for H5N1, encourage biosecurity, and provide resources to producers.

For updates on how the H5N1 virus is affecting dairy cattle across the country, and to find resources on protecting Wisconsin dairy cattle, visit DATCP’s H5N1 in Dairy Cattle webpage: https://datcp.wi.gov/Pages/Programs_Services/AvianInfluenzaCattle.aspx.