With Nebraska seeing its first case of highly pathogenic avian influenza (H5N1) in dairy cattle last month, state officials in 3 midwestern states have now reported new outbreaks of H5N1 in poultry on commercial farms. The cases were detected in Iowa, Minnesota, and Wisconsin, and are not the first for any of these states. For Iowa, the latest finding marks the state’s 8th outbreak in domestic birds this year, while Minnesota has reported 8 poultry outbreaks since mid-September alone.1
The Iowa Department of Agriculture and Land Stewardship (IDALS) and the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) detected its latest H5N1 case on October 2. According IDALS, state officials and the USDA found the virus in a commercial turkey flock in the west central region of Iowa, in Calhoun County. Before that, Iowa’s last poultry outbreak occurred in April.1
In birds, H5N1 can cause the following2:
- Sudden increase in bird deaths without any clinical signs
- Lethargy and/or lack of energy and appetite
- Decrease in egg production
- Soft, thin-shelled and/or misshapen eggs
- Swelling of the head, eyelids, comb, wattles, and hocks
- Purple/blue discoloration of the wattles, comb, and legs
- Coughing, sneezing, and/or nasal discharge
- Stumbling and/or falling down
Minnesota, meanwhile, reported 2 outbreaks of the virus on September 28 at commercial breeder poultry operations in Becker and Otter Tail Counties,3 which are located in Minnesota’s west central region and border each other. Together, the 2 farms house more than 36,000 birds, according to the University of Minnesota.1
“Minnesota has now recorded eight outbreaks in poultry since the middle of September, part of a national rise in activity,” wrote the University of Minnesota in a news brief.1
Wisconsin followed, with another confirmation on October 1 of H5N1 in a commercial flock in Jefferson County, which is found between Madison and Milwaukee. The Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) reported the case on October 2, urging all livestock owners to implement strong biosecurity measures to prevent the disease from infecting their flocks and herds.
Wisconsin’s latest detection marks the state’s second outbreak in Jefferson County since September 24, with the September 24 outbreak affecting more than 3 million commercial poultry.4 According to the DATCP, 520,298 poultry reside on the commercial farm most recently affected by the virus.4
“The affected premises [have] 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,” wrote the DATCP a news release announcing the latest bird flu detection.4
The state government agency said it is working with USDA animal health officials on a joint incident response.
Last month, Nebraska reported its first case of H5N1 in a dairy cattle herd. Officials detected the virus through state tracing and investigation after it was found in collected milk samples.5
“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,” Wisconsin’s DATCP said.4
Earlier this fall, the USDA echoed DATCP’s message, advising dairy farms to adopt stronger biosecurity measures. "APHIS recommends enhanced biosecurity measures for all dairy farms, particularly as we enter fall migratory bird season,” the federal agency said.6 “Producers should immediately report any livestock with clinical signs, or any unusual sick or dead wildlife, to their state veterinarian.”
References
- Schnirring L. H5N1 outbreaks hit more commercial poultry in 3 states. University of Minnesota. October 3, 2025. Accessed October 6, 2025. https://www.cidrap.umn.edu/avian-influenza-bird-flu/h5n1-outbreaks-hit-more-commercial-poultry-3-states
- Highly pathogenic avian influenza detected in a commercial turkey flock in Calhoun County. Iowa Department of Agriculture and Land Stewardship. News release. October 2, 2025. Accessed October 6, 2025. https://iowaagriculture.gov/news/HPAI-calhoun-county-Oct-2-2025
- Highly pathogenic avian influenza response. Minnesota Board of Animal Health. Accessed October 6, 2025. https://bah.state.mn.us/hpai
- Highly pathogenic avian influenza confirmed in Jefferson County. News release. The Wisconsin Department of Agriculture, Trade and Consumer Protection. October 2, 2025. Accessed October 6, 2025. https://datcp.wi.gov/Pages/Highly-Pathogenic-Avian-Influenza-Confirmed-in-Jefferson-County04.aspx
- Bautista-Alejandre A. USDA confirms first case of bird flu in Nebraska dairy cattle. dvm360. September 16, 2025. Accessed October 6, 2025. https://www.dvm360.com/view/usda-confirms-first-case-of-bird-flu-in-nebraska-dairy-cattle
- USDA confirms highly pathogenic avian influenza in dairy herd in Nebraska. News release. US Department of Agriculture (USDA) Animal and Plant Health Inspection Service. September 15, 2025. Accessed October 6, 2025. https://www.aphis.usda.gov/news/agency-announcements/usda-confirms-highly-pathogenic-avian-influenza-dairy-herd-nebraska