This story was last updated on 12/16/2024 at 4:40 p.m. We will continue to update as more information becomes available.
Since May 2024, state and federal officials have confirmed cases of Highly Pathogenic Avian Influenza A (H5N1) at 13 dairies and 11 poultry flocks in Iowa.
The virus was first detected in U.S. poultry in February 2022. Earlier this year, it spilled over to dairy cows.
On Dec. 6, the U.S. Department of Agriculture announced the start of its National Milk Testing Strategy. Part of this requires testing samples of raw, unpasteurized milk at dairy processing facilities. The USDA said this will allow the agency to identify where the disease is present, monitor trends and help states identify potentially affected herds.
While some dairy cows have died in the U.S., most recover 10-14 days after the initial infection. With chickens and turkeys, the virus is far more deadly and can wipe out a flock within days. Poultry are culled to prevent the spread of the disease.
The USDA and Iowa Department of Agriculture and Land Stewardship first confirmed bird flu infections in two dairy herds in northwest Iowa in early June, making it the tenth state in the outbreak.
“Highly Pathogenic Avian Influenza continues to pose a significant threat to our livestock and the livelihoods of the farmers that care for them,” said Iowa Secretary of Agriculture Mike Naig in a press release on June 7.
IDALS expanded HPAI testing requirements, which were already in place for poultry, to include dairy farms within a 12-mile radius of infected poultry sites. Naig said the goal is to better understand the possible spread of the virus and boost the agency’s ability to respond to future outbreaks.
While there are no restrictions at this time for moving dairy cattle within Iowa, IDALS said the USDA’s federal order from April is still in effect. It requires negative tests for HPAI (H5N1) in lactating cows before they are moved across state lines. Labs and state veterinarians are mandated to report positive test results to the USDA.
On June 25, IDALS announced new testing requirements for dairy cattle to participate in fairs and livestock shows in the state. The order went into effect July 1.
Each lactating dairy cow will need to test negative for the H5N1 virus, no more than a week before arriving at an exhibition. A bulk milk sample representing the whole herd must also be taken, along with individual samples from up to five sick cows on a farm. The order also requires a Certificate of Veterinary Inspection for dairy cattle going to livestock shows and fairs.
Producers are encouraged to bring their own milking equipment, and exhibitions will need to develop and implement biosecurity measures. Cattle from herds with H5N1 detections are banned from exhibitions until the order lifts.
IDALS said producers who suspect cases of avian influenza should contact their veterinarian immediately and report possible cases to the department at (515) 281-5305.
2024 timeline of bird flu cases confirmed in Iowa
May 28: A commercial egg-layer operation with 4.2 million chickens in Sioux County. This was the first case of bird flu in poultry for 2024.
June 2: A commercial turkey operation with over 100,000 birds in Cherokee County.
June 5: A dairy with 4,500 cattle in O’Brien County. This was the state’s first case of avian influenza infecting dairy cows.
June 7: A dairy with 250 cattle in Sioux County.
June 12: A dairy with 1,700 cattle in Sioux County.
June 14: A dairy with 1,000 cattle in Sioux County; a dairy with 3,000 cattle in Plymouth County.
June 15: A dairy with 520 cattle in Sioux County.
June 17: A dairy with 10,000 cattle in Sioux County.
June 19: A dairy with 100 cattle in Sioux County.
June 20: A commercial turkey flock with over 46,000 birds in Sac County.
June 21: A dairy in Sioux County with fewer than 50 cattle; a second dairy in Sioux County with 500.
June 22: A dairy in Sioux County with 5,000 cattle.
June 27: A dairy in Sioux County with 980 cattle; a second dairy in Sioux County with 2,500.
Dec. 6: A commercial egg-layer operation with 4.3 million chickens in Sioux County.
Dec. 8: A commercial turkey flock with 31,000 birds in Palo Alto County.
Dec. 9: A commercial egg-layer operation with 1.6 million chickens in Sioux County.
Dec. 11: A commercial turkey flock with 45,000 birds in Sac County.
Dec. 14: A commercial egg-layer flock with 350,000 chickens in O'Brien County.
Dec. 16: A commercial egg-layer operation with 429,000 chickens in Sioux County; a commercial turkey flock of 30,000 birds in Worth County and a mixed-species backyard flock of 34 birds in Monona County.

Monitoring health and safety for livestock and people
Since the end of March, more than 700 herds and several dozen people in the U.S. have tested positive for avian influenza A (H5N1). The U.S. Centers for Disease Control and Prevention said the risk to humans remains low, but people who interact with animals, raw milk and feces should wear personal protective equipment.
Pat Gordon, a professor of veterinary medicine at Iowa State University, said during a June 19 webinar that people working with dairy cows should wear eye protection and gloves at a minimum.
"If you can do a mask, probably worthwhile, especially if you're in an area where there's a lot of milk splash. Be cognizant of where you're placing your hands before hand washing," said Gordon.
The first three dairy workers in the U.S. with confirmed H5N1 had eye infections. One also developed respiratory symptoms.
Teri Bos, the director of Community Health Partners in Sioux County, said in early June that her office is working hard to monitor the health of farm workers and others who may be exposed to bird flu.
“We follow up with those individuals for a period of time, really just monitoring if they have any symptoms,” Bos said. “At the national level, at the state level, but also at the county level, this is something that is an emerging illness and we are taking it very seriously.”
The U.S. Food and Drug Administration is monitoring the national milk supply and dairy products, including baby formula, for the virus. The agency said pasteurization effectively inactivates H5N1 and warns against drinking raw milk.
Several cats from a north Texas dairy farm became ill and died after drinking raw milk from infected cows in March.
Federal support
The USDA offers producers financial support for developing and implementing biosecurity plans and reimbursement for veterinary costs associated with sample collection for H5N1 testing.
On July 1, the agency expanded its Emergency Assistance for Livestock, Honeybees, and Farm Raised Fish Program – also called ELAP – to help cover lost profits from the H5N1 virus.
Matt Russell, executive director of USDA Iowa Farm Service Agency, said it also creates an incentive to get tested.
“Because if you are seeing some cows be sick and they happen to have H5N1, then this program kicks in and will provide some support for that loss,” said Russell.
To be eligible for recovery assistance, producers need a positive test result from the National Veterinary Services Laboratories. Dairy producers can apply at their county’s Farm Service Agency office.