With CDC reports showing H5N1 avian influenza continuing to devastate poultry flocks and dairy herds across the country, researchers on the University of Wisconsin campus are leading efforts to protect the state of Wisconsin’s agricultural supply chains.
The Wisconsin Veterinary Diagnostic Laboratory is a state agency housed on the UW campus performing diagnostic testing to monitor the spread of the virus in dairy herds. It was formed under the National Milk Testing Strategy — a federal order issued by the U.S. Department of Agriculture in December 2024 as part of a larger national framework to detect H5N1 in dairy herds.
WVDL is one of the largest of its kind in the region, according to director Keith Poulsen. In June 2025, the lab began regular screening of all of Wisconsin’s roughly 5,200 dairy herds.
Being able to effectively track a virus is imperative to controlling it, according to Poulsen. Known as “active observational surveillance,” these efforts are critical in containing a virus that has seen unprecedented global spread in the last several years, Poulsen said.
“The most important part of any infectious disease control program is knowing where a virus is — and, more importantly, where a virus isn’t,” Poulsen said.
While seasonal surges tied to bird migration are expected, the global crisis we’re experiencing now is far from normal, Poulsen said. Since 2022, migratory birds have been spreading H5N1 into domestic poultry at unprecedented rates, Poulsen said.
Now, the first confirmed spillover to cattle was reported by the USDA in March 2024. Additional spillovers have followed, with influenza now confirmed in over 1,000 dairy herds across 18 states, according to the American Veterinary Medical Association.
While Wisconsin’s dairy herds have yet to be affected by H5N1, the virus has been detected in three different poultry operations across the state.
The introduction of H5N1 into Wisconsin’s dairy herds would create a large economic and animal health problem, according to Poulsen. When California experienced a large outbreak in October 2024, farmers lost $400 million in milk production alone, and it is possible Wisconsin could see similarly devastating economic impacts in the event of an outbreak, according to Poulsen.
The CDC is closely monitoring the risk of H5N1 spilling over to humans. While human-to-human transmission hasn’t been observed, the fast-evolving nature of the virus could eventually make this a possibility, according to Poulsen.
“It would make Covid look small,” Poulsen said. “Mortality would be much higher in people — it would be a devastating global pandemic.”
Still, the CDC says the current public health risk remains low.
WVDL’s testing volume is what sets it apart from other milk testing programs across the nation, running 635,000 tests in 2023, according to internal reports. With thousands of samples coming in every month, efficiency is crucial — particularly during surge-response emergencies, according to Poulsen.
Samples that arrive in the morning are processed within a day, allowing time to issue alerts or run confirmatory tests in the event of a non-negative result, according to Poulsen.
The most time-consuming part of the process is transferring milk from a bulk tank into labeled tubes. Robots known as automated liquid handlers are key to this process, sorting samples into 96-well plates for RNA extraction, according to Poulsen. That same efficiency is what allowed the WVDL to handle 12,000 COVID-19 samples per week for the university during the height of the pandemic, Poulsen said.
The WVDL is also one of the only programs in the country doing antibody testing on top of standard PCR tests, according to Poulsen. These additional tests expand the lab’s testing output, acting as crucial source of data for epidemiologists studying the virus and refining testing methods, Poulsen said. This data is used by UW researchers collaborating with WVDL that are creating long-term solutions to combat avian influenza, according to Poulsen.
UW microbiology professor Adel Talaat’s work benefits from the data collected by the WVDL. For the last three years, Talaat has used this data to develop a vaccine aimed at protecting both dairy herds and poultry flocks from H5N1.
Talaat said his team has tested their vaccine in both chicken and mice — targeting the poultry strain in chicken and the cattle strain in mice.
“We’ve had some encouraging results so far,” Talaat said. “Our vaccine gives a strong immune response.”
Before the vaccine can be distributed, the vaccine must undergo further controlled testing on farm animals, Talaat said. Once the vaccine demonstrates proof of concept, the team can apply for conditional licensing from the USDA, and due to the urgent need for the vaccine, the process could move faster than normal, Talaat said.
Although the team faces a number of challenges, including access to funding and facilities, the vaccine could be ready within a year and they remain hopeful about the future of H5N1 management, Talaat said.
“I’m optimistic that, by using a combination of vaccination and worldwide security measures, we will be able to control the infection, and it will not be as big a problem as we see right now,” Talaat said.
