When highly pathogenic avian influenza, or HPAI, first appeared in U.S. dairy cattle, it shocked the scientific community. The virus, long associated with birds, had crossed a species barrier no one anticipated. In Michigan, however, the response framework was already underway.
In the inner circle of that response was Kimberly Dodd, who now serves as dean of the Michigan State University College of Veterinary Medicine, or CVM, but at the time was the director of the MSU Veterinary Diagnostic Laboratory, or VDL. As news broke in early 2024 of dairy cattle testing positive for the virus, the VDL team was already two years into an unprecedented nationwide response to HPAI in domestic poultry and wild birds. Long-standing partnerships with state and federal agencies in Michigan had been strengthened by shared experience, which supported a unified local response.
“When this began, we weren’t just responding to an outbreak,” Dodd said. “We were watching history unfold in real time. There was no playbook for this. The virus was in a place it had never been before.”
George Smith, director of MSU AgBioResearch, which oversees MSU’s dairy cattle herd, remembers his first reaction clearly. “My immediate thought was, ‘No way — this is impossible,’” he said. “But within hours, our focus shifted from disbelief to action. We needed to mobilize resources and do it immediately.”
Smith helped redirect emergency funding from the Michigan Alliance for Animal Agriculture and the U.S. Department of Agriculture’s federal capacity dollars, which allowed researchers to get on farms within days — not months — to begin collecting data.
“If our faculty had to wait for a traditional grant cycle, we’d have lost precious time,” Smith said. “This was about giving farmers answers fast.”
Michigan’s early warning system
The VDL, a member of the United States Department of Agriculture, or USDA, National Animal Health Laboratory Network, is part the nation’s early warning system. Because Michigan was one of the first states to detect HPAI in cattle, the VDL was among the first laboratories to use new testing protocols to detect the virus in milk and other sample types that had never been needed before. These early results in Michigan and other states helped shape the country’s response. The VDL team worked around the clock, processing hundreds of samples each day.
“We had to innovate rapidly,” Dodd said. “We were implementing new diagnostic approaches on the fly to ensure accurate results, protecting animal health and safeguarding the food system.”
Tim Boring, director of the Michigan Department of Agriculture and Rural Development, or MDARD, said Michigan’s readiness made a national impact.
“Michigan was one of the first states really to be impacted,” Boring said. “It went from one or two dairy farms to several dozen across the state. The emergence of this disease in dairy cattle was new for everyone, but because of our partnerships with Michigan State, we were able to stand up a response in real time.”
Those partnerships — between MDARD, MSU Extension, AgBioResearch and the College of Veterinary Medicine — proved decisive. State agencies and researchers came together quickly, leveraging well-established connections to mount a swift, collective response.
Inside the lab
The VDL’s mission is simple and relentless: protect animal and public health.
“We’re the only lab in Michigan approved to test any species for high-path avian influenza, from cats and cows to canaries and chickens,” Dodd said. “Core to our mission is serving as the first line of defense for animal-disease outbreaks.”
When the virus moved into dairy cattle, the VDL partnered with veterinary researchers in CVM to confirm the most effective sample types for testing.
“Because the virus replicates in the mammary gland, milk testing became our best tool,” she said.
Smith said that discovery paved the way for the National Milk Testing Strategy, a nationwide monitoring program that screens bulk-tank milk for early signs of infection. Michigan was one of the first states to implement the program in December 2024.
“Milk testing is an efficient early warning system,” Smith said. “It lets us survey across the state and move fast to support producers.”
Boring noted that the program’s reach is unprecedented.
“We’re about 10 months into regular monthly milk testing across all Michigan dairy farms,” he said. “VDL has been instrumental in implementing this broad, science-based monitoring. It gives us confidence the disease is not actively present on farms and shows what recovery looks like for farms moving past infection.
“Michigan’s response has been widely regarded as a national model,” Boring said. “It’s the direct result of long-standing partnerships between the state, MSU and federal agencies like USDA and CDC. Everyone was working off the same playbook.”
Dodd called the VDL the cornerstone for animal-disease testing, saying its scientists don’t just detect known threats but develop methods to spot the next one.
Biosecurity on the ground
Now, every farm visit begins with rubber boot covers and disinfected tires.
“Dairy facilities are designed differently than poultry barns,” Smith said. “We had to adjust fast to reduce farm-to-farm spread while keeping people and cattle safe.”
For poultry producers, the biosecurity transformation has been staggering.
“Everything we’re doing to protect our birds comes at a huge cost with still-unknown reward,” said Joe Sullivan, veterinarian at Herbruck’s Poultry Ranch. “Downtime is a huge expense. Things that used to be convenient are now risks. Every site needs its own equipment, even if it costs $100,000.”
At Michigan Turkey Producers, staff veterinarian Caitlin Green said the mindset shift was immediate.
“We’ve poured gravel and concrete and turned picturesque spaces into cleanable surfaces,” she said. “Then comes training. We developed a hospital mindset on a working farm.”
Boring said the state’s experience with avian outbreaks helped producers adapt. “Our poultry industry has been tightening biosecurity for years,” he said. “Applying those lessons to dairy operations was new, but the same principles — restrict access, disinfect, educate workers — works across species.”
Inside Michigan’s poultry operations
For Michigan’s poultry and egg producers, avian influenza has been a constant threat since the virus first arrived in North America nearly a decade ago. The emotional and financial toll has been heavy.
“The human element is huge,” Green said. “It’s easy to talk about the number of birds lost, but the emotional toll on farmers is enormous. It’s taken a lot of the joy out of this work.”
Sullivan still recalls the shock of those first outbreaks. “The silence in the room was like, ‘Wow, it’s real. It’s here,’” he said. “This is incredibly real. No one would make this up. Watching a bird die from it is terrible.”
Both veterinarians praised MSU’s diagnostic response. “We rely on the VDL,” Sullivan said. “They’ve done a great job getting us back up and running quickly.”
“The virus is doing research constantly,” Green said. “Every new animal it infects teaches it something new. We have to stay ahead of it, or at least next to it.”
Both veterinarians also agree that new tools are needed. “We need a vaccine,” Sullivan said. “The longer we wait to use one in animals, the greater the need for one in humans. We’re watching the start of a potential pandemic.”
Green agreed. “If we wait until we have an answer, it will be too late,” she said. “We need action now.”
Avian flu research
More than a year and a half after Michigan confirmed the nation’s first cases of HPAI H5N1 in dairy cattle, MSU CVM researchers, Annette O’Connor, Catalina Picasso Risso and Zelmar Rodriguez, working in partnership with MDARD and USDA, have made major strides in understanding the virus’s behavior, impact and transmission in this unexpected species.
Through coordinated investigations across seven dairy farms, the university’s researchers analyzed results from more than 10,000 samples and confirmed milk as the most reliable medium for detecting the virus — much more consistent than nasal or vaginal swabs. They also found that older cows and those further into lactation were more likely to shed the virus. Infected cows shed virus for up to 40 days, increasing the risk of prolonged transmission if containment lagged.
The research also quantified the toll of H5N1 on herd productivity. Milk output dropped an average of 5.7%, peaking at 22%, and required more than four months to recover. Bulk-tank somatic cell counts tripled, feed intake fell sharply and each affected cow represented roughly $500 in economic loss. This means the average cell count in herd milk rose sharply, signaling widespread udder inflammation caused by the virus — a key indicator of stress and reduced milk quality.
For a 500-cow herd, that equates to more than $79,000 in direct impact — mostly from reduced milk yield — with only partial offsets from lower feed costs.
Scientists say none of this viral behavior is entirely unexpected. Influenza A viruses mutate and reassort many times each year, which is why humans receive new flu vaccines annually. Most spillover events into new species go unnoticed because infected animals either clear the virus or fail to transmit it efficiently. In this case, one mutation enabled H5N1 to infect and replicate efficiently in cattle — and because it emerged in a densely populated dairy environment, conditions were ideal for spread.
Why avian flu matters to everyone
“My mom is not a scientist,” Dodd said with a laugh. “She called me after watching the news and asked, ‘Is this why egg prices are so high?’ And sure, that’s part of it. But the bigger picture is how a disease like this affects every one of us — from farmers to families buying groceries.”
Smith echoed the economic and human stakes. “There’s too much at risk not to invest,” he said. “This touches food security and price stability for families in Detroit, Ypsilanti, Charlotte — everywhere. Research is how we keep cows healthy, herds productive and groceries affordable. Also, who doesn’t like ice cream?”
“For anyone who thinks this is abstract — it isn’t,” Green said. “What we’re doing is a desperate attempt to protect uninfected birds and the people who care for them.”
It's all about One Health
When Michigan’s agricultural and public health leaders talk about “One Health,” they’re describing more than a philosophy — they’re describing a way of working. The approach recognizes that the health of people, animals and the environment are closely connected and that protecting one means protecting all.
That principle has guided Michigan’s response to highly pathogenic avian influenza as it spread across species and industries in unexpected ways. Smith said the outbreak offered a textbook example of why collaboration across scientific disciplines matters.
“As we look back at the challenges the state of Michigan faced with regard to HPAI it really illustrates the intersection between human health and animal health in the context of an unexpected emerging disease,” Smith said.
The virus revealed just how intertwined those systems are — and why solutions can’t come from a single field.
“This, in essence, is a great example of a One Health problem — the interaction of animal health, human health, plant health and environmental health, and how we work at that intersection to keep people healthy, to keep animals healthy, to keep plants healthy, and to keep the microbes below ground and above ground viable as well,” Smith said.
At the state level, that framework has defined how MDARD coordinates its disease response and research partnerships.
Boring said the state’s One Health model set Michigan apart nationally.
“Michigan’s response also is being recognized nationally as a model of the One Health approach — linking human, animal and environmental health,” Boring said. The collaboration between state and federal agencies, industry and academic researchers was the driving force behind Michigan’s success.
For the VDL, the One Health mission is built into daily operations by linking animal diagnostics to public health preparedness.
Dodd said the lab’s focus on early detection and global readiness is a direct reflection of that philosophy.
“Our goal is to detect the next COVID before it becomes a pandemic,” Dodd said. “That’s what we train for every day — anticipating the next threat before it crosses the line between species and before it reaches people.”
Together, Michigan’s researchers, veterinarians and public officials are proving what One Health looks like in practice: a unified response that bridges science, policy and community, ensuring that when the next outbreak comes, the state will be ready to meet it from every angle.
Preparing for what’s next
More than a year after Michigan’s first confirmed cases of HPAI H5N1 in dairy cattle, the state has shifted from crisis response to steady management. There are no active infections in Michigan herds as of fall 2025, and routine milk testing continues statewide under the direction of MDARD in partnership with the VDL.
The virus still circulates among wild birds and the risk to backyard and commercial flocks remains high. In Michigan, the virus has been detected in several commercial flocks so far this fall and in 30 commercial flocks nationwide in October alone. Fall migration of wild birds is underway, and the cooler temperatures are favorable for the virus. Additional commercial and backyard detections are possible, and unfortunately likely, throughout the fall and early winter.
While HPAI remains an ongoing threat to animal and human health, it’s not the only one. “In public health circles, experts talk about ‘Disease X’ — the unknown threat that could spark the next global crisis,” Dodd said. “We can’t predict what it will be, but we can prepare. That’s why federal funding for diagnostic networks and research is so vital.”
Boring added a note of caution.
“We’re not out of the woods yet with HPAI,” he said. “We need continued research into how this virus behaves across species and the long-term impacts on animal health. The fact that Michigan is still leading that work is a credit to the strength of our collaboration with MSU.”
It’s truly a virus that won’t quit.
“This virus is really good at its job,” Dodd said. “As a virus, its goal is to replicate and spread and it’s doing that exceptionally well. Every test we run and every sample we analyze is part of understanding how to stay one step ahead. That’s what keeps me up at night — and what keeps us pushing forward.”
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Video by Garret Morgan, Nick Schrader, Anthony Siciliano, G.L. Kohuth and Jacob Templin-Fulton.
