“We’re going on a bear hunt. We’re going to catch a big one… We’re not scared.”
So goes a beloved children’s book written by Michael Rosen. The story is a metaphor for how to address fear. Kay Russo, DVM, often reads it to her son and daughter, ages 4 and 6.
“This unfortunate family seems to deal with a lot of issues as they’re going on their hike,” Russo says. “Ultimately, every time they reach one of these issues, the book basically says, ‘You know, we can’t go over it. We can’t go around it. We can’t go under it. We have to go through it.’”
That story illustrates how the dairy industry must deal with the growing impact of H5N1, says Russo, Novonesis technical services manager for dairy and poultry. She’s watched the spread of the virus with alarm and urges U.S. leaders across dairy and agriculture to step up and take action.
“Address it head-on,” she says. “Don’t hide.”
As with all major threats, she says ag needs a comprehensive, cohesive plan to address the virus in dairy – and to also look at how to protect the beef, pork and poultry industries.
“At this point, I believe it’s important to take one day at a time and systematically answer the questions that we need to get answered in order to define a sustainable path forward,” Russo says.
“We have a very clear picture that it’s in the udder and is being shed in milk. But where else do we need to be concerned? That matters because that is going to define the control tactics to reduce spreading it from cow to cow. Those questions are ultimately going to be the pillar of our understanding and help to define strategies for controlling the virus in a sustainable way.”
On The Front Line
Help can’t come soon enough for dairy producers and veterinarians in the trenches working with cows.
Veterinarians such as Dr. Barb Petersen in Texas have been dealing with the virus in their clients’ dairy herds since at least March.
“It has been circulating here as early as February, based on retrospective feedback from owners and fellow veterinarians,” says Petersen, owner of Sunrise Veterinary Service in Amarillo.
By early March, she had begun sending daily emails and text messages to her Texas Panhandle dairy clients who needed answers and support.
Petersen, who has been in practice 15 years, did her best to provide both. But she didn’t know what she was dealing with. Neither did any other veterinarian Petersen reached out to within 200 miles of her practice.
“We started to text and email each other, and give summaries of ‘OK, here’s the test that this doctor has run. Here’s what another colleague has run,’” Petersen recalls.
“We tested for every single viral bacterial mycotoxin, lepto, rumensin toxicity, nitrates… I mean, you name it, every single thing that we vaccinate for, we tested for, for sure, right off the bat. And then even some of the things that we don’t or can’t vaccinate for. We tried to cast a really wide net.”
None of the initial tests, conducted by the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL), provided an answer.
Recurring Symptoms Emerge
Some members of the animal health community suspected winter dysentery – an acute, highly contagious gastrointestinal disorder that can affect housed dairy cattle of all ages.
Petersen was skeptical.
“The first clinical symptom I saw was cows that had indigestion. They had manure that wasn’t well-digested, manure with particles of feed in it,” she says.
As she checked more cows and talked with colleagues, more information came to light and she began to identify recurring symptoms: thick, colostrum-like milk; lesions on cow vulvas; high temperatures; respiratory distress; a drop in feed consumption; and a corresponding lack of rumination. None of it added up to winter dysentery.
“This is a really strong and fierce reminder to keep your hands on the cows,” Petersen says. “It’s wonderful to have data, but you have to trust and then verify.”
When Russo at Novonesis got news of the problem from a colleague, she called Petersen.
Russo has worked as a dairy veterinarian and is also a board-certified poultry veterinarian. She and Petersen discussed what kinds of tests had already been done and what health concerns had been ruled out.
“I said, ‘You know, I may sound like a crazy person, a tinfoil-hat-wearing person, but this sounds a bit like (highly pathogenic avian) influenza to me. We’ve seen this particular strain of influenza that’s been circulating, that’s been jumping into mammalian hosts,’ and I kind of left it there,” Russo recalls.
More conversations between Russo, Petersen and other veterinarians ensued. Russo encouraged Petersen to collect some of the dead birds she had encountered at the dairies and submit them to TVMDL for testing, which she did.
On March 19, Petersen received a call from the Texas lab, confirming the wild birds were positive for H5N1.
At about the same time, barn cats at the dairies Petersen worked with were getting sick and starting to die. They had consumed some of the H5N1-infected birds and milk that had not been pasteurized.
“I spent one weekend picking up dead birds and the next weekend picking up dead cats. It was very sad,” Petersen says.
Science Provides Answers
Petersen sent some of the dead cats and a pooled sample of milk to TVMDL pathologists for testing. Because of their heavy workload, she sent the same material to a former veterinary classmate at Iowa State University (ISU), Dr. Drew Magstadt, now a pathologist at the school’s diagnostic laboratory.
“Whenever I’ve gotten into a real jam professionally – like, you have a question that you can’t seem to find an answer to – the group of folks that have always helped me solve it have been pathologists,” Petersen says. “It’s been pathologists that I could give the clues to who helped finish the puzzle.”
On a warm March night in Amarillo, Petersen sat resting on her back porch at home when a text message from Magstadt popped up on her phone.
“There’s something in the results,” he wrote. “Can I call you?”
On the phone, Magstadt shared what he’d found in the lab tests done on the cats and milk: H5N1.
“I was like, ‘Are you serious?’” Petersen asked Magstadt. “Are you going to run those tests again?”
“Yes,” he said. “Just to make sure.”
The initial H5N1 confirmation flabbergasted Magstadt. The next day, he retested the samples to confirm the finding.
“I had thought we would find the results were negative and we would move on to other testing. So I was very, very surprised when the results came back positive,” says Magstadt, ISU clinical associate professor and a pathologist at the Iowa State Veterinary Diagnostic Laboratory.
The National Veterinary Services Laboratory (NVSL) then confirmed Magstadt’s findings. The documentation of H5N1 by NVSL in a sample of milk from a dairy cow represented an industry first.
“The most surprising part of this, in my mind, is the fact that we’re finding so much virus as we are in the milk, in the mammary gland,” Magstadt says.
‘Show Us The Data’
On April 23, the U.S. Food and Drug Administration (FDA) reported it had detected “viral particles of H5N1 avian influenza” in pasteurized milk available for purchase at grocery stores.
Russo is quick to point out this doesn’t mean the actual virus is in milk. Rather, it’s the genetic material known as RNA.
“I think the FDA needs to show us the data,” Russo says. “The fact that there is viral material in some of the milk on shelves, as detected by rt-PCR. That test doesn’t say whether it is alive or dead. Virus isolation is necessary. The first tests have not grown virus, thankfully, but we need more data.”
No unusual human illnesses have been documented. Government health officials say they have seen nothing unusual in flu activity, according to a senior official at the Centers for Disease Control and Prevention (CDC) who was interviewed for this story. The overall assessment and risk to human health remains low from H5N1, the official says.
“CDC looks for a host of flu-like symptoms,” he told “U.S. Farm Report” host Tyne Morgan during a phone interview. “They do so by looking at people coming into emergency rooms, care systems, etc.”
Yet anecdotal evidence suggests the people most likely to be infected – dairy farm workers who have their hands on cows regularly – aren’t necessarily going to doctors for treatment.
The World Health Organization (WHO) website references just one “laboratory-confirmed case of human infection with an influenza A (H5N1) virus on 1 April 2024” on a dairy farm.
“It’s a mild, mild case and the only symptom he had was pinkeye,” Sid Miller, state commissioner of the Texas Department of Agriculture, told “AgriTalk” host Chip Flory at the time, as reported on AgWeb.
That Texas case marked the second confirmed human case of influenza A(H5N1) detected in the U.S. — and the first in the dairy industry. The first documented case, identified in 2022, involved a person in Colorado who worked with infected poultry that tested positive for the virus.
During his interview with Miller, Flory asked whether the virus could impact beef cattle at some point.
“You’ve seen what’s happened in the cattle markets,” Flory said. “They’re looking at it like this is a major problem for beef.”
Problems aren’t anticipated for Texas beef cattle, which consist primarily of feedlot cattle in the Panhandle, Miller replied.
“The cattle that get it are the older lactating cows, and we don’t have those in the feedlot,” Miller explained. “I think we’re OK, but we’re certainly going to research that.”
Tip Of The Iceberg?
So far, H5N1 has been officially confirmed in only 32 herds in eight states, according to data from USDA’s Animal and Plant Health Inspection Service (APHIS).
Some veterinarians working with dairies in Texas believe the virus is more active than current data suggest. Nick Schneider, a consulting dairy practitioner, is one of them.
“The thing is, when you get into the Panhandle of Texas, I’m not sure there’s anybody (dairy farms) that did not have it,” says Schneider.
Texas is home to 335 Grade A dairies with an estimated 625,00 cows, according to information on the Texas Association of Dairymen website. More than 100 of those operations are in the Panhandle.
The virus likely is being under-reported by the dairy industry because the presence of the virus in dairy cows is new, and there are no reporting requirements, Russo says.
“It’s not a foreign animal disease like it’s considered in poultry, where there are reporting requirements,” she explains. “This is considered an emerging disease (in dairy cattle).”
The dairy industry needs to be “very forward looking” now and address the virus, advises Schneider, the Texas dairy consultant.
“Looking at what happened in the rearview mirror is great, but if you’re not looking at where you’re going, it’s really just a pointless endeavor,” he says.
To that end, he advises gaining insights and expertise in preparation for whatever new information emerges next.
“We need to think about this potentially being something we have to live with, as being a part of the industry in the future,” Schneider says. “I hope I’m wrong. I would love to be wrong about that. But it’s something that we definitely need to consider when we’re thinking of how we’re going to manage it.”
Lessons From Swine And Poultry
Russo also advocates learning the lessons from swine and poultry, which have faced a variety of viral challenges for years.
“It’s important that we don’t try to reinvent the wheel as the cattle industry, but sort of cross the aisle to interact with the poultry folks and the swine folks who have gone through this repeatedly over the years and learn from the defined principles they use and try to adapt them into the bovine space,” she says.
Both swine and poultry have modified their animal management practices from the farm to the marketplace as a result of those experiences.
“Poultry, for instance has very distinct biosecurity principles they abide by to include lines of separation,” Russo says. “One is they keep the outside world out. Another is their use of PPE (physical protective equipment) to protect employees and also the birds from anything that might be carried onto the farm.”
The latter is a message Dr. Barb Petersen has taken to heart. Petersen says she was exposed to H5N1 for more than a month before she learned about the virus and its ability to infect dairy cows and people.
“I’m very fortunate that I never got sick,” she says.
Her advice? “Protect yourselves and your people on the dairy. There’s been underreporting of the virus. Understandably, there’s been a lot of fear. But every dairy that I’ve worked with has – with the exception of one – had sick human beings at the same time they had sick cows.”
Based on that knowledge, Petersen has acquired PPE available through Texas Health and Human Services.
“All the states have personal protective equipment available. Go and get it for your dairies,” she encourages other veterinarians. “If a dairy is on the fence, just provide it to them, offer it to everybody.”
Petersen says she has worked with people infected by H5N1 who do not interact with dairy cows. “I’m talking owners and feeders who don’t usually touch cows,” she says.
Research is underway to determine how much of a health risk the virus poses to humans, Russo says.
“This is a rapidly evolving situation, and the people that are working on it are doing everything they can to ensure the safety of those individuals that are most at risk,” she says.
A Paradigm Shift
The virus continues to hit the U.S. poultry industry hard.
Cal-Maine Foods, the largest producer and distributor of fresh shell eggs in the U.S., announced April 2 that chickens at its facility in Parmer County, located in the southwest part of the Texas Panhandle, tested positive for the virus. As a result, Cal-Maine had to cull nearly 2 million chickens − 1.6 million hens and 337,000 pullets.
In the AgriTalk discussion aired earlier this spring, Flory asked Miller, the Texas ag commissioner, whether he believes state agriculture department investigators are in front of the latest issues with HPAI in dairy cattle.
“I think so,” Miller replied. “We’ve got about 10 months before the ducks and geese come back, so I think we’ll have it figured out by then.”
Moving forward, the U.S. livestock industry might operate in a new world – one where the H5N1 virus is endemic.
Russo is undaunted by the challenge.
“This is not insurmountable, but it’s an issue we need to address swiftly,” she says.
Culled dairy cows going into the food supply deserve special attention, she says.
“We need to do the work so that we can define those movement strategies for the practitioners that are being asked to write health certificates on these farms that have the virus circulating,” Russo says.
The dairy industry needs to be more proactive for the sake of the poultry industry, she adds.
“Putting our heads in the sand, and hoping it burns itself out is not going to work. It’s just not,” she says. “It would take down the entire poultry industry by doing that, because this is highly pathogenic to them.”
That is not hyperbole, Russo says: a dime-sized piece of manure with H5N1 can infect up to 1 million chickens or turkeys.
In essence, the livestock industry needs to go on a bear hunt, as the children’s story says.
‘We can’t go over it. We can’t go around it. We can’t go under it. We have to go through it.”
With that as the focus, solutions to H5N1 can be found and help delivered to livestock producers and veterinarians on the front lines and, ultimately, the U.S. agriculture industry can insure a safe food supply.
This story will be updated by Bovine Veterinarian and Farm Journal editorial staff as more information is available.
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