By CASEY SMITH AND LESLIE BONILLA MUNIZ
As avian flu continues to spread to dairy cows across the United States, Hoosier officials said farmers are keeping a close eye on their herds, but animal testing mostly remains optional.
So far, scores of dairy farm cows in 12 states — including Michigan and Ohio — have been infected with H5N1, also known as bird flu, according to the U.S. Centers for Disease Control (CDC). The disease has also jumped to at least three farm workers — among the nation’s first confirmed cases ever of a human getting infected by the virus.
Indiana officials said the state doesn’t have confirmed cases of H5N1 infections in cows or humans yet.
Detecting bird flu in Indiana cows might not be as efficient as in other states, however. Hoosier dairy farmers don’t have an obligation to test their cows — in part because some farmers may not want to self-report cases.
Denise Derrer Spears, a spokesperson with the Indiana State Board of Animal Health (BOAH), said the agency has offered dairy producers the opportunity to be a pilot state in the federal government’s voluntary herd testing program, but no producers showed interest in participating. Currently, Indiana is not enrolled in the program.
“BOAH has hosted multiple dairy industry briefing calls and has heard from producers — they are concerned about the disease and are seeking information on ways to prevent introduction of the virus to their farms,” Spears said. “This is all new to dairy farmers. We are working with them and the veterinary community to help them ramp up their preparedness efforts.”
Tracking the virus
Avian flu is most commonly found in wild and farm birds worldwide, with periodic outbreaks occurring in other mammals, according to the CDC.
H5N1, a particular strain of bird flu, periodically flares up more expansively. It was cited for causing more than 100 million bird deaths globally in 2022 and has been detected in dozens of species of mammals. In the United States, the virus has been detected in more than 200 different mammals, including cats, goats and raccoons.
The virus most often gets transmitted when one animal eats or comes in contact with feces and saliva from an infected animal.
But bird flu viruses rarely infect humans. According to the World Health Organization (WHO), from 2003 through April 1 of this year, 23 countries reported a total of 889 human cases of H5N1. Federal health officials said the most common symptoms in people include eye redness (conjunctivitis), respiratory difficulties, fever, cough, sore throat and pneumonia.
The first known case of transmission to a human in the United States was documented in 2022.
The second known case was reported in March 2024, in a dairy farm worker in Texas. A third case involving a dairy worker in Michigan was confirmed in late May.
Despite cases in neighboring states, Indiana currently only requires testing of lactating dairy cattle that are moving across state lines, per the requirements of the U.S. Department of Agriculture’s (USDA) federal order issued on April 29.
Spears said Indiana has not opted to mandate testing at this time “because we have not had any positive cases.”
“We know dairy farmers and veterinarians are aware and watching for clinical signs, because we have heard from them with questions and subsequent tests have not been positive,” she said.
Spears noted that more than 750 tests have been run on cattle moving out of Indiana to other states since April 29. But she said Indiana does not have a good accounting of how many tests have occurred overall, given that only non-negative tests are reported to BOAH.
The state agency has been dealing “actively” with the current strain of H5N1 off and on since 2022, Spears continued.
She said BOAH works “closely” with the poultry sector on “awareness, biosecurity, prevention and preparedness.”
“They are very ready to respond and we are here to support and coordinate that response,” Spears said, adding that BOAH “has long worked to encourage good preventive measures for all types of diseases on all livestock and poultry farms through good biosecurity and having a relationship with a private veterinarian.”
Hoosier poultry remains mostly unaffected
Throughout the state’s poultry population, Hoosier outbreak reports have totaled just 12 since 2022. Most involved turkey flocks; as well as four affected duck flocks.
Indiana regulators and industry groups say that’s because the state’s “well-prepared” system has largely kept the disease away from bird livestock.
The country’s poultry disease regulations date back to almost a century ago. It came after disease ravaged farmers’ hatcheries.
Hobart Creighton, of Warsaw-based egg producer Creighton Brothers, was among the farmers asking the USDA to implement a cooperative regulatory program, according to Indiana State Poultry Association (ISPA) President Rebecca Joniskan.
The National Poultry Improvement Plan launched in 1935. It sets standards – like for testing – used to keep tabs on the health of the country’s poultry breeding stock, hatchery, and poultry products, according to ISPA’s website.
ISPA administers the plan for Indiana, in concert with the USDA and BOAH.
Joniskan said poultry producers partake in a 365-day surveillance program, outbreak or not. When disease strikes, they test more. The plan dictates some testing, and some, per Joniskan, the board requires.
After another deadly outbreak in 2015 and 2016, poultry producers and the National Poultry Improvement Plan office in 2018 agreed to step up their anti-disease efforts.
“The spread of that disease was largely due to biosecurity breaches, you know, from feed trucks or even the UPS delivery truck people,” Joniskan said. “… We looked at that situation, learned from that situation, and said, ‘We can make this better.'”
Biosecurity efforts, she said, focus on the threshold between inside and outside.
“As we go into a barn, we have what we call our ‘line of separation,'” Joniskan said. “… We just try to be really careful about how we move across that threshold.”
Farmers, she said, typically change into dedicated outfits when they enter: protective boots, gloves, coveralls, and so on. Visitors might receive disposable barriers.
An exit is followed by a load of laundry or a trip to the trash.
It’s made a difference.
“Somewhere between 80% to 85% of the incidents today are being caused by introduction of the disease directly to the farm by a wild bird or some other wild animal, and that only in 15% to 20% of the cases can (epidemiologists) show that there was actually a biosecurity breach,” Joniskan said. “We’d really like to see this disease go away, but we’re pleased to see that the efforts, the money and time that has been invested in biosecurity has really paid off, in large part.”
Risk to humans still ‘low’
Spears said one of the challenges of being proactive now — and keeping the avian flu from spreading to dairy cows — is the difficulty of preventing the virus at farms when it’s spread by wild, migratory waterfowl.
“There is no fool-proof way to eliminate all possible exposures to that reservoir,” she said. “Meanwhile, we are learning more about how the H5N1 virus behaves in cattle vs. poultry. The disease manifests itself very differently, and the risk of spread is different. We are working to educate farmers and work with their veterinarians to advise them on the latest information and how to protect their herds.”
Poultry will die very quickly from the virus that will spread very rapidly through the flock, she continued.
That warrants a “much different response” at the farm level from cattle, where the virus will make the cow sick, “but the animal generally recovers in a few days.”
“That means control of spread once it affects a farm is very different,” Spears said. “BOAH has a response plan for additional area surveillance should we have a test-positive case in cattle.”
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