A case of H5N1 found in on a Caroline County chicken farm marks the first case of avian flu in Maryland since 2023. Photo by Scott Olson/Getty Images.
Researchers monitoring H5N1 say risk to public currently low, but could evolve into more serious public health concern
Maryland has recorded its first case of bird flu in more than a year, after the virus was confirmed at a Caroline County farm through “routine sampling of a broiler operation,” according to a statement Friday from the Maryland Department of Agriculture.
It comes after the Highly Pathogenic Avian Influenza A(H5N1) virus was detected recently on two farms in Kent County, Delaware, the department said.
“This marks the first case of H5N1 at a Maryland commercial poultry operation since 2023 and the third commercial operation in the Delmarva region in the last 30 days when two Kent County, DE returned positive results,” the agency said Friday.
State officials have quarantined the affected properties, which are undergoing “depopulation” procedures – meaning chickens, usually thousands, will be killed in order to prevent the spread of the disease.That’s important, say state officials, public health researchers and farmers’ representatives, as bird flu has the potential to evolve into a harder-to-manage virus that, in the worst case, could lead to another pandemic.
The last time a commercial chicken farm in Maryland had a bird flu outbreak was in November 2023, also in Caroline County, according to data from the U.S. Department of Agriculture.
The Delmarva Chicken Association, a trade association for chicken farmers in Delaware, Virginia and Maryland, said in an email Wednesday, before the latest Maryland case was detected, that whenever H5N1 is detected on a chicken farm, “the chickens on the farm are depopulated to prevent the spread of the disease from farm to farm.”
Health officials said bird flu is not currently a major public health concern for the most people, either in the food supply or as a potential ailment. But they have been watching it more closely, as there have been cases where it spread from birds to mammals and recently led to the death of a backyard chicken farmer in Louisiana, the first U.S. death of a person from contracting H5N1.
“The risk is still low to everybody. Our food supply in terms of eggs and poultry are safe, because these infected animals never make it into the food supply,” said Andrew Pekosz, a professor and virologist at Johns Hopkins Bloomberg School of Public Health.
“They shouldn’t be overly concerned at this point in this time with these infections, but it’s very sobering to public health officials and virologists like myself,” he said.
Pekosz said researchers are monitoring bird flu closely for signs that it could develop into the next pandemic.
“It’s something that we’re trying to prepare for,” Pekosz said. “We know that H5N1 has signatures that would classify it as a virus that could cause a pandemic, were it to infect and start to spread among humans.”
Bird flu has been around for many years, but has been of particular interest within the past two years as more migratory birds have been infected than in previous years, and more cases of bird flu are being detected in mammals
“From a public health perspective, the issue is every time this virus sees a mammal, it has the potential to pick up mutations to make it better able to replicate in mammals, and as it does that, it will also pick up mutations that will probably make it better at infecting humans,” Pekosz said. “That’s when it becomes a real pandemic threat.”
At the moment, however, the threat to the general public is still low. Those most at risk are workers on chicken farms or those who work with backyard flocks. Pekosz said those handling birds or responsible for depopulation should adhere to already established biosecurity measures, which include wearing protective gear and washing hands when exposed to flocks.
“This is one of those things where the general public is relatively safe – it’s an example of how the system worked in terms of detecting these viruses early,” Pekosz said.
The Delmarva Chicken Association said that broiler chickens, those raised for meat production, are routinely tested for bird flu before slaughter.
“It’s also important to note that on Delmarva, every broiler chicken flock is tested for HPAI before harvesting – so there is constant HPAI testing happening even when there is no active HPAI situation in the region,” the association said in a recent email. “That’s done to ensure that only healthy broiler chickens enter the food supply.”
Should bird flu develop into a full-fledged pandemic, Pekosz noted that scientists know much more about how H5N1 works than they did when COVID-19 first arrived a few years back.
“We’re actually much better prepared … We have some sense of how it’s spreading,” he said. Pekosz added that there is currently a H5N1 vaccine under development, and that some antiviral treatments for seasonal influenza also work on H5N1.
“When SARS‑CoV‑2 first emerged, we knew nothing about it — we had to go from zero up to some level of understanding and response,” Pekosz said. “We’re not starting from zero here. We’re fairly well prepared. It’s really more of a matter of how efficiently we can roll out responses to H5N1.”
by Danielle J. Brown, Maryland Matters
January 10, 2025
Maryland Matters is part of States Newsroom, a nonprofit news network supported by grants and a coalition of donors as a 501c(3) public charity. Maryland Matters maintains editorial independence. Contact Editor Steve Crane for questions: [email protected].
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