Maryland has detected bird flu among three different commercial poultry flocks in the past week, marking the state’s first outbreak in more than a year. The discoveries come shortly after the establishment of a joint command with Delaware following the latter state’s detection of H5N1 in two other poultry operations.
Although the deadly bird flu has circulated in North America since 2022, the past few months have been especially brutal for the poultry industry. More than 20 million egg-laying hens died in the fall, the worst rates since the outbreak began, and egg prices have risen as a result.
About 134 million birds in the commercial poultry industry have been affected by the US outbreak so far, according to the US Department of Agriculture (USDA).
The USDA is creating a new stockpile of H5N1 vaccines for poultry, though there is no plan to use them yet, Eric Deeble, deputy under-secretary for marketing and regulatory programs for the USDA, told reporters on Thursday.
The outbreaks signal the need for increased vigilance of animals – and the people who come into contact with them, officials said.
Hospitals should test all flu-positive patients, especially those in intensive care units, within 24 hours to speed up contact tracing and public health investigations, the US Centers for Disease Control and Prevention (CDC) announced in a health alert on Thursday.
Collaboration between states and localities is important for dealing with cross-boundary outbreaks – and existing relationships like these may take on a greater role in the incoming Trump administration, amid uncertainty about the leadership of national agencies.
In Delmarva, a peninsula between the Chesapeake Bay and the Atlantic Ocean that encompasses all of Delaware and parts of Maryland and Virginia, chickens are big business – $4.4bn last year, to be exact.
The region is a leading national producer of broilers, or young chickens slaughtered for their meat, raising 601 million chickens each year – about 6.5% of the nation’s poultry supply. The largely rural area is peppered with rows of long, low-slung chicken houses, each temporarily home to thousands of birds.
The first warning that bird flu had landed in Delmarva once again came from wastewater. Routine testing of wastewater near Georgetown, the center of poultry processing operations in Delaware, detected H5 bird flu during the week of 7 December.
Then, there was a probable case in a person with no known exposure to animals, detected through routine monitoring of positive flu A cases.
Next, there were the snow geese.
Migratory birds have been winging their way from the Arctic to the Caribbean for their annual migration along the Atlantic flyway, a journey that started later than usual this year due to unseasonably warm temperatures in the north, Alex Turner, the national incident coordinator for the USDA, said on Thursday. That means more cases in commercial and backyard poultry are likely to be detected as the migration season is still winding down, he said.
Starting in late December, between 40 and 50 snow geese were found sick or dead on Prime Hook Beach, next to a national wildlife refuge with 10,000 acres of marshland that eases Delaware’s coastline into the sea.
In early January, seven snow geese were also found along Maryland’s eastern shore, near the Blackwater national wildlife refuge. In both cases, the geese tested positive for the highly pathogenic avian influenza. And then the virus was detected in chickens.
It started in Delaware’s Kent county, first in a flock on 3 January and then, after officials began looking in the surrounding area, in another flock on 9 January.
As soon as the first infection was detected in wild birds, Delaware and Maryland formed a command center to track the outbreak and conduct follow-up sampling across the affected area in both states.
“During an active response, we do not consider any state lines,” said Stacey Hofmann, a spokesperson for the Delaware-Maryland Avian Influenza Joint Information Center. “At the first suspect case in a commercial poultry farm or a backyard flock, our multi-state response team is already communicating, and it is all hands on deck.”
Maryland soon found cases, all in broiler farms, in adjoining counties: first in Caroline county on 10 January, then in Queen Anne’s county on 14 January, and another in Caroline on 15 January.
“Every commercial flock in Delaware and Maryland is tested for avian influenza before it heads to processing,” Hofmann said. “There are no exceptions.”
Producers and backyard-flock owners can also report sick or dead birds to their state department of agriculture, she said, before adding that because the “poultry industry is extremely important to our economies”, they had “been preparing for HPAI [highly pathogenic avian influenza] for years”.
After suspected cases of bird flu are confirmed by the USDA’s national lab, birds in the infected flocks are killed in order to prevent further spread of the virus.
The response isn’t limited to birds. While state agriculture departments are “focused on the farms”, health departments offer “guidance to those agencies to pass along to workers”, said Chase Cook, director of communications at the Maryland department of health.
That guidance may include what type of preventive gear, such as goggles and respirators, to wear around infected birds, as well as what symptoms to watch for potential infection among humans.
Since March 2024, there have been 67 confirmed and seven probable cases of H5N1 in the US, as well as other cases later discovered through blood tests. In three of the confirmed cases, there was no known exposure to animals.
At least 23 people have caught bird flu from commercial poultry operations, and one person in Louisiana became sick after contact with a backyard flock and wild birds.
The patient in Louisiana died this month from the variant of H5N1 that is circulating among birds. The same strain made a 13-year-old girl in British Columbia, Canada, extremely ill.
Nirav Shah, principal deputy director of the CDC, said the accelerated timeline for testing hospitalized patients like those in Louisiana and Canada should help reveal how they are getting sick and whether the virus is changing.
“The system right now tells us what has already happened,” Shah said on Thursday. “What we need is to shift to a system that tells us what’s happening in the moment.”
