As avian flu continues to spread across the country, recent detections in New Jersey—including in Mercer County—have raised concerns among farmers, pet owners, and public health officials. While the overall risk to humans remains low, the virus has affected poultry, wild birds, mammals, and a limited number of people nationwide, prompting renewed attention to prevention and biosecurity.
Avian influenza, commonly known as bird flu, was first documented in 1878 in Northern Italy and originally referred to as the “fowl plague,” according to the Centers for Disease Control and Prevention. Scientists later identified the disease as being caused by a type A influenza virus, now classified as either highly pathogenic avian influenza (HPAI) or low pathogenic avian influenza (LPAI).
An HPAI outbreak began in the United States in 2022, with confirmed cases in wild birds, commercial poultry, and one human. In 2025, the virus has resurfaced with continued detections in poultry, wild birds, and dairy cows, and 70 human cases—primarily among workers—have been confirmed. However, there is no evidence of person-to-person transmission.
As of May 5, 2025, the New Jersey Department of Health reports no human cases in the state. Confirmed H5N1 cases in wild birds have occurred in Burlington, Warren, and Salem counties, with presumptive positives reported in 13 additional counties including Mercer, Hunterdon, and Monmouth. Confirmed poultry cases have been found in live bird markets in Hudson, Mercer, and Union counties, and in backyard flocks in Atlantic and Salem counties. No cases have been reported in commercial poultry farms, livestock, or cattle.
A March 7 press release from the New Jersey Department of Agriculture confirmed three poultry cases of HPAI in live bird markets—two in Hudson County and one in Mercer County. “The risk of HPAI to the general public remains low and no live poultry were sold to the public that may have been infected,” the release stated.
Affected markets are quarantined and do not receive new poultry until they complete cleaning and disinfection. According to Dr. Sandy Strilec, a veterinarian with the New Jersey Department of Agriculture, these markets typically remain closed for 120 days.
Farm Precautions in Hopewell Valley
Symptoms of HPAI in birds include sudden death, lethargy, reduced egg production, loss of appetite, diarrhea, and respiratory or neurological signs such as coughing, sneezing, or unusual posture.
Strilec said the most important step poultry owners can take is to prevent wild birds from contacting domestic flocks—by blocking access to feeders, water sources, and ponds. Netting may help, though wild birds can still fly over and drop feces. Predator cutouts can deter them. Additionally, Strilec recommends changing or cleaning shoes between farm visits to prevent contamination.
In Hopewell Valley, local farmers are taking the threat seriously, even if they haven’t seen infections firsthand.
Wildflower Farm in Pennington raises chickens, ducks, geese, and turkeys—about 800 birds annually—alongside lambs, vegetables, and global seed varieties. Founder Tomia MacQueen said she has not experienced any unexplained bird deaths but has taken steps to limit wild bird access.
“Unfortunately, we have a pair of wild geese that nest on our pond every year on the island and they’re very hard to get rid of,” MacQueen said. “We remove the nest only because the male has gotten aggressive with our geese. One of our two dogs has been trained to chase off wild geese and not our domestics, which helps to reduce them being comfortable there.”
The farm encourages free-roaming birds as part of its sustainability-focused education program.
“There’s no way that we can live within our own farm philosophy and one hundred percent protect our birds at the same time, so we have to take some risk,” MacQueen said.
MacQueen also recommends isolating sick birds, sanitizing footwear, and maintaining diversified income streams to mitigate financial risk.
“We have produce boxes, we are also seed growers for a number of companies,” she said. “So, we do rely on that production and count on that produce income to hopefully offset any potential problems with the Avian Flu.”
Double Brook Farm in Hopewell also pasture-raises poultry along with pigs, sheep, cattle, and other livestock. Owner Jon McConaughy believes their outdoor approach may give birds added resilience.
“They’re interacting with wild birds and other things in their environment, that’s giving them probably a resistance that chickens in confinement don’t have,” McConaughy said.
The farm limits outside feed sources and contact with other operations to reduce exposure risk.
“If we were to have an incident with our egg layers, it’s not our entire income…we didn’t set it up for that purpose but…these big industrial egg laying facilities, if they have an issue, it’s their entire revenue,” McConaughy said. “It’s not a huge impact to the farm because it’s just one of the revenue inputs.”
Public Health Risk and Monitoring
Nationwide, 70 human cases of H5N1 have been confirmed since 2024—41 linked to exposure to infected dairy cows and 26 to poultry. According to a February 2025 CDC risk assessment, the threat to the general public remains low, with a very low likelihood of infection. However, the risk is considered moderate to high for those with direct exposure to infected animals or contaminated environments, especially without protective equipment.
The CDC continues to monitor the virus’s genetic changes, noting that any mutations enabling sustained human-to-human transmission would warrant an updated risk assessment.
“It’s a low risk, but I know CDC in our state’s health department is encouraging folks who have some higher chance of exposure, so that might include farmers, poultry farmers, or dairy farmers, to wear personal protective equipment if they’re going to be interacting with animals that are sick,” Strilec said.
Other Animal Cases in New Jersey
In Hunterdon County, six feral cats tested positive for HPAI, according to USDA and local health officials. The first two cases were reported on Feb. 28, with four additional cats from the same property later confirmed. One of the cats was humanely euthanized due to severe symptoms.
The New Jersey Department of Health said cats may be exposed through contact with infected animals, consumption of raw milk or meat, or contaminated clothing. In this case, there was no known exposure to infected livestock or milk, though contact with wild birds remains a possibility.
The virus was also confirmed in captive bears in Ocean County, according to NJDOH. No other mammal cases have been confirmed in the state.
Signs of HPAI in cats include lethargy, discharge from eyes or mouth, sneezing, breathing difficulty, seizures, loss of coordination, and blindness. The NJDOH urges pet owners to call their vet before bringing in symptomatic animals to allow clinics time to prepare. Residents concerned about stray cats should contact animal control.
Wildlife Detections and Public Guidance
The New Jersey Department of Environmental Protection identified a bald eagle in Princeton near Lake Carnegie as a presumptive positive for HPAI on Feb. 10. No follow-up confirmation has been released.
In Burlington County, a deceased Canada goose tested positive for H5N1 in February, marking the first such detection there since 2022. Officials urged residents not to touch or feed wild birds or step in feces.
In Allentown Borough, Monmouth County, multiple dead geese led to temporary park closures in February. The parks have since reopened.
Residents are encouraged to report sick or dead wild birds to the NJDEP through its online Wild Bird Disease Reporting Form. Poultry deaths should be reported to the Division of Animal Health. Anyone who believes they or their pets have been exposed to H5N1 should contact local health officials.
Looking Ahead
While the virus continues to circulate, local farmers say preparation and perspective matter.
“In terms of resiliency, the best thing that we can do is look at other income streams, other niches, so that if anything happens, you have a way to kind of hold yourself over until you can get birds on your land again,” MacQueen said. “We just have chosen not to panic about it, and if unfortunately, it happens, then it happens.”
