Bird Flu, or Highly Pathogenic Avian Influenza, cases found in New Jersey

U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) have confirmed the presence of Highly Pathogenic Avian Influenza (HPAI) in wild birds across several counties in New Jersey.

The recent findings underscore the ongoing challenge of managing avian influenza outbreaks, with implications for both wildlife and domestic poultry.

In Ocean County, bufflehead ducks collected on March 20, 2024, tested positive for the avian flu strain on April 9, 2024. This discovery highlights the susceptibility of diverse avian populations to the virus.

Subsequent investigations revealed additional cases, including a red-tailed hawk in Hunterdon County and a bald eagle in Cumberland County.

The bufflehead duck, known scientifically as Bucephala albeola, is a small sea duck commonly found foraging underwater. The presence of the virus in such species highlights the potential for transmission among diverse avian populations.

Avian influenza, caused by the influenza A virus, poses a significant threat to both bird populations and, in some cases, humans. The strain detected in New Jersey, HPAI EA H5N1, is particularly concerning due to its high pathogenicity and potential for transmission to other species, including humans.

While the risk of transmission to humans is generally low, close contact with infected birds or their environments can lead to severe illness, including pneumonia. The Centers for Disease Control and Prevention (CDC) emphasize the importance of avoiding contact with sick or dead birds and practicing proper hygiene when handling poultry.

The good news is that, so far, H5N1 is not considered a major public health threat in the U.S. The Centers for Disease Control and Prevention (CDC) has categorized the risk to the general public as “low,” but continues to monitor the situation carefully.

“In the short term, there is very little threat,” says Yale Medicine infectious diseases specialist Scott Roberts, MD. “In the long term, in the coming years or decades, however, I’m much more concerned.” He gives two reasons: One is that there has been a mortality (or death) rate of about 50% in the almost 900 people around the world who have been infected with bird flu between 2003 and 2024.

However, 50% may be an overestimate, Dr. Roberts says, adding that there may be cases where people have no symptoms, are only mildly symptomatic, or haven’t sought care for their symptoms. He also noted that if the virus did spread in humans, the percentage might be significantly lower if preventive approaches, including a vaccine, and treatments were made widely available.

Another reason for concern is that bird flu is now being detected in new animal species. In addition to outbreaks in cows—a relatively new development for the bird flu virus—there have been sporadic infections in some wild mammals. “It’s natural to wonder if it’s only a matter of time before this virus is able to spread among humans,” Dr. Roberts says.

Dairy cows are a “new and unexpected host” of the H5N1 virus, and the spread of the virus among cows is a sign that it could mutate in them, making it easier for it to spread to other animals or potentially humans, according to the CDC.

The disease appears to be milder in cows, although this could make it more difficult to track, Dr. Roberts says. “The virus is also infecting other animals,” he adds. “To me, that sounds like it’s mutating to adapt, evolve, and infect new species.”

Many experts are concerned about the possibility of this virus infecting pigs at some point, because pigs can be infected with both human and animal flu viruses, adds Dr. Roberts. “Then, we have this sort of mixing pot, where you can get a genetic reassortment of different flu strains. That’s really the big, long-term concern that could take years or decades—if it were to happen,” he says.

The recent cases in New Jersey are part of a broader trend of avian influenza outbreaks nationwide. Federal agencies, including APHIS, are closely monitoring the situation and working to prevent further spread, particularly to domestic poultry populations.

Efforts to mitigate the risk of transmission include early detection through surveillance programs, public awareness campaigns, and coordination with state and local authorities. Additionally, measures such as biosecurity protocols on farms and restrictions on the movement of poultry can help prevent outbreaks in commercial poultry operations.

Bird flu in the milk supply has been a major concern among consumers, but the Food & Drug Administration (FDA) has been sampling retail milk and other dairy products, such as cottage cheese and sour cream, as well as powdered milk formula and powdered milk products sold as toddler formula; it reports that although dead byproducts of the virus have been present, it found no live infectious virus, thanks to pasteurization, a food production process of heating liquids for short periods of time to kill harmful bacteria.

However, the FDA advises people not to drink, manufacture, or sell raw cow milk and products, such as cheeses, ice cream, and yogurt, made with raw milk. (Raw, unpasteurized milk and milk products are sold legally in most states.) While neither of the two human infections was linked to raw milk, more than half of a resident population of domestic cats on a farm in Texas died after they were fed raw, unpasteurized colostrum (milk produced during the first few days after birth) from H5N1-infected cows, according to a CDC report.

There also is no evidence that anyone in the U.S. has gotten bird flu after eating properly handled and cooked poultry products, but the CDC notes that uncooked poultry and poultry products (such as blood) may have caused a small number of H5N1 infections in people in Southeast Asia.

Poultry and other animal foods should be safe to eat as long as they are prepared properly, according to the CDC. This includes cooking poultry and eggs to an internal temperature of 165°F, which can kill viruses, including H5N1. (Use a food thermometer to be sure.) The FDA provides more information on raw milk on its website.

As investigations continue and additional cases may emerge, it is essential for authorities and the public to remain vigilant and take appropriate precautions to minimize the spread of avian influenza. By working together, stakeholders can mitigate the impact of these outbreaks on both wildlife and agricultural sectors.

Since bird flu isn’t spreading among humans, most people don’t need to worry about precautions, Dr. Roberts says. But people who are exposed to cows or poultry, especially in states where bird flu has been identified, should consider them, he says. So should hunters who handle wild birds and people who raise chickens at home.

One problem is that experts are still learning how bird flu is transmitted. “We understand much less about H5N1 transmission than we do about COVID,” Dr. Roberts says. But most people infected with bird flu get it from unprotected contact with infected birds, according to the CDC. The agency adds that infection also can happen when people inhale the virus in droplets or dust from the infected animals, or touch a contaminated surface.

The CDC has a list of recommended precautions, including:

• Avoid sick or dead birds. Check with your state or local government about their policy for reporting wild birds and other animals that look sick or are dead. Avoid wild birds even if they don’t look sick, since they can have an infection without symptoms.
• Don’t touch surfaces or materials that could be contaminated. That includes animal litter or feces, mucus, raw milk, or saliva.
• Avoid poultry farms and bird markets. If you must visit those places, wear a well-fitting face mask and don’t touch the animals.
• Use the following protective measures if you are unable to avoid contact with wild birds or sick or dead animals:
  • Wear gloves and, after removing them, wash your hands properly.
  • Wear an N95 respirator or a well-fitting mask.
  • Use eye protection, such as goggles.

It’s important to throw away your gloves and face mask after any exposure.

Check the CDC website for further advice for specific situations and groups, including hunters and people who raise chickens in their backyards. It also offers special advice for people who work with animals on farms.

For anyone who wants to keep up with the news about bird flu, the CDC is providing regular updates based on its flu surveillance systems.