The widening U.S. bird flu outbreak has made its way to Maryland, which has counted two cases on commercial poultry farms—one in Caroline County and another in Queen Anne’s County—since the start of the year.

Health experts say the general public is at little risk of exposure and illness, thus far. While human infections of this H5N1 avian influenza can be deadly, there have been no confirmed cases of human-to-human spread.

“The general public should have very little concern unless they’re involved in what we know are high-risk activities, one being working on poultry farms” and another being drinking raw, unpasteurized milk, said Andy Pekosz, an expert on respiratory viruses and emerging diseases at Johns Hopkins Bloomberg School of Public Health.

“On the flip side, biologists like myself are very concerned about the situation,” he said. “There have been way too many outbreaks in dairy cow farms. It’s spread across way too many states.”

As of this week, the Centers for Disease Control and Prevention counted 67 U.S. cases of bird flu infections in humans since 2024, none in Maryland. One person, a 65-year-old Louisiana man with underlying health conditions, died after he was likely exposed to the virus from wild birds and a non-commercial backyard flock, the Louisiana Department of Health reported earlier this month.

The CDC on Thursday also called on hospitals to test patients they believe may have the bird flu, particularly those in intensive care units.

The U.S. Department of Health and Human Services announced earlier this month that it has awarded $306 million to monitor this outbreak and prepare for more human infections. More than half of that will go to regional, state and local programs.

The U.S. Department of Agriculture has confirmed 928 dairy herd infections in 16 states, mostly California. More than 12 million birds also have been affected in the last 30 days, including 54 commercial flocks and 55 backyard flocks, according to the USDA.

For now, Maryland’s dairy cows have not been affected, according to the state Department of Agriculture. Infected commercial chicken farms in the state have culled tens of thousands of infected chickens. They were likely infected by wild, migrating birds, said Jennifer Trout, the Maryland State Veterinarian.

No infected meat or eggs got into the food supply, Trout said.

“I don’t really have the ability to control Mother Nature in the flyway. But luckily for us, we’ve got a really good (disease monitoring) system in place,” she said. “These animals are tested through routine surveillance, pre-harvesting testing.”

How dangerous is the bird flu?

Earlier avian flu outbreaks have proven especially deadly for humans, causing roughly half of the infected to die. This current version of avian flu seems to be less dangerous, causing mild respiratory illness and conjunctivitis, better known as pink eye, according to the CDC.

Other symptoms include coughing, fever, muscle aches and fatigue. Symptoms usually last up to two weeks. More severe cases can cause pneumonia, organ damage, septic shock and death. It’s not clear how long people are contagious, but scientists believe it’s similar to regular, seasonal influenza, according to the CDC.

“To date, there has been only one death in the entire U.S. due to avian flu. For comparison of risk, there are likely to be at least 10,000 deaths due to seasonal influenza in the US this year,” said Dr. George Rust with the Florida State University College of Medicine.

“CDC data show that in Maryland, there have been 141 deaths due to COVID-19 in the past three months.” (The state of Maryland reported 186 COVID-19 deaths between Oct. 14 and Jan. 14, the most current data available.)

Antiviral drugs are the recommended treatment for anyone testing positive for the bird flu.

What’s different about this outbreak?

Human infection by the H5N1 avian flu first emerged a generation ago, though other strains of bird-infecting flu have been recorded for about 150 years. Public health experts say this outbreak is different in that it’s spreading quickly among mammals, which are genetically more similar to humans than birds.

That, they say, could eventually lead to a mutated strain that would allow avian flu to spread among humans. Someone could also be infected by the normal flu and the bird flu at the same time, allowing H5N1 to “swap genes” and create a mutation leading to human-to-human transmission. That would become the next pandemic.

“Should the bird flu virus pick up the capacity to readily infect people, then I’m afraid we would have, once again, a large pandemic with much illness, infections of people who are older and frail and immunocompromised and the very young,” said Dr. William Schaffner, a professor of preventative medicine at Vanderbilt University and one of the nation’s leading experts in infectious diseases.

“That would be followed by a substantial number of deaths but unlikely to be at the 50% level. It would be more like what we see with seasonal flu.”

House pets can get sick or die if they eat a dead or infected bird or drink unpasteurized milk.

How safe is the food supply?

Aside from widespread testing on farms, cooking poultry and eggs to an internal temperature of 165 degrees kills all bacteria and viruses, including the bird flu. The same applies to cooking ground beef to 160 degrees and whole cuts of beef to 145 degrees, according to the CDC.

There are no known cases of people in the United States getting avian flu from eating properly cooked and handled food. Though some cases have emerged in Southeast Asia, likely because of exposure to poultry blood, according to the World Health Organization.

Similarly, pasteurization makes drinking milk safe.

“Pasteurization protects the milk supply from viral contamination, as well as from many other infectious diseases,” said Rust, the FSU College of Medicine professor. “H5N1 virus has been found in high concentrations in milk from infected dairy cattle, so consuming raw milk, or unpasteurized cheese or yogurt, creates unnecessary risk.”

Are there vaccines and treatments?

The United States has stores of vaccines against an earlier variant of the bird flu and is now making more that should be even more effective against the variants currently circulating, Schaffner said. Studies are also underway to develop vaccines that would work in dairy cows, he said.

Seasonal flu vaccines alone are not effective against bird flu, according to the CDC.

“The government is stockpiling millions of doses of a vaccine for avian flu and is funding the development of new mRNA vaccines as well,” Rust said. “We need to maintain a robust public health infrastructure to prevent such outbreaks rather than gearing up after a pandemic has begun.”

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