Since Friday, hundreds of dead and sick birds have dropped along Lake Michigan’s shore — all likely infected with bird flu.
It’s the latest in a string of deaths and infections in and around Chicago. Outbreaks of the virus, also called H5N1 or avian flu, have decimated poultry flocks and infected cattle herds nationwide.
Bird flu’s risk to humans is currently low, infectious disease experts told the Sun-Times. Only 67 cases have been reported in the U.S. and aside from one death earlier this year, the infections have mainly been mild and weren’t transmitted from person to person.
But because influenza can rapidly change, that could all turn on a dime, experts cautioned. Bird flu’s widespread presence in wild birds, poultry, cows and other mammals means the virus is mutating and risks becoming transmissible among humans.
Complicating matters more is a sudden lack of federal guidance, experts told the Sun-Times.
“Influenza is extremely unpredictable, and that’s what makes it a scary disease to deal with,” said Dr. Ron Hershow, director of the division of epidemiology and biostatistics at the University of Illinois Chicago.
“We’re dealing with an unpredictable shape-shifter.”
Influenza survives by replicating and multiplying into imperfect copies, which is why a new flu vaccine is needed every year, Hershow said.
Bird flu is a type of influenza and a subtype of the disease humans normally contract, said Dr. Robert Murphy, an infectious disease specialist at Northwestern Medicine and executive director of the Robert J. Havey Institute for Global Health at Northwestern University.
Avian flu was first identified in humans within the past 15 years in southeast Asia, Murphy said. Roughly 900 cases were reported in a 10-year period, largely among people working in markets with birds, such as ducks and chickens.
In that time, half of the people infected died, Murphy said.
“That was the big fear,” he said. “That’s a mortality rate worse than the flu.”
The current strain has mutated to transmit among mammals, including cows, cats and zoo animals.
The current risk to household pets is from raw or undercooked pet food, said Dr. Will Sander, a professor with the veterinary medicine department at the University of Illinois at Urbana-Champaign.
Pet-grade meat isn’t screened for viruses the way human-grade meat is, Sander said. Backyard chicken coops are also getting hit when wild birds defecate on open enclosures.
‘We need to take this seriously now’
The virus has yet to become transmissible from human to human.
“But if it mutates more and more and starts getting the characteristics more like the typical flu that impacts humans, that’s our worry,” Murphy said. “And that chance recently went from unlikely to possible, which is a big step in public health.”
The virus first spread from wild birds to chickens, said Hershow at UIC. It’s since devastated poultry flocks as the disease is highly deadly for birds.
“The big scare we are all dealing with is if the virus can spread in wild birds, to domestic flocks and somehow spread to cattle, then, of course, it’s possible the disease can eventually evolve to humans and then start to spread person to person,” he said.
If the virus mutates to transmit among humans, a big concern is if it becomes airborne — making it easier to spread like RSV and COVID-19, Murphy said. Currently, infection requires physical contact with an infected animal, similar to how SARS is spread.
Experts have benefited from the many hard lessons learned from the COVID-19 pandemic, Murphy said.
“A big mistake in the last 20 years was that we didn’t take coronaviruses seriously,” he said. “We will do better the next time around, but we need to take this seriously now. If this gets out of control, it is on us completely.”
Preparing for a potential mass outbreak requires a “bread-and-butter public health approach,” Murphy said.
That means robust testing since it’s an infection not routinely screened for, Murphy said. In the final days of the Biden administration, the U.S. Centers for Disease Control and Prevention updated its guidelines to encourage anyone hospitalized with influenza to get checked for avian flu. Murphy also said tests should be available over the counter and at walk-in clinics.
A larger supply of antiviral drugs and vaccines is also needed, Murphy said. There is a vaccine for H5N1, and Moderna was recently given $590 million to speed up its development of a vaccine.
“We have about 2 to 3 million doses in the U.S. ready to go. That’s good if it really takes off among people exposed to cows or birds, but that’s not enough for the general population,” he said.
A strong response to a major outbreak requires leadership and coordination from the CDC, but the agency has been silent on bird flu since the beginning of the Trump administration.
“The CDC is being muzzled, and that couldn’t come at a worse time,” Hershow said.
Contributing: Tyler Pasciak LaRiviere
