When avian influenza first hit dairy cows a year ago, it was thought that it would affect small, isolated herds and could disappear as quickly as it appeared. Instead, the virus has infected more than 900 herds, dozens of people, and killed one person, and the outbreak shows no signs of slowing down.
More than a dozen experts said in interviews that the pandemic remains inevitable. But a series of developments over the past few weeks indicate that that possibility is no longer remote.
Experts say the opportunity to contain the outbreak is wasted, mirroring failures during the COVID-19 pandemic, including flimsy guidelines, insufficient testing and long delays in releasing data. He said that
As one example of the confusion, the New York Times reported that several dairy herds in Idaho that were infected in the spring showed mild symptoms again in the late fall. In mid-January, the Department of Agriculture announced that no new infections had been confirmed in the Idaho herd since October. However, state officials publicly discussed mild cases in November.
Experts said it was not surprising that a second bout of infection would make cattle less sick, and could be welcome news for farmers. But reinfection suggests the virus, called H5N1, could circulate indefinitely on farms, creating an opportunity to evolve into more dangerous forms, a “high-risk” scenario, according to the University of Pennsylvania's Evolution said biologist Louise Moncla.
“H5 may end up circulating endemicly in asymptomatic dairy farms, making rapid or easy detection difficult,” Dr. Moncla said.
They say it's impossible to predict whether the virus will evolve the ability to spread between people, let alone when that will happen. But the worry is that if bird flu finds the right combination of genetic mutations, it could spread rapidly.
“I'm not worried enough to pack up and head for the hills just yet, but over the past four to six weeks there have been increasing signs that this virus has the potential to cause a pandemic,” Richard said. Webby, influenza expert at St. Jude Children's Research Hospital.
Federal officials have also subtly changed their tone when discussing the outbreak, emphasizing how rapidly the situation is changing.
For the general public, H5N1 is a “low risk compared to other risks we face today,” said Dr. Nirav Shah, principal deputy director of the Centers for Disease Control and Prevention. But “100 percent, that could change,” he said. “This is a dangerous virus.”
Health experts stress there are precautions Americans can take. Avoid touching sick or dead birds or other animals. Get tested if you have flu-like symptoms. Do not consume raw milk or meat or feed it to pets.
If a larger outbreak breaks out, the federal vaccine stockpile has millions of doses of vaccine that may first need to be updated to match the evolving form of the virus. In either case, authorities would have to scramble to produce enough for the population.
The CDC recommends treatment with the antiviral drug Tamiflu, but studies have shown the drug has little effect on reducing disease.
Underscoring the concerns of many experts, Robert F. Kennedy Jr., who would lead the federal health department if a case is confirmed, has been a vocal critic of the coronavirus vaccine and said he has no concerns about bird flu. He said the vaccine “appears to be dangerous.”
Even if the second Trump administration pushes ahead with vaccine development, just as the first administration did when the coronavirus pandemic was brought under control, it remains to be seen how many Americans will roll up their sleeves to get vaccinated. It's unknown. Influenza usually affects children and the elderly, but pandemic influenza can also hit young people hardest. But the mistrust created by the coronavirus outbreak could lead Americans to avoid precautions, at least initially.
evolving threat
Unlike coronaviruses, which wreaked havoc with their sudden arrival, influenza viruses typically occur in specific animal species or specific geographic regions.
When the H5N1 virus emerged in East Asia nearly 30 years ago, it primarily sickened birds. Over the next few years, at least 940 people became infected, almost all of whom had close and continuous contact with infected birds. About half of those people died.
However, since the virus was detected in wild waterfowl in the United States in January 2022, it has affected more than 136 million commercial, backyard, and wild birds, leading to soaring egg prices. Dozens of species of mammals, including wild and domestic cats, raccoons, bears, and sea lions, are also affected.
H5N1 has been infecting dairy cows for at least a year, but cows were not known to be susceptible to this type of influenza. In some cows, it has lasting effects, reducing milk production and increasing the chance of spontaneous abortion.
And in 2024, the virus infected 67 Americans, compared to just one in 2022. The sources of all these infections are not known. A person may have transmitted the virus to someone in their household.
Dr. James Lawler, director of the University of Nebraska's Global Center for Health Security, said many of these developments are typical steps toward a pandemic. But, he said, “we're just shrugging off each milestone when we should have accelerated and expanded action at the federal, state and local levels.”
The first outbreak at a dairy farm in Texas appeared to be declining last summer. But in late August, California announced its first case. Numbers in the state quickly spiked, prompting Gov. Gavin Newsom to declare a public health emergency in December.
“That was kind of a signal to me, like, 'OK, this is not over yet,'” said Dr. Manisha Jutani, the Connecticut Department of Public Health Commissioner. “In the last few months, I feel like the tempo has picked up,” she said.
Several other recent events have raised the level of alarm among experts. In early December, scientists reported that a single mutation helped the virus infect human cells more efficiently in a laboratory setting.
And late last year, two people, a 13-year-old Canadian girl and a Louisiana resident over 65, became seriously ill. Previously, most people infected with H5N1 did not experience severe symptoms. The Louisiana patient had health problems and was caring for a sick and dying bird that died in early January.
The girl was placed on life support due to organ failure, but eventually recovered. Scientists still don't know how she became infected. Her only risk factor was obesity.
Both patients were infected with a new version of the virus currently circulating in birds, which is different from the virus in dairy cows. In both cases, the virus may mutate during the infection process, making it more contagious to humans.
“It is now clear that new viruses are forming in wild bird reservoirs,” Dr. Moncla says. “It's becoming difficult to manage all the different threats.”
Some experts find it particularly concerning that the virus appears to be present in food sources such as raw milk and raw pet food. Domestic cats have died in many states, at least one brand of pet food has been recalled, and new federal guidelines for pet food quality have been issued.
“I think raw pet food is very concerning,” said Dr. Jeanne Marazzo, director of the National Institute of Allergy and Infectious Diseases.
Pasteurization, like cooking meat at high temperatures, kills live viruses. Still, neither procedure is perfect, Dr. Marazzo said. “There is no way to police production and sterilization in a way that ensures the food supply is 100 percent safe.”
flawed response
In the year since the pandemic began, federal officials have announced other measures to prevent and prepare for a pandemic. But experts say each has major flaws.
The U.S. Department of Agriculture has delayed the start of trials of an H5N1 vaccine for cattle, leaving interested companies in limbo. Dr. Marazzo said the agency released genetic information from the virus samples but did not say when or where they were collected. The details will help scientists track the evolution of the virus.
It is also unclear how many herds have been reinfected or have been battling infection for months. In Idaho, some herds infected in the spring appeared to have recovered, but showed mild symptoms again in November.
“The data available to date shows no evidence of new infections or reinfections in previously affected herds, but rather the initial infection,” a USDA spokesperson said in an emailed response. It turns out that this has not been eliminated.” But outside experts said the course of symptoms suggested a second round of the disease.
The USDA's bulk milk testing program began in December, nearly a year after the outbreak began, but it does not yet include Idaho. Involving private companies could help expedite the program.
Ginko Bioworks, a company that has worked with federal agencies during the coronavirus pandemic, has already evaluated about half of the nation's commercial milk supply for bacteria, antibiotics and other substances.
Adding H5N1 to the list is easy, so “why not just add an assay to this infrastructure that we already have?'' said Matt McKnight, manager of the company's biosecurity division.
Earlier this month, the Biden administration announced $306 million in new funding, about a third of which will go toward surveillance, testing and support for farmers.
But farmworkers in some places, like the Texas Panhandle, still don't know what avian influenza is, how it spreads or why it's important to them, according to the National said Bethany Alkoter, director of research and public health programs at the Farmworker Health Center.
As a result, many workers are still not wearing protective gear, including in milk parlors where the virus is believed to be spread, he said.
Human testing is carried out voluntarily, and infectious diseases are often overlooked. Few farmworkers choose to be tested out of fear of immigration officials or their employers.
“If you don't look for it, you won't find it, right?” said Dr. Deborah Birx, who served as White House coronavirus response coordinator under President Trump. “This is not about lockdowns or restrictions on movement. It's about protecting individual Americans by informing them.”
