If the goal of that description was to calm the waters around the passing of the patient, whose case was first disclosed about three weeks ago, it failed. Instead, researchers who have closely followed the explosive spread of the avian virus are renewing their calls for both federal and local health officials to get in the game—before more damage is done.

“This is how pandemics start,” Rick Bright, the renowned immunologist, vaccine researcher and former federal health official, tells Fortune. “We’ve had months to prepare, to activate and expand surveillance, to educate people about the risk, and even to make vaccines available that can help to reduce the risk of the current form of the virus.

“I hope that this death is not minimized or blamed on underlying medical conditions,” Bright adds. “The virus is changing quickly. We need to step up the pace of all efforts to track it and update our medical countermeasures to be ready when it pops.”

Interviews with multiple experts echoed those themes. They want to see health agencies rapidly expand available testing, use current vaccines that are already in stock to immunize people at highest risk, and ramp up both public awareness and transparency around the spread of the virus itself.

“There is a non-zero chance that this virus can cause a pandemic,” says Angela Rasmussen, a virologist at the Vaccine and Infectious Disease Organization at the University of Saskatchewan. “We need to be doing everything we can to prevent that from happening.”

The Louisiana case was attributed to the patient’s exposure to a combination of non-commercial backyard flock and wild birds. CDC’s analysis of the virus revealed that it belonged to the same D1.1 genotype of H5N1 bird flu as a case in British Columbia late last year that left a teenager hospitalized in critical condition. (That patient has since recovered.)

While virologists keep tabs on the various strains of the virus and the development of mutations that might enable the virus to spread to another person easier, experts are now worried about the possibility of reassortment during flu season. With each new human infection, there is a possibility that the virus will not only evolve but potentially combine with a seasonal flu virus—that is, reassort—and form a strain that can spread easily among people and cause more severe illness. That’s the nightmare scenario.

“It is evolving, and multiple forms of the virus are appearing in different animal species,” says Bright, who has been consistent in his calls for more testing of workers—as well as cattle and poultry themselves—at dairy and egg farms. “The more this virus is allowed to spread and infect other species and stay around us, the likelier these new variants and mutated versions of the virus are going to infect people—and they are mutating to adapt and cause more severe illness. It just screams at us to wake up.”

In its own announcement of the death in Louisiana, the federal Centers for Disease Control and Prevention said that while tragic, a death from H5N1 was “not unexpected” considering the virus’s known propensity to cause severe illness. The agency noted that of the roughly 950 human cases of bird flu reported to the World Health Organization globally, about half have been fatal.

The CDC’s statement also pointed out that, to date, no person-to-person spread of bird flu has been identified. But that is precisely what global experts believe could happen next—the very reason they’re pushing for health officials to act with more urgency.

“I would be in favor of vaccinating at-risk groups for both seasonal influenza viruses and H5 viruses,” says Debby van Riel, who along with her Netherlands-based team has been studying the pathogenesis of respiratory virus infections for a decade. “The increased circulation of seasonal [flu] increases the risk of reassortments” in those who have that virus and an H5 infection at the same time,” the researcher says.

Sounding the alarm

It is still not clear when—or if—U.S. health officials will sound the alarm and begin offering workplace vaccinations. From the outset of bird flu’s advance on American dairy farms and commercial flocks, local and national agencies have largely shied from any bigger-picture proclamations, other than to maintain that the overall risk to the general public was considered low.

The damage to those commercial industries has been severe. By the CDC’s accounting, bird flu has struck down nearly 131 million poultry and been found in 919 dairy herds across the country. The agency said there have been 66 confirmed human cases in the U.S. since last year, almost all of them people who worked on farms with infected cows or birds.

“My big concern is just the number of human infections. We really need to get that number down,” Angela Rasmussen says. “Part of that means we need to get the dairy cattle outbreak under control. We need to do a better job educating people who are dairy and poultry farmers, who are backyard farmers who are raising animals, or who are in contact with animals, including pets.”

Some of those on the front lines of bird flu’s spread have pointed at the U.S. Department of Agriculture for failing to act more forcefully when it began receiving reports of mass infections on farms. Outbreaks in dairy cows were first detected last March but herds in 16 states have now been affected. By many accounts, there’s been a breakdown in getting testing or protective equipment to local farmers, who may fear shutdowns and loss of income if an infection is found. And the Biden administration was slow to require widespread testing of bulk raw milk to determine which dairy herds were infected, issuing the federal order only a month ago.

But the blame game isn’t paramount right now; controlling the spread of the disease is. And researchers fear that the clock is ticking.

“The last step that we need for the triangle of a pandemic is [the virus] spreading from person to person,” Bright says. “My concern is that we're not watching close enough for that to happen, because we're discounting it for various reasons: This person was a little overweight, or this person had asthma, or this person was older.

“If we're going to dismiss it and close our eyes, then we are going to miss that transition from a one-off to a person-to-person transmission. And this is exactly what bit us in the butt with COVID.”

Practical next steps

What steps should U.S. health officials be taking? Experts Fortune spoke to suggest several:

1. Begin raising awareness of the virus. 

“Most people really haven’t heard of H5N1,” Bright says. “I don’t think the CDC communications have reached most of America to, No. 1, inform them—even in a calming way—that there’s a new virus among us.” Kids, for example, may have no idea of the risk attached to something as relatively ordinary as touching or picking up a dead bird.

2. Immediately start offering vaccinations to farmworkers who are at risk. 

The U.S. government has approved three vaccines for H5N1 since 2007, and Bright says there are millions of those shots contained in the national strategic stockpile. “Providing the H5N1 stockpiled candidate vaccines to dairy farm veterinarians and workers would be a place to start,” says Seema Lakdawala, a virologist at Emory University School of Medicine. Finland, for example, is offering farmworkers bird flu shots after they experienced prior outbreaks on their fur farms.

Experts also suggest that the U.S. consider making vaccines available for farmers who want to immunize their cows and poultry flocks. The World Organization for Animal Health supports the use of vaccinations as an adjunct to other biosecurity and disease control measures during outbreaks.

3. Get transparent about what’s happening, including more aggressive testing. 

As Lakdawala noted, it’s difficult to effectively contain the bird flu spread when even those trying to help don’t know the scope of the problem. “There is no individual cow testing. This limits the ability to identify and isolate infected cows to reduce the transmission of H5N1 between cows, and it perpetuates the outbreak,” the virologist says.

4. Expedite the development of H5 rapid tests, then distribute them in bulk to farmers to test sick cows or their milk.

The move could help farmers identify and remove a cow to protect the rest of the herd, says Bright. “Put those powerful tools into the hands of farmers," he adds. "We’re not doing that yet.” Farmworkers and their family members could self-test, too. 

5. Clear a regulatory pathway for next-generation H5N1 vaccines. 

One way to do that is via Emergency Use Authorization, but the Food and Drug Administration generally won’t consider an EUA so long as a viable alternative exists–in this case, traditional seasonal flu vaccines. “We have to admit to ourselves that our traditional vaccine approach can be quickly outpaced by a rapidly changing, spreading virus,” Bright says.

6. Boost and diversify our supply of antiviral medications. 

The infected Canadian teen received three different antivirals on her road to recovery. The U.S. has only two basic classes of such drugs in its strategic national stockpile–and one is in short supply, Bright says. Federal officials should also encourage accelerating efforts to approve other treatment options, including those able to help fight inflammation and cytokine storm, a hyperactive immune response our body can make in response to infections like flu.

The death in Louisiana stands alone, but for how long? “The virus has the potential to evolve with every new human infection, and I fear that we will eventually see onwards human transmission of mutant H5N1 viruses in the future,” says Scott Hensley, a viral immunologist at the University of Pennsylvania Perelman School of Medicine in Philadelphia.

The time for urgency, the experts say, is now—even if acknowledging the scope of the bird flu problem upsets people and companies with a vested interest in seeing it downplayed.

“If [a major human outbreak] does happen, things are going to go from ‘There's a low risk to the general public’ to ‘It's a pandemic,’” Rasmussen says. “And I mean, it’s going to be measured in days and maybe weeks that we will have a window to contain this if it starts spreading human-to-human. The best thing that we can do is make sure that it doesn't start.”

For more on bird flu:

• Bird flu could merge with seasonal flu to make mutated virus that could spread among humans, CDC warns
• Bird flu FAQ: Everything you need to know about the latest H5N1 outbreak
• What are the symptoms of bird flu and how does it spread?
• California declared a state of emergency over severe bird flu case. What it means for the rest of the country
• Bird flu begins its human spread, as health officials scramble to safeguard people and livestock