Bird Flu Is out of the News but Still Circulating

For months, the bird flu was apparently everywhere in the United States: new newspapers reported that the highly pathogenic H5N1 avian1 virus quickly swept hundreds of herds of dairy cattle and led to massive works of pulp herds, concerning infections in humans and grocery pools where a noral egg could not be found.

But almost as quickly as the bird flu has borrowed itself in daily conversations, it has disappeared from them and the thoughts of most people – which made the public facilitated the public to think that the threat of avian flu had declined. Far from it, the experts say. “The flu is still there, and we just don’t know enough,” said Angela Rasmussen, virologist at the University of Saskatchewan.

What made the virus disappear apparently-and what does that mean for the future of the bird flu?

On the support of scientific journalism

If you appreciate this article, plan to support our award -winning journalism by subscription. By buying a subscription, you help to ensure the future of striking stories about discoveries and ideas that shape our world today.

An expert scenario has definitely excluded that the bird flu virus currently in circulation – a member of a flu subtype called H5N1 for proteins on its surface – simply disappears, explains Jennifer Nuzzo, epidemiologist at Brown University. “There was this pious wishes that it will just wipe and disappear, and we simply have not seen that, and it is simply not the way the influenza viruses work,” explains Nuzzo. “It does not disappear.”

Experts always monitor H5N1 avian flu in a variety of animals: wild birds, commercial poultry animals, wild mammals, dairy and human cattle – and find it, but at lower rates. But the virus is delicate, behaving somewhat differently in each host. Here is what we know about the current state of the virus.

The most reliable data on the prevalence of the bird flu comes from poultry operations. Indeed, the virus is so devastating in chickens and turkeys that farmers must shoot down the herds as soon as they detect an infection to reduce propagation. They are also able to report epidemics to the federal government to receive partial compensation. There is no way to ignore a sick herd or any incentive to hide one.

And right now, poultry tolls with avian flu are relatively low. Farmers reported that three million poultry birds killed by the virus or slaughtered to arrest it in March and April combined, against 23 million and 12 million in January and February, respectively. May has seen more than five million dead birds after the virus infiltrated several massive eggs laying installations in the county of Maricopa, Arizona. But the rates of June have dropped well below a million birds, and the cases of July to date remain very low, with a single commercial installation assigned so far.

These lower bird flu levels are not particularly surprising, given the past behavior of the virus in poultry to date, explains Mike Perse, specialist in poultry at Virginia Tech. “We generally see a reduction in infections during the summer,” he says. Since the start of the current epidemic at the beginning of 2022, data from the US Ministry of Agriculture show that, each year, the monthly touched poultry birds have tended to decrease less than five million in June, July and August.

Two factors seem to contribute to the apparent seasonal trend, says Persia. The virus seems to vacillate in higher ambient temperatures, and wild migratory birds which generally introduce the virus into poultry herds do not move as largely now as the breeding season is in full swing.

But the history of the epidemic tells an edifying story: each fall, the number of touched poultry birds increases again – it would therefore be premature to assume that H5N1 is done with us. “I am optimistic that it may be the last, and it disappears forever. I would not take altitude as proof of this, however, “said Jada Thompson, agricultural economist at the University of Arkansas. “We have to maintain vigilance.”

The evaluation of the epidemic of American dairy cattle was more difficult. The cows that are sick of the bird flu eat less and produce thick and discolored milk. But the infection is not as fatal in cattle as in poultry, which makes the virus more difficult to see in the first. And there is no reward for Lost Milk to encourage farmers to point out to be affected.

In addition, the virus jump to dairy cattle at the end of 2023 was extremely unexpected and was not publicly confirmed before March 2024, giving dairy producers and virologists shortly to understand the trends in the bird flu in the species. Last year, the cases continued throughout the summer, especially in the hard state of Colorado. The propagation has proven to be difficult to contain, in part because of the movement of animals required by the dairy industry. And although the virus can be monitored by milk, those responsible have started to demand such tests last December, after a full year of viral traffic.

This year, infections were reported, with only two confirmed herds as having the virus all June. But we do not know how to interpret the trend – deer farmers are also revealed between prudence and optimism.

Throughout the epidemic, the risk of pulpe of birds for humans was low, although dairy and poultry workers with exposure to infected animals have been more vulnerable. The first human infection detected in 2024 came shortly after confirmation that dairy cattle had fallen ill with H5N1. Additional human cases occurred in gusts throughout the months that followed, totaling 70 confirmed infections, including a death, in mid-February. Since then, the infections that represent Centers for Disease Control and Prevention have stalled.

Experts doubt that it is a good thing. “I cannot exclude the reason why we do not find infections: we just don’t seek them,” says Nuzzo.

Throughout the epidemic, the CDC has kept a count of the tests it performs, and these figures paint a clear image. As of July 1, the CDC noted that more than 880 people had been subject to targeted tests after exposure to infected animals. On March 1, this number was greater than 840; On the other hand, the February 1 issue was greater than 660. The CDC tested more than four times more people in February than in March, April, May and June. Another way in which experts have kept an eye on avian flu have crossed the national surveillance of existing flu, but because normal influenza infections are in a seasonal lull, the same goes for tests via this network.

The result is a lot of question points. “We are in a way a perfect storm without testing,” explains Rasmussen.

Even wastewater surveillance, which has proven to be useful to understand the levels of the virus that causes the cocvid as the test rates have dropped, is limited. The approach seeks the presence of viruses in community water processing factories, but H5N1 is propagated so largely between species that it is almost impossible to use these detections to permanently trace sources.

“No news in my world is good news.” —Aangela Rasmussen, Virologist, Saskatchewan University

“You don’t know how it happened,” said Nuzzo about the wastewater virus. “You don’t know if people are infected; You don’t know if [the virus is present] Because the birds dragged in wastewater. In some cases, the points of H5N1 wastewater levels were even linked to farmers who spilled the milk from their infected cows.

Nuzzo suspects that there have certainly been more human influenza cases than the 70 confirmed to date but that the virus does not spread widely. “I don’t think there is a huge iceberg of infections that we miss,” explains Nuzzo.

Nuzzo and Rasmussen find this cold comfort, however. Instead, they point out how essential it is to have as many integration as possible on what H5N1 does. Choosing not to seek evidence of the behavior of the virus means transmitting the opportunity to seize the first signs of a pandemic.

“No news in my world is good news,” says Rasmussen. “We simply do not collect data, and these are two very, very different things.”

The current approach of the United States is simply wrapped in a situation which is already difficult to analyze – given the complexity of a multispecific epidemic and the unpredictable nature of rapidly evolving flu viruses.

“This is the kind of thing that could become a pandemic tomorrow, [or] It could never become a pandemic. And I don’t know which one will happen, ”explains Rasmussen.

“It is a huge risk, but it is also a risk that may never happen,” she says. “But we will not know if we stop looking for it.”