When the deadly H5N1 bird flu virus makes its first appearance In an American poultry farm in February 2022, About 29,000 turkeys In an installation of Indiana, were sacrificed to try to avoid a greater epidemic.
It didn't work. Three years later, the highly pathogenic, or HPAI avian flu, spread to the 50 states. The number of commercial birds that have died or have been killed exceeds 166 million And The price of eggs is at a record level.
Poultry producers, experts in infectious diseases and government representatives now concede that H5N1 is probably there to stay. This recognition encourages some of them to wonder if the long -standing practice of the slaughter of each bird in a infected farm is durable in the long term.
Instead, they discuss strategies such as targeted depopulation, vaccinations and even the relocation of wetlands and water bodies to attract wild birds with viruses far from poultry farms.
But each of these alternatives implies a variety of logistics, economic and environmental costs that can eclipse the planned savings.
“People talk about common sense solutions to bird flu,” said Dr Maurice PiteskyA veterinarian and a commercial poultry expert in UC Davis. “But that's what mass slaughter is. There is a reason why we have done: it's common sense.”
The current version of the bird flu – known as H5N1 2.3.4.4b – is very contagious and very fatal. He plowed the commercial chickens, turkeys and ducks in the country with a mortality rate of almost 100%.
“There is a reason for which they call it” very pathogenic avian flu “, said Angela RasmussenVirologist to organize vaccines and infectious diseases from the University of Saskatchewan in Canada. “He immediately passes through a herd like a hot knife through the butter.”
And that is why most researchers and veterinarians promote mass slaughter, describing it as human and profitable.
A natural death of H5N1 is not pleasant for a chicken, said Rasmussen. The virus produces gastrointestinal infection, so that birds end up dying of diarrhea as well as respiratory distress.
“It's like Ebola without hemorrhage,” she said.
Saving birds that do not seem sick is a bet. They can be infected and capable of spreading the virus through their poop Before having external signs of illness. The only way to know with certainty is to test each bird individually – an expensive and time -consuming perspective. And if even a single infected bird is missed, it can spread the virus to an entire herd of replacements, said Rasmussen.
In addition, she said, all the additional work that would make sure that some chickens can stay alive would only do the labor costs and ultimately make the eggs more expensive.
It also has the potential to increase the total amount of viruses on farms, which is dangerous for human poultry workers, said Dr Ashish JhaDean of the Brown University School of Public Health.
“One of the reasons to reduce early is that you don't want many exhibitions to the human bird,” he said. “The more we introduce human infections, the more we will see mutations that increase the risk of epidemic or wider pandemic.”
For all these reasons, international trade agreements require mass slaughter – also known as “seize” – so that importers do not get a side of H5N1 with their poultry, said Dr Carol CardonaVeterinary and avian influenza researcher at the University of Minnesota.
This is not the only financial incitement to mass slaughter. The American Department of Agriculture Refund farmers For eggs and birds that must be killed to contain an epidemic, but not for birds that die from flu.
However, sometimes it meant kill more than 4.2 million birdsmost of which may have been healthy.
Bill Mattos, president of the Poultry Federation in Californiasaid that a more targeted approach could be possible when not all birds live under the same roof. In California, for example, farms that raise chickens of flesh generally use several autonomous buildings with ventilation systems, separate entries and outputs.
Biosecurity measures like these can prevent pathogens from spreading between the barns, said Cardona. The risks could be reduced more by forcing workers to change their clothes and their boots when they move from barn to the barn, or by affecting workers to a single barn, she said.
But others, including Dr. John Korslund, veterinarian and former USDA researcher, are skeptical about the function of such a practice, given the virulence of H5N1.
“Chickens are infected and lose the virus very early, often before visible evidence of clinical disease,” said Korslund. “There is a good chance that” healthy “buildings on infected premises can actually be in reality in the first stages of infections incubation.”
Although it is possible, some buildings could remain without viruses and some birds could be recovered, the drawbacks of this approach are huge, Korsland said. “Many additional viruses will be put in the environment,” he said.
Indeed, the influenza particles of an installation can escape the exhaust fans and browse great distances, known as Michael OsterholmDirector of the Center for Infectious Disease Research and Policy at the University of Minnesota. Studies have shown that “the farm virus movement was associated with wind management and speed,” he said.
Bird flu vaccines can offer some protection. China and France use them, and the USDA has granted a conditional license this month for an H5N2 vaccine designed for chickens, According to Zoetisthe company that developed it.
While some announce vaccines as a potential tool to inoculate the country's poultry farms, others say that costs could be too much.
Most American trade partners do not want to import poultry products from countries that will vaccinate their birds due to fear that the shots can hide the presence of the virus. And most will be fully infected, even if only one region or type of poultry is infected.
The United States exports more than 6.7 billion pounds of chicken meat Each year, Second just against BrazilAccording to the National Chicken Council. So as long as foreign buyers are resisting vaccination, the gunshots will probably not be deployed even if the laying hens are wiped out by the virus.
As members of the US Congress and the Caucus Senate of Chicken written in a letter This month at the USDA, “if a layer of eggs in Michigan is vaccinated for HPAI, the United States could probably not export a non-vaccinated Mississippi chicken.”
The new H5N2 vaccine could appease these concerns. Although it would offer H5N1 protection, this would cause antibodies that seem distinct from those resulting from a real infection, said Cardona.
Pitesky said that none of these measures will work if we do not do a better job with the surveillance of the flu and the agricultural placement.
Officials of fauna and agriculture should increase their tests on wild birds to determine where the virus moves and how it evolves, he said. This will require global coordination because infected birds can travel between the United States, Canada, Russia, East Asia and Europe.
Poultry farms near ponds, lagoons or wetlands that attract wild birds should be on a high alert during the migration season, Pitesky said. Farmers must use applications such as Ebird,, Bird or the Wildlife Alert Alert Network To keep an eye on the moment when birds are nearby so that they can intensify their biosecurity measures if necessary, he said.
It may be possible to attract wild birds far from agricultural facilities by strengthening wetlands in more remote regions, he said.
“I continue to push the idea of starting to flock some of these wetlands, but we have not done so strategically,” said Pitesky.
The idea has meaning, but has been pushed back like “a pie in the sky, on which I repel,” he said. “I am like, what we are doing right now does not work obviously.”
