On July 7, the U.S. Centers for Disease Control (CDC) ended its emergency response to the bird flu (H5N1) outbreak. “The rationale is, in short, there haven’t been any human cases,” said Nirav Shah, former CDC deputy director. Since the current bird flu outbreak began in 2022, there have been only 70 human cases and only one human death, and there are currently no known human cases.
The CDC’s acknowledgement that bird flu is not a major concern for human health at this time is bad news for the pharmaceutical industry. Just a few weeks earlier, on May 28, the U.S. Department of Health and Human Services (HHS) canceled a $590 million contract with Moderna to develop an H5N1 vaccine for humans. Since the current strain of bird flu has been around for over three years and doesn’t spread from one human to another, there is little justification for a vaccine.
For poultry, however, highly pathogenic avian influenza (HPAI) is still a death sentence. The USDA HPAI emergency response policy, which has been in effect since April 2022, requires owners of infected flocks to “stamp out” the disease by “depopulating” their flocks, which means killing all of the birds, even those with no symptoms, and composting them in giant piles. Since April 2022, over 170 million birds have been depopulated because of positive HPAI tests.
The US Animal and Plant Health Inspection Service (APHIS) justifies depopulation by saying that HPAI “often causes mortality and morbidity rates in domestic poultry between 90-100 percent.” Also, international trade agreements require depopulation in flocks whose eggs or meat will be exported to other countries. But since it’s impossible to completely eradicate the virus, there seems to be no end in sight with this zero-tolerance policy.
The real culprits, USDA says, are migrating wild birds who continue to spread the virus to new areas. But if the wild birds are healthy enough to migrate even if they’re carrying the flu, is it possible for closely related domestic birds to develop immunity to HPAI as well? A 2014 study in Nigeria found that, even in domestic poultry, HPAI wasn’t always fatal. Egg layers had only an 11.11 percent mortality rate, while broilers had a 73.95 percent mortality rate. This shows that there is a marked difference in susceptibility between different breeds of chickens, suggesting that it might be possible to control (but not eradicate) HPAI with a combination of breeding and better, more natural poultry management practices.
As long as current policies and international trade agreements remain in effect, depopulation will continue. But it’s interesting from an eco-ag perspective to speculate on what might be possible if the focus was on designing more natural housing and production systems that could keep poultry healthy even when exposed to a pathogen, rather than continuing to spend millions of dollars on futile efforts to keep them away from a ubiquitous virus.
