Bird flu, aka highly pathogenic avian influenza (HPAI), is making an appearance already this fall with several cases now confirmed on several Midwest and Mid-Atlantic. The risks of the disease are heightened now as migratory birds make their way south, a danger that will likely repeat in the spring when they head back north.
The current “H5N1” subtype outbreak is considered the worst animal disease event in US history. The outbreak started in 2022 and has resulted in the loss of some 60 million poultry birds in the US alone. An unknown number of wild birds have been killed by the virus as well, likely in the tens of millions. In 2022, the virus also caused outbreaks among various wild mammals, farmed mink, and several different marine mammals. This year’s fall resurgence has so far caused 41 new infections in both commercial and backyard flocks in 14 states in just the last 30 days, including multiple commercial turkey facilities in Iowa, Minnesota, South Dakota, and Utah.
Researchers say the H5N1 has become increasingly infectious since first emerging in Europe in 2020. It actually evolved from an earlier strain called H5N8 that was first detected in Egypt around 2016. According to the latest research, the new H5N1 virus mutated through interactions with non-deadly varieties of bird flu, known as low-pathogenic avian influenza (LPAI) viruses, that had been circulating among wild birds in Europe.
Unfortunately, H5N1 is so widespread in wild birds now that scientists think there is little chance of eradicating the disease. Bird flu is believed to be endemic in certain migratory birds in the US now with the virus spreading through all North American flyways, making it impossible to control.
As most poultry producers are well aware, the best defense is to implement strong biosecurity measures. And for those that already have a biosecurity strategy, experts recommend regular reviews to be sure everyone involved in the operation is aware of and is following the preventative measures. The USDA’s “Defend the Flock” campaign has multiple resources available HERE.
Some countries are currently exploring bird flu vaccinations to control the disease and help limit farmer losses. That’s not something that will likely be available to US producers anytime soon, however, as the industry is worried about the impact to poultry exports. Researchers with the USDA’s Agricultural Research Service (ARS) started testing four vaccine candidates earlier this year but officials have maintained that biosecurity prevention remains the best defense.
Another solution that researchers are exploring is gene-editing to create chickens resistant to HPAI. A recent study suggests genetic engineering could reduce the toll of bird flu, though so far this has proven to be pretty limited. The scientists found that breakthrough infections still occurred, especially when birds were exposed to high doses of the virus. What’s more, when the scientists edited just one gene, the virus quickly mutated to adapt, suggesting more than one gene would need to be tweaked. However, experts not involved in the study say it is highly unlikely that genetically engineered birds are the answer because the virus replicates, mutates, and adapts so quickly. (Sources: USDA, WOAH, Poultry World, The New York Times, Reuters)
