Last week, the United States Department of Agriculture reported that a pig on a backyard farm in Oregon had been infected with the bird flu. This marks a concerning new development in the ongoing situation with the A/H5N1 strain of bird flu, which has already been known to infect a wide range of animals, including birds, wild animals, and dairy cattle. While there has been no sustained human-to-human transmission of the virus thus far, the detection of A/H5N1 in a pig raises new alarms about the virus’s potential spread and evolution.
How did we get here?
The primary strain of concern is clade 2.3.4.4b of A/H5N1, a subtype of influenza A. This variant has been circulating globally since 2020 and has rapidly spread across a broad spectrum of animal species—many of which, such as dairy cattle, have never previously been infected with bird flu. While Europe has been a hotspot for the spread of A/H5N1, the focus has recently shifted to the United States, where the virus has had a significant impact.
In 2024, the virus made its first appearance in US dairy cattle, infecting over 400 herds across at least 14 states. This spread to farm animals, alongside infections in wild birds and other species, further complicates the situation and raises concerns about potential long-term impacts on animal health and agricultural industries.
EDITED by:
“KORÇA BOOM”
