A previously unseen strain of bird flu has been identified in U.S. dairy cattle, marking the first time this variant has been found in cows, according to the latest reports from agricultural health authorities.
Until now, all 957 bird flu cases detected among dairy herds this year were linked to a single strain. However, recent genome sequencing of milk samples in Nevada has confirmed the presence of a different strain, raising concerns among experts.
The newly detected strain was the predominant genotype found in wild birds over the past fall and winter. Officials identified it through a national milk testing program launched in December to monitor bird flu in dairy cattle.
Nevada’s agricultural department recently quarantined herds in two counties following bird flu detections. Although specific details about the strain were not initially disclosed, this discovery underscores the ongoing risks associated with virus transmission between wildlife and livestock.
So far, nearly 70 people, mostly farmworkers, have contracted bird flu in the U.S. since April. The virus has also devastated poultry farms, leading to the deaths of millions of egg-laying hens and pushing egg prices to record levels.
Experts stress the importance of containing the outbreak swiftly to prevent further spread. Previous cases showed that infected cattle transported across state lines contributed to the virus’s rapid transmission. New regulations now require lactating dairy cattle to undergo bird flu testing before interstate movement.
Veterinary specialists warn that cattle previously exposed to the earlier strain may not have immunity against this newly identified variant, making biosecurity measures even more critical.
