Mid-week California Dairy B3.13 Mutation Bulletin
H5N1 2.3.4.4b B3.13 PB2 E627K now circulating in CA dairy herds
USDA uploaded new dairy sequences to GISAID yesterday which drew immediate attention from Henry Niman, a veteran evolutionary microbiologist, and Susanne Rust, a top-notch LA Times reporter. The 4 accessions all contained PB2 E627K mutations, not seen since since last March in a Texas human spillover:
H5N1 mutation detected in U.S. dairy herds prompts caution on pandemic potential
SACRAMENTO, the United States, March 12 (Xinhua) -- Scientists are sounding the alarm about a concerning genetic mutation of the H5N1 bird flu virus, recently identified in four dairy cow herds, as this mutation could increase the risk of mammal-to-mammal transmission and disease severity.
The mutation, known as PB2 E627K, was detected in sequence data uploaded by the U.S. Department of Agriculture (USDA) on Tuesday, according to evolutionary molecular biologist Henry Niman, whose findings were reported by the Los Angeles Times.
“That is the mutation found in the first human case, which was extremely pathogenic in ferrets," Yoshihiro Kawaoka, an infectious disease expert at the University of Wisconsin-Madison and the University of Tokyo, told the Los Angeles Times. "Finding the same mutation in cows is significant.”
The mutation was previously seen in a Texas dairy worker last March but was not detected again until the latest sequences were uploaded to the Global Initiative on Sharing All Influenza Data (GISAID), a Germany-based public genetic repository.
Time will tell whether the mutation has convergent staying power in cattle and whether it will bring enhanced onward transmission or enhanced pathogenicity risks to other mammals, expecially humans.
Regardless, this development points out the continuing risks for allowing ongoing circulation of influenza viruses. Over time newly adapted avian influenza viruses “converge” toward genetic makeups that optimize circulation in mammals. It’s a fascinating process to watch, but it will have real consequences at some point.
John