Bird flu: it would take a single mutation…

Just out from Science, an article (“A single mutation in bovine influenza H5N1 hemagglutinin switches specificity to human receptors“) demonstrating how very easy it would be for H5N1 to become a deadly human pandemic.

Here’s the editor’s summary, which tells you everything you need to know:

In 2021, a highly pathogenic influenza H5N1 clade 2.3.4.4b virus was detected in North America that is capable of infecting a diversity of avian species, marine mammals, and humans. In 2024, clade 2.3.4.4b virus spread widely in dairy cattle in the US, causing a few mild human cases, but retaining specificity for avian receptors. Historically, this virus has caused up to 30% fatality in humans, so Lin et al. performed a genetic and structural analysis of the mutations necessary to fully switch host receptor recognition. A single glutamic acid to leucine mutation at residue 226 of the virus hemagglutinin was sufficient to enact the change from avian to human specificity. In nature, the occurrence of this single mutation could be an indicator of human pandemic risk. 

Add that to news, less than an hour ago, of a 7.0 magnitude earthquake off the coast of Northern California, and its aftershock (not to mention tsunami warning), and today isn’t feeling too sparkly.

Stay safe out there.