And whereas many geese and geese appear to have the ability to survive being contaminated with the virus, different chicken species are way more susceptible. H5N1 is very lethal for chickens, for instance—their heads swell, they wrestle to breathe, they usually expertise excessive diarrhea. Seabirds like puffins and guillemots additionally appear to be particularly inclined to the virus, though it’s not clear why. Over the previous couple of years, we’ve seen the worst ever outbreak of chicken flu in birds. Tens of millions of farmed birds have died, and an unknown variety of wild birds—within the tens of 1000’s on the very least—have additionally succumbed. “We don’t know what number of simply fell into the ocean and had been by no means seen once more,” says Peacock.
Alarmingly, animals that hunt and scavenge affected birds have additionally change into contaminated with the virus. The record of affected mammals contains bears, foxes, skunks, otters, dolphins, whales, sea lions, and lots of extra. A few of these animals seem to have the ability to go the virus to different members of their species. In 2022, an outbreak of H5N1 in sea lions that began in Chile unfold to Argentina and ultimately to Uruguay and Brazil. A minimum of 30,000 died. The ocean lions may additionally have handed the virus to close by elephant seals in Argentina, round 17,000 of which have succumbed to the virus.
That is unhealthy information—not only for the affected animals, however for folks, too. It’s not only a chicken flu anymore. And when a virus can unfold in different mammals, it’s a step nearer to having the ability to unfold in people. That’s much more probably when the virus spreads in an animal that folks have a tendency to spend so much of time interacting with.
That is partly why the virus’s unfold in dairy cattle is so troubling. The type of the virus that’s spreading in cows is barely completely different from the one which had been circulating in migrating birds, says Lakdawala. The mutations on this virus have probably enabled it to unfold extra simply among the many animals.
Proof means that the virus is spreading by means of the usage of shared milking equipment inside cattle herds. Contaminated milk can contaminate the tools, permitting the virus to contaminate the udder of one other cow. The virus can be spreading between herds, presumably by hitching a experience on people who work on a number of farms, or by way of different animals, or probably by way of airborne droplets.