Since it first arose, H5N1 has been identified in a range of species including mink, dolphins, grizzly bears, foxes, and a polar bear.
It’s been especially devastating for marine mammals; in Argentina, bird flu killed 17,400 southern elephant seal pups, roughly 96 percent of all young born in 2023, researchers estimated.
Maybe I am missing something but assertion that the current public health risk is low seems to be based on more or less nothing. Why is the risk low? People are still working among animals some of whom are definitely infected, every day, in messy conditions. The consequences once it figures out how to spread person-to-person will be somewhere from moderate to apocalyptic, and what we're doing right now is clearly just half-measures to delay that happening by a little bit. Why is that low risk?
What matters more for public health risk is virility, and mortality tends to have a negative correlation with virility. In simpler terms, the more deadly it is the worse it is at spreading. It's not a hard rule but is true more often than not, though I don't know any details about avian flu. I assume if the CDC has determined the public health risk is low that it's probably because it's not particularly virile.
Do you mean transmissibility? I get what you mean, but I've never heard this word used this way. (Virulence is, more or less, the non-fatal version of mortality -- how much damage the disease does -- so not that.)
Be that as it may, once the disease is established in a new species it tends to get less harmful because of exactly what you're talking about -- but plenty of diseases through history have been in the short run both fast-spreading and deadly, especially right after they jump into a new population. Which is exactly what H5N1 is doing right now (on all three counts).
The risk is low because we have not yet detected a variant with the mutations needed to facilitate human to human spread. If we do it will jump from low to extreme very quickly.
"It is okay! The fire is only in the building next door along with the 10-15 others it spread to. Once we've detected it in our building, the risk won't be low anymore, of course."
(Edit: Actually, once it's spreading inside our building the risk won't be low -- we've already detected it in our building a couple of times, but it didn't spread so it's fine.)
I am going to assume you don't really understand what it would mean if there was a pandemic with a 10-50% case fatality rate in the modern global economy where it would be on every single continent on earth in a matter of days. I can assure you that housing prices would be the last fucking thing on your mind.