AFAIK is also isn't super contagious, less opportunity for it to evolve

It’s super contagious in the reservoir species. But it’s not in humans. The point made above was about age if the pathogen not infectiousness.

But it isn't very lethal in that species, is it? In the species that it spreads rapidly in, it likely won't be very lethal which was the point

How many humans get rabies per year versus how many that get influenza?

I’m not sure that’s relevant? I didn’t see anything stated about rates of infection. Absolutely if influenza were as fatal as rabies we would be extinct. But we also wouldn’t be posting on hacker news about it either. The statement was about longevity of the pathogen and fatality.

> Absolutely if influenza were as fatal as rabies we would be extinct.

The chance that it would evolve to be as infectious would be greatly reduced. They teach this in first semester immunology.

Not necessarily. What would be reduced is the likelihood of showing any symptoms while still being infectious.

I don’t see why you think that’s true - if infections are latent long enough to spread and it’s virulent enough, with a fatal outcome, it could rapidly wipe out most people. There’s no reason to believe a viral infection that mutates from an animal infection to human wouldn’t be both easily transmitted and highly lethal. It’s not a great evolutionary adaptation for the long term, but transitory effects can often be sub optimal and catastrophic.

COVID is a perfect example. It could easily have been significantly more lethal and it was very infectious in its first blush with humanity. What process other than luck prevented it from being both highly lethal and highly contagious rather than moderately lethal and highly contagious?

If you have a reference to a first semester immunology text that supports this supposition I’m very interested to read the justification. Otherwise this feels like a big of an appeal to authority.

Is not really designed for surviving outside. Very long filaments are fragile out of vascular systems.

Viruses like rabies are interesting because they are actually not as serious in the species they evolved to infect; just turns out they rapidly kill some other species (us) that they don’t care about.

Make no mistake, rabies virus also has multiple immune evading mechanisms that are unluckily supercharged in humans.

Yeah I expect that’s the case - the bubonic plague spread via the reservoir fleas and rats, etc.

That may actually have not been the case: https://theconversation.com/the-black-death-may-not-have-bee...

Sounds a little like funnel web spider venom - just an evolutionary accident it's so potent to humans, at no evolutionary drawback for its main role.

Thought rabies usually killed dogs?

https://www.cdc.gov/mmwr/volumes/68/wr/mm6823e1.htm#:~:text=....

CDC says it kills 99% regardless.

Why would it evolve this way?

I doubt that rabies has evolutionary developed to target dogs. It’s just a “happy” accident that dogs are so plentiful and can infect many other animals (until recently at least).

If I had to guess I’d say rabies had evolutionarily targeted species that today are largely asymptomatic and can easily survive a rabies infection, like bats or birds.

Rabies most probably evolved from a virus from plants so is very "alien" to animals. As long as can hide in their main host, it does not care about killing everybody else (if accidentally ends in the wrong place). This can be also and advantage and selected by evolution in some cases ("enemy of my host is my enemy" situations).

Tuberculosis is likewise at least 5000 years old, and kills around 50% of those infected.

>Roughly one-quarter of the world's population has been infected with M. tuberculosis, with new infections occurring in about 1% of the population each year. However, most infections with M. tuberculosis do not cause disease, and 90–95% of infections remain asymptomatic.

https://en.wikipedia.org/wiki/Tuberculosis#Epidemiology

5000 years is literally a blip in evolutionary timescales.

Is that an imperial or metric blip?