Don't bat immune systems work like this? Except they end up in equilibrium instead of eliminating the viruses, which is why it's so dangerous to come into contact with them.

I think almost everyone would avoid this if it meant you became deadly to your dog or cat.

Fascinating. Looks like you’re right. However, disease and other stressors can disrupt that equilibrium.

https://news.usask.ca/articles/research/2020/bat-super-immun...

Which means bats are the Mr Burns of the animal kingdom.

https://www.youtube.com/watch?v=aI0euMFAWF8

Next up: scientists are creating the everything vaccine for dogs and cats.