Evidence shows that there is a negative correlation between transmission and virulence, where the more virulent a virus is the less it spreads. I believe this i

Evidence shows that there is a negative correlation between transmission and virulence, where the more virulent a virus is the less it spreads. I believe this is at least partially due to the fact that if it kills the host, it can't spread as far as if the host lives and keeps spreading. However, I believe that correlation is over the long run, and that there is plenty of evidence towards diseases that both spread easily and are deadly in the short run (smallpox, cholera, etc). Selection pressures seem to push viruses to be less deadly over time, but that's just it: over time. Cholera is an interesting example of this because it relied on the fecal transmission route, where it would easily spread through tainted water. It didn't matter all that much if the hosts died, as long as it got into the water supply.