[SauronOfMordor]

"Also, it's important to remember that a disease acts differently when it's first introduced to a population " -- Can you expand on that?

After a few generations of exposure, the only survivors are those who have some degree of immunity to the disease.

[Gladwin]

After a few generations of exposure, the only survivors are those who have some degree of immunity to the disease.

Hmm, then the symptoms would be different?