Local Diseases

[Mediolanicus]

Thanks for the responses guys. I understand that the situation with the diseases in Eurasia was totaly different from that in the Americas during the european colonization.
Let my ask a (slightly) different question now: What about the various toxins and parasites found in food and water. For example, tha natives of one land might be used in consuming a species of mushroom or some certain root, but for a foreigner it could be lethal. Same goes for the water.
I guess such things cannot be clasified as "diseases", for they are not transmittable, and immunity can be acquired only by generations-long consuming of that toxin.
Any thoughts on that?

(Of course, that would have lethal results for the first couple of waves of foreign soldiers, since they would learn to avoid some certain igredients after a while)

Also, my knowledge of biology is (obviously) not the best. :P Let me know if the things I'm saying are wrong.

Back then, everyone would have been used to eating and drinking slightely contaminated water.

So, that was not as much a problem as you have now when say a Western European starts drinking non-bottled water in India.