The global transfer of disease in the pre-modern world helped in the colonization of the Americas because the native American Indians were not immune to the diseases that the settlers and colonizers brought with them. The Europeans were more or less immune to small pox, but the native Americans, having been cut off from the rest of the world for millions of years, had no defense against it. These germs killed and wiped out whole communities, paving the way for foreign domination. Weapons and soldiers could be destroyed or captured, but diseases could not be fought against.

(i) By the mid-sixteenth century, Europe defeated America not with military power but just with the germ of smallpox they brought with them.

(ii) America had been cut off from regular contact with the rest of the world for millions of years, they had no immunity against these diseases that came from Europe.

(iii) Smallpox proved to be a deadly killer for them. It spread deep into the continent, killed and devastated the whole community, thus paving the way for European conquest.