Smallpox also had a big impact on surplus and population. Smallpox's impact on population was enormous, because it was easily spread and could kill more than half of a civilization at times. Since there was massive decrease in population, they didn't have enough people to create a surplus. Of course, this was an advantage for the Europeans because they were immune and could have a lot of food and not be starving. The European population was growing while the American population was dicreasing rapidly.