By and large, disease had the greatest impact in catastrophically reducing Indian populations while allowing a relatively small number of Spaniards to not only conquor but dominate empires of millions. What were some of the main diseases that the Spaniards (and later African slaves) brought with them and what explains the indigenous peoples inability to resist these diseases?

By and large, disease had the greatest impact in catastrophically reducing Indian populations while allowing a relatively small number of Spaniards to not only conquor but dominate empires of millions. What were some of the main diseases that the Spaniards (and later African slaves) brought with them and what explains the indigenous peoples inability to resist these diseases?