The pattern of European colonization resulted in the introduction of diseases into the colonized territories to which there was no natural resistance among the indigenous populations. The Europeans brought with them smallpox, influenza, cholera, tuberculosis, plague, malaria, and typhus, among other illnesses. Even such minor ailments as measles and chickenpox proved fatal and killed millions of American Indians. During the first century of European contact with the Americas, the indigenous populations were assaulted by a succession of major epidemics which killed 50 to 90% of their populations. Several of these epidemics were intentionally spread by Europeans (for example, in the case of the British, by the deliberate donation to Indians of infected blankets from a smallpox hospital). In less than a century, all the tribal peoples of the West Indies had been exterminated.
The process has continued through the 1980s in the case of isolated tribes in the Amazon basin, especially where the land is coveted for agricultural or mining purposes. Those of European origin are still intentionally introducing killer microbes to breakdown local resistance to seizure of indigenous lands.