USA HISTORY

Detailed explanation-1: -European settlers brought these new diseases with them when they settled, and the illnesses decimated the Native Americans-by some estimates killing as much as 90 percent of their population.

Detailed explanation-2: -When the Europeans arrived, carrying germs which thrived in dense, semi-urban populations, the indigenous people of the Americas were effectively doomed. They had never experienced smallpox, measles or flu before, and the viruses tore through the continent, killing an estimated 90% of Native Americans.

Detailed explanation-3: -In addition to deliberate killings and wars, Native Americans died in massive numbers from infections endemic among Europeans. Much of this was associated with respiratory tract infections, including smallpox, tuberculosis, measles, and influenza (1, 2).

Detailed explanation-4: -Smallpox was the disease brought by Europeans that was most destructive to the Native Americans, both in terms of morbidity and mortality. The first well-documented smallpox epidemic in the Americas began in Hispaniola in late 1518 and soon spread to Mexico.

Detailed explanation-5: -Along with measles, influenza, chickenpox, bubonic plague, typhus, scarlet fever, pneumonia and malaria, smallpox spelled disaster for Native Americans, who lacked immunity to such diseases.