and delaware between may 1763 and april 1764, reported to captain william grant of the 42nd regiment "that the small pox has been very general & raging amongst the indians since last spring and that 30 or 40 mingoes, as many delawares and some shawneese died all of the small pox since that time, that it still continues amongst them". in the mid to late nineteenth century, at a time of increasing european-american travel and settlement in the west, at least four different epidemics broke out among the plains tribes between 1837 and 1870. when the plains tribes began to learn of the "white man's diseases", many intentionally avoided contact with them and their trade goods. but the lure of trade goods such as metal pots, skillets, and knives sometimes proved too strong. the indians traded with the white newcomers anyway and inadvertently spread disease to their villages. in the late 19th century, the lakota indians of the plains called the disease the "rotting face sickness". the 1862 pacific northwest smallpox epidemic, which was brought from san francisco to victoria, devastated the indigenous peoples of the pacific northwest coast, with a death rate of over 50% for the entire coast from puget sound to southeast alaska. in some areas the native population fell by as much as 90%. some historians have described the epidemic as a deliberate genocide because the colony of vancouver island and the colony of british columbia could have prevented the epidemic but chose not to, and in some ways facilitated it. effect on population numbers graph of population decline in central mexico caused by successive epidemics