<P> During the Seven Years' War, British militia took blankets from their smallpox hospital and gave them as gifts to two neutral Lenape Indian dignitaries during a peace settlement negotiation, according to the entry in the Captain's ledger, "To convey the Smallpox to the Indians". In the following weeks, the high commander of the British forces in North America conspired with his Colonel to "Extirpate this Execreble Race" of Native Americans, writing, "Could it not be contrived to send the small pox among the disaffected tribes of Indians? We must on this occasion use every stratagem in our power to reduce them ." His Colonel agreed to try . On the deliberate communication of smallpox to Native Americans during the 1836--40 epidemic, historian Ann F. Ramenofsky in 1987 wrote, "Variola Major can be transmitted through contaminated articles such as clothing or blankets . In the nineteenth century, the U.S. Army sent contaminated blankets to Native Americans, especially Plains groups, to control the Indian problem ." While specific responsibility for the 1836--40 smallpox epidemic remains in question, scholars have asserted that the Great Plains epidemic was "started among the tribes of the upper Missouri River by failure to quarantine steam boats on the river", and Captain Pratt of the St. Peter "was guilty of contributing to the deaths of thousands of innocent people . The law calls his offense criminal negligence . Yet in light of all the deaths, the almost complete annihilation of the Mandans, and the terrible suffering the region endured, the label criminal negligence is benign, hardly befitting an action that had such horrendous consequences ." Well into the 20th century, deliberate infection attacks continued as Brazilian settlers and miners transported infections intentionally to the native groups whose lands they coveted ." </P> <P> After Edward Jenner's 1796 demonstration that the smallpox vaccination worked, the technique became better known and smallpox became less deadly in the United States and elsewhere . Many colonists and natives were vaccinated, although, in some cases, officials tried to vaccinate natives only to discover that the disease was too widespread to stop . At other times, trade demands led to broken quarantines . In other cases, natives refused vaccination because of suspicion of whites . The first international healthcare expedition in history was the Balmis expedition which had the aim of vaccinating indigenous peoples against smallpox all along the Spanish Empire in 1803 . In 1831, government officials vaccinated the Yankton Sioux at Sioux Agency . The Santee Sioux refused vaccination and many died . </P> <P> While epidemic disease was a leading factor of the population decline of the American indigenous peoples after 1492, there were other contributing factors, all of them related to European contact and colonization . One of these factors was warfare . According to demographer Russell Thornton, although many lives were lost in wars over the centuries, and war sometimes contributed to the near extinction of certain tribes, warfare and death by other violent means was a comparatively minor cause of overall native population decline . </P> <P> From the U.S. Bureau of the Census in 1894: "The Indian wars under the government of the United States have been more than 40 in number . They have cost the lives of about 19,000 white men, women and children, including those killed in individual combats, and the lives of about 30,000 Indians . The actual number of killed and wounded Indians must be very much higher than the given...Fifty percent additional would be a safe estimate ..." </P>

Many native american died after the spanish invasion because of