History of smallpox In the late 1770s, during the American Revolutionary War, smallpox returned once more and killed thousands. Peter Kalm in his "Travels in North America", described how in that period, the dying Indian villages became overrun with wolves feasting on the corpses and weakened survivors. Smallpox was also used as a weapon by the British. In 1799, the physician Valentine Seaman administered the first smallpox vaccine in the United States. He gave his children a smallpox vaccination using a serum acquired from Edward Jenner, the British physician who invented the vaccine from fluid taken from cowpox lesions. Though vaccines were misunderstood
Smallpox short duration of the infectious stage. In temperate areas, the number of smallpox infections was highest during the winter and spring. In tropical areas, seasonal variation was less evident and the disease was present throughout the year. Age distribution of smallpox infections depended on acquired immunity. Vaccination immunity declined over time and was probably lost within thirty years. Smallpox was not known to be transmitted by insects or animals and there was no asymptomatic carrier state. The clinical definition of smallpox is an illness with acute onset of fever equal to or greater than followed by a rash characterized by