Though no longer regarded as a threat, smallpox has killed millions in the past. Smallpox is an acute, highly contagious disease causing a high fever and successive stages of severe skin eruptions. The disease dates from the time of ancient Egypt or before. It has occurred worldwide in epidemics throughout history, killing up to 40% of those who contracted it and accounting for more deaths over time than any other infectious disease. Spreading to the New World with European colonization, it killed huge numbers of the indigenous people, who had no immunity, greatly contributing to the annihilation of native cultures.

Smallpox is caused by a virus that may be airborne or through direct contact with the infected. There is no specific treatment for smallpox. An antibiotic may be administered to prevent secondary bacterial infection. After 1980, WHO officially declared that smallpox has been eradicated as a disease.

Outbreak history

	Eurasia
-	430BC: The Plague of Athens decimated the city of Athens, killing around a third of the population, according to Thucydides.
-	165-180: The Antonine Plague swept through the Roman Empire and Italy. This was followed by a second major outbreak in the Empire, known as the Plague of Cyprian (251–266)
-	The next major epidemic believed to be smallpox occurred in India. The exact date is unknown. Around 400

	The America
-	1500s: Smallpox devastated the Aztec population. It killed most of the Aztec army, the emperor, and 25% of the overall population
-	1500s: Smallpox spread rapidly in the Inca empire and within a few years smallpox claimed between 60% and 90% of the Inca population
-	1633: Plymouth, Massachusetts, the Native Americans were struck by the virus and it wiped out the entire population groups of Native Americans. It reached Lake Ontario in 1636 and the lands of the Iroquois by 1679, killing millions.
-	1636-1698: 6 outbreaks occurred in Boston
-	1721: Boston, The entire population fled the city, bringing the virus to the rest of the 13 colonies.
-	Late 1770s: During the American Revolutionary War, smallpox returned once more and killed an estimated 125,000 people