1980 – The World Health Organization confirms the eradication of smallpox. Smallpox was an infectious disease caused by variola virus (often called smallpox virus), which belongs to the genus Orthopoxvirus. The date of the appearance of smallpox is not settled. It most probably evolved from a terrestrial African rodent virus between 68,000 and 16,000 years ago. The earliest evidence of the disease dates to around 1500 BC in Egyptian mummies. The disease historically occurred in outbreaks. In 18th-century Europe, it is estimated that 400,000 people died from the disease per year, and that one-third of all cases of blindness were due to smallpox. Smallpox is estimated to have killed up to 300 million people in the 20th century and around 500 million people in the last 100 years of its existence. Earlier deaths included six European monarchs, including Louis XV of France in 1774. As recently as 1967, 15 million cases occurred a year. The last naturally occurring case was diagnosed in October 1977, and the World Health Organization (WHO) certified the global eradication of the disease in 1980, making smallpox the only human disease to have been eradicated to date.