Smallpox (also known by the Latin names Variola or Variola vera) is a very contagious and deadly disease in humans caused by a virus. It is estimated that smallpox is 20-60% fatal, while many survivors are left blind and scars from smallpox are nearly universal. Smallpox was responsible for an estimated 300-500 million deaths in the 20th century, and as recently as 1967, the World Health Organization (WHO) estimated that 15 million people contracted the disease and that two million died in that year.

After successful vaccination campaigns, the WHO in 1980 declared the eradication of smallpox, though cultures of the virus are kept by the Centers for Disease Control and Russian authorities. In the 1970s, most nations discontinued smallpox vaccination because such vaccinations have a small possibility (1 case in one million) of serious or even fatal side effects. Nonetheless, after the 2001 anthrax attacks took place in the United States, concerns about smallpox have resurfaced as a possible agent for bioterrorism. As a result, there has been increased concern about the availability of vaccine stocks. Moreover, President of the United States George W. Bush has ordered all military personnel to be vaccinated against smallpox and has implemented a voluntary program for vaccinating emergency medical personnel who would likely be the first people to respond in case of a bioterrorist attack.

Famous victims who died from the disease include Mary II of England, Louis XV of France and Peter II of Russia. Henry VIII's fourth wife, Anne of Cleves, survived the disease but was scarred by it.

Smallpox victim

After first contacts with Europeans, the death of a large part of the native population of the New World was caused by European-transmitted diseases. Smallpox was the chief culprit. On at least one occasion, germ warfare using smallpox infected blankets was used against Native Americans by the British army.

Smallpox is described in the Ayurveda books. Treatment was done by inoculation with year-old smallpox matter. The inoculators would travel all across India pricking the skin of the arm with a small metal instrument using "variolous matter" taken from pustules produced by the previous year's inoculations. The effectiveness of this system was confirmed by the British doctor J.Z. Holwell in an account to the College of Physicians in London in 1767.

In 1796, Edward Jenner developed a smallpox vaccine by using cowpox fluid. After independent confirmation, this practice of vaccination against smallpox spread quickly in Europe and national laws requiring vaccination began appearing as soon as 1805. The last case of wild smallpox occurred on September 11, 1977. One last victim was claimed by the disease in the UK in September 1978, when Janet Parker, a photographer in the University of Birmingham Medical School, contracted the disease and died. There was a research project working on smallpox in the building at the time, though the exact route by which Ms. Parker became infected was never fully elucidated.