The smallpox came in the mail, in a little piece of 350-year-old human skin. And the surprise discovery is dramatically rewriting the history of one of the most notorious diseases to plague humankind.

In the 20th century alone, an estimated 500 million lives succumbed to smallpox, making it the sole human disease to have been eradicated. However, a new report, the Future State of Smallpox ...

Of all the diseases ever suffered by humans, smallpox is the only one to be completely eradicated from the face of the Earth. The few known remaining samples are under heavy guard in research labs ...