Virus found could rewrite smallpox history

The discovery of smallpox DNA in a 17th century child mummy may shorten the timeline of the deadly infectious disease's history, according to a study published on Thursday.

Specimens of the smallpox-causing variola virus now exist only in secured laboratory freezers. The highly contagious and sometimes fatal disease was finally eradicated in the late 1970s through a worldwide vaccination campaign.

But the origins of the virus remain unknown.