INFECTIOUS DISEASE: DNA From 17th Century Mummy Of A Child From Lithuania May Rewrite History Of Smallpox.

The researchers captured, sequenced, and completely reconstructed the smallpox DNA and then compared the strain to those from modern samples dating between 1940 and 1977, when the last known case of the disease occurred in Somalia.

The findings showed that the evolution of the smallpox virus happened more recently than previously believed and that the ancestor of all available smallpox viral strains were no older than 1580 albeit it is not yet clear what animal is the true reservoir of the pathogen and when the virus first jumped from animals to humans.

The researchers, who published their findings in the journal Current Biology on Dec. 8, also found that the evolution of the pathogen into two circulating strains, the variola major and minor, occurred after 1796, after scientist Edward Jenner came up with a vaccine.

“Our data clearly show that the VARV lineages eradicated during the 20th century had only been in existence for ∼200 years, at a time of rapidly expanding human movement and population size in the face of increasingly widespread inoculation and vaccination,” the researchers wrote in their study.

It’s a little unsettling that something so deadly and virulent could erupt so suddenly.