Ancient DNA suggests Vikings may have been plagued by smallpox
Some Vikings may have died from now-extinct strains of one of humankind’s deadliest pathogens: smallpox. Researchers collected DNA from viruses in the remains of northern Europeans living during the Viking Age, some of whom were likely Vikings themselves, and found that they were infected with extinct but related versions of the variola virus that causes smallpox, the team reports in the July 24 Science. The new finding pushes back the proven record of smallpox infecting people by almost 1,000 years, to the year 603. Researchers had previously discovered ancient traces of variola virus DNA in a mummy from the mid-1600s, which put the common origin of modern strains in the 16th or 17th century (SN: 12/8/16). It is still uncertain when the virus that causes smallpox first began to infect people. The disease is estimated to have killed as many as 500 million people and is the only human pathogen to have been...