Diverse variola virus (smallpox) strains were widespread in northern Europe in the Viking Age.
Implies that the virus was circulating among people even earlier, about 1700 years back at the time when the Western Roman empire declined and people were migrating across Eurasia.
Suggest a pan-European presence of smallpox from the late 6th century.
The genetic makeup of the viral strain recovered from the 11 individuals is different from the modern version which was eradicated in 1979.
In the course of the evolution, however, the active gene count of the virus is shown to have reduced.
The general understanding about pox viruses is that the ones with lesser genes are more deadly.
Implications of the Study:
Nowhere close to being related to the coronavirus.
It does provide important information on how a virus may become deadlier over time.
The DNA evidence suggests that diseases such as plague and hepatitis b are associated with major prehistoric migrations — something that seems now to be true of variola too.
About Small Pox:
Smallpox was an infectious disease caused by one of two virus variants, variola major and variola minor.
The last naturally occurring case was diagnosed in October 1977, and the world health organization (WHO) certified the global eradication of the disease in 1980.
Smallpox is one of two infectious diseases to have been eradicated, the other being rinderpest in 2011.
