Explained: What new research on smallpox tells us about its origins

Context:

• Deadliest disease
• Eliminated by Vaccination

Finding of the Study:

• 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.

Reference: https://indianexpress.com/article/explained/smallpox-research-vikings-origins-6526058/