Daily Briefing: How smallpox reached the Americas
Nature, Published online: 31 July 2026; doi:10.1038/d41586-026-02432-5 Viral sequences from Chilean mummies confirm smallpox was introduced to the Americas from Europe. Plus, the month’s best science images and the changing patterns of Europe’s wildfires.
The remains of two mummified individuals discovered in Chile have provided evidence that Orthopoxvirus variola, the virus responsible for smallpox, was introduced to the Americas by European colonizers. The genetic analysis revealed a unique smallpox variant, suggesting it branched off from a European strain around the thirteenth century.
This particular variant had fewer genes compared to samples found in seventh-century Viking settlements, hinting that the virus may have shed genes as it adapted to human hosts—a process that could be happening with related viruses today.
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