'Clear Evidence': Ancient DNA From Chilean Mummies Reveals Who Brought Smallpox to The Americas

Key Points:

• Researchers have found the first solid genetic evidence linking smallpox to the catastrophic population decline in Indigenous communities in the Americas after European colonization, by analyzing variola virus DNA from two mummified individuals in northern Chile dating between 1492 and 1631 CE.
• The virus genomes, nearly identical and named CAM9, suggest simultaneous infection and place smallpox in South America shortly after European arrival, bridging medieval European strains and modern variants in the virus's evolutionary history.
• The study reveals that the virus's evolution slowed in the Americas for centuries post-contact, with mutation rates increasing again in the 19th century likely due to widespread vaccination efforts.
• This breakthrough underscores the challenges of recovering ancient viral DNA and highlights the importance of supporting scientific research and capacity building in Global South countries, where such archaeological treasures are found.
• The findings, published in Science, provide new insights into the spread and adaptation of smallpox, illustrating how human events like colonization and vaccination influence viral evolution.