Smallpox DNA has been discovered in the naturally preserved remains of two Indigenous individuals buried in northern Chile, offering molecular proof that the deadly virus reached the Americas through European colonization. The findings, published in a scientific journal, reveal fragments of the variola virus — the pathogen responsible for smallpox — in remains dated between approximately 1492 and 1631. This time frame overlaps with the shift from Inca rule to Spanish colonial dominance in the region. Smallpox was a highly infectious and deadly disease, with a mortality rate of about 30% among those infected. It was officially eradicated worldwide in 1980 through a global effort led by the World Health Organization (WHO). The first recorded smallpox outbreak in the Americas occurred in 1518 on Hispaniola, and subsequent waves of the disease had a devastating impact on Indigenous populations, contributing to massive loss of life during the colonial period. This study provides direct molecular evidence supporting historical records that suggest smallpox was introduced to the Americas by Europeans. The Chilean strains were found to be closely related to those previously identified in Europe, though the study does not specify how or by whom the virus was brought to the region. The mummified remains also showed small skin lesions, which earlier research linked to chronic arsenic exposure from naturally occurring arsenic in local rivers. However, the presence of variola DNA confirms that both individuals were infected with smallpox, though it is unclear whether the disease was the cause of their deaths. Researchers reconstructed two smallpox genomes using ancient DNA fragments, but no intact virus particles were found. Ancient DNA often degrades over time, breaking into short pieces, and the study's reconstruction does not suggest a plausible way for smallpox to return today. The study notes that the virus evolved through a process called reductive evolution, in which certain genes became non-functional or disappeared as variola adapted to human hosts. The Chilean genomes help fill a gap in the evolutionary history of smallpox, connecting medieval European strains with later lineages. This allows scientists to trace how the virus spread and changed as it moved across continents. The study also observed that gene inactivation occurred at a steady pace until the late 16th century, after which genetic changes slowed before increasing again. While the authors suggest that colonial-era epidemics may have influenced this pattern, the study does not confirm the exact reasons behind these genetic shifts.