Genetic analysis of ancient DNA recovered from mummies in Chile has provided the strongest evidence to date that smallpox arrived in the Americas following European colonization. The findings, published in the journal Science, center on bone samples from an archaeological site in northern Chile.
Researchers led by geneticist Shigeki Nakagome of Trinity College Dublin examined 13 bone samples. Their analysis uncovered evidence of smallpox infections in two individuals—a man and a woman—believed to have died between 1492 and 1631. This period aligns with the arrival of Europeans in the Americas.
While historians have long accepted that smallpox was introduced to the Americas after contact with Europeans, this discovery marks the first genetic evidence of the disease in this particular region of South America. The presence of the virus in these mummies raises further questions about how the pathogen spread across the continents after its initial introduction.
Smallpox was historically one of the world's most virulent diseases, responsible for killing approximately one-third of those infected. Survivors often bore disfigurement and scarring from the illness. The disease was declared eradicated in 1980 and no longer circulates naturally.
Experts have theorized that the virus may have spread through established Native American trade networks. Another potential pathway for transmission suggested by researchers is through Africa, linked to the expansion of the slave trade. The exact vectors and speed of the virus's initial spread across vast distances remain subjects of ongoing study.
Patricia Foster, a biologist at Indiana University not involved in the study, told The Associated Press that the findings offer crucial genetic confirmation of long-understood historical assumptions. "Nobody would ever question that smallpox came to this hemisphere from colonization, but this proves it," Foster stated.
This research represents a significant advancement in understanding historical pandemics through ancient DNA. The technique has previously been used to shed light on other ancient diseases and mysteries. For example, ancient DNA from human remains in Colombia provided insights into the history of syphilis, and analysis of remains from Renaissance Italy may have resolved questions surrounding a ruler's death.