When a mysterious flesh-rotting disease broke out in Europe in 1495, two years after Christopher Columbus returned from the Americas, suspicion fell on his crew.

A new study published in the journal Nature provides compelling evidence that syphilis originated in the Americas and spread globally through European colonization.

The implications of this research are manifold. The study paints a grim picture of colonialism’s unintended consequences. While European explorers brought smallpox, measles, and other deadly diseases to the Americas, syphilis may have been the New World’s equally devastating gift in return.

Christopher Columbus returned with the unwelcome souvenir after his travels in the Americas, new research claims, causing a serious outbreak of the killer illness