New genetic evidence presented by US researchers suggests that Christopher Columbus may have brought syphilis to Europe from the New World, sparking a debate about the disease's origins. Through a genetic analysis of the syphilis family tree, researchers discovered that its closest relative is a South American cousin that causes yaws, an infection from the same bacteria sub-species. Evolutionary biologist Kristin Harper from Emory University in Atlanta stated that the findings indicate syphilis or its precursor originated in the New World and was transmitted to the Old World relatively recently in human history. This research is published in the journal Public Library of Science Neglected Tropical Diseases. She stated that the research supports the "Columbian theory," which connects the first recorded European syphilis outbreak in 1495 to Columbus and his crew returning. The combination of genetic data and the epidemic in Naples in 1495 provides strong evidence for the Columbian hypothesis. Syphilis, a sexually transmitted disease caused by the bacterium Treponema pallidum, begins as a sore and can progress to a rash, fever, and potentially lead to blindness, paralysis, and dementia. The most recent evidence regarding its origins has been found in skeletal remains from both the New World and the Old World, with chronic syphilis leaving distinctive lesions on bones. During a telephone interview, Harper described it as having a worm-eaten appearance. Harper utilized phylogenetics to analyze the evolutionary connections among organisms in her study on the Treponema bacterial family responsible for syphilis, bejel, and yaws. She examined 26 strains of Treponema, including two previously unsequenced yaws strains from Guyana. Harper sequenced 21 different regions in an attempt to identify DNA variations among the strains. They came to the conclusion that although yaws is an ancient infection, venereal syphilis is a more recent development. Harper believes that a nonvenereal form of the tropical disease evolved into venereal syphilis in order to survive in the cooler European climate. However, the exact process of this evolution is unclear. Harper stated that the ancestor of syphilis originated from the New World, but its exact characteristics remain unknown. In a commentary in the same journal, Connie Mulligan and colleagues from the University of Florida disagreed with Harper's analysis, suggesting that her conclusions were too reliant on genetic changes observed in samples from Guyana. Mulligan proposed that more insightful information could be obtained from DNA obtained from ancient bones or well-preserved tissues. Harper admits that further research is necessary to elucidate the transmission of syphilis to the New World. "This is like a blurry picture," she remarked.