New genetic evidence suggests that Christopher Columbus may have introduced syphilis to Europe from the New World, according to US researchers. The study analyzed the genetic makeup of syphilis and found that its closest relative is a South American cousin that causes yaws. This finding has reignited a longstanding debate about the origins of the disease. Evolutionary biologist Kristin Harper from Emory University explained that while some believe syphilis is an ancient disease, their research indicates it was brought to the Old World from the New World relatively recently in human history. The study was published in the journal Public Library of Science Neglected Tropical Diseases. She stated that the research supports the "Columbian theory," which connects the first documented European syphilis outbreak in 1495 to the return of Columbus and his crew. Combining the genetic data with the Naples epidemic in 1495 provides strong backing for the Columbian hypothesis. Syphilis, a sexually transmitted disease caused by Treponema pallidum bacteria, begins as a sore and can progress to a rash, fever, and potentially lead to blindness, paralysis, and dementia. The most recent evidence of its origins comes from skeletal remains discovered in both the New World and the Old World. Chronic syphilis can cause distinct lesions on bones. During a telephone interview, Harper described the appearance of the bacteria as worm-eaten. She utilized phylogenetics to analyze the evolutionary relationships among 26 strains of Treponema, which are responsible for syphilis, bejel, and yaws. The study also involved sequencing two previously unsequenced strains of yaws from Guyana. Harper explained that they sequenced 21 regions in search of DNA variations among the strains. They reached the conclusion that although yaws is an ancient infection, venereal syphilis emerged relatively recently. Harper believes that a nonvenereal form of the tropical disease transformed into venereal syphilis that could thrive in the cooler European climate. However, the process of this transformation is not clear. "We can only confirm that the precursor of syphilis originated in the New World, but its exact characteristics remain unknown," she stated. In a commentary in the same journal, Connie Mulligan and colleagues from the University of Florida disagreed with Harper's interpretation, suggesting that her conclusions were overly reliant on genetic changes observed in the Guyana samples. Mulligan proposed that more accurate information could be obtained from DNA extracted from ancient bones or preserved tissues. Harper acknowledges that further research is necessary to fully understand how syphilis arrived in the New World. "This is a low-quality image," she stated.