Prehistoric syphilis.

Prehistoric syphilis

Syphilis-causing organisms, called treponemes, have long plagued certain scientists, but not in the usual sense. Rather, historians of disease are unsure how and where treponemes originated.

Noting that the earliest reports of syphilis and related diseases did not appear in the Old World until after 1500, many scientists have suggested that Columbus's crew and other voyagers might have carried treponemes back with them when they returned from from the New World. Several decades ago, this theory received support from the discovery of 3,000-year-old human bones from the New World that seemed to show signs of treponemal disease.

However, in the last 20 years, medical historians have suggested that syphilis did indeed affect Europeans in the Middle Ages, but was misdiagnosed as leprosy at the time. Before 1500, say these researchers, people believed that leprosy spread by sexual contact, was highly contagious and responded to mercurial compounds. Yet all of these factors fit syphilis more than leprosy.

Now, immunological tests on bones from a Pleistoceneepoch bear prove that treponemal infections in the New World date back at least 11,000 years. In the Sept. 3 NATURE, scientists report that, using antibodies specific to treponemes, they successfully identified treponemal material on the bear's bones. This is the first successful use of immunology to detect an ancient disease-causing organism, says Bruce Rothschild of St. Elizabeth Hospital Medical Center Hospital in Youngstown, Ohio, who worked with William Turnbull of the Field Museum of Natural History in Chicago.

According to Rothschild, this finding "pushes back the history of any identifiable treponemal disease substantially.'

Although the new finding does not resolve the debate about the origin of treponemal infections, the immunological technique will help scientists trace the history of these and other infections. While paleopathologists could previously only diagnose ancient infections, this new technique allows a direct identification of the infectious organism itself. Using the appropriate antibodies, says Rothschild, scientists might apply this technique to the history of smallpox or tuberculosis.