The genetic evidence corroborates that historical fact that the first recorded Old World outbreak of syphilis appeared in 1494 or 1495, originating proximately in Naples, Italy, and spread across the continent by mercenaries from an invading French force of King Charles VII. Syphilis was long known prior to Columbus in the New World. Also relevant is the "virtual absence of syphilitic lesions from Pre-Colombian Old World skeletons." The role of Columbus, who returned from his first voyage to the Americas in March of 1493, as the source of this disease in Europe was hypothesized in writing as early as the early 1500s, but this study solidifies the claim. This outbreak went on to kill five million people in Europe.
Syphilis is caused by the bacterium Treponema pallidum subsp. pallidum and is related closely to a non-venereal version of the disease and an infectious disease known as "yaws". The current study was helped by the discovery of the full genome in 1998.
Syphilis (unless antibiotic-resistant) can be easily treated with antibiotics including penicillin. The oldest and still most effective method is an intramuscular injection of benzathine penicillin. If not treated, syphilis can cause serious effects such as damage to the heart, aorta, brain, eyes, and bones. In some cases these effects can be fatal.
In the United States, the recent trend is for syphilis to be found at very high rates (in relative terms) in minority men who have sex with men, and is rare for other populations (these are 2005 numbers many of which are updated here, but show the same general trends):
In 2004, about 64% of reported early-stage syphilis infections occurred among men who had sex with men, up from 5% in 1999, according to the CDC. . . .
In 2004, 41% of all cases of P&S syphilis reported to CDC occurred among African-Americans and 40% of all cases occurred among non-Hispanic whites. The 2004 rate for African-Americans was 6 times greater than the rate among non-Hispanic whites . . . .
In 2004, 16% of all cases of P&S syphilis reported to CDC occurred among Hispanics. The rate of P&S syphilis among Hispanic men increased 12% (from 4.9 to 5.5 cases per 100,000 population) between 2003 and 2004. The rate among Hispanic women remained essentially unchanged (0.7 cases per 100,000 population). The rate among Hispanics in 2004 was 2 times greater than the rate among non-Hispanic whites. . . .
Between 2000 and 2004, there was a 90% increase in the number of P&S syphilis cases among men and a 49% decrease in the number of cases among women.
In context, syphilis is still a rare disease in the United States with "about 8,000 cases reported in 2004." Reporting is quite complete for syphilis with the total number of cases believed to be under 10,000. In Colorado in 2005, there were 48 cases of sexually transmitted syphilis reported, all but two or three of which were men, and one case passed from mother to child (probably one of the small number of women with reportable cases in the state).
Infection rates for curable STDs including syphilis are far higher in the United States than in Europe.
Hat Tip: Science News.
See also on New World-Old World ecological exchanges: New World Worms, and New World Foods. Also, notably, there are no Old World marsupials (the Americas have opossums and about 250 species of marsupials as well as all of the world's monotremes are found in and around Australia).