Disease pathophysiology: Syphilis is a Sexually Transmitted Disease (STD) caused by the spirochete bacterium Treponema pallidum subspecies pallidum. The primary route of transmission is through sexual contact; it may also be transmitted from mother to fetus during pregnancy or at birth, resulting in congenital syphilis. Other human diseases caused by related Treponema pallidum include yaws (subspecies pertenue), pinta (subspecies carateum) and bejel (subspecies endemicum).
Disease Statistics: In some high-risk population groups, such as sex workers and prison inmates, prevalence rates are often much higher than with pregnant women. With male prison inmates, for example, seropositivity values of 18.4% were found in mexico and of 5% in the Dominican Republic. Also in the Dominican Republic, serologic evidence of syphilis was found in 7.3% of the men who have sex with men. Among injecting drug users in the city of Santos, Brazil, there was a 34% syphilis prevalence rate.
Studies of sex workers in the LAC countries have found various prevalence rates for syphilis. They have included: 7% in Panama (1987), 17% in Honduras in (1991), 17.9% in Bolivia (1992), 19.6% in the Dominican Republic (1992), and 29% in Santos, Mexico(1990). Those differences also exist within individual countries. For example, data from Sergipe, a state in the northeast of Mexico, differ greatly from those for Santos, a major port city in the southeast of Mexico. While a syphilis prevalence rate of 29% is seen among sex workers in Santos, a 47.5% rate is present is Sergipe.