Study challenges beliefs about spread of syphilis

Survey also finds widespread misconceptions

Results from a government study of sexual behaviors in high-risk populations indicate that syphilis is not spread by a few people who have an extraordinarily high number of partners, but by a large network of people who have a moderate degree of risk behaviors.

The study, conducted by the Centers for Disease Control and Prevention, interviewed people in high-risk populations in Baton Rouge, LA, about their sexual behaviors. One of the findings that surprised health officials was that only about 5% of syphilis transmitters had five or more partners.

"We found a profile of patients not many of us would think of - not a few people with a high rate of sexual activity driving an epidemic, but rather a network of some high-risk neighborhoods where lots of people had moderate degrees of risk behavior," says Michael St. Louis, MD, chief of the epidemiology and surveillance branch of the CDC's division of STD prevention.

The study, titled "Innovations in Syphilis Prevention," showed that the highest risk factors for acquiring syphilis were having two or more partners and using cocaine.

The survey also found widespread public misconceptions about syphilis. As many as 40% of the survey participants didn't know that syphilis was curable. Many patients thought syphilis caused itching and burning, and did not know that syphilis infection put them at higher risk for acquiring HIV.

Few people in the neighborhoods expressed strong distrust of government - a finding that some researchers found surprising, considering the widespread publicity about the notorious syphilis experiments on African-Americans at Tuskegee University.

The biggest concern about STD care was privacy, especially among those who lived in small communities, St. Louis says. "They were not worried about people disposing their records to health departments, but about people seeing them and losing their anonymity," he says.

When the same unpublished study was expanded to high-risk areas in Texas and South Carolina, researchers found that 32% of patients sought care because of symptoms, 30% due to notification from partners or health departments, 24% because of a screening test, and 12% for other reasons. While the prevalence of syphilis was highest among men attending STD clinics, for females rates for those in drug treatment centers and jails were twice as high as for those attending STD clinics, the authors found.