The number of syphilis cases rose nationwide in 2002 for the second straight year, and San Francisco had the highest rate of infection in the nation, federal health officials said this week.
From 2001 to 2002, the overall rate of syphilis increased 9.1%, from 2.2 cases to 2.4 cases per 100,000 population -- the highest rate since 1999, according to a study by the Centers for Disease Control and Prevention.
The rate in San Francisco was 40.6 cases per 100,000, apparently driven largely by infection among gay and bisexual men. The high number of cases may be attributed in some part to improved screening and outreach efforts, health officials said.
The city, in collaboration with community groups, has opened three testing sites and created a Web page, and the number of syphilis tests has risen 33% from 1999 to 2002.
"San Francisco has seen a tremendous increase in the proportion of gay men, and men who have sex with men, being tested for syphilis," said Dr. Jeffrey Klausner, director of sexually transmitted disease control in San Francisco.
Even so, Klausner emphasized, the increase is not due solely to stepped up screening.
"We know that the increased number of cases is definitely related to increased transmission," he said. "People are coming in with lesions; people have sores, and there is an increased number of syphilis cases of the brain. That's real disease and real transmission."
Nationwide, authors of the study estimate that more than 40% of all syphilis cases reported in 2002 occurred among gay and bisexual men.
The new CDC data, however, showed significant reductions in the number of syphilis cases among women and African Americans. The number of cases among women overall fell by 19%; among African Americans in general by more than 10%, and among African American women nearly 22%.
Health experts noted that although African Americans still have the highest rate of infection in the nation, strategies to provide them with greater access to health care, particularly in the South, seemed to be working.
State health officials said California's cases almost doubled from 2001 to 2002, rising to 1,046. Preliminary estimates for 2003 indicate the rate of infection is slowing. "It seems that the rate of increase is leveling off, and perhaps even plateauing," said Michael Samuel, director of the surveillance and epidemiology division of the state's sexually transmitted disease control office.
Most troubling, health officials said, is that the new data indicate that gay and bisexual men continue to engage in risky behavior that also exposes them to the HIV virus. Syphilis sores facilitate the transmission of HIV, and public health experts fear that the rise in syphilis may presage a corresponding rise in HIV cases.
While releasing the CDC figures Thursday, officials cited a study in New York City comparing the behavior of gay and bisexual men with syphilis to those without syphilis. The men with syphilis were more likely to report engaging in unprotected anal intercourse, attending private sex parties to meet partners, and using methamphetamine and Viagra or other drugs before having sex. They also were more likely to have HIV.
Both groups reported an average of 11 or more partners in the previous six months.
The Internet has fueled the problem, officials said. When syphilis began to surface among gay and bisexual men in Los Angeles three years ago, activists were able to mobilize prevention campaigns focusing on bath houses and sex clubs, said Lee Klosinski of AIDS Project Los Angeles.
"But now, most people are finding sex partners on the Internet, and the Internet has emerged as a more problematic area in terms of syphilis transmission," Klosinski said.