Rates of the sexually transmitted disease chlamydia are climbing in the U.S., and rates of syphilis -- once on the verge of elimination -- rose for the seventh consecutive year, the Centers for Disease Control and Prevention said Tuesday in its annual report on STDs.
Gonorrhea rates did not increase, but they ceased falling a few years ago, frustrating goals set by public health leaders.
Chlamydia infections in the United States now top 1.1 million, the most since record-keeping for the disease began and the most for any STD that doctors are required to report, according to 2007 data, the latest available.
Cases of gonorrhea, which peaked in the 1970s at about 1 million and then dropped for years, remain flat at 355,991, according to the CDC report. The disease is the second-most common STD for which data are collected by law.
Women bear the brunt of both chlamydia and gonorrhea, especially their long-term consequences, CDC officials said.
Untreated, both can lead to pelvic inflammatory disease -- an infection of the uterus and fallopian tubes that can cause chronic pain, infertility and life-threatening ectopic pregnancy, or pregnancy outside the uterus.
Chlamydia and gonorrhea "lead to tremendous problems in our female population, with fertility leading the list," said Dr. John M. Douglas Jr., director of the CDC's Division of STD Prevention.
Infection with the bacterium Chlamydia trachomatis can cause a discharge from the vagina or penis and a burning sensation when urinating, but often does not. Although the consequences are most severe for women, in men, an untreated infection can spread to the epididymis -- the tube that carries sperm from the testes -- causing pain, fever and, rarely, sterility.
The report found that chlamydia infections occurred at a rate of about 370 per 100,000 people in 2007. That's a 7.5% increase from 2006.
Part of that increase may be due to better detection, Douglas said. More people, especially women, are being screened, and a more sensitive test is now in use.
Even so, many people with the disease are not identified, and public health officials believe that the true number of chlamydia infections is closer to 3 million. Young men especially often don't go to the doctor and thus never learn of their infection, but continue to infect their partners, said Linda M. Niccolai, an epidemiologist at Yale School of Public Health.
The bacterial infection is easily treatable with antibiotics, Niccolai added.
The data for gonorrhea -- 119 reported cases per 100,000 people, similar to the rate in 2006 -- have some health officials doubting that they can reach their 2010 goal for this disease of 19 cases per 100,000.
But more alarming is the continued rise of syphilis, a still rare but more serious STD. Reported cases of syphilis rose in 2007 to 11,466, or 3.8 cases per 100,000 people. That is a 15% increase from 2006 and represents yet another increase after a decade of decline in the 1990s.
In 2000, public health officials believed that syphilis was close to being eliminated, but a dramatic jump in infections among gay and bisexual men reversed the downward trend. Men who engaged in homosexual sex made up 65% of the 11,466 cases reported in 2007, roughly the same as in 2006.
As in previous years, chlamydia, gonorrhea and syphilis continued to disproportionately affect African Americans and, to a lesser extent, Native Americans, Alaska Natives and Latinos.
Public health officials attribute the disparities to socioeconomic and cultural factors, including lower access to regular healthcare and distrust of the healthcare system.
Los Angeles County launched a series of public health campaigns in mid-2007 that target young African American women and Latinas as well as gay and bisexual men. The Los Angeles area had the most cases of chlamydia of any metropolitan area in the country -- 440,030 in 2007 -- and the second-highest number of gonorrhea and syphilis cases.
Dr. Jonathan E. Fielding, county director of public health, called on private practitioners to routinely screen patients for STDs, especially sexually active young women, and to press for partners to be treated. "There are things that could make a huge difference, and they're just not getting done," Fielding said.