The national syphilis rate in the United States increased for the fourth consecutive year in 2004, according to new data on nationally notifiable sexually transmitted diseases (STDs) released today by the Centers for Disease Control and Prevention (CDC). The report, which provides data on three STDs -- chlamydia, gonorrhea and syphilis -- also finds that in 2004, the gonorrhea rate reached an all-time low, and chlamydia rates increased, possibly due to expanded and improved screening.
The national rate of primary and secondary (P&S) syphilis -- the early stages of the disease that indicate recent infection -- has increased every year since an all-time low in 2000. From 2003 to 2004, the rate of P&S syphilis increased 8 percent from 2.5 to 2.7 cases per 100,000 population. The number of cases increased from 7,177 in 2003 to 7,980 in 2004.
The rise in the national P&S syphilis rate is largely due to increases among men. Overall, the P&S syphilis rate among men increased 11.9 percent from 2003 to 2004 (4.2 cases per 100,000 to 4.7 cases per 100,000) and 81 percent since 2000 (2.6 cases per 100,000 to 4.7 cases per 100,000). While surveillance data are not available by risk behavior, a separate CDC analysis suggests that approximately 64 percent of all adult P&S syphilis cases in 2004 were among men who have sex with men, up from an estimated 5 percent in 1999.
Significant progress in addressing the syphilis epidemic has been made as a result of CDC's National Plan to Eliminate Syphilis, launched in 1999. Between 1999 and 2004, black P&S rates have decreased 37 percent (14.3 to 9.0 cases per 100,000), while rates among women overall have decreased 55 percent (2.0 to 0.9 cases per 100,000).
However, in 2004, for the first time in over a decade, the P&S syphilis rate increased in blacks, rising 16.9 percent (7.7 cases per 100,000 in 2003 to 9.0 cases per 100,000 in 2004). Mirroring overall trends, this increase was primarily due to a 22.6 percent increase in the P&S rate among black men (from 11.5 cases per 100,000 to 14.1 cases per 100,000). After years of steady decline, the P&S syphilis rate among women held steady at 0.8 per 100,000 in 2004.
"Syphilis increases, especially among men who have sex with men, demonstrate the need to continually adapt our strategies to eliminate syphilis in the United States," said Dr. Ronald Valdiserri, acting director of CDC's HIV, STD and TB prevention programs. "While there is no silver bullet to reduce syphilis rates, innovative screening and
prevention programs around the country are having a positive impact in many areas and providing crucial lessons that will help us meet new challenges."
In 2003, the CDC partnered with health departments and community groups in cities with the highest syphilis rates to implement strategies to better address the disease. The results of these efforts were recently reported in the journal Sexually Transmitted Diseases (Vol. 32, No. 10 Supplement). A wide range of approaches were evaluated and results suggest that increased syphilis awareness in the community and among healthcare providers caring for men who have sex with men can increase early treatment. Efforts to improve partner counseling, testing and referral services can also play a key role in outbreak control.
The CDC is also working with public health and community partners to refine the National Plan to Eliminate Syphilis in order to address the resurgence of syphilis among men who have sex with men and continue the significant reductions already seen in some populations.
The national rate of gonorrhea reached an all-time low in 2004, falling 1.5 percent between 2003 and 2004 (from 115.2 to 113.5 cases per 100,000). Despite this reduction, several significant challenges remain.
The CDC conducted sentinel surveillance in 28 cities and found the proportion of cases resistant to fluoroquinolone antibiotics (a first-line treatment for gonorrhea) increased from 4.1 percent in 2003 to 6.8 percent in 2004. Resistance is especially worrisome in men who have sex with men, where it was eight times higher than among heterosexuals (23.8 percent vs. 2.9 percent). In April 2004, the CDC recommended that fluoroquinolones no longer be used as treatment for gonorrhea among men who have sex with men. These antibiotics were also not recommended to treat the disease in anyone in California or Hawaii, where resistance has been widespread for years. Outside of these states, the prevalence of fluoroquinolone resistance among heterosexuals remains low at 1.3 percent.
Racial disparities in gonorrhea were seen in 2004. Blacks were most affected, with a rate 19 times higher than that of whites (629.6 cases per 100,000 vs. 33.3 cases per 100,000).
Chlamydia was the most common infectious disease in the United States reported to the CDC in 2004, with 929,462 cases. The national rate increased 5.9 percent (301.7 per 100,000 in 2003 to 319.6 in 2004). The increase is likely due to screening and identification of cases of the disease rather than an actual increase in infection rates. However, experts caution that the majority of chlamydia cases remain undiagnosed. CDC estimates that 2.8 million new chlamydia infections occur each year.
"Reported cases are just the tip of the iceberg. Health care providers urgently need to step up screening for chlamydia, particularly among young, sexually active women, who are at greatest risk of infertility and other complications if the disease is not diagnosed and treated," said Dr. John Douglas, director of CDC's STD prevention programs.
The rate of reported chlamydia cases was 3.3 times higher among women than men in 2004 (485 cases vs. 147.1 per 100,000), most likely due to increased screening among women.
The CDC estimates that 19 million STD infections, including HIV and other non-notifiable STDs, occur each year. In addition to their immediate and long-term health consequences, these diseases result in direct medical costs of an estimated $13 billion annually.