Chlamydia Sets U.S. Record For Most Cases of Reportable Disease

April 8, 2014 - 2:43 PM


Chlamydia trachomatis bacterium (National Institutes of Health)

( – A total of 1,422,976 new cases of Chlamydia trachomatis were reported to the Centers for Disease Control and Prevention (CDC) in 2012, “the largest number of reported cases for any notifiable disease in the U.S.," a CDC spokeswoman told

A list of the National Notifiable Infectious Conditions that are reported by 57 state and territorial jurisdictions can be found on CDC's website.

Approximately 110 million Americans – more than a third of the entire U.S. population - were infected with a sexually transmitted disease (STD) as of 2008, the latest date for which figures are available, the CDC spokeswoman confirmed. That includes more than a million Americans living with HIV.

CDC estimates that nearly 20 million new STD cases are contracted annually, including gonorrhea (334,826 new cases reported in 2012), HIV (47,500 new cases reported in 2010), and primary and secondary syphilis (15,667 new cases in 2012).

They cost the nation nearly $16 billion in health care costs annually.

Young people aged 15 to 24 account for 50 percent of all new venereal infections even though they make up just 25 percent of the sexually active population, the CDC notes.

“STDs are hidden epidemics of enormous health and economic consequence in the United States,” the health agency stated in its annual “Sexually Transmitted Disease Surveillance 2012” report, which was released in January.

But “the annual surveillance report captures only a fraction of the true burden” of STDs in America because other common venereal diseases such as human papillomavirus (HPV), herpes, and trichomoniasis are not routinely reported to the agency, the CDC spokeswoman confirmed.

Women aged 20 to 24 have the highest chlamydia infection rate (3,695.5 cases per 100,000), more than twice the rate as men of the same age (1,350.4 cases per 100,000), according to the report, which added that “during 2008-2012, the chlamydia rate in men jumped 25%, compared with an 11% increase in women during this period.”

However, “for the first time since nationwide reporting of chlamydia began, the rate in women did not increase” in 2012, while “the rate in men increased 3.2%.” Blacks were 6.8 times more likely than whites to contract the disease.

Chllamydia rates by sex

Chlamydia rates by sex (Centers for Disease Control & Prevention)

Chlamydia is a bacterial infection that can be treated with antibiotics. However, it is often asymptomatic, and untreated infections can result in pelvic inflammatory disease (PID), which the CDC points out is “a major cause of infertility, ectopic pregnancy, and chronic pelvic pain.”

In 2012, the average chlamydia infection rate in the U.S. was 456.7 per 1,000 population. Mississippi had the highest rate (774.0 per 1,000) while New Hampshire had the lowest (233.0 per 1,000).

CDC also reported 334,826 new cases of gonorrhea (up 4.1% since 2011) and 15,667 new cases of primary and secondary syphilis (up 11.1% percent since 2011, primarily among gay and bisexual men, who account for 75% of all new cases), noting that “antimicrobial resistance remains an important consideration in the treatment of gonorrhea.”

“Surveillance data from several major cities throughout the country indicate that an average of four in 10 MSM [men who have sex with other men] with syphilis are also infected with HIV,” the agency reports.

Syphilis can lead to visual impairment, stroke and make victims more susceptible to HIV infections, according to the CDC. Black youth aged 15 to 19 were 16 times as likely to contract syphilis as their white counterparts.

“Because STDs and the behaviors associated with acquiring them increase the likelihood of acquiring and transmitting HIV infections, STDs among MSM may be associated with an increase in HIV diagnoses,” the report stated.

Although syphilis plunged 89.7% between 1990 and 2000, largely due to the National Plan to Eliminate Syphilis From the United States, it inched its way back up between 2001 and 2009, the CDC reports. “In 2010, the overall rate decreased for the first time in 10 years” and remained at that level in 2011. But in 2012, “the rate increased 11.1% from that of 2011.”

Gonorrhea and syphilis can also be treated if diagnosed early enough, which is why the CDC recommends screening for all sexually active individuals at least once a year. Men who have sex with other men should be screened every three to six months, the agency advises.

CDC pointed out that STDs can be prevented by not having sex or being in a “long-term monogamous relationship” with a partner who is not infected.