And it's almost the most passed-on STD in Aiken, Richmond and Columbia counties.
Health reports show that chlamydia -- a curable STD that often shows no symptoms -- has been on the rise in South Carolina since 2004, and nearly 2,000 cases were diagnosed in Columbia and Richmond counties in 2006, the last year for which statistics are available.
In South Carolina, health officials don't think a chlamydia outbreak is to blame, but rather better testing methods are finding those with the disease.
Other STDs are also prevalent.
According to the Department of Health and Environmental Control, one in four Americans has an STD, and 19 million new cases are diagnosed every year -- nearly half of them in people between ages 15 and 24.
Health officials are hoping people will come forward to get tested. April is national STD awareness month.
Last year, when South Carolina DHEC publicized STD testing, 37 percent of the calls workers got about that service came in April, said Tony Price, the public information coordinator for the agency's STD HIV division.
Although the agency does not have statistics on how many people followed up with testing, he said, 86 percent of the people who called asked for a number to set up an appointment.
Richmond and Columbia counties could not be compared to Aiken in county rankings because the states showed data from a different time frame.
The last report DHEC did on STD rates in the state -- with data up to June 2007 -- shows that for most of the major categories, Aiken County was in the middle of the pack when all counties were ranked.
South Carolina as a whole, however, does not fare as well in some categories.
Although the state's syphilis ranking fell last year -- dropping South Carolina from the top 10 in the infectious disease to No. 30 in the country, Mr. Price said, "South Carolina ranks No. 2 for gonorrhea and No. 3 for chlamydia."
Reach Sandi Martin at (803) 648-1395, ext. 111, or firstname.lastname@example.org.
NATIONAL STD AWARENESS MONTH
April is national STD Awareness Month. To find where you can be tested -- often for free -- visit www.hivtest.org.
South Carolina also has an HIV/STD hot line. Call (800) 322-AIDS for information about being tested or about STDs.