A U.S. sexually transmitted diseases epidemic is increasing and the most common infection, chlamydia, has risen to record levels, government officials say.

Reported cases of chlamydia, gonorrhea and syphilis all increased in 2014. Chlamydia cases had dipped in 2013, but last year's total of more than 1.4 million - or 456 cases per 100,000 - was the highest number of annual cases of any condition ever reported to the federal Centers for Disease Control and Prevention. The chlamydia rate was up almost 3 percent from 2013, the CDC reported Tuesday.

Sexually transmitted diseases are among more than 70 diseases that are reportable to the CDC, including measles, chickenpox and tuberculosis. Flu is reported differently, by hospitalizations.

"America's worsening STD epidemic is a clear call for better diagnosis, treatment, and prevention," said the CDC's Dr. Jonathan Mermin.

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Gonorrhea cases totaled 350,062, up 5 percent from 2013, and the most contagious forms of syphilis jumped 15 percent to 20,000. As in previous years, the syphilis increase was mainly in gay and bisexual men.

Most gonorrhea and chlamydia infections were in 15- to 24-year-olds, an ongoing trend. Both can cause infertility in women but can be treated with antibiotics. They often have no symptoms, and while yearly screening is recommended for sexually active women younger than 25, many don't get tested and infections go untreated, the CDC said.