ATLANTA - Sexually spread diseases, for years on the decline, are on the rise, with reported chlamydia cases setting a record, government health officials said Tuesday.

The increase in chlamydia, a sometimes symptomless infection that can lead to infertility in women, is likely because of better screening, experts said. In 2007, there were 1.1 million cases, the most ever reported, said officials at the Centers for Disease Control and Prevention.

Thousands of women become infertile each year because of untreated chlamydia and gonorrhea infections, said Dr. John M. Douglas Jr., director of the CDC's Division of STD Prevention.

Chlamydia can infect men as well as women, but rates are nearly three times higher for women. That's at least partly due to 1993 federal recommendations that emphasize testing for sexually active women age 25 and younger. That emphasized screening in recent years is no doubt driving the record numbers, said Dr. Jonathan Zenilman, a professor of infectious diseases at the Johns Hopkins University School of Medicine.

The latest numbers translate to a rate of 370 cases per 100,000 people in 2007, up 7.5 percent from 2006.

Florida's rate jumped up even more dramatically than the national average, with the state reporting 58,528 cases of chlamydia in 2007, up 20 percent. About 9,000 of those cases were in Broward and Palm Beach counties. Gonorrhea cases totalled 23,664, about the same as the year before, with about 3,225 cases in the two counties. The state counted 883 cases of syphilis, up 23 percent, with 193 in the two counties.

Staff Writer Bob LaMendola contributed to this report.

The Associated Press