Reported cases of sexually transmitted diseases shot up 10 percent in Minnesota last year, with chlamydia and gonorrhea among teens and young adults driving the spike.

The numbers, released Thursday by the state Department of Health, prompted officials to call for regular testing and safer sex practices.

"Untreated STDs can have serious health consequences, and we need to increase our efforts in partnership with our most impacted communities," said Dr. Ed Ehlinger, Minnesota's health commissioner.

Chlamydia is known as a "silent" infection because most infected people have no symptoms. If symptoms do occur, they may not appear until several weeks after exposure. Both men and women are at risk of infertility from the disease.

Chlamydia reached a record 18,048 reports statewide in 2012, a 7 percent increase from 2011, with the majority of cases occurring within the 15- to 24-year-old age bracket. Adding gonorrhea and syphilis to the tally, 2012 saw 21,465 reported STD infections.

Gonorrhea cases jumped 35 percent, with teens and young adults accounting for 65 percent of last year's 3,082 cases. The same demographic accounted for 69 percent of chlamydia cases.

"Today's report is proof that there is much work left to be done," said Sarah Stoesz, president and CEO of Planned Parenthood Minnesota, North Dakota and South Dakota.

Even those being regularly tested for STDs should remember that their sexual partners might not be, said Kris Ehresmann, director of infectious-disease epidemiology at the state Health Department.

The problem isn't confined to the metro area, she said. Minneapolis had the highest STD rates, and 80 percent of gonorrhea cases were in the metro area. But suburban and outstate Minnesota accounted for 30 and 31 percent of chlamydia cases, respectively.

Gonorrhea also tends not to show symptoms until it spreads to other parts of the body.

While reports of other STDs were rising, syphilis fell 8 percent from 2011, totaling 335 cases, with new infections primarily within the metro area and among males, especially those having sex with other men.
Staff writer Paul Walsh also contributed to this report.
Jeff Hargarten is a University of Minnesota student reporter on assignment for the Star Tribune.