Cases of two sexually transmitted diseases are skyrocketing, according to a report released Thursday by the Utah Department of Health. Chlamydia cases increased by 50 percent, while gonorrhea cases nearly doubled between 2003 and 2007, it says.

Chlamydia was the most frequently reported communicable disease in Utah, with 23,166 cases, and gonorrhea was No. 4 with 3,451 cases during the five-year period covered in the report. The vast majority of those cases were among Wasatch Front residents and the two diseases were most commonly diagnosed in 15- to 29-year olds.

The health department is tackling the problem with a new education campaign called "Catch the Answers," targeting young adults, parents and health care providers with information about the two STDs. It asks and answers common questions and refers the public to a Web site, www.catchtheanswers.com, for more information.

Radio advertisements, billboards and ads on buses and TRAX are also part of the campaign, which kicks on Saturday at the U92 Cinco De Mayo Custom Car Show and Concert at the USANA Amphitheatre. Magnets with campaign slogans will be planted on vehicles throughout the parking lot, symbolizing the way that STDs spread through a population. Doors open at 11 a.m.

Education campaign funding was provided by the 2008 Legislature.

The two diseases are "silent" in that they often result in no symptoms but can cause pelvic inflammatory disease, ectopic pregnancy and even infertility. An infected mother can also pass the disease to her child during birth.