FARMINGTON — Every Monday, Davis County Health Department director Lewis Garrett gets a report of the previous week's diseases, and every Monday, chlamydia leads the list.

It's the most commonly reported infectious disease in the United States, and it holds the same title in Davis County and throughout the state.

In 2006, Davis County reported a 16.8 percent increase from the previous year in reported cases of the sexually transmitted disease. Statewide, the increase was not much less at 12.4 percent, or 572 more cases than the year before, according to preliminary numbers.

"It's unacceptable to me and the health department," Garrett said. "Any time you have a disease that's steadily increasing year after year, it's a significant concern."

But it's not just climbing chlamydia rates that have Utah health officials worried. Gonorrhea rates in Utah increased a staggering 195 percent between 2000 and 2005, from 231 to 896 cases. The jump is nearly five times the increase found in other Western states and comes at a time when the national rate is on the decline, according to the U.S. Centers for Disease Control and Prevention.

For the same time period, chlamydia cases in Utah increased 110 percent, from 2,188 in 2000 to 4,602 in 2005, according to the state health department.

"Gonorrhea and chlamydia have reached new heights," said Tim Lane, program manager for the Utah Department of Health's STD Control Program. "We're setting records, and not the kind of records we want."

Health officials attribute the growing caseloads to a number of factors, including people's lack of awareness about sexually transmitted diseases, as well as better and more frequent testing and better reporting methods among health agencies. Davis County's recently released annual disease surveillance and control report also points to more aggressive "contract tracing," where health-department interviewers attempt to contact infected people's sexual partners and get them treated for the particular disease.

A large part of the problem, according to officials, is that many people don't know they're infected. Chlamydia, in particular, is asymptomatic, so it is easy to unknowingly spread the disease to sexual partners.

Screening for high-risk STDs, then, is vital, experts said.

State law requires that chlamydia, gonorrhea, syphilis and HIV be reported to either local health departments or the state health department. Recent increases in the first three diseases have made health officials concerned about a corresponding jump in the fourth.