FARMINGTON — Chlamydia may have led the pack as the most common communicable disease in Davis County in 2007, just as it has for at least the past four years, but the number of the sexually transmitted disease cases has declined since 2006.

The Davis County Health Department received reports of 482 cases of chlamydia in 2007, according to the department's annual communicable disease report. That compares to 538 cases in 2006.

Gonorrhea, which tied for seventh place this year, with 47 cases, also saw a decline from 55 cases in 2006.

"This is the first time in over 10 years that we've seen a slowing or decline in sexually transmitted disease rates," Davis County epidemiologist Brian Hatch told the Davis County Board of Health on Tuesday.

Hatch said it's too early to tell if the decline is due to random variation, but he's optimistic that the message of safe-sex practices is getting out to the public.

"Hopefully, next year we'll see this continue to drop," he said.

If the list of communicable diseases were a race, one might say that cryptosporidiosis came from out of nowhere to land a second-place finish with 294 cases in 2007.

The gastrointestinal disease is caused by a parasite that was transmitted by fecal matter in swimming pools, which came under strict regulations across the Wasatch Front last year.

Before 2007, Davis County hadn't had a reported case of crypto since 2004, when one case was reported.

Though 294 cases were reported, between 6,000 and 15,000 Davis County residents could have been affected by the parasite, Hatch said.

Davis County Health Department director Lewis Garrett said he's concerned that summer 2008 could show another outbreak of crypto if people aren't careful about making sure they're clean and healthy before they go swimming.

Superchlorination, which makes pools unsuitable for swimming, as well as the parasites, could be on order again if an outbreak happens.

The South Davis Recreation District board recently approved the purchase of ultraviolet treatment equipment for the recreation center, located in Bountiful, said Commissioner Bret Millburn.

Southern Davis County cities generally had higher rates of infection than northern cities.

The health department was busy during 2007 with potential rabies exposures at two schools during the fall.

An elementary school boy found a bat and brought it to Fremont Elementary in Sunset. Eight of 10 students who handled the bat were treated for exposure, though none contracted the disease. At Layton High School, three of five students who handled another bat were treated.

No human cases of rabies were reported.

Top 5 communcable diseases in Davis County for 2007

• Chlamydia — 482 cases

• Cryptosporidiosis — 294 cases

• Chickenpox — 111 cases

• Hepatitis C — 94 cases

• Latent tuberculosis — 88 cases