May is national Lyme disease month, a time of year when the ticks that can cause the illness are out in force.

The Nevada County Board of Supervisors today is expected to adopt a resolution proclaiming Lyme disease month here. The blacklegged tick that can carry the infection is prevalent in the county, as in other regions throughout the state and nation.

"Since its emergence more than 30 years ago, Lyme disease has grown to be the fastest-spreading tick-borne disease in the United States," according to the National Lyme Disease Association.

"The Centers for Disease Control and Prevention records roughly 20,000 new Lyme infections every year; however, the CDC believes that only 10 percent of all cases which meet its surveillance case definition are reported, meaning that at least 200,000 new infections occur annually."

In Nevada County, an average of 12 percent of the ticks are infected with the Lyme disease bacteria, according to the proposed resolution. California is home to more species of Borrelia - the bacteria carried by ticks - than any other state, it added.

"This tick can be carried by many animals and can be found on grasses," said County Agricultural Commissioner Jeff Pylman in a letter to the supervisors. "The ticks are so small that many people who get Lyme disease do not recall being bitten and do not have the typical bulls-eye rash."

The groups at highest risk for Lyme infection are people over the age of 30 and boys between the ages of 5 and 19.

Children are in great danger of tick bites due to more time spent outside or playing with pets.

To contact Editor Jeff Pelline, e-mail jpelline@theunion.com or call 477-4235.