What Bayer Environmental Science's Maxforce Tick Management System.

Why Black-legged deer ticks transmit Lyme disease, as well as malaria-like babesiosis and ehrlichiosis, an acute infection.

Background Mice and other rodents can harbor the bacteria that cause Lyme disease and transmit the germs to the ticks that feed on them. Infected ticks then travel -- sometimes by deer-back -- to spots where you or your pets can pick them up. The Maxforce strategy is to draw the rodents into baited "car washes" that brush them with the insecticide fipronil. The stuff kills ticks but doesn't hurt the rodents. Gary Maupin, who co-designed the system, said this approach breaks "the natural cycle" of Lyme disease transmission." Maupin's study showed a 50 percent reduction in Lyme disease in the offspring of mice given the fipronil treatment.

Why here? Why now? "There's an increasing number of [Lyme disease] cases, and an increasing population of infected ticks . . . farther south along the Mason-Dixon line," said Maupin. Maryland reported 700 cases in 2003, twice the number of a decade ago. Virginia reported 195.

How much? $400 to $1,200 for six months of prevention. The small plastic "car wash" boxes -- placed every 35 feet or so around a property -- must be installed and maintained by licensed pest control workers. Maupin predicted the price will drop in a few years.

In the meantime "The message we need to get out to the public is do frequent tick checks" if you or your pets have been outdoors, said Karon Damewood, an official at the Maryland Department of Health and Mental Hygiene. DEET-based repellents keep ticks away.

-- Matt McMillen