A long-term effort to reduce the tick population on Gibson Island is working, but the mites continue to spread Lyme disease throughout the state.

In 1997, Maryland was one of five states the U.S. Department of Agriculture selected for a pilot study on tick populations. At that time, residents in Gibson Island were concerned about ticks, so researchers set up a Rube Goldberg-like device treatment system that allows deer to unwittingly kill off the pests.

Known as 4-Poster Deer Treatment Systems, the contraptions are set up with bins containing corn, which acts as bait for deer. As a deer walks inside the system, it rubs against...