The culprit: Lyme disease is caused by the bite of a blacklegged tick. Stephen Reiss for NPR hide caption toggle caption Stephen Reiss for NPR Shots - Health News Did You Get Bit By A Lyme-Infested Tick? Here's What To Do March 6, 2017 One scientist is predicting a risky year for tick-borne Lyme disease in the Northeast, and it's spreading. But don't panic. We've got tips.