Understanding Lyme Disease In the U.S., Lyme disease ranks among the most widespread tick-borne infections, with thousands of new cases diagnosed annually. It’s caused by the bacterium Borrelia burgdorferi and transmitted to humans through the bite of infected black-legged ticks, also known as deer ticks. Ticks thrive in wooded, grassy, and moist environments. Since Bloomfield, NJ, and surrounding areas are home to parks, trails, and outdoor recreation spaces, residents are at risk of ...