Copyright © 2017 American Academy of Pediatrics. From: Lyme Disease145,146 Red Book® 2015, 2015 Figure Legend: Using darkfield microscopy technique, this photomicrograph reveals the presence of spirochetes, or corkscrew-shaped bacteria known as B burgdorferi, which is the pathogen responsible for causing Lyme disease (magnification x400). B burgdorferi are helical-shaped bacteria, and are about 10 to 25µm long. These bacteria are transmitted to humans by the bite of an infected deer tick. Courtesy of Centers for Disease Control and Prevention Date of download: 10/2/2017 Copyright © 2017 American Academy of Pediatrics. All rights reserved.