Topics in this publication on tickborne borrelia infections include: Lyme disease epidemiology and transmission; Clinical manifestation and treatment of Lyme disease; Neuroborreliosis; Prevention of Lyme disease; Lyme disease diagnosis - serology; Lyme disease diagnosis - alternatives to serology; Lyme disease co-infections; Relapsing fever borrelia (global review); Emerging tickborne borrelia - B. miyamotoi; Lyme Disease and the immune response. Led by Elli Theel Director of the Infectious Diseases Serology Laboratory of Mayo Clinic, this issue includes authors from the United States, United Kingdom, and Canada to present their expertise on tickborne disease for the clinical pathologist, the infectious disease specialist, and other clinicians who work with patients with these diseases.