|File:Borrelia burgdorferi (CDC-PHIL -6631) lores.jpg|
Today, 36 species of Borrelia are known. 12 of these cause borreliosis, a zoonotic, vector-borne disease transmitted primarily by ticks or lice. The vector of transmission is dependent on the species of Borrelia. Borreliosis is also known as Lyme disease. Borrelia burgdorferi and Borrelia afzelii are among the species that cause Lyme disease. Other species such as Borrelia hermsii or Borrelia parkeri cause relapsing fever. In this case, the vector are ticks, which are spread by rodents.