🦠microbiology review

Borrelia

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Borrelia is a genus of spiral-shaped bacteria known as spirochetes, primarily responsible for causing Lyme disease and relapsing fever in humans.

5 Must Know Facts For Your Next Test

  1. Borrelia burgdorferi is the most well-known species within this genus, causing Lyme disease.
  2. These bacteria are transmitted to humans through the bite of infected ticks or lice.
  3. Borrelia species have a unique double-membrane structure that classifies them as Gram-negative.
  4. The genome of Borrelia is linear rather than circular, which is uncommon among bacteria.
  5. Symptoms of Borrelia infection can range from mild flu-like symptoms to severe neurological and cardiac issues.

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