Borrelia Miyamotoi

Borrelia miyamotoi is a species of spiral-shaped bacteria that is closely related to the bacteria that cause tick-borne relapsing fever (TBRF). In immunocompromised patients, it can cause meningoencephalitis.

First identified in 1995 in ticks from Japan, it is distantly related to the bacteria that cause Lyme disease. B. miyamotoi has since been detected in two species of North American ticks, the black-legged or “deer” tick (Ixodes scapularis) and the western black-legged tick (Ixodes pacificus)—these ticks are already known to transmit several diseases, including Lyme disease, anaplasmosis and babesiosis. While less common than Lyme, B. miyamotoi infections occur at a similar frequency compared to babesiosis and anaplasma. A study from Yale School of Public Health showed that B. miyamotoi infections range along both the east and west coasts, far larger than previously believed.​​

Signs and Symptoms​

  • Fever
  • Chills
  • Headache
  • Rash
  • Body and joint pain and fatigue
Microscopic slides used during tick testing and showing Borrelia miyamotoi, a species of spiral-shaped bacteria

Spirochetes detected in cerebral spinal fluid

Image courtesy of Gugliotta JL, 2013

Blood tests for Lyme disease are not helpful in the diagnosis of B. miyamotoi infections. Currently, confirmation of a diagnosis relies on 1) the use of polymerase chain reaction (PCR) tests that detect DNA from the organism or 2) antibody-based tests.