B. miyamotoi

What you need to know about Borrelia miyamotoi

What is 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). It is more distantly related to the bacteria that cause Lyme disease. First identified in 1995 in ticks from Japan, 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.

What type of illness does B. miyamotoi cause?

In a 2015 case series, patients with this infection were most likely to have fever, chills, and headache. Other common symptoms included body and joint pain and fatigue. Unlike Lyme disease, rash was uncommon, presenting in only 4 out of 51 patients.

What type of testing is available for patients who might be infected?

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. Both types of tests are under development and not widely commercially available but can be ordered from a limited number of CLIA-approved laboratories.

How is B. miyamotoi treated?

Physicians have successfully treated patients infected with B. miyamotoi with a 2-4 week course of doxycycline. Amoxicillin and ceftriaxone have also been used.

What more do researchers need to know?

Researchers and health care providers need more information about the signs and symptoms of this infection. Fewer than 60 well-documented cases of human infection have been reported in the United States to date.

It is also unclear how common this infection is in the United States. Improved means of diagnosing B. miyamotoi disease will help researchers learn how many people are affected by it.

What is CDC doing?

CDC is working to better define the public health importance of this infection and is reviewing options for tracking the disease with our partners in state and local health departments. CDC is also developing and evaluating laboratory diagnostic tests to detect the presence of B. miyamotoi in infected individuals and measure their specific immune responses.

How can I avoid this disease?

B. miyamotoi is transmitted by the bite of infected blacklegged ticks. This bacterium can be transmitted within the first 24 hours of tick attachment but the probability of transmission increases with every day an infected tick is allowed to remain attached. People living in areas where blacklegged ticks are common should continue to take precautions against tick bites and see their physician if they experience fever, rash, or malaise after a tick bite or after spending time in tick habitat. For more information, visit CDC’s Ticks site.