Blood smear not reliable in diagnosing Borrelia miyamotoi disease

Borrelia miyamotoi disease (BMD) is another tick-borne pathogen that can be difficult to diagnose with serologic tests. BMD is a spiral-shaped bacteria that is closely related to the bacteria that causes tick-borne relapsing fever.


by Daniel J. Cameron, MD, MPH

Some doctors have suggested that a blood smear should be used to confirm the diagnosis of BMD. But as Telford and colleagues demonstrate, a blood smear may not be so reliable. [1]

microscope, labIn an effort to determine whether blood smears can detect B. miyamotoi in the blood of acute BMD patients, researchers examined sera from 20 patients, who were positive for BMD by PCR testing.

The authors “looked for evidence of BMD using standard malariological thick smears from anticoagulated blood samples.”

But after examining 100 thick smear fields in 20 patient samples, the authors could not find evidence of BMD in any of the patients.

Blood smears have poor sensitivity for confirming Borrelia miyamotoi disease. Click To Tweet

They were, however, able to find evidence of BMD in 2 of the 20 patient samples after examining 300 thick smear fields.

The authors conclude, “microscopy of blood smears is not sensitive enough for confirming a diagnosis of BMD.”

The Centers for Disease Control and Prevention (CDC) continues to recommend using PCR and antibody-based tests to confirm a diagnose of B. miyamotoi.

Editor’s note: I am not sure how sensitive the PCR and antibody tests are for BMD.


Related Articles:

Borrelia miyamotoi detected in Canada

Doctors face challenges in diagnosing Borrelia miyamotoi

The best antibiotics to treat Borrelia miyamotoi?



  1. Telford SR, 3rd, Goethert HK, Molloy PJ, Berardi V. Blood smears have poor sensitivity for confirming Borrelia miyamotoi disease. J Clin Microbiol. 2019.


2 Replies to "Blood smear not reliable in diagnosing Borrelia miyamotoi disease"

  • Jarkko Kause
    01/30/2019 (9:34 pm)

    Did they wait for how many hours, rechecking the findings hourly?
    Those kind of spirochaetes bore themselves easily into the red blood cells as well as white blood cells. They dive to other tissues as well, particularly to bloodless ones. Like intervertebral discs, other joints, ligaments and tendons. It may take anything from 2-12 hours to see these bacteria coming out of those cells. That is when they can be seen moving in the plasma.

    • Dr. Daniel Cameron
      01/31/2019 (12:51 am)

      I summarized the frustration by the authors when testing for Borrelia miyamotoi. Hopefully your suggestion or others will lead to better tests.

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