Blood Smears Have Poor Sensitivity for Confirming Borrelia miyamotoi Disease

Abstract

Borrelia miyamotoi disease (BMD) is a newly recognized borreliosis that is cotransmitted by ticks wherever Lyme disease is zoonotic. Unlike Borrelia burgdorferi sensu lato, the agent of Lyme disease, B. miyamotoi is closely related to relapsing fever spirochetes, such as Borrelia hermsii. Some authors have suggested that the disease caused by B. miyamotoi should be considered a hard-tick-transmitted relapsing fever, and thus, the main mode of confirming a diagnosis for that infection, microscopy to analyze a blood smear, may have clinical utility. To determine whether blood smears may detect B. miyamotoi in the blood of acute BMD patients, we made standard malariological thick smears from anticoagulated blood samples that were previously determined to contain this agent (by PCR) and analyzed them for morphological evidence of spirochetes. Spirochetes were not detected in the blood smears from 20 PCR positive patient blood samples after examination of 100 thick smear fields and only 2 of 20 demonstrated spirochetes when the examination was extended to 300 thick smear fields. Inoculation of severe combined immunodeficient (SCID) mice yielded isolates from 5 of 5 samples, but 0 of 3 BALB/c mice became infected. We conclude that in strong contrast to the diagnosis of typical relapsing fever, microscopy of blood smears is not sensitive enough for confirming a diagnosis of BMD but that SCID mouse inoculation could be a useful complement to PCR.

Development and Validation of a Protein Array for Detection of Antibodies against the Tick-Borne Pathogen Borrelia miyamotoi

“…PCR detection of B. miyamotoi is often aimed at amplification of 16S rRNA or glycerophosphodiester phosphodiesterase ( glpQ ) or flagellin B ( flaB ) gene fragments. Due to the relatively short spirochetemia ( 15 ), PCR detection of B. miyamotoi is applicable only in the acute phase of disease or during a febrile relapse ( 10 , 16 ).…”

Borrelia miyamotoi: A Comprehensive Review

“…Spirochetes can be visualized in blood and CSF using dark-field microscopy, or with Giemsa staining or acridine orange staining [ 21 , 22 , 23 ]. Microscopy can confirm a Borrelia species infection; however, it cannot be used to distinguish between species and has low sensitivity [ 29 ]. In order to see spirochetes in a blood smear or CSF sample, the density needs to be greater than 10 4 cells/mL [ 11 , 26 ].…”

Pathogenesis of Relapsing Fever

“…Firstly, although most likely of little clinical utility, it is possible to isolate B. miyamotoi from blood of infected individuals (Wagemakers et al, 2014). Secondly, and of greater clinical relevance, DNA from B. miyamotoi sensu lato can be detected by molecular methods in blood (plasma or serum) (Platonov et al, 2011) or cerebrospinal fluid (CSF) (Hovius et al, 2013) and, albeit less sensitive, spirochetes can be directly visualized by dark-field microscopy (Telford et al, 2019). The above-mentioned diagnostic modalities can be used only in febrile episodes, during which spirochetemia occurs.…”