Borrelia miyamotoi Polymerase Chain Reaction Positivity on a Tick-Borne Disease Panel in an Endemic Region of Rhode Island: A Case Series.

Background: Borrelia miyamotoi is a newer cause of ixodid (hard-bodied) tick-borne illness. Because symptoms are generally nonspecific and pathognomonic clinical features are lacking, whole blood polymerase chain reaction (PCR) may be useful for confirming a diagnosis. A tick-borne disease panel ("TBD-3") bundled with Borrelia species (including B. miyamotoi) PCR ("TBD-3M") was offered for patients with suspicion of TBD during 2014-2015 at South County Hospital in Rhode Island, an endemic region for many tick-borne illnesses. Materials and Methods: Imugen laboratory was queried for all TBD-3M panels and Borrelia PCR's sent from South County Hospital patients between January 1, 2014, and August 31, 2015. One positive whole blood B. miyamotoi PCR sample (genus and species specific) was considered evidence for B. miyamotoi infection. Demographics, clinical presentations, coinfections, laboratory abnormalities, and treatment courses for B. miyamotoi disease were examined. Results: A total of 2324 patients had a bundled tick-borne panel performed for unexplained fever and other symptoms. In addition, 258 patients had individual Borrelia PCR's performed. Overall, 78 patients were positive for B. burgdorferi PCR (3.0% positivity rate) and 18 patients were positive for B. miyamotoi PCR (0.7% positivity rate). Most patients presented with a "summer influenza"-like illness (94% reporting fever). Sixteen of these 18 patients were empirically prescribed doxycycline. One patient was concomitantly positive for B. miyamotoi PCR, B. microti PCR, and IgM Lyme antibodies. Three additional B. miyamotoi positive patients had positive Lyme serology. Conclusions: Borrelia whole blood PCR was bundled to a pre-existing tick-borne panel to potentially account for unexplained fevers and other nonlocalizing symptoms in high-risk patients. Treatment recommendations for B. miyamotoi are based on case reports of successful treatments in other causes of relapsing fever, and the same antibiotics regimens are used for both. The utility of B. miyamotoi PCR in first-line screening of patients with unexplained fever may be minimal, given the low positivity rate observed and uniform effective empiric treatments prescribed. Copyright (C) 2017 Wolters Kluwer Health, Inc. All rights reserved.

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