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Borrelia Miyamotoi

Borrelia miyamotoi is a member of the relapsing fever group of Borrelia that was first reported to cause human disease in the United States in 2013. It is transmitted by the same tick species that transmits Lyme disease, Ixodes scapularis. B. miyamotoi is geographically widespread. A survey of nymphal Ixodes scapularis ticks in 11 Lyme disease–endemic states reported that 2% were infected with B miyamotoi and 20% with B burgdorferi.

Unlike with Lyme disease, patients infected with B miyamotoi typically do not develop a rash. The most common clinical presentation is fever accompanied by headache (96%), myalgia (84%), arthralgia (76%), and malaise/fatigue (82%). Fever may be relapsing in untreated patients. Severely immunocompromised patients may develop chronic meningitis. Laboratory abnormalities include elevated liver enzymes in 75% of patients, leukopenia in 51% and thrombocytopenia in 60%. Leukopenia and thrombocytopenia are less commonly observed in patients with Lyme disease. Both doxycycline and amoxicillin appear to be effective for treatment of immunocompetent patients with this infection.

Patients infected with B miyamotoi may be misdiagnosed as having Lyme disease because this infection may cause positive results with enzyme-linked immunosorbent assays (EIA) used to diagnose Lyme disease. No diagnostic tests for B miyamotoi infection have been approved by the US Food and Drug Administration. Active infection is best diagnosed in a blood sample using polymerase chain reaction (PCR).

Molloy PJ, Telford SR III, Chowdri HR, et al. Borrelia miyamotoi disease in the northeastern United States: a case series. Ann Intern Med. 2015; 163(2):91-98

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