RESUMEN
An adult male presented to a hospital in southwestern Connecticut with tachypnea, generalized weakness, altered mental status, and relapsing fever with maximum recorded temperature of 106 °F. He required active cooling, antipyretic therapy, broad spectrum antibiotics, and intubation for airway protection after an episode of emesis. Initial laboratory and imaging workup were remarkable for elevated inflammatory markers, acute kidney injury, and bilateral lower lobe infiltrates. Further workup with lumbar puncture and electroencephalography were unrevealing. Extensive testing for causes of relapsing fever including tickborne diseases revealed that the patient was seropositive for Borrelia miyamotoi. Notably, he had no rash, and workup found no evidence of coinfection by other Borrelia, Ehrlichia or Anaplasma species. This case illustrates the need for clinicians to test for tick-borne diseases when evaluating for cases of relapsing fever in New England and is among the first case reports to demonstrate Borrelia miyamotoi as a cause of severe pyrexia.