This technology includes Borrelia hermsii isolate for diagnostic development of serologic tests. Borrelia hermsii is the major identified cause of Tick-Borne Relapsing Fever (TBRF) in humans in the western United States. Initial signs and symptoms of infection include fever, nausea, headache and malaise. Most cases are diagnosed on clinical suspicion and epidemiologic risk. Common source, case clusters notable. Microscopy and serologic detection of antibody responses to infection may aid in the laboratory confirmation or infection. Culture recovery of the infectious agent is not often attempted.