Infection with Borrelia miyamotoi in California, USA, has been suggested by serologic studies. We diagnosed B. miyamotoi infection in an immunocompromised man in California. Diagnosis was aided by plasma microbial cell-free DNA sequencing. We conclude that the infection was acquired in California.
Keywords: Borrelia miyamotoi; California; Ixodes pacificus; USA; bacteria; immunocompromised host; microbial cell-free DNA sequencing; parasites; relapsing tick-borne fever; tick-borne diseases; ticks; vector-borne infections.