Coinfection with Borrelia burgdorferi and the agent of human granulocytic ehrlichiosis.

To the Editor: Lyme disease and human granulocyte ehrlichiosis are infections carried by the deer tick, Ixodes scapularis. Ticks may harbor both Borrelia burgdorferi and the human granulocytic ehrlichiosis bacterium, the causative agents of these diseases, and dual infections can occur.1 We assessed the risk of exposure to human granulocytic ehrlichiosis among 86 persons with serologic evidence of Lyme disease living in southern Connecticut and Rhode Island — areas in which Lyme disease and human granulocytic ehrlichiosis are relatively common. We used an enzyme-linked immunosorbent assay (ELISA) and immunoblotting (for IgM and IgG antibodies) with B. burgdorferi as the . . .