Prevalence of antibodies against the human granulocytic ehrlichiosis agent in Lyme borreliosis patients from Germany.

To contribute to the discussion of whether or not human granulocytic ehrlichiosis (HGE) occurs in midwestern Germany, sera from individuals with different risk categories for tick exposure were retrospectively examined by means of an immunofluorescence assay. The seroreprevalence for the HGE agent accounted for 5.5% of the 270 patients tested. Specific antibodies were detected more often in patients with early Lyme infection than in patients with stage III disease or in asymptomatic individuals seropositive for Lyme disease. Investigation of 50 patients with an active or recent syphilis infection revealed no cross-reactivity between Treponema pallidum antibodies and the HGE agent. The prevalence of HGE antibodies (13.1%) among 76 Lyme borreliosis patients from this urban area was significantly higher (P < 0.05) than that in the control groups (2.6%). The findings indicate that concomitant or serial infections with Borrelia burgdorferi and the HGE agent or closely related organisms may be a common occurrence in tick-exposed patients from Germany.