Incidence and prevalence of Infection with human granulocytic ehrlichiosis agent in Germany. A prospective study in young healthy subjects

Only limited data are available on incidence and prevalence of infection with the human granulocytic ehrlichiosis (HGE) agent in a healthy population. In a prospective study, we tested 361 male soldiers (age 18-29 years) from southwestern Germany for the HGE agent immunoglobulin G (IgG) using an indirect immunofluorescence antibody assay and for Borrelia burgdorferi IgG with an ELISA at the beginning and the end of their 10-month military service. Using a standardized questionnaire, the subjects were asked about clinical symptoms at the beginning and the end of the observation period. Of these 361 subjects, 14.9% were HGE agent IgG positive at study entry. 19 participants (5.3%) seroconverted from IgG negative to positive during the observation period resulting in an incidence rate of 6.4% per year. 20 subjects converted from initially HGE agent IgG positive to negative resulting in a reconversion rate of 6.6% per year. Concurrence of Borrelia IgG and HGE agent IgG was observed in 21.1%, whereas 13.7% were HGE agent IgG positive but Borrelia IgG negative (not significant). Clinical symptoms associated with HGE were not present in seroconverting subjects. Infection with the HGE agent occurs frequently in southwestern Germany but was asymptomatic in these young subjects.