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

BACKGROUND: Only limited data are available on incidence and prevalence of infection with the human granulocytic ehrlichiosis (HGE) agent in a healthy population.
MATERIALS AND METHODS: 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.
RESULTS: 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.
CONCLUSION: Infection with the HGE agent occurs frequently in southwestern Germany but was asymptomatic in these young subjects.