Seroprevalence of ehrlichiosis, Lyme borreliosis and tick-borne encephalitis infections in children and young adults in Slovenia

Background: Little is known about the seroprevalence of ehrlichiosis in adults and much less about the same in children. Methods: One hundred and forty-three healthy children and young adults (6-24 years of age, male to female ratio, 1:1) were assessed for the presence of antibodies to the agents of human granulocytic ehrlichiosis (HGE), human monocytic ehrlichiosis (HME), Borrelia burgdorferi sensu stricto (BB), and tick-borne encephalitis (TBE) virus in Slovenia, where tick-related infections are endemic. Antibodies to HGE and HME agents were assayed by indirect immunofluorescence, and antibodies to BE and TEE by enzyme-linked immunosorbent assay. A questionnaire about tick exposure was answered by all subjects. In the event of a positive result, a detailed interview was conducted. Results: Of 143 study subjects, 22 (15.4%) had detectable antibodies to HGE agent, 22 (15.4%) were positive to BE, 18 (12.6%) were positive to TEE virus (12 of these were vaccinated) and 4 (2.8%) were positive to the HME agent. The history of persons seropositive to an HGE agent had been uneventful. Conclusions: Our study documents a high seroprevalence of HGE in children and young adults in Slovenia, similar to the seroprevalence of LB and higher than that of TEE and HME. Although the majority of these infections are probably asymptomatic or mild, active surveillance for acute HGE infections in children in areas endemic for tick-related infections is necessary.