[Seroprevalence of Central European tick-borne encephalitis in the Lorraine region].

Background: Central European encephalitis, caused by the tick-borne encephalitis virus (TBEV), is exceptional in France. Most cases have been described in Alsace. As 2 cases of tick-borne encephalitis were diagnosed in the Nancy region, a seroepidemiological survey was conducted in the Lorraine region (Meurthe & Moselle, Moselle, Vosges, Meuse) in 1996.

Methods: The survey was proposed to approximately 1,000 persons attending preventive medicine clinics. The subjects were asked to fill out a self-administered questionnaire on factors related to tick bite exposure and underwent TBEV serology tests.

Results: 1,777 subjects participated in the survey. Half of them lived in rural areas, 91% had occasional or regular contact with the forest environment and 21% had experienced tick bites. TBEV serology (IgG) was positive in 19 subjects (1.6%; 95% CI: 0.9%-2.3%); 9 sera were positive on Western blot (0.76). No IgM positive serum was found. Seroprevalence was higher in subjects with a past history of tick bites compared with the others (2.9% vs 1.3%, p = 0.074).

Conclusion: The low seroprevalence of TBEV in this survey is not in favor of widespread tick-bite encephalitis virus in the Lorraine general population.