The present study provides evidence and documentation of the first case of infection with the tick-borne encephalitis (TBE) virus acquired in the federal state of Vorarlberg (Austria). The area in which the viral infection was discovered lies in the vicinity of Ludesch in the Illvalley (Bludenz district). In order to investigate the current state of immunity to TBE in the Vorarlberg community, a total of 218 representative sera samples taken from donors resident in the districts of this state were investigated for antibody titers (IgG) of TBE. 38% of the samples had antibody titers representative of sufficient patient immunity, with the highest immunity (63%) in persons aged 20-40 years. Donors living in urban areas had a higher percentage of immunity (43%) than those living in rural areas (33%). Further, men were more immune to infection (43%) than women (33%). The lowest level of immunity (18%) to TBE was found in the Bregenzerwald communities. Based on this report, wider criteria for administering TBE vaccines to patients from the Illvalley should be applied, in particular among the elderly and those living in rural areas.