Tick-borne encephalitis (TBE) in Skåne, southern Sweden: A new TBE endemic region?

Abstract

No case of tick-borne encephalitis (TBE) has previously, to our knowledge, been reported from the region of north-eastern Skåne in southern Sweden. However, since the y 2001 we have identified 6 cases of TBE in this region occurring in a limited geographical area covering about 100 km². Sera from 393 patients living in the vicinity of those TBE cases were analysed for the presence of TBE virus-specific IgG by use of ELISA. TBE virus IgG titres >126 VIEU (Vienna Units) were detected in 28 (7.1%) of the patients’ sera. However, in only 3 of the ELISA TBE virus IgG positive sera were neutralizing antibodies against TBE virus demonstrated. Those 3 sera all had IgG titres of >380 VIEU. The TBE seroprevalence rate in this non-randomized population sample in north-eastern Skåne was calculated at 0.8%.