Cognitive impairment after tick-borne encephalitis.

BACKGROUND/AIMS: Tick-borne encephalitis (TBE) is a potentially debilitating disease caused by the TBE virus. Natural foci of TBE were localized in the Lublin region (Poland). We observed the growing tendency of the incidence of TBE in the Lublin region at the beginning of the 1990s. Farmers and forestry workers were most often infected due to the occupational risk.

METHODS

Forty farmers with TBE since the beginning of the year 2001 were included in the study. Serological measurements as well as medical and neuropsychological examination confirmed the infection. Dementia and mild cognitive impairment were diagnosed on the basis of DSM-IV-R, ICD-10 and Petersen criteria, respectively.

RESULTS

Long-term consequences of the illness have been reported in 22 subjects. In this group, cognitive impairment of the amnestic type was diagnosed. No decline in cognitive status was observed in the examined patients for 6 months.

CONCLUSIONS

The diagnosis of human TBE is usually based on serology, which has a number of pitfalls. The outcome of the disease can mimic many neurological diseases. For that reason, the history of farmers with cognitive decline should be carefully examined. There is reasonable likelihood of cognitive decline in patients with TBE.