A 10-year follow-up study of tick-borne encephalitis in the Stockholm area and a review of the literature: need for a vaccination strategy.
143 people treated for tick-borne encephalitis (TBE) were included in a retrospective follow-up study. Sequelae and epidemiological characteristics in 114 individuals were analysed. The case fatality rate and the prevalence of residual paresis were low, 1.4 and 2.7%, respectively. However, 40 (35.7%) individuals were found to have a postencephalitic syndrome after a median follow-up time of 47 months, and a majority (77.5%) of these were classified as moderate to severe. Various mental disorders, balance and co-ordination disorders and headache were the most frequently reported symptoms. Increasing age was correlated to a longer duration of hospital stay, longer convalescence and increased risk of permanent sequelae. Results from a neuropsychiatric questionnaire showed marked differences between the subjects with sequelae compared to controls. 57% had noticed a tick bite before admission, and 48% were aware of at least one person in their environment who previously had contracted TBE. 79% were permanent residents or visited endemic areas often and regularly. In conclusion, we have found that TBE in the Stockholm area has a low case fatality rate, but gives rise to a considerable number of different neurological and mental sequelae, which justifies vaccination of a defined risk population in endemic areas.
Haglund
M
M
Department of Infectious Diseases, Stockholm Country Council, Huddinge Hospital, Sweden.
Forsgren
M
M
Lindh
G
G
Lindquist
L
L
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D002648:Child; D004675:Encephalitis, Tick-Borne / Q000150:complications / Q000453:epidemiology* / Q000276:immunology*; D005260:Female; D005500:Follow-Up Studies; D006261:Headache / Q000150:complications; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000150:complications; D008875:Middle Aged; D004856:Postural Balance; D015995:Prevalence; D012678:Sensation Disorders / Q000150:complications; D016036:Seroepidemiologic Studies; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology; D014611:Vaccination