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

Abstract

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.

Tick-borne encephalitis virus in ticks detached from humans and follow-up of serological and clinical response

“…It has been found that as much as 46 % of patients may suffer from postencephalitic symptoms (Haglund et al, 1996;Günther et al, 1997;Kaiser, 1999;Mickiene et al, 2002;Kaiser, 2011). The TBE virus (TBEV) belonging to the genus Flavivirus is a positive-sense single stranded RNA virus transmitted by ticks of the species Ixodes.…”

Autonomic and peripheral nervous system function in acute tick‐borne encephalitis

“…It is well known that a TBE infection causes considerable long‐term morbidity (Haglund et al. 1996; Kaiser 2011). Whether affection of the ANS and PNS contributes to long‐term sequelae of TBE is speculative.…”

“…1997; Haglund et al. 1996; Kaiser 2011). The case fatality rate in Europe is approximately 1% (Haglund et al.…”

“…The case fatality rate in Europe is approximately 1% (Haglund et al. 1996; Kaiser 2011). Diffuse brain edema and involvement of the medulla oblongata and the central portions of the brain are thought to be the main causes of mortality (Dumpis et al.…”

Infeksjonsrisiko hos orienteringsløpere

“…En slik lav forekomst var ikke høyere enn forekomsten i den øvrige befolkning i tilsvarende område (20). I Sverige har de fleste smittede bodd i Stockholms-området, der den gjennomsnittlige årlige insidens av skogflåttencefalitt i årene 1955-93 var 3,4 per 100 000 innbyggere (23).…”