The clinical and epidemiological profile of tick-borne encephalitis in southern Germany 1994–98

Abstract

Seven hundred and nine patients fell ill in southern Germany (Baden-Württemberg) after infection with the tick-borne encephalitis (TBE) virus between 1994 and 1998. Detailed clinical and epidemiological data on TBE were available for 656 patients. A biphasic course of the disease occurred in 485 patients (74%). TBE presented as meningitis in 320 patients (49%), as meningoencephalitis in 270 (41%) and as meningoencephalomyelitis in 66 (10%). Eight of the patients (1.2%) died from TBE. Four hundred and forty-five patients (68%) had noticed a tick bite and the first symptoms occurred, on average, 7 days later. The most frequent neurological symptoms were impairment of consciousness (31%), ataxia (18%) and paresis of the extremities (15%) and cranial nerves (11%). Laboratory investigations revealed leucocytosis in the peripheral blood in 224 out of 392 patients (74%), elevation of the erythrocyte sedimentation rate in 223 out of 245 (91%), increased C-reactive protein in 127 out of 155 (82%), pleocytosis in the CSF of all patients tested, damage of the blood-CSF barrier in 255 out of 322 (79%), abnormalities in EEG in 165 out of 214 (77%) and abnormalities in MRI in 18 out of 102 (18%). In general, adolescents up to 14 years of age had a more favourable course of the disease than adults. Of 230 patients who were re-examined at a later time, 53 (23%) had moderate or severe sequelae. Patients with sequelae presented more frequently (P < 0.001) with impaired consciousness (Glasgow Coma Scale < 7), ataxia, pareses of the extremities or cranial nerves, a need for assisted ventilation, abnormal findings in MRI, pleocytosis > 300 cells/microl and impairment of the blood-CSF barrier (total protein > 600 mg/l). In view of the severity of the illness and the high frequency of sequelae, active immunization against TBE is recommended for all subjects living in and travelling to areas of risk. Prevention of TBE by post-exposure prophylaxis with hyperimmunoglobulins is less effective and therefore should be performed only when absolutely necessary.

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

“…Other case studies described clinical symptoms of ANS dysfunction during acute disease and as persisting sequelae of TBE (Tomazic et al. 1996; Kaiser 1999; Jereb et al. 2002).…”

“…Indeed, TBEV antigens were found in >50% of fatal cases in the medullar tegmentum and the pons including its raphe nuclei and the locus coeruleus, which are all parts of the central ANS. MRI shows lesions in the basal ganglia, diencephalon, cerebellum, and brainstem in approximately 20% of TBE cases (Kaiser 1999; Marjelund et al. 2004).…”

“…Age in the d‐PNP group was higher and there was a male preponderance in the TBE group. It is well known that TBE shows a male predominance (Kaiser 1999), but underlying mechanisms are not yet identified. We matched the female/male ratio in TBE versus d‐PNP.…”

“…1999; Kaiser 1999). It is caused by the Tick‐borne encephalitis virus (TBEV), which belongs to the family Flaviviridae, and is transmitted by infected ticks of different species.…”

Tick-Borne Encephalitis Virus: A General Overview

“…However, due to differences in seroprevalence rates in Europe and in Russia, the higher morbidity of Eastern TBE forms could, at least partly, be the result of selective notification of mainly severe cases (Süss, 2003). In contrast to the forms mentioned above, infections caused by European strains typically take a biphasic course in 72-87% of patients (Kaiser, 1999;Günther et al, 1997;Holzmann, 2003): After a short incubation period (usually 7-14 days, with extremes of 4-28 days), the first (viremic) phase presents as an uncharacteristic influenza-like illness lasting 2-4 days (range 1-8 days) with fever, malaise, headache, myalgia, gastrointestinal symptoms, leukocytopenia, thrombocytopenia and elevated liver enzymes as frequent symptoms. This is often followed by a symptom-free interval of about one week (range 1-33 days) before the second phase.…”