TBE

Tick-borne encephalitis

Profile

Early summer meningoencephalitis (TBE) or tick-borne encephalitis is an infectious disease caused by the TBE virus. Ticks are the most common carriers of TBE in Europe.

Occurrence

TBE occurs in large parts of Europe and in Asia. Austria is one of the most affected countries in Central Europe.

Pathogen reservoir

Small rodents, especially voles and mice, are considered the main hosts of ticks. Wild, domestic and farm animals such as foxes, hares, deer, wild boars, sheep, cattle, goats or dogs are also important for tick reproduction and ecology. Humans are accidental and definitive hosts.

Infection route

Transmission occurs via the bite of infected ticks. The TBE virus is transmitted to humans during the biting and sucking act of the tick. In very rare cases, infection occurs through raw milk from an infected animal. Transmission from human to human is not possible.

Incubation period

The incubation period is between three and 28 days, on average eight days

Symptomatology

About ten to 30 percent of infected persons show symptoms, whereas the rest have an asymptomatic course. Two to ten days after the tick bite, flu-like symptoms appear, such as headache, fever, fatigue and joint pain. In most cases, the symptoms subside after a few days. For about five to 15 percent of all patients, after a symptom-free period of about seven days, a second phase of the disease occurs in which the central nervous system is affected. It is only in this phase that meningitis or cerebral inflammation occurs, with symptoms such as severe headaches, photophobia, dizziness, difficulty concentrating, speech disorders and walking difficulties. These symptoms can last for weeks to months. In very severe cases, paralysis of the arms, legs or facial nerves can occur and lead to permanent disabilities. About one percent of patients with neurological symptoms die from TBE. In children, the disease is mild in most cases.

Therapy

After a symptomatic onset of the disease, there is no therapy, only treatment to relieve individual symptoms by bed rest and painkillers.

Prevention

The best prevention against TBE is vaccination. Measures to avoid tick bites are also recommended: Well-closing, closed clothing, scan the body for ticks when you have been out in the forest, bushes, high grass in meadows.

Situation in Austria

In Austria, TBE is a notifiable disease. There is a risk of contracting TBE via a tick bite throughout the entire federal territory. It is one of the most affected areas in Europe. For travelers to Austria there is a recommendation for TBE vaccination.

Gemeldete FSME-Fälle in Österreich

Specialized information

TBE is a notifiable disease. Austria is one of the most affected regions in Europe. TBE has been vaccinated in Austria since 1976, and an Austria-wide information campaign with a vaccination campaign has been taking place annually since 1981. As a result, the TBE vaccination rate in Austria is about 85 percent and the number of cases has been significantly reduced from 300-700 cases per year before the annual vaccination campaign to 41-216 cases per year in the past 40 years.

About ten to 30 percent of infected persons have symptoms, whereas the rest have an asymptomatic course. In a symptomatic course, flu-like symptoms occur two to ten days after the tick bite, including headache, fever, fatigue, and joint pain. In most cases, the symptoms subside after a few days. For about five to 15 percent of all patients, a second phase of the disease occurs after a symptom-free period of about seven days, in which the central nervous system is affected. It is only in this phase that meningitis or cerebral inflammation occurs, with symptoms such as severe headaches, photophobia, dizziness, concentration disorders, speech disorders and walking difficulties. These symptoms can last for weeks to months. In very severe cases, paralysis of the arms, legs or facial nerves can occur and lead to permanent disabilities. About one percent of patients with neurological symptoms die from TBE. In children, the disease is mild in most cases.

The vaccination schedule for Austria contains the latest recommendations for TBE vaccination.

The Europe-wide surveillance by the ECDC provides a wealth of information as well as distribution maps of ticks.

Diagnostic

TBE diagnosis is based on the detection of specific IgM antibodies in CSF (intrathecal production) and/or serum, mainly by ELISA (enzyme-linked immunosorbent assay).

TBE antibodies appear 0-6 days after disease onset and are usually detected when neurologic symptoms are present. Specific IgM antibodies may be detectable for up to ten months in vaccinated individuals or individuals who acquired the infection naturally; cross-reactivity with IgG antibodies may also be observed with other flaviviruses. Detection by PCR methods could be valuable for early diagnosis of TBE.

Last updated: 10.10.2023

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