Tick-borne encephalitis (TBE) is an acute inflammation of the brain, meninges or spinal cord caused by viruses. In most cases, the pathogens enter the human bloodstream via a tick bite.
TBE is not to be confused with the disease Lyme disease, in which no virus but disease-causing bacteria (Borrelia) are transmitted by ticks. In contrast to Lyme disease, the disease TBE can be effectively prevented with a vaccination.
Ticks absorb the TBE virus through the blood of infected host animals. These are mostly rodents like mice, but sometimes also hedgehogs, goats, cattle or sheep. The pathogen does not harm the ticks. However, they can pass it on to humans through their saliva.
In a few cases, the TBE pathogen is also transmitted to humans via virus-contaminated raw milk from goats, sheep or – very rarely – from cows. However, transmission from person to person is impossible – TBE is therefore not contagious. And: Not every tick bite automatically transmits the TBE virus, since not every tick is infected with the pathogen.
Nevertheless, vaccination before a stay in TBE risk areas is recommended, since significantly more people are infected there. The TBE risk areas have continuously expanded in recent years due to ever warmer weather conditions. Around 90 percent of TBE cases in Germany occur in Bavaria and Baden-Württemberg. However, the pathogen is also widespread in south-eastern Thuringia and southern Hesse, as well as occasionally in central Hesse, Saxony, Saarland and Rhineland-Palatinate.
If a tick is discovered on the body, it should be removed as soon as possible – the TBE virus is transmitted within the first few hours after the bite.
A vaccination against the tick-borne TBE virus protects against a dangerous inflammation of the brain and spinal cord with a 99 percent probability. A person can be vaccinated from the first year of life.
A TBE vaccination is recommended for:
The TBE vaccination is an inactivated vaccine. This means: A serum with killed viruses is injected into the muscle. The vaccines are available from two manufacturers. The two can be used interchangeably to build up stable vaccination protection, the so-called basic immunization. However, it is preferable to always vaccinate with the same agent. The family doctor is the first point of contact for arranging a vaccination appointment.
How often is a TBE vaccination administered? Three vaccinations are required to get full vaccination protection. A TBE vaccination is possible and recommended for children from the age of one. This is what the TBE vaccination scheme for the basic immunization looks like:
If the protective effect is urgent, for example because you are about to travel to a country with a high risk of TBE infection, the doctor can offer a rapid vaccination. Within a month, it achieves a high protective effect, which, however, wears off faster than with the conventional method. This is how the quick vaccination works:
The basic immunization protects for a period of at least three years. After that, the TBE vaccination protection must be refreshed for the first time. From then on, those under 50 should be re-vaccinated every five years. People over 50 need a TBE booster vaccination every three years.
According to current expert opinion, anyone who has survived TBE is immune to the pathogen and is therefore protected from renewed infection. However, since it is not certain whether the immune protection will last for life, the Robert Koch Institute still recommends a booster vaccination three to five years after the illness.
The TBE vaccination is generally well tolerated. Any side effects are mostly of a harmless nature. They often only appear after the first basic vaccination – and quickly subside again. Possible side effects include:
Statutory health insurance usually covers the costs of a TBE vaccination for people who live in risk areas and people who are exposed to an increased risk of infection through their job.
If you do not belong to this group, please inquire with your health insurance company about the assumption of costs. The insurer may have a special offer, for example for a planned trip to a risk area.
Ticks become active from a temperature of three to six degrees. It is therefore advisable to take protective measures, especially in spring and summer, but also in autumn. Ticks like to sit in vegetation close to the ground (usually at a height of 30 to 60 centimetres).
To avoid contact with the parasites, it helps to cover your arms and legs with long clothing when going for a walk, to avoid the undergrowth as much as possible and to apply anti-insect repellent as a precaution before spending time in nature.
If flu-like symptoms such as a severe headache and high fever occur one to four weeks after a tick bite (see also TBE: Symptoms), a doctor should be consulted. This also applies to neurological complaints such as signs of paralysis, balance disorders or numbness. It could be a beginning TBE.
If neurological signs appear suddenly and get worse within hours, the emergency doctor must be called (emergency number: 112). If there is a concrete suspicion of TBE, the patient is usually admitted to the hospital and medically monitored.
If, after a few days or weeks, a circular reddening occurs around the bite site – the so-called reddening – you should also go to the doctor immediately. It could be Lyme disease that needs to be treated with antibiotics as soon as possible.
Supposedly harmless – a tick bite can even trigger a stroke: How to protect yourself from Lyme disease
In Germany, around 400 to 500 people become infected with the TBE virus every year. The incubation period, i.e. the time between infection and the appearance of the first symptoms, is seven to 14 days on average – in exceptional cases up to 28 days.
The classic course of a TBE extends over two phases.
Depending on the location of the inflammation, there are three different types:
There is no special antiviral therapy against the TBE pathogen. The treatment aims to relieve the symptoms and thus support the body in fighting the virus. The classic measures include:
If there is a suspicion of a particularly severe course (usually due to meningoencephalomyelitis), the patient is admitted to the intensive care unit. There, the vital functions, such as the regular heartbeat or breathing, are monitored and countermeasures are taken in the event of complications.
About 30 to 40 percent of those who are seriously ill have to contend with long-term consequences. They suffer from headaches and fatigue, are emotionally unstable and less resilient than usual. Neurological failure symptoms such as paralysis or problems with concentration, memory, coordination, speech and hearing can also occur.
The same applies here: In the case of a combined inflammation of the brain, the meninges and the spinal cord, the risk of permanent symptoms is higher than in the case of pure meningitis. One to two percent of the seriously ill die every year from TBE.
First, the doctor asks the patient about certain TBE indications (anamnesis interview). He would like to know exactly what the symptoms are, whether a tick bite is known in the past few weeks, whether he has stayed in a TBE risk area and whether the patient has been vaccinated against TBE. The conversation can provide a first indication of an infection.
In order to gain certainty, physical examinations are then necessary. To do this, the doctor takes blood and has it checked in the laboratory for increased inflammation levels and TBE-specific antibodies. The so-called IgM antibodies against the TBE virus are visible after two to four weeks – the IgG antibodies one to two weeks later. Both markers must be present.
In addition, cerebrospinal fluid is obtained from the brain and spinal cord via a small puncture in the spinal cord canal and also examined for specific antibodies. The cerebrospinal fluid examination provides clear evidence of a TBE infection. A conspicuous blood test alone is only of limited value.
In order to rule out other diseases or possible brain damage, the doctor usually also carries out a magnetic resonance imaging. The imaging process provides high-resolution insights into the brain – and shows TBE-typical abnormalities such as signal changes in the thalamus (area in the diencephalon where sensory impressions arrive and are passed on to the cerebrum).
If there is evidence of TBE, the doctor and laboratory are obliged to inform the responsible health authority within 24 hours of the diagnosis. The Robert Koch Institute collects the data to get an overview of TBE cases in Germany.
This article was written by Janina Schrupp , medical editor
You might be interested in: PUSH – flu-like symptoms – sick after the tick bite? When to go to the doctor
The original of this post “FSME – a tick bite with serious consequences: How to recognize symptoms and protect yourself” comes from FOCUS doctor search.
