Brief overview
- What is TBE? TBE stands for early summer meningoencephalitis. This is a virus-related acute inflammation of the meninges (meningitis) and possibly also the brain (encephalitis) and the spinal cord (myelitis).
- Diagnosis: doctor-patient consultation (anamnesis), blood tests, taking and analysis of a nerve fluid sample (cerebrospinal fluid puncture), possibly magnetic resonance imaging (MRI).
- Treatment: only symptomatic treatment possible, for example with analgesics and antispasmodics. In case of neurological symptoms such as paralysis, possibly physiotherapy, occupational therapy or speech therapy. In severe cases, treatment in the intensive care unit.
TBE: Description
Early summer meningoencephalitis (TBE) is an acute inflammation of the meninges and often additionally of the brain and spinal cord. It is triggered by the TBE virus. In Germany, ticks almost always transmit TBE. Therefore, the disease is also called tick-borne encephalitis. Rarely, transmission occurs through virus-infected raw milk from goats, sheep and – extremely rarely – cows. TBE infection from person to person is not possible.
Not every tick bite leads to a TBE infection, and not every infection leads to illness: In the risk areas of Germany, on average only about 0.1 to 5 percent of ticks carry the TBE virus. In some areas, up to 30 percent of all ticks carry the TBE pathogen.
However, it should be remembered that the disease can be severe and even fatal: The healing process can take months. Sometimes permanent neurological impairments (such as concentration problems) remain. In about one in a hundred patients, TBE infection of the nervous system leads to death.
TBE: Frequency
People mainly become infected with TBE during outdoor recreational activities, such as camping or hiking. Most illnesses are observed in spring and summer.
Children get tick bites more often than adults and are therefore generally more at risk of contracting TBE. In children, however, the infection is usually mild and heals without permanent damage.
Do not confuse with Lyme disease
TBE: Symptoms
If TBE viruses have been transmitted in a tick bite, it takes some time before the first symptoms appear: The pathogen must first spread in the body and reach the brain. On average, about one to two weeks pass between the infection (tick bite) and the outbreak of the disease. This period is called the TBE incubation period. In individual cases, it can take up to 28 days for early summer meningoencephalitis to break out.
Two-phase course of the disease
The first signs of TBE are flu-like symptoms such as a general feeling of illness, fever, headache and aching limbs. Occasionally, abdominal pain also occurs. The symptoms are often dismissed as a cold or flu. After about a week, the symptoms subside and the fever drops again.
In a small proportion of patients, the fever rises again after a few days. This marks the beginning of the second phase of the disease. This manifests itself as follows:
- In about 40 percent of patients, meningitis is accompanied by encephalitis. Doctors then speak of meningoencephalitis.
- In about ten percent of patients, the spinal cord also becomes inflamed. This is called meningoencephalomyelitis.
- Very rarely, the inflammation of TBE is limited to the spinal cord alone (myelitis) or to nerve roots originating from the spinal cord (radiculitis).
The exact TBE symptoms in the second stage depend on the spread of the inflammation :
TBE symptoms in isolated meningitis
TBE symptoms in meningoencephalitis
If, in addition to the meninges, the brain is also affected by the inflammation (meningoencephalitis), further TBE symptoms appear: In the foreground are a disturbance of movement coordination (ataxia), impaired consciousness and paralysis of the arms, legs and cranial nerves. The latter can cause hearing, swallowing or speech disorders, for example. In addition, the inflammation of the brain can also cause seizures.
The most severe TBE symptoms can occur with meningoencephalomyelitis, which is the simultaneous inflammation of the meninges, brain and spinal cord. The spinal cord represents the connection between the brain and the rest of the body. If inflammation occurs here, the consequences can therefore often be observed all over the body:
TBE symptoms in children
In children and adolescents, TBE usually progresses with only nonspecific symptoms similar to those of a flu-like infection. Severe TBE symptoms are rarer than in adults. The disease usually heals without secondary damage in young patients.
Consequential damages of TBE
Severe courses of the disease and permanent damage from TBE occur particularly in older adults. They are almost never observed in children.
Double infection: TBE plus Lyme disease
Rarely, TBE viruses and Lyme disease bacteria are transmitted at the same time during a tick bite. Such a double infection is usually severe. Those affected can suffer permanent neurological damage.
Vaccination against TBE
Experts recommend TBE vaccination to all people living in TBE risk areas (see below) and to certain occupational groups (foresters, hunters, etc.). On the other hand, the vaccination is useful for travelers to TBE areas if there is a possibility of TBE infection (for example, during planned hiking tours).
You can read more about the effect and side effects of the vaccination against TBE in the article TBE vaccination.
TBE areas
TBE transmission is also possible in many other countries, such as Austria, Switzerland, the Czech Republic, Hungary, Croatia, Poland, Sweden and Finland. In Italy, France, Denmark and Norway, on the other hand, infection is rare.
You can find out more about the distribution of TBE viruses in Germany and abroad in the article TBE areas.
TBE: Causes and risk factors
TBE viruses come in three subtypes: In our country, the central European subtype is widespread. In the Baltic States, on the coasts of Finland and in Asia, the Siberian and Far Eastern subtypes occur. All cause similar clinical pictures.
TBE: Routes of infection
The ticks can “catch” the TBE pathogen when they suck blood from infected wild animals (especially small rodents such as mice). The animals carry the pathogen without contracting TBE. If an infected tick now bites a human during its next blood meal, it can introduce the TBE virus into the human bloodstream with its saliva.
A direct transmission of TBE from person to person is not possible. Therefore, infected or diseased persons are not contagious!
TBE risk factors
It is not possible to predict how severe an infection will be in individual cases. In most cases, a TBE infection causes no or only mild symptoms. Severe courses of the disease are rare. Those affected are almost exclusively adults. Age plays an important role here: the older a patient is, the more often TBE takes a severe course and the more often it leaves permanent damage.
TBE: Examinations and diagnosis
The saliva of a tick contains, among other things, anesthetic substances, so that many people do not feel the tick bite. For the doctor, this means that even if the patient cannot remember a tick bite, this does not rule out TBE.
The diagnosis of TBE is established when both specific IgM and IgG are detectable in the blood, the patient exhibits the appropriate disease symptoms, and has not been vaccinated against TBE.
In addition, the physician can take a sample of the cerebrospinal fluid (CSF) (CSF puncture). This is examined in the laboratory for specific antibodies and traces of the genetic material of the TBE viruses. However, the viral genome can only be detected in the CSF during the first phase of the disease. Later, only the immune system’s response to the pathogens – in the form of spcific antibodies – can be measured.
TBE is notifiable. Therefore, if a patient is diagnosed with acute TBE by direct virus detection (genetic material) or indirect virus detection (specific antibodies), the physician must report this to the responsible health department (with the patient’s name).
Examination of dead ticks?
- Even if the tick is infected with TBE viruses, this does not necessarily mean that it has transmitted the pathogens to the patient.
- Methods for detecting TBE viruses (and other pathogens) in ticks vary in sensitivity. So despite a negative test result (no TBE viruses detectable in the tick), the tick may still be infected and have transmitted the viruses.
TBE: Treatment
There is no causal TBE treatment, i.e. no therapy that specifically targets the TBE virus in the body. One can only support the body in its fight against the pathogen. The aim is to alleviate TBE symptoms and prevent long-term damage as far as possible.
For very persistent headaches, TBE patients are sometimes given opiates. These are powerful painkillers, but they can be addictive. They are therefore used only when absolutely necessary and in a very controlled manner.
In the case of neurological disorders such as movement or speech disorders, physiotherapy, occupational therapy or speech therapy may be useful.
In the case of severe TBE (for example, with impaired consciousness or respiratory paralysis), patients must be treated in the intensive care unit.
In most cases, TBE runs its course without complications and heals completely. This is especially true if the infection causes pure meningitis.
About three years after meningitis and encephalitis due to TBE, existing symptoms are not expected to improve significantly.
Overall, the risk of death from early summer meningoencephalitis is about one percent.
Lifelong immunity?
TBE: Prevention
An effective protection against TBE is the above-mentioned TBE vaccination. But you can do even more to prevent infection – and that is by avoiding tick bites as much as possible. To do this, you should heed the following advice:
- Apply a tick repellent to your skin before going into the woods and meadows. Note, however, that it only has a temporary effect and does not provide 100 percent protection.
- Do not touch wild animals such as mice or hedgehogs. These often have ticks!
Remove ticks properly
If you discover a sucking tick on your skin, you should remove it as soon as possible. To do this, use tweezers or a special instrument for tick removal. If you have neither at hand, you should still remove the bloodsucker as quickly as possible, for example with your fingernails.
After removing the tick, you should carefully disinfect the small wound.
In the following days and weeks, watch for possible signs of TBE (or Lyme disease). If such appear, you should immediately consult a doctor.
