Encephalitis — Symptoms
Symptoms — Encephalitis
Symptoms of encephalitis may be mild to begin with, but can become more serious over hours or days.
Occasionally the symptoms may develop gradually over several weeks or even months.
The first symptoms of encephalitis can be similar to flu, such as:
- a high temperature
- a headache
- feeling and being sick
- aching muscles and joints
Some people may also have a spotty or blistery rash on their skin.
But these early symptoms do not always appear and sometimes the first signs of encephalitis may be more serious symptoms.
More severe symptoms develop when the brain is affected, such as:
- confusion or disorientation
- seizures or fits
- changes in personality and behaviour, such as feeling very agitated
- difficulty speaking
- weakness or loss of movement in some parts of the body
- seeing and hearing things that are not there (hallucinations)
- loss of feeling in certain parts of the body
- uncontrollable eye movements, such as side-to-side eye movement
- eyesight problems
- loss of consciousness
There may also be symptoms of meningitis, such as a severe headache, sensitivity to bright lights, a stiff neck and a spotty rash that does not fade when a glass is pressed against it.
When to get medical advice
Dial 999 immediately to request an ambulance if you or someone else has serious symptoms of encephalitis.
It’s a medical emergency that needs to be seen in hospital as soon as possible.
Page last reviewed: 3 December 2019
Next review due: 3 December 2022
Tick-borne encephalitis virus (TBEV) of the family Flaviviridae. Three subtypes of the causative agent are known: the European (Western), the Far Eastern (spring-and-summer encephalitis) and the Siberian.
TBEV is transmitted by the bite of infected ticks (which often remain firmly attached to the skin for days) or occasionally by ingestion of unpasteurized milk. There is no direct person-to-person transmission.
Nature of the disease
Infection may induce an influenza-like illness followed, in about 30% of cases, by high fever and signs of central nervous involvement. Encephalitis developing during this second phase may result in paralysis, permanent sequelae or death. Severity of illness increases with age of the patient.
Tick-borne encephalitis (TBE) tends to occur focally even within endemic areas. Currently, the highest incidences of clinical cases are being reported from foci in the Baltic States, the Russian Federation and Slovenia. High incidencesare also reported from foci in the North-Western Federal Area of the Russian Federation. Other countries that have reported cases within their territories, or that are considered to be at risk because of focally high prevalence of the virus in ticks, include Albania, Austria, Belarus, Bosnia, Bulgaria, China, Croatia, Denmark, Finland, Germany, Greece, Hungary, Italy, Mongolia, Norway, Poland, the Republic of Korea, Romania, Serbia, Slovakia, Slovenia, Sweden, Switzerland, Turkey and Ukraine.
Risk for travellers
Travellers to endemic areas may be at risk during April to November. The risk is highest when hiking or camping in forested areas up to an altitude of about 1500 m.
Prevent blood-feeding ticks from becoming attached to the skin by wearing appropriate clothing, including long trousers and closed footwear, when hiking or camping in countries or areas at risk. The whole body should be inspected daily and attached ticks removed as soon as possible. The consumption of unpasteurized dairy products should also be avoided in those areas.