Tick-borne encephalitis

Tick-borne encephalitis (TBE) is a viral infection spread to humans by the bite of a type of parasite known as a tick.

Information written and reviewed by Certified Doctors.

Contents

Introduction

Tick-borne encephalitis (TBE) is a viral infection spread to humans by the bite of a type of parasite known as a tick.

A tick looks like a small black or dark brown spider.

Initial symptoms of TBE are similar to flu and include:

  • fever (temperature of 38C (100.4F) or above)
  • headache
  • [tiredness]
  • muscle pain

In around 1 in 3 cases of TBE initial symptoms are then followed by additional symptoms.

These symptoms are caused by the virus spreading to the layer of protective tissue that covers the brain and spinal cord (meningitis) and /or the brain itself (encephalitis).

In some case these ‘second-stage’ symptoms can be relatively mild, such as:

  • feeling sick
  • being sick
  • increased sensitivity to bright lights

While in others the second-stage symptoms can be more wide-ranging, such as:

  • seizures (fits)
  • inability to speak
  • inability to control physical movements

Read more about the symptoms of tick-borne encephalitis.

Treatment

There is currently no cure for TBE so treatment is based on helping relieve symptoms and make a person feel as comfortable as possible until the infection has passed.

If a person only experiences initial symptoms of TBE then no treatment, other than over-the-counter painkiller ibuprofen to relieve symptoms such as fever and headache, is required.

If a person develops second-stage symptoms, then depending on the severity, they may need to be admitted to hospital. Hospital treatment may involve providing supportive treatments such as intravenous fluids, help with breathing and nursing care.

Read more about the treatment of tick-borne encephalitis.

How can you catch it

They are mainly found in forested areas of central, eastern and northern Europe, including Austria, Bosnia-Herzegovina, Croatia, Estonia, Latvia, Czech Republic, Slovakia, Germany, Hungary, Macedonia, Montenegro, Poland, Serbia, Slovenia, Switzerland, Russia and Ukraine.

There are also two sub-types of TBE known as:

  • Far Eastern – found in eastern Russia during spring and summer and in some countries in East Asia, particularly forested regions of China and Japan
  • Siberian – found in Siberia

The TBE virus is found naturally in small animals such as mice and voles and in domestic animals such as sheep, goats and cattle. Ticks are the main carriers of the virus, picking up the virus when they feed on the blood of an infected animal. Once the tick is infected with the virus, it carries this for life.

Humans become infected with TBE when they are bitten by an infected tick. The virus is present in the tick’s saliva, which contains a natural anaesthetic, so you may not notice you have been bitten. It is important to check your body regularly for ticks when in risk areas.

Ticks live in forests, woods, grasslands, riverside meadows, marshes, brushwood and shrublands. They usually live in the undergrowth, where they can easily get onto the clothes or skin of passers-by.

Very rarely, drinking unpasteurised milk from infected animals, especially goats, can expose you to the TBE virus.

A seasonal disease

TBE is a seasonal disease as different seasons of the year have a significant impact on tick activity.

In Europe tick activity starts in spring once the temperature reaches 6C (42.8F) and lasts until November when temperatures fall.

Tick activity peaks in May/June and September/October, but in fact most cases of TBE occur during summer months as this is when people are most likely to go hiking, camping and so on.

Some experts are predicting TBE could become more widespread due to climate change resulting in a trend of milder winters and warmer springs. This in turn would mean the ‘window of opportunity’ for tick activity would grow longer.

Complications

If the infection spreads to the brain there is a risk of a person experiencing long-term (and possibly permanent) after effects, such as:

  • worsening memory
  • problems with concentration and a shortening attention span
  • changes in behaviour, such as becoming more impulsive and having poor judgement

These sort of long-term after effects occur in around 1 in 10 people who have contracted TBE.

Read more about complications of tick-borne encephalitis.

Prevention

There is a vaccine that provides protection against TBE in around 9 out of 10 people who receive it. The vaccine is not given as part of the routine childhood vaccination schedule.

It is usually only recommended for people who are planning to work in, or travel in, parts of the world known to have moderate to high levels of infected ticks.

You can also protect yourself against ticks by taking common sense precautions, such as:

  • Wear long-sleeved tops and long trousers (tucked into socks). You can also treat your clothes with insecticides such as permethrin.
  • Apply insect repellent containing DEET to exposed skin.
  • Check your body for ticks regularly. Common places to find them are the hair line, behind the ears, elbows, backs of knees, the groin and armpits.

Read more about preventing tick-borne encephalitis and the tick-borne encephalitis vaccine.

Who is affected

There are an average 3,000 hospital admissions due to TBE in Europe every year (not including Russia).

People who regularly work in rural areas, such as woodcutters, farmers, and hunters, have an increased risk of exposure to TBE.

Hikers and campers in these areas can also have an increased risk.

But this could change in future if the disease becomes more widespread due to climate change. So it is still recommended you are vaccinated if you are at a potentially high risk of exposure.

Outlook

For most people with TBE the outlook is good. The infection can be unpleasant but usually passes within eight days.

But for the one third of people who experience the second stage of infection the outlook is much less favourable. Symptoms can persist for months and though uncommon, the infection can sometimes be fatal.

It is estimated that around 1 in 50 people who catch TBE will die from it.

Symptoms

Symptoms of tick-borne encephalitis (TBE) occur in two stages.

Stage one

The initial symptoms of TBE usually occur 7–14 days after a tick bite. Two-thirds of people infected with TBE get these symptoms, while the other third will have no symptoms.

Symptoms include:

  • fever (temperature of 38C (100.4F) or above)
  • headache
  • [tiredness]
  • muscle pain
  • feeling sick

These first-stage symptoms usually last between one and eight days. After this, there are no symptoms for the following 1–20 days.

Around one-third of those who experience first-stage symptoms go on to develop the second phase of the disease.

Stage two

The second phase of the disease starts with a sudden rise in temperature. The virus starts to affect your central nervous system (brain and spinal cord), which can result in:

  • meningitis - inflammation of the membranes surrounding the brain and spinal cord, and /or
  • encephalitis - inflammation of the brain

These conditions can sometimes cause paralysis (inability to move certain body parts).

(People can sometimes progress to second stage symptoms without having any first stage symptoms)

In the second stage of illness, children usually develop meningitis. Around one-third of people who experience second-stage symptoms will develop encephalitis. Adults over the age of 40 are particularly vulnerable to encephalitis. There is a higher risk of death in people over the age of 60.

Viral meningitis

Viral meningitis is not as serious as bacterial meningitis, which is life-threatening. But the viral form of the condition can still cause a range of unpleasant symptoms, including:

  • headaches
  • fever (temperature of 38C (100.4F) or above)
  • chills
  • muscle or joint pain

In severe cases of viral meningitis, symptoms can also include:

  • feeling sick
  • being sick
  • aversion to bright light (photophobia)

Read more about the symptoms of viral meningitis.

Symptoms of encephalitis

Encephalitis also usually begins with flu-like symptoms, such as a headache and generally feeling unwell.

More serious symptoms follow over the space of a few hours or days. These include:

  • a high temperature (38C (100.4F) or above)
  • feeling sick
  • being sick
  • changes in mental state, such as confusion
    drowsiness or disorientation
  • seizures (fits)
  • photophobia
  • inability to speak
  • paralysis
  • stiff neck
  • uncharacteristic behaviour, such as being unusually aggressive

Read more about the symptoms of encephalitis.

When to seek medical advice

Second-stage symptoms of TBE need to be treated in hospital.

Flu-like symptoms that rapidly get worse and change a person’s mental state should be treated as a medical emergency. Call for an ambulance.

Diagnosis

If a doctor thinks you may have tick-borne encephalitis (TBE), they will ask about your symptoms, medical history, where you have been travelling and if you think you may have been bitten by a tick.

They will then test your blood for antibodies to the virus. Antibodies are proteins produced by your immune system to fight infection. If antibodies are found, you may need further tests to confirm the results.

Further tests may include:

  • an MRI scan (brain scan to check for signs of inflammation indicating encephalitis)
  • a lumbar puncture, where a sample of your spinal fluid is checked for the TBE virus and signs of inflammation of the membranes covering the brain and spinal cord

Accessing healthcare abroad

In case of an emergency, it is a good idea to keep a list of important telephone numbers with you when travelling abroad. These should include:

  • the local emergency services number
  • the representative of the travel company you booked your visit with
  • your travel insurer (it is recommended you take out travel insurance that would cover the cost of any healthcare, and if necessary, the costs of returning you home)
  • the British consulate in the area you are visiting

Treatment

If you are infected with tick-borne encephalitis (TBE) and do not experience any symptoms, or only mild first-stage symptoms, you will usually get better without treatment. Iburofen or paracetamol can be taken to relieve any flu-like symptoms.

In cases of stage-two TBE, there is no specific medication used to treat the infection.

If you develop a severe form of viral meningitis and /or encephalitis, you need to go to hospital where you will be given supportive treatments such as intravenous fluids, help with breathing and nursing care to support your body while you recover.

Around 1 in 8 people with a second-stage infection need to be admitted to an intensive care unit (ICU), where doctors will aim to:

Read more about the treatment of viral meningitis and the treatment of encephalitis.

Complications

The American health organisation, the Centre for Disease Control, estimates that around 1 in 10 people who go on to develop a second-stage tick borne encephalitis (TBE) infection will experience long-term (and often permanent) after-effects of infection.

  • memory problems, which affect 70% of people who have complications
  • personality and behavioural changes, which occur in just under half of all people
  • aphasia – speech and language problems, which occur in around 1 in 3 people
  • epilepsy, which occurs in 1 in 4 affected adults and 1 in 2 affected children
  • changes in emotions, such as anxiety and anger; mood swings are also common
  • problems with attention, concentrating, planning and problem solving
  • physical and motor difficulties
  • low mood and a sense of feeling different
  • [fatigue] (extreme tiredness)

Individual care plans

Due to these complications, if you are recovering from encephalitis you may need specialised services, including:

  • a neuropsychologist – a healthcare professional specialising in brain injury and cognitive rehabilitation
  • an occupational therapist – they can identify problem areas in a person’s everyday life, such as dressing or getting to the shops, and help them devise practical solutions
  • a physiotherapist – a therapist who uses physical methods, such as massage, manipulation and exercise, to promote health and wellbeing
  • a speech and language therapist – they use specialist techniques to improve all aspects of communication

Before being discharged from hospital, your health and social care needs will be fully assessed.

An individual care plan designed to meet those needs will be drawn up for you.

If you are the primary carer of someone who is recovering from TBE, such as their spouse or parent, you should be invited to discussions about the care plan, and your own circumstances and requirements should be taken into account.

Caring for someone with emotional and behavioural problems can be stressful, so it is important you do not neglect your own mental and physical wellbeing. See Carers Direct - your own wellbeing for more information and advice.

Seeking further help

Seek additional help if you are experiencing problems after having TBE. Many healthcare professionals are unaware of the problems following TBE, and it can sometimes be a struggle to find the right help for you.

Prevention

Tick-borne encephalitis (TBE) can be prevented by avoiding tick bites when in risk areas.

Precautions

Protecting yourself

The best way to lower your risk of TBE is to avoid tick bites as much as possible when in risk areas:

  • Wear long-sleeved tops and long trousers (tucked into socks). You can also treat your clothes with insecticides such as permethrin.
  • Apply insect repellent containing DEET to exposed skin.
  • Check your body for ticks regularly. Common places to find them are the hair line, behind the ears, elbows, backs of knees, the groin and armpits.
  • Avoid eating and drinking milk and unpasteurised dairy products in countries where there is a high risk of TBE.

What to do if you find a tick

After a tick has attached itself to you, it may not start feeding for several hours. Adult ticks, once they have fed, can be up to the size of a coffee bean, but tick larvae can be tiny.

If you find a tick on your body, remove it as quickly as possible with a pair of tweezers or tick remover:

  • Place the tweezers as close as possible to your skin and pull the tick off firmly and slowly until the tick lets go of your skin (make sure you remove its head and mouth).
  • Avoid squeezing the body of the tick and the contents of its stomach into the site of your bite.
  • After you have removed the tick, wash your hands and the affected area with soap and water.

There is also an effective vaccine against tick-borne encephalitis. Read more TBE vaccination.

Vaccination

There is a vaccination available to protect against tick-borne encephalitis (TBE).

TBE vaccine is recommended for anyone who plans to live or work in a high-risk area, or hike and camp in these areas during late spring or summer. It provides protection for nine out of ten people receiving it.

Plan ahead. For full protection you should allow as much as three months before your trip for the vaccine to become effective.

The vaccine

The vaccination requires a course of three doses for full protection. The second dose is given one to three months after the first and provides immunity for about one year. A third dose, given five to 12 months after the second, provides immunity for up to three years.

The course can sometimes be accelerated. This involves two doses being given two weeks apart.

If you are under 60, you should have your first booster three years after your original course of the vaccine. Further boosters should be given every three to five years.

If you are over 60, you should have booster doses every three years. This is because studies have shown that TBE immunity (resistance) does not last as long in older people.

Side effects

Any reactions to the TBE vaccination are usually mild and do not last long.

Adults may experience swelling, redness and pain at the site of the injection. Other possible side effects include tiredness, headache, muscle pain and nausea.

Children usually experience mild side effects such as restlessness, headache, pain and tenderness where they have been injected. They may also experience a fever (temperature of 38ºC/100.4ºF or above) after their first dose. This usually disappears within 24-48 hours. Serious side effects are rare.

Precautions

You should not have the vaccination if:

  • you are allergic to eggs, as the vaccine contains egg protein
  • you have a fever

You must also tell your doctor or nurse if any of the following apply to you:

  • you have a condition, or are receiving treatment, that affects your immune system
  • you have a brain disorder
  • you are pregnant
  • you are breastfeeding

You may still be advised to have the vaccine, but your doctor or nurse will need to check your risk with a travel medicine specialist before giving it to you.

Content supplied by NHS Choices