Tick-borne encephalitis

What is tick-borne encephalitis?

Tick-borne encephalitis (TBE) is a viral infection that is spread by ticks. Ticks are spider-like creatures that are found outdoors but they are particularly common in grassy and wooded areas. Ticks can spread tick-borne encephalitis and Lyme disease when they bite a person. Tick-borne encephalitis is caused by the TBE virus (TBEV). Tick-borne encephalitis generally produces very mild, if any, symptoms in most people. In rare cases, the virus can infect the brain and cause long term damage (encephalitis). Very rarely, people who develop encephalitis can die. There are different types of tick-borne encephalitis around the world – the European type is the mildest one.

What are the symptoms of tick-borne encephalitis?

Most people who are bitten by a tick carrying the TBE virus do not get any symptoms at all. After about one week, some people who are infected, will get flu-like symptoms including:

  • high temperature
  • feeling tired and weak
  • headache
  • muscle aches
  • feeling sick

The symptoms usually go away on their own after about five days, but in a very small proportion of people the infection spreads to the brain and causes more serious symptoms beginning a few days or weeks later.

Where is tick-borne encephalitis found?

Tick-borne encephalitis, and the ticks that spread it, is very common in Eastern Europe. It is also found in southern Germany, Switzerland and Austria, and in parts of Scandinavia and Finland. A very small number of people are known to have caught tick-borne encephalitis in England. TBEV has been found in ticks in southern and eastern England. The risk of catching tick-borne encephalitis in the UK is very low.

Occasionally we see tick-borne encephalitis cases in Ireland, however, these have been cases brought into Ireland from another country. To date, there have been no cases of tick-borne encephalitis notified that have been caught in Ireland.

How do you catch tick-borne encephalitis?

In Europe, TBEV is carried by a particular type of tick (Ixodes ricinus). These ticks feed on blood from mammals (including humans) and birds. They bite the skin to obtain blood. When they bite the skin, they can pass on the TBEV. The risk of catching tick-borne encephalitis remains very low in countries that have ticks that carry tick-borne encephalitis.

In addition, in countries with high levels of tick-borne encephalitis, the disease can also be passed on by consumption of unpasteurised milk or milk products from infected animals, although this is extremely rare. Tick-borne encephalitis is not passed from one person to another.

How do I protect myself and my family from tick-borne encephalitis?

The best way to protect yourself against tick-borne encephalitis (and Lyme disease) is to protect yourself against tick bites. HPSC has information on what to do to reduce your chances of being bitten by a tick. The HSE has useful information about ticks as well.

Ticks are active from spring to autumn and can be found in both urban and rural environments. Ticks are most likely to be found in the following areas:

  • Shady and damp woodland clearings with grass
  • Open grassland, parkland, fields and bushes
  • Walking paths, especially those bordered by long grasses
  • Wooded and forested areas
  • Vegetation close to lakes and seaside beaches

See here for information on protecting yourself against Lyme disease – protecting yourself against Lyme disease will also protect you against tick-borne encephalitis.

If you are travelling outside Ireland, check whether you are visiting a place where tick-borne encephalitis is present. Tick-borne encephalitis can be found in rural and forested areas of central, eastern and northern Europe. The incidence varies widely, but the highest rates are reported from Lithuania, Latvia, Estonia, Slovenia and Czechia.

There is a vaccine against tick-borne encephalitis – you can get more information from your travel clinic.

Created: 09/05/2023