Key message 3: Tick-borne diseases are found only in certain geographical areas in Europe

The risk of contracting a tick-borne infection is determined by the overall number of ticks in the area (tick density), the proportion of ticks in the area that carry disease (tick infection rate), and human behaviour (exposure). People engaged in recreational or occupational outdoor activities in a risk area are at increased risk of tick bites.

Most ticks are not infected with TBE virus and the risk of infection is small. TBE virus-infected ticks are found only in certain risk areas, and within these risk areas only a fraction of the ticks carry the virus (0.1–5%). 

It is important to know where the TBE risk areas are and to take precautions to reduce the risk of infection if you are likely to be exposed. 

The number of reported TBE cases has increased in Europe in the last two decades. The mean number of TBE infections in Europe excluding Russia between 1990 and 2007 was 2805 cases per year, up 193% from a mean of 1452 cases per year (1976–1989). 

The geographical distribution of TBE infected ticks within regions and countries is such that the risk of infection can change dramatically from one area to another within short distances. Many TBE-endemic countries communicate updated information on the risk of tick-borne diseases within their borders. Always check with local authorities about the risk of infection.

Countries with increased risk of TBE include Austria, Slovakia, Hungary, the Czech Republic, the Baltic States, southern Germany and southern and eastern Sweden. TBE is prevalent in Russia all the way from the western border with Europe to its eastern border. The TBE virus strain in Russia causes more severe disease than the central European strain and fatalities are not uncommon. 

There is no common definition of what constitutes a TBE risk area in Europe. A TBE endemic area is an area where the TBE virus circulates between ticks and vertebrate hosts and can be transmitted to humans.