A survey on cases of tick-borne encephalitis in European countries.

The European Network for Diagnostics of "Imported" Viral Diseases (ENIVD) is finalising a project to improve the diagnostic and monitoring of encephalitis viruses in Europe. Part of this study was to analyse the present surveillance situation for tick-borne encephalitis (TBE), which is the most important flavivirus infection of the central nervous system in the European Union (EU) and Russia. A questionnaire was mailed to contact points in all Member States of the EU and three non-EU countries (Norway, Russia and Switzerland) to summarise their TBE surveillance and prevention activities. Information was requested on case definition, type of laboratory tests for TBE diagnostics, investigations regarding tick-transmitted diseases, mapping of endemic foci, vaccination programmes, and recommendations for travellers. The survey gives an overview of the existing epidemiological and laboratory sources of information and the number of TBE cases from 2004 until 2007, but also showed that, in particular, case definitions, diagnostic assays for confirmation, and methods/indicators for mapping risk areas differ widely across the participating countries. The data will help to develop recommendations for the standardisation and quality control or TBE surveillance and diagnostics.