Table 1. Overview of TBE in CEVAG countries^{1, 16}.

Country	Notifiable disease	Natural foci	Case definition	Incidence rates (cases per 100,000 population)a
Bulgaria	No	Of negligible epidemiological significance	No Encephalitis cases are reported in bulk irrespective of the cause	N/A
Croatia	Yes, mandatory since 2007	Northwestern and eastern regions New foci emerging south of the river Sava	N/A	2006–2011: 1.1 (Zagreb region)
The Czech Republic	Yes, since 1954 (since 1971 laboratory confirmed cases only)	Endemic in most areas Highly endemic areas include: Southern Bohemia, Berounka	Clinical symptoms (signs of aseptic meningitis/meningoencephalitis with proven neuroinfection in CSF). Presence of specific anti-TBEV antibodies.	2009: 7.8 2010: 5.6 2011: 8.2
Estonia	Yes, since 1949	Endemic Highly endemic areas include: western (Pärnumaa, Läänemaa), and eastern (Ida-Virumaa) regions, Saaremaa and Hiiumaa (Western islands) and southeastern region (Polvamaa, Tartumaa)	Possible: typical case history (biphasic infection) with epidemiological links (e.g., tick attack) Confirmed: clinically compatible case with positive laboratory tests Laboratory testing: ≥ 4-fold increase in antibody titer in paired serums or IgM antibodies in serum/CSF or positive PCR	1998: 27.0 2008: 6.7 2009: 13.3 2010: 15 2011: 18.7
Hungary	Yes, since 1977	Endemic Highly endemic areas include: western region and along the river Danube (Zala, Somogy and Vas), northern region (Nógrád) and around Lake Balaton	Aseptic meningitis, encephalitis or meningoencephalomyelitis laboratory confirmed Hospitalization is not necessary for diagnosis	Until 1996: 1.3–3.8 1997–2000: 0.67
Latvia	Yes, since 1955	Endemic Highly endemic areas include: northwestern regions (near the coast) of Talsu and Ventspils	No official case definition	2002: 6.52 2003: 15.66 2005: 6.2 2006: 7.41 2007: 7.5 2008: 8.10 2009: 14.6 2010: 21.97 2011: 97.21 (Kuldīgas region)
Lithuania	Yes, since 1960	Endemic Highly endemic areas include: Kaunas, Panevėžys and Šiauliai	No official case definition, but reported cases are serologically proven hospitalized TBE cases	2003: 100 (Panevėžys) 2004–2008: 6.9–13.5 2009: 17.4
Poland	Yes, since 1970	Endemic in much of the country Highly endemic areas include: northeastern (Bialystock) and southwestern regions	Possible: clinically compatible case and onset of illness during periods of increased tick activity (April–November). Probable: clinically compatible case and increased probability of infection during previous 6 weeks (living in or visiting to endemic areas), and demonstration of specific IgM antibodies in serum, with no history of vaccination against any flaviviral disease during the previous 3 mo Confirmed: clinically compatible case and demonstration of specific IgM and IgG antibodies in serum, or demonstration of intrathecal synthesis of specific IgM or IgG antibodies, detection of specific anti-TBEV antibodies by neutralization test, or positive virus isolation from tissues, blood or CSF	2003: 0.89 2009: 0.52
Romania	Yes, since 1996	Endemic emergent course and natural foci in full territorial expansion Highly endemic areas include: Tulcea district, Transylvania at the base of the Carpathian Mountains and the Transylvanian region	No official case definition Clinical manifestation and diagnostic tests	N/A
Slovakia	Yes, since 1950	Endemic Highly endemic areas include: Trenčín region in the northwest New foci identified in the East	No official case definition	2006: 1.7 2007: 1.1 2008: 1.5 2009: 1.4 2010: 1.7 2011: 2.0 (8.35 in the Trenčín region)
Slovenia	Yes, since 1977	Endemic Highly endemic areas include: Gorenjska and Koroska	Confirmed TBE case: fever, clinical signs/symptoms of meningitis or meningoencephalitis, elevated CSF cell count (> 5x105 cells/l), and serum IgM antibodies to TBEV and/or IgG seroconversion	1991–2011: 57.2–76.9 (Gorenjska and Koroska) 2000–2009: 7.6–18.6 2006: 33.4 (aged 55–64 y)
Turkey	No	Very scarce data on TBEV and no published diagnosed/reported cases	No official case definition	N/A

CSF, cerebrospinal fluid; N/A, Not available; PCR, polymerase chain reaction; TBE, tick-borne encephalitis; TBEV, tick-borne encephalitis virus. ^aNationwide rates, at least specified.