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Chapter 12a: Epidemiology by country – overview

Burden of disease and case In addition to the use of different case
definitions and case classifications, there is a
definition lack of implementation of routine diagnostics
in patients with encephalitis particularly with
To date, tick-borne encephalitis virus (TBEV) regard to detecting TBE. This is exemplified by
foci have been identified in Europe, Siberia, the Polish experience: between 2004 and
far-eastern Russia, northern China, South 2008, only 39% of the country’s hospitals had
Korea, and Japan. Roughly 10,000– 12,000 tick access to TBEV-serology. Therefore a pilot
-borne encephalitis (TBE) cases are identified project of enhanced surveillance for TBE was
annually from countries where the disease is implemented in 2009. Testing for TBE in
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reportable. Mortality rates between 0.2% to patients with signs of meningitis or
20% are reported, depending on region and encephalitis in the entire country doubled in
3
perhaps on viral subtype. Severe long-term 2009 compared with previous years, and 38
sequelae of TBE are well described both in new endemic districts were identified. Seven
children and in adults (see Chapters 6 and 8). of the new endemic districts were located far
away from previously known endemic foci,
Because TBEV is present in reservoir animals most notably in the northwest of the country.
in nature, eliminating or eradicating the
disease is impossible. Thus, TBE is an Finally, vaccine uptake may substantially
important concern for the individual who modify the number of cases in a TBE risk area,
becomes infected, but the disease is also of as exemplified again by Austria, where in the
public health relevance, as acknowledged by last decade less than 100 cases are reported
the World Health Organization (WHO) in all annually; this number was up to 700 cases
3-5
position reports from 1983 to date (2011). In annually before the introduction of a
addition, in 2012 the European Center for vaccination program. TBE vaccine uptake in
Disease Prevention and Control (ECDC) Austria is around 84%. Neighboring countries
decided to add TBE to the list of mandatory with lower vaccine uptake continue to have
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notifiable diseases and provided for the first increasing TBE case numbers. The following
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time ever a uniform disease case definition figures show countries with their respective
(Table 1). current vaccination recommendations and
vaccine reimbursement policies (Figure 1,
As the ECDC case definition and reporting Table 2).
have not been implemented around the globe
and not even throughout Europe, data on the To date, only Austria has a national universal
burden of disease from different countries due vaccination recommendation for the whole
to the TBEV are difficult to compare. population established long time ago.
Moreover, even if clear case definitions are Switzerland is the only other country that
provided and routinely implemented by local followed same pathway, in February 2019 the
authorities, differences between countries entire country – except the cantons of Geneva
exist regarding the classification of clinical and Ticino – is now defined as a TBE risk area
diseases associated with TBEV infections. For by the FOPH (BAG) and VTC (EKIF). TBE
example, Austria reports only “serologically vaccination is recommended for all persons in
proven hospitalized cases,” whereas the Czech Switzerland (≥6 years), who are tick-exposed
Republic reports any case with “clinical and and either live in a risk area or stay there
laboratory signs of aseptic meningitis/ temporarily; for children between 1 and 5
meningoencephalitis, not necessarily associat- years, the situation should be individually
6
ed with hospitalization.” assessed. The entire Swiss population has a

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