Page 435 - TBE_Book_V2_2019

Chapter 13: TBE as a matter of public health

As a response to all these public health also become an international public health
challenges, and to encourage the control of problem because of the increasing mobility of
TBE in Eurasia, an international effort was people traveling to risk areas. Today, the risk
launched in 1999 with the aim to investigate of infection is especially high for all people
and alleviate this situation. International living in or visiting endemic areas who pursue
experts created a new body, the International leisure activities outdoors. In most regions,
Scientific Working Group on Tick-Borne the main risk has shifted from an occupational
Encephalitis (ISW-TBE). This Working Group to a leisure time health risk. As a result, over
gathers data from internationally recognized the last 30 years, a continuous increase in TBE
3
scientific experts from TBEV endemic and non- morbidity has been observed in Europe, and
endemic regions with extensive personal both the importance and awareness of TBE
experience in the field and a high level of have increased in Europe.
commitment to improving the knowledge of
and response to TBE. 1 Circulation of TBEV also depends on the
population density of ticks and their hosts (see

Chapter 3). Virus prevalence in the tick
population within TBEV foci is determined by
Epidemiology of TBE from the
the duration of viremia in hosts because the
public health perspective virus is mostly ingested by ticks while
engorging on a viremic host. Virus circulation
As outlined in more detail in Chapters 3, 11, in nature is also influenced by the percentage
and 12 of this book, TBEV is mainly of immune hosts in a particular region.
transmitted through tick bites. Food-borne
infections through unpasteurized milk and Climate is another determinant of tick-borne
milk products have no major impact in terms disease dynamics. Even if major discrepancies
of epidemiology, but are of increasing in annual TBE incidences cannot be explained
importance due to the growing popularity for by recorded temperature increases alone, the
more ‘natural’ (unprocessed and raw/ seasonal shifts in reported cases of TBE in
unprepared) foods. In contrast to the central and northeastern Europe suggest that
otherwise sporadic cases, food-borne TBE- TBEV transmission dynamics have changed –
infections occur as outbreaks with a high perhaps as a result of warmer temperatures
4
number of cases (see chapter 11). and changes in humidity.
Consequently, these types of TBE infection
occur even in western European countries. Of note, a much higher percentage of TBE-
This has become a major public health debate positive individuals (whether locals or
pitting ‘healthy food’ activists and enthusiasts travelers) has been observed among risk
5
against health officials with obligations to groups such as:
enforce food regulations. Thus, governments • individuals working in agriculture and
must find solutions.
forestry
Most natural TBE foci are well described, but • hikers, ramblers, joggers, and other
new TBE areas have emerged to date (e.g., people engaged in outdoor sports
Japan and The Netherlands, see Chapter 12b) • foragers of mushrooms and berries
and latent TBEV-foci reemerge. Approximately • anyone who spends time outdoors (e.g.
10,000–12,000 cases of TBE are reported each having a picnic, walking, gardening, dog-
year, but this figure is believed to be an walking, or sunbathing on the grass).
2
underestimate of the actual number. TBE has

430
437