Page 198 - TBE_Book_V2_2019

Chapter 11: General epidemiology of TBE

Ixodes and Dermacentor. In at least 2 more During the last century a number of scientists,
expeditions to study the transmission of this especially from Russia and the Czech Republic,
disease (later named Russian Spring Summer studied in detail the landscapes that are
Encephalitis, and currently known as tick- associated with the occurrence of TBE.
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borne encephalitis [TBE]) Pavlovsky recog- Rosicky and Blaskovic defined landscape
nized that it was associated with specific types types of TBE natural foci (Figure 1).
of landscape, and from this observation he
developed his theory on the nature of human According to this classification, a theriodic
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diseases. focus is a focus in a forest with game animals
as the main vertebrate hosts for adult ticks. A
In his theory, Pavlovsky describes a natural boskematic focus is a focus where meadows
focus (“Nidus”) of a disease as an area where dominate and where farm animals are the
specific climate, vegetation, soil, and favorable main vertebrate hosts for adult tick stages.
microclimatic conditions exist so that vectors, The theriodic-boskematic form is a mix of the
donors, and recipients of infection find two, having both types of landscape.
favorable conditions to exist. In this respect a
natural focus of disease is related to a specific Another classification was made by Blaskovic
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geographical landscape. According to this et al., who categorized the natural foci
theory, humans acquire a zoonosis with according to their main geographic location
natural foci only if they stay in the territory of into Hercynian foci (located mainly in the
the natural focus in a definite season of the Central German Uplands), Carpathian foci
year and if they are attacked as prey by (located in the far southeastern part of
hungry vectors or come into contact with the Europe), and Pannonian foci (located at the
animal reservoir (via hunting), which have western part of the Hungarian Danube
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already acquired the infection as carriers or lowlands). Similarly, Korenberg et al. made a
donors of the respective agent. classification according to the main geographic
type (and not so much landscape type) for the
TBE foci in Eurasia (Figure 2).

Figure 1: Different landscape types of TBE natural foci
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(according to Rosicky and Blaskovic et al. )

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