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Chapter 11: General epidemiology of TBE

known endemic area of low activity) to 35% in mammalian flavivirus (TBMF) species.
the Black Forest area, a highly endemic region (https://talk.ictvonline.org/ictv-reports/
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for TBE. Also a number of game animals have ictv_online_report/positive-sense-rna-viruses/
been tested as indicator animals for TBEV w/flaviviridae). They distinguish single virus
circulation. species according to several characteristics:
• Nucleotide and deduced amino acid
These studies, in Germany but also in other sequence data.
European countries (e.g. Denmark), showed • Antigenic characteristics.
high seroprevalence rates against TBEV. • Geographic association.
Studies in Germany showed the sero- • Vector association.
prevalence rate in red deer and reindeer in • Host association.
the former German Democratic Republic was • Disease association.
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up to 72% positive. A similar rate of 83% was • Ecological characteristics.
reported in a study from the Danish island of
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Bornholm, also in the red deer population. A However, this actual species description no
study in red deer from Slovakia showed lower longer includes many of the known and
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antibody rates of 35%. ecologically different TBMF, as no virus
subtypes or strains below species level are
listed. However, there is a number of
In natural transmission cycles of the flaviviruses with specific names often found in
boskematic type, the testing of antibody rates literature, which cause severe human and
in farm animals may give good evidence of animal disease. The known subtypes of TBMF
TBEV transmission and also of the risk of
are listed in Table 4 including some features
alimentary TBEV transmission. Therefore, a
regarding their geographical distribution and
number a seroprevalence studies in cows, epidemiology.
sheep, and goats from different countries are
also available. In most available studies, these All viruses listed are genetically closely related
data show that the seroprevalence rate is to the viruses of the TBEV complex. Therefore
around 5%. There are some exceptions in besides their medical and veterinary
Germany. In the former German Democratic importance they also play a role regarding the
Republic, an antibody prevalence rate of 60% diagnosis of flavivirus diseases due to cross-
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in cows was reported. A recent study in reactivity of antibodies with TBEV antibodies
several federal states of Germany revealed in areas of overlapping geographical
seroprevalence rates of 0% to 43% in goats distribution. For some of the viruses (Omsk
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and sheep. The patchy distribution of high hemorrhagic fever, Louping ill virus Kyasanur
antibody rates in these animals correlated Forest disease virus) in laboratory tests the
only in part with the presence of human TBE neutralizing cross-reaction of TBEV vaccine
disease. induced antibodies was shown. However, no
data are available on the field effectiveness of

TBEV vaccines against these viruses.
Other tick-borne mammalian
flaviviruses Acknowledgments: ST was supported by State
funded budget project of ICBFM SB RAS
The International Committee on the #AAAA-A17-117020210027-9.
Taxonomy of Viruses (ICTV) lists in the genus
Flavivirus a total of eight tick-borne
Contact: gerharddobler@bundeswehr.org

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