Page 393 - TBE_Book_V2_2019

Chapter 12b: TBE in Slovakia

Continuation of Table 1: Virus, vector, transmission of TBE in Slovakia

 Kurínec, 1982: 0.8% nymphs and 6% male ticks (I. ricinus) in south-central
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Slovakia
 Carpathian and Pannonian types of TBE natural foci, 1972–1982: The
proportion of infected ticks in both types of natural foci was 1.7% in total. In
Carpathian elementary foci (ranging from 0.4% to 4.1%; average 2.5%
infected ticks). In Pannonian elementary foci (ranging from 0.07% to 6.0%;
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average 0.9% infected ticks)
Infected tick  Western and Central Slovakia, 1980-1984: Western Slovakia, April–July 1980
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species (%) (0.7%), May 1984 (0.1%), Central Slovakia April–May 1982 (0.2%)
 Western Slovakia, 1985–1990: In Slovakia surveillance of TBEV in ticks,
carried out during 1985–1990 by the Virology Institute of Slovak Academy of
Sciences in Bratislava, showed that the TBEV spread rates among ticks ranged
from 0.30% (Jarok, Bardoňovo in 1987) to 0.38% (Malacky in 1990) in the 25
sites in the western region (data not published)
 Žiar nad Hronom, Banská Štiavnica a Žarnovica, 2002-2007: In the small
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sample of 142 ticks tested, there were 4.98% infected with TBEV

During 2007–2016, we have observed a growing trend in the number of TBE
outbreaks. A total of 26 outbreaks (those with 2 or more people) were
responsible for 142 TBE cases (13.9%) in studied period. There were 13 family
outbreaks with at least 2 linked TBE cases in a single outbreak. Larger outbreaks
with 3 and more cases were recorded 13 times. The highest number of
outbreaks (6) was recorded in 2013 (4 family outbreaks, 2 large outbreaks). In
2016, there was the largest number of TBE cases (44) reported in a single
outbreak over the past 30 years. 10
The most probable and also confirmed common factor in the transmission of
TBEV during outbreaks was goat milk and its products (61.5%, 16 outbreaks).
Sheep’s milk and products have caused probably 7 outbreaks (26.9%) and cow’s
milk was the probable cause of 2 TBE outbreaks (7.7%). In one TBE outbreak, the
Dairy product probable TBE transmission factor was mixed goat and sheep milk reported.
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transmission In the majority of outbreaks (22) the probable transmission factor of TBEV was
identified epidemiologically. Sheep cheese was considered as TBEV transmission
factor in TBE outbreak with the highest number of TBE cases (44) over the past
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30 years by retrospective case control study.
In 4 outbreaks TBEV was serologically confirmed in goats. In 3 outbreaks TBEV
was tested directly in sheep milk. In 1 outbreak the sheep milk was TBEV
positive, however it was not the milk from which the incriminated cheese was
made. In other 2 outbreaks TBEV was not found in the sheep milk.

2018 again was a peak year for alimentary transmission: In 5 outbreaks together
21 TBE cases were recorded, 3x from consumption of sheep cheese, 1x from
consumption of goat cheese, 1x from consumption of goat milk, in all cases the
TBEV was detected in milk.

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