Page 116 - TBE_Book_V2_2019

Chapter 5: TBE in adults

Photo 2. Photo 3.

TBE with affection of the brain stem.

In a recent Polish study a median incubation
period as long as 22 days (range, 4-34 days)
38
has been reported However, in a case of
food-borne TBEV transmission, the incubation
period may be even shorter and depends
upon the number of viable virus particles
ingested with food. 3-4 days have been
39
reported by Hudopisk et al. and by Dumpis
40
et al. in a recent outbreak of alimentary TBE
in Austria, the length of the incubation period
41
ranged between 9 and 14 days.
Symptoms of TBEV infection usually appear in
Movements are limited to the hands, due to a 2-phase course. In order to harmonize the
bilateral flaccid paralysis of the arms, shoulders, use of terminology, TBEV infection is
and the levator muscles of the head
categorized into a first phase, which
progresses to a second (neurological) phase of
Time frames of the clinical the disease. Sometimes, the disease
presentation and definitions progression is terminated after the first phase;
this clinical pattern is termed ‘abortive’.
The incubation period is difficult to assess in Monophasic disease expresses only 1 phase of
many TBE cases, because tick bites often the disease with neurological symptoms. The
remain unnoticed. There are few data and typical course of the infection exhibits the
only rough estimates about the percentage of aforementioned 2 phases and is called
infected individuals who develop symptomatic ‘biphasic’. The TBEV-Sib might even cause a
2
disease. Published data suggest an average chronic disease. 38,39
incubation period of 7–10 days (range, 4–28
days) after a bite of an infected tick. 8,37

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