**6.1. Abortive form of TBE**

Data on the frequency of this clinical manifestation of the disease caused by European TBEV subtype are conflicting. According to some reports it represents more than a half of all clinically manifested TBEV infections [32, 52]. However, this is not confirmed by the results of a prospective clinical trial on the etiology of acute febrile illness after a tick bite carried out by Lotric‐Furlan and coworkers: of the 56 patients diagnosed with TBEV infection during the initial phase of illness, in 55 (98.2%), CNS involvement with pleocytosis later appeared, whereas only one (1.8%) had an isolated initial phase of the disease [51, 53]. In the Russian publications, this clinical manifestation is named "fever form" and is reported to represent up to 50% of all clinical presentations of TBE [54]. Abortive form of TBE most frequently presents itself by a moderate fever, headache, fatigue, and other nonspecific symptoms of the initial phase of the disease. The fever usually subsides in a few days and the disease does not have long-term consequences [55, 56].
