• TBE appears with non-characteristic clinical symptoms, which cannot be distinguished from oth-er forms of viral encephalitis or other diseases.
• Cerebrospinal fluid and neuro-imaging may give some evidence of TBE, but ultimately cannot confirm the diagnosis.
• Thus, proving the diagnosis “TBE” necessarily requires confirmation of TBEV-infection by detec-tion of the virus or by demonstration of specific antibodies from serum and/or cerebrospinal fluid.
• During the phase of clinic symptoms from the CNS, the TBEV can only rarely be detected in the cerebrospinal fluid of patients.
• Most routinely used serological tests for diagnosing TBE (ELISA, HI, IFA) show cross reactions resulting from either Infection with other flaviviruses or with other flavivirus vaccines.