The Detectability of the Viral RNA in Blood and Cerebrospinal Fluid of Patients with Tick-Borne Encephalitis.

BACKGROUND: The detection rate of viral RNA in tick-borne encephalitis (TBE) is low and variable between studies, and its diagnostic/prognostic potential is not well defined. We attempted to detect RNA of TBE virus (TBEV) in body fluids of TBE patients. METHODS: We studied 98 adults and 12 children with TBEV infection, stratified by the disease phase and presentation. EDTA blood and cerebrospinal fluid (CSF) samples were obtained upon hospital admission. RNA was extracted from freshly obtained plasma, concentrated leukocyte-enriched CSF, and whole blood samples, and real time PCR was performed with a Rotor-Gene Q thermocycler. RESULTS: TBEV RNA was detected in (1) plasma of one (of the two studied) adult patients with an abortive infection, (2) plasma of two (of the two studied) adults in the peripheral phase of TBE, and (3) plasma and blood of an adult in the neurologic phase of TBE presenting as meningoencephalomyelitis. No CSF samples were TBEV RNA-positive. CONCLUSIONS: The detection of TBEV RNA in blood might be diagnostic in the peripheral phase of TBE. The lack of TBEV RNA in the CSF cellular fraction speaks against TBEV influx into the central nervous system with infiltrating leukocytes and is consistent with a relatively low intrathecal viral burden.

Anti-TBE Intrathecal Synthesis as a Prediction Marker in TBE Patients.

Tick-borne encephalitis (TBE) is an emerging vector-borne disease in Europe caused by tick-borne encephalitis virus (TBEV), which belongs to Flaviviridae. Although most of the patients quickly recover from TBE, some require further neurological and psychiatric treatment due to persistent symptoms. The aim of the study was to evaluate the usefulness of an antibodies index for predicting the course of the disease and potential persistent sequalae. Sixty-six patients (49 males and 17 females, mean age 45.97 ± 13.69 years) with TBE hospitalized in the Department of Infectious Diseases and Neuroinfections, Medical University of Bialystok, Poland, in years 2016-2019 were included to the study. TBE antibodies titer in serum and CSF samples were measured with an Anti-TBEV ELISA (IgM, IgG) EUROIMMUN test. Patients who developed persistent sequelae after TBE had significantly lower IgG intrathecal index at admission. Additionally, IgG2/IgG1was significantly higher in patients who developed sequelae. IgG intrathecal index might be a useful tool for the prediction of TBE sequelae development.