Tick-borne encephalitis emergence as the third leading cause of encephalitis/meningoencephalitis in western Auvergne-Rhône-Alpes, France
Abstract
OBJECTIVES: In 2017, the first autochthonous cases of tick-borne encephalitis (TBE) were reported in the region of Saint-Étienne, a forested and mountainous area in Auvergne-Rhône-Alpes (AURA), France. We aimed to describe the frequency of TBE among patients in this area with acute and subacute neurological symptoms and to characterize the confirmed TBE cases. METHODS: We included patients over two years of age with neurological symptoms evolving for up to three months and having undergone cerebrospinal fluid (CSF) analysis between January 1, 2021 and December 31, 2023 at Saint-Étienne University Hospital. We retrospectively analyzed available CSF and/or serum for antibodies against TBE virus (TBEV) by means of enzyme-linked immunosorbent assay and chemiluminescent immunoassay, respectively. Seroneutralization testing confirmed positive specimens. RESULTS: Among the 544 included patients, 84 had a nervous system infection, including seven cases of TBE. TBEV represented the second cause of infectious encephalitis/meningoencephalitis (six cases), along with varicella-zoster virus (six cases) and after herpes simplex virus (seven cases). TBEV was also responsible for one case of meningitis. Overall, TBEV ranked among the first five causes of central nervous system infection. We retrospectively diagnosed one patient through systematic screening. In the remaining six cases, the median time to diagnosis was 23 days (range 6-157). All patients lived in rural autochthonous areas, including four in the Pilat Massif, where the estimated annual incidence rate was 13 cases per 100,000 inhabitants. None died. CONCLUSIONS: In Western AURA, TBE needs to be systematically screened in patients presenting with evocative symptoms, and prevention should be prioritized.
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BibTeX
@article{mayer2026tickborne,
title = {{Tick-borne encephalitis emergence as the third leading cause of encephalitis/meningoencephalitis in western Auvergne-Rhône-Alpes, France}},
author = {Émilie Mayer and Aurélie Velay and Céline Cazorla and Nazli Ayhan and Laura Pezzi and Anne Carricajo and Maëlle Detoc and Marie-France Lutz and Anne Frésard and Martin Fayolle and Oulfa Boussetta-Charfi and Florent Rousset and François Ballereau and Amandine Gagneux-Brunon and Jean-Philippe Camdessanché and Sylvie Pillet and Elisabeth Botelho-Nevers},
journal = {Infectious Diseases Now},
year = {2026},
month = oct,
doi = {10.1016/j.idnow.2026.105281},
url = {https://hal.science/hal-05785789v1},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Tick-borne encephalitis emergence as the third leading cause of encephalitis/meningoencephalitis in western Auvergne-Rhône-Alpes, France
AU - Émilie Mayer
AU - Aurélie Velay
AU - Céline Cazorla
AU - Nazli Ayhan
AU - Laura Pezzi
AU - Anne Carricajo
AU - Maëlle Detoc
AU - Marie-France Lutz
AU - Anne Frésard
AU - Martin Fayolle
AU - Oulfa Boussetta-Charfi
AU - Florent Rousset
AU - François Ballereau
AU - Amandine Gagneux-Brunon
AU - Jean-Philippe Camdessanché
AU - Sylvie Pillet
AU - Elisabeth Botelho-Nevers
PY - 2026
DA - 2026/10/08
JO - Infectious Diseases Now
DO - 10.1016/j.idnow.2026.105281
UR - https://hal.science/hal-05785789v1
AB - OBJECTIVES: In 2017, the first autochthonous cases of tick-borne encephalitis (TBE) were reported in the region of Saint-Étienne, a forested and mountainous area in Auvergne-Rhône-Alpes (AURA), France. We aimed to describe the frequency of TBE among patients in this area with acute and subacute neurological symptoms and to characterize the confirmed TBE cases. METHODS: We included patients over two years of age with neurological symptoms evolving for up to three months and having undergone cerebrospinal fluid (CSF) analysis between January 1, 2021 and December 31, 2023 at Saint-Étienne University Hospital. We retrospectively analyzed available CSF and/or serum for antibodies against TBE virus (TBEV) by means of enzyme-linked immunosorbent assay and chemiluminescent immunoassay, respectively. Seroneutralization testing confirmed positive specimens. RESULTS: Among the 544 included patients, 84 had a nervous system infection, including seven cases of TBE. TBEV represented the second cause of infectious encephalitis/meningoencephalitis (six cases), along with varicella-zoster virus (six cases) and after herpes simplex virus (seven cases). TBEV was also responsible for one case of meningitis. Overall, TBEV ranked among the first five causes of central nervous system infection. We retrospectively diagnosed one patient through systematic screening. In the remaining six cases, the median time to diagnosis was 23 days (range 6-157). All patients lived in rural autochthonous areas, including four in the Pilat Massif, where the estimated annual incidence rate was 13 cases per 100,000 inhabitants. None died. CONCLUSIONS: In Western AURA, TBE needs to be systematically screened in patients presenting with evocative symptoms, and prevention should be prioritized.
SN - 2666-9927
SN - 2666-9919
ER -