A new hot spot for tick-borne encephalitis (TBE): A marked increase of TBE cases in France in 2016

• DOI: 10.1016/j.ttbdis.2017.09.015
• Publication Date: 2017-09-28T07:17:24Z
• Authors: Aurélie Velay; Morgane Solis; Wallys Kack-Kack; Pierre Gantner; Marianne Maquart; Martin Martinot; Olivier Augereau; Dominique De Briel; Pierre Kieffer; Caroline Lohmann; Jean Dominique Po...; Emmanuelle Cart-T...; Xavier Argemi; Isabelle Leparc-G...; Sylvie de Martino; Benoit Jaulhac; Sophie Raguet; Marie-Josée Wendling; Yves Hansmann; Samira Fafi-Kremer
• Keywords: Adult; Male; Adolescent; Enzyme-Linked Immunosorbent Assay; Encephalitis Viruses, Tick-Borne; 03 medical and health sciences; [SDV.MHEP.MI]Life Sciences [q-bio]/Human health and pathology/Infectious diseases; Tick-borne encephalitis; Tick-borne diseases; Humans; Prospective Studies; Child; Aged; Retrospective Studies; [SDV.MP.VIR] Life Sciences [q-bio]/Microbiology and Parasitology/Virology; [SDV.MHEP.ME] Life Sciences [q-bio]/Human health and pathology/Emerging diseases; Aged, 80 and over; [SDV.MHEP.ME]Life Sciences [q-bio]/Human health and pathology/Emerging diseases; 0303 health sciences; Incidence; Zoonotic infection; Middle Aged; Antibodies, Bacterial; 3. Good health; Immunoglobulin M; Immunoglobulin G; [SDV.MP.VIR]Life Sciences [q-bio]/Microbiology and Parasitology/Virology; [SDV.MHEP.MI] Life Sciences [q-bio]/Human health and pathology/Infectious diseases; Female; France; Seasons; Encephalitis, Tick-Borne

Tick-borne encephalitis virus (TBEV) is a zoonotic agent causing severe encephalitis. In 2016, in Northeastern France, we faced a TBEV infection increase, leading to a warning from the Regional Health Agency. Here, we report the confirmed TBE cases diagnosed between January 2013 and December 2016, with particular emphasis on the year 2016.A total of 1643 blood and cerebrospinal fluid (CSF) samples from everywhere in France, corresponding to 1460 patients, were prospectively tested for anti-TBEV-specific IgM and IgG antibodies by ELISA. Additional 39 blood and CSF samples from patients with suspected Lyme neuroborreliosis were retrospectively investigated.The TBEV seropositivity rate was estimated to 5.89% and 54 patients were diagnosed as TBE-confirmed cases. A significant increase in TBE cases was observed during the year 2016 with 29 confirmed cases, instead of a mean of eight cases during the three previous years (p=0.0006). Six imported cases and 48 autochthonous cases, located in the Alsace region (n=43) and in the Alpine region (n=5) were reported. Forty-six patients experienced neurological impairment. Nine patients showed an incomplete recovery at last follow-up (from 15days to eight months post-infection). TBE diagnosis was performed earlier for patients taken in charge in the Alsace region than those hospitalized elsewhere in France (p=0.0087). Among the 39 patients with suspected Lyme neuroborreliosis retrospectively investigated, one showed a TBEV recent infection.The TBE increase that occurred in France in 2016 highlights the need to improve our knowledge about the true burden of TBEV infection and subsequent long-term outcomes.