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.
Source: By Velay A1, Solis M2, Kack-Kack W2, Gantner P2, Maquart M3, Martinot M4, Augereau O5, De Briel D5, Kieffer P6, Lohmann C7, Poveda JD8, Cart-Tanneur E9, Argemi X10, Leparc-Goffart I3, de Martino S11, Jaulhac B11, Raguet S12, Wendling MJ13, Hansmann Y10, Fafi-Kremer S2. A new hot spot for tick-borne encephalitis (TBE): A marked increase of TBE cases in France in 2016. Ticks Tick Borne Dis. 2017 Sep 28. pii: S1877-959X(17)30226-1. doi: 10.1016/j.ttbdis.2017.09.015. [Epub ahead of print]