A New Hot Spot for Tick-Borne Encephalitis (TBE): A Marked Increase of TBE Cases in France in 2016

Ticks Tick Borne Dis. 2018 Jan;9(1):120-125. doi: 10.1016/j.ttbdis.2017.09.015. Epub 2017 Sep 28.

Abstract

Objectives: 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.

Methods: 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.

Results: 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.

Conclusion: 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.

Keywords: Tick-borne diseases; Tick-borne encephalitis; Zoonotic infection.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Antibodies, Bacterial / blood
  • Child
  • Encephalitis Viruses, Tick-Borne / physiology*
  • Encephalitis, Tick-Borne / blood
  • Encephalitis, Tick-Borne / epidemiology*
  • Encephalitis, Tick-Borne / parasitology
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • France / epidemiology
  • Humans
  • Immunoglobulin G / blood
  • Immunoglobulin M / blood
  • Incidence
  • Male
  • Middle Aged
  • Prospective Studies
  • Retrospective Studies
  • Seasons
  • Young Adult

Substances

  • Antibodies, Bacterial
  • Immunoglobulin G
  • Immunoglobulin M