[Tick-borne encephalitis in a child in a nonendemic country: A case report]

Tick-borne encephalitis (TBE) is an arbovirus induced by tick-borne encephalitis virus (TBEV) transmitted by tick bite. The disease is rare in France (two to three cases per year) but endemic zones extend from Western Europe to the east coast of Asia (10,000-15,000 cases per year). An 8-year-old boy was admitted to our pediatric ward in Strasbourg (France) for febrile headache with diplopia. Four days after a tick bite, he declared a febrile headache together with maculopapular rash on the elbows, knees, and cheeks. Fourteen days after the outbreak of symptoms, he showed confusion, drowsiness, and binocular diplopia. Brain MRI was normal and the electroencephalogram found diffuse slow activity with no discharge. Lumbar puncture found meningitis with 92 cells (60% neutrophils, 40% lymphocytes). The diagnosis was made with specific IgM and IgG antibody isolation in the serum (Elisa). Lyme serology was negative. The evolution was slowly favorable and the child remained hospitalized for 8 days. The neurological control examination 2 weeks later was normal except for a moderate left deviation during tandem walk and left Romberg manoeuver. Meningitis or meningoencephalitis in a child must raise the diagnosis of TBE in children, even in nonendemic countries, given the recent increased incidence of TBE and the development of tourism. Recent travel in endemic areas, a history of tick bite, and a clinical course in two phases must be sought. The diagnosis is serologic and prevention is based on vaccination.