Last year, 62 cases of tick encephalitis diagnosed in France were notified, “which corresponds to a 60 % increase in the number of cases compared to 2023, and 77 % compared to 2022, the first full year of monitoring by compulsory report”. In 2021, cases of tick encephalitis were registered on the list of compulsory reporting diseases due to the increase in infections in Europe, as well as the expansion of the area and the virus circulation period.
“The characteristics of the cases reported in 2024 suggest an improvement in the exhaustiveness of surveillance and the more frequent realization of diagnostic tests of the disease, rather than a brutal increase in incidence,” said Public Health France in its annual assessment. Indeed, the increase in reports concerns “mainly of the low -serious forms of the disease”.
In detail, 71% of cases notified in 2024 were men, aged 6 to 90 years. “All cases declared in 2024 had a start date of the signs between September 2023 and December 2024,” said SPF. And the peak of cases, which corresponds to the start date of the signs, was in July-August, with 16 and 17 cases respectively, or 53 % of the total of the year. The median declaration period of cases (start of the nurses to the regional health agency) was 23 days.
55 cases declared in 2024 had acquired their infection in France. “For contaminated cases in France, the Department of Contamination was known as at risk for all cases,” said the public health agency. A cluster of 11 people was identified in Haute-Savoie during the summer of 2024, in a limited area between Thônes and Annecy, “confirming the sustainable installation of the virus in this area”.
28 cases (45.2 % vs 26.3 % in 2023) presented an initial non -specific infectious syndrome, 24 (38.7 % vs 42.1 % in 2023) meningitis and 28 (45.1 % vs 60.1 % in 2023) Encephalitis or meningoencephalite, details Public Health France. In addition, a case presented a peripheral paralysis and two cases presented a myelitis.
Most cases had to be hospitalized (52 patients or 84% of cases).
