Bisserier A, et al.
Serological evidence of tick-borne encephalitis virus in Limousin, France. Int J Infect Dis. Published online January 27, 2026. doi:10.1016/j.ijid.2026.108424
In France, most reported cases of tick-borne encephalitis (TBE) have historically originated from the Alsace region in northeastern France. More recent studies, however, have demonstrated circulation of TBE virus in additional regions, including Auvergne–Rhône-Alpes and Haute-Savoie. Given this evolving epidemiological landscape and the limited data on TBE virus circulation in central France, a seroprevalence study was conducted in the Limousin region in 2023.
A total of 880 serum samples were collected from patients who attended Limoges University Hospital and underwent Lyme disease serology between January 2020 and January 2023. TBE virus IgG antibodies were detected by ELISA in 23 of 880 samples (2.61%). All IgG-positive and equivocal samples tested negative for TBE IgM antibodies. Confirmation by virus neutralization testing showed that 22 of 28 sera (78.6%) were positive, with neutralizing antibody titers ranging from 1:20 to 1:20,480.
One patient who had previously received TBE vaccination exhibited a neutralization titer of 1:6,827. Sera from patients vaccinated against dengue or yellow fever showed mean TBE neutralization titers of 1:1,027 and 1:680, respectively, suggesting possible serological cross-reactivity. Notably, one patient living in a rural environment, engaging in hunting and hiking activities, and with no travel history to known TBE-endemic areas, exhibited a high neutralization titer of 1:10,240.
To date, no study has definitively demonstrated the presence of TBE virus or Louping ill virus in Limousin, and no human TBE cases have been reported in the region. However, the seroprevalence data obtained in this targeted population suggest that TBE virus may circulate in Limousin, central France. These findings highlight the need for further surveillance and epidemiological studies to better assess the risk of TBE in this region.