Report of two severe cases of Japanese encephalitis virus in travelers returning to France, 2023-2024: clinical, diagnostic, and public health implications.

BACKGROUND

Japanese encephalitis virus (JEV) is a mosquito-borne pathogen responsible for Japanese encephalitis (JE) clinical cases in Asia and the Western Pacific. Non-JE-vaccinated patients can develop potentially life-threatening neurologic forms.

CASE SUMMARY: Here, we present two severe, non-fatal JEV cases in returning travelers from Cambodia (Case 1) and Cambodia and Vietnam (Case 2), imported to France in 2023-2024. Neither patient was vaccinated, and both presented neurologic symptoms requiring hospitalization. Cases were confirmed by RT-qPCR, IgM, and IgG rise and seroneutralization. Interestingly, this is the second report to describe the detection of the JEV genome in urine by RT-qPCR.

CONCLUSION

This study highlights the critical importance of JE vaccination and the implementation of other personal protective measures to avoid mosquito bites when traveling to a JEV-endemic region.