De Langhe et al.
Pediatric case report and overview of autochthonous tick-borne encephalitis, Belgium Emerg Infect Dis. 2025;31(9):1868-1870. doi:10.3201/eid3109.250093
For a long time, Belgium was considered TBE-free. However, since 2020, several TBE cases have been reported, and the TBE virus has been detected in the country (see e.g. Snapshot week 26/2025). One case involved a 6-year-old girl who developed symptoms three weeks after returning from a stay in Thailand.
Three weeks after her return to Belgium, the child presented with fever, diarrhea, and myalgia. Initial infectious serology focused on pathogens commonly acquired in Thailand, but all results were negative. A stool test, however, revealed Salmonella enterica serovar Bareilly and Campylobacter jejuni. She was treated with azithromycin, and her fever resolved after a 5-day hospital stay.
Four days after discharge, the girl was readmitted with recurrent fever and arthralgia. Soon after, meningeal signs appeared. Extended serology demonstrated TBE-IgM positivity, and sequencing of the virus from a serum sample confirmed the European subtype.
This case highlights the importance of recognizing the clinical features of TBE virus infection and considering TBE in patients with unexplained neurological symptoms, especially when presenting with a biphasic course. After traveling to a tropical country, clinicians may initially attribute illness to infections acquired abroad; however, the anamnesis should not exclude infections contracted domestically. In this case, the infection was acquired in Belgium, which is now considered a TBE-endemic country.