Lower Austria reports slight rise in tick-borne encephalitis

Lower Austria has recorded 15 cases of tick-borne encephalitis, known as FSME, so far in 2026, compared with 13 during the same period last year, ORF reported. The provincial health directorate said the increase was within the usual annual fluctuations.

FSME is a viral infection mainly transmitted to people through the bite of an infected tick. It can cause inflammation of the brain or meninges. There is no treatment for the underlying infection, but a highly effective vaccine is available.

The cases are generally assigned to the patient’s place of residence. Three patients live in Amstetten district and two in Zwettl district. Baden, Horn, Lilienfeld, Melk, Mödling, St. Pölten, Scheibbs, Tulln, Waidhofen an der Thaya and Wiener Neustadt each recorded one case. The health directorate said the numbers were too low to indicate a particular cluster.

No deaths from FSME have been recorded in Lower Austria this year or last year. Two of the 15 patients were aged 18 or younger, while three were aged between 19 and 40. Five cases each were recorded among people aged 41 to 65 and 66 to 80. No cases have so far been reported among people over 80.

The national reference centre at the Centre for Virology at the Medical University of Vienna has confirmed nine hospitalised FSME cases from Lower Austria this year, along with one case treated as an outpatient. The centre confirmed seven hospitalised cases from the province during the comparable period last year and 13 in 2024.

Virologist Judith Aberle said 2026 was a somewhat stronger year for Lower Austria, but remained within the usual range of fluctuations. The figures from the reference centre mainly cover confirmed cases involving patients hospitalised in Lower Austrian hospitals, while the epidemiological reporting system generally records cases according to residence.

Across Austria, the increase has been more pronounced. By Monday, the national reference centre had confirmed 155 hospitalised FSME cases, compared with 132 during all of 2025.

Aberle said the vaccination is 99 percent effective when the recommended schedule is followed. The number of cases can vary significantly from year to year, with socioeconomic, climatic and ecological factors all playing a role.

Warmer temperatures that last into autumn and milder winters can allow ticks to remain active for longer, according to environmental physician Hans-Peter Hutter. He said, however, that a longer period of tick activity did not automatically mean more FSME cases. Hot and dry summers can also be unfavourable for ticks, which need moisture. Other factors include the number of suitable host animals, the spread of the virus, people’s leisure activities and vaccination coverage.