Vilibic-Cavlek et al.
An Overview of Tick-Borne Encephalitis Epidemiology in Endemic Regions of Continental Croatia,
2017-2023. Microorganisms. 2024;12(2):386. doi:10.3390/microorganisms12020386
In Croatia, Tick-Borne Encephalitis (TBE) was first reported in 1953 in the northwestern region of the country. Since then, in addition to this Pannonian focus, continental and Mediterranean TBE foci have been identified. Recently, an analysis of TBE epidemiology based on data from humans, horses, and sheep in endemic regions of continental Croatia was carried out.
During the testing period (2017-2023), TBE was confirmed in 12.7% of patients with neuroinvasive disease. The main clinical presentations in patients with confirmed TBE were meningitis (54.8%) and encephalitis (30.9%). TBE in Croatia showed a bimodal seasonality (spring/summer and October/November). In June 2019, a small alimentary outbreak occurred in Gorski Kotar.
TBE IgG antibodies were detected in 273 out of 2240 (12.2%) horses, with the highest prevalence in the easternmost and northwestern counties. Among 300 sheep tested in 2022, 29 (9.7%) were TBE IgG-positive in northeastern Croatia. The seropositivity in horses and sheep confirmed their role as sentinels in TBE monitoring.
In Croatia, the natural TBE foci remain active in the northwestern and northeastern regions. The high prevalence of TBE IgG antibodies in horses and sheep indicates that continental Croatia is also endemic for the TBE virus.