Ličkova et al.
Surveillance of tick-borne encephalitis virus foci in Slovakia: a seroprevalence study in ruminants combined with virus detection in ticks. Ticks Tick Borne Dis. 2025;16(1):102444. doi:10.1016/j.ttbdis.2025.102444.
Alimentary transmission of the tick-borne encephalitis (TBE) virus is the second most common route of infection in humans, typically occurring through the consumption of unpasteurized milk or milk products from sheep or goats. In Slovakia, alimentary infections usually account for 16% to 18% of TBE cases; however, in 2023, this figure rose sharply to 33.8%.
To better understand this trend, a study was conducted analyzing serum samples from 357 goats and 672 sheep across 32 farms in 18 districts of Slovakia. The results showed that 6.1% of the samples were TBE-ELISA seropositive, while 4.1% were classified as borderline. Among these, 93.6% of the ELISA-positive and 85.7% of the borderline samples were confirmed positive through plaque reduction neutralization tests (PRNT) and immunofluorescence assays (IFA). The overall TBE seropositivity rate in ruminants was 9.5%, with goats showing a higher seroprevalence (11.5%) compared to sheep (5.0%).
These findings provide valuable insights for assessing the risk of alimentary TBE infections. Additionally, the detection of TBE virus-infected ticks in the same areas offers direct evidence of viral circulation. In conclusion, the authors highlight that monitoring TBE seroprevalence in farm animals is an effective tool for identifying regions where the virus is actively circulating.