New research helps detect outbreaks of tick-borne encephalitis virus in Slovakia

Scientists from the Virological Institute of the Biomedical Research Center of the Slovak Academy of Sciences (BMC SAS) in collaboration with several scientific institutions and veterinary experts have conducted an extensive study investigating outbreaks of tick-borne encephalitis virus (TBEV) in Slovakia, the results of which have now been published in the scientific journal Ticks and Tick-borne Diseases. The research confirmed that antibody monitoring in livestock such as sheep and goats is an effective tool to identify areas with circulating virus and can contribute to better assessment of the risk of infection in humans.

“Antibodies to tick-borne encephalitis have been confirmed in approximately one tenth of the more than one thousand blood samples from sheep and goats examined in 18 locations in Slovakia. This indicates the presence of the virus in those areas,” says the head of the research, Dr Boris Klempa from BMC SAS.

Sheep had antibodies more often

Antibodies were found in animals in the districts of Krupina, Lučenec, Poltár, Detva, Stará Ľubovňa, Trenčín, Spišská Nová Ves, Zvolen, Košice surroundings and Považská Bystrica. The proportion of animals with antibodies was more than twice as high in sheep (11.9 per cent) than in goats (5 per cent), suggesting that sheep may be more susceptible to infection or have a longer lasting immune response.

Based on these findings, targeted tick collections were carried out around the farms, resulting in the detection of the virus in approximately three percent of samples.

“We were able to isolate three new variants of tick-borne encephalitis virus whose genetic analysis showed a high diversity of the virus in Slovakia,” adds Dr. Klempa.

Scientists collaborated with farmers

This research was possible thanks to the cooperation of several scientific institutions – BMC SAS, the Institute of Parasitology of the Slovak Academy of Sciences, the Institute of Zoology of the Slovak Academy of Sciences, Comenius University and the Regional Public Health Office in Banská Bystrica, as well as the State Veterinary and Food Administration of the Slovak Republic.

At the same time, the scientists appreciate the willingness of Slovak farmers to participate in the research and to provide samples for analysis. “Without the cooperation of farmers, we would not have been able to obtain such extensive data, which helps us to better understand the epidemiology of the virus in Slovakia,” said Dr Klempa.

Regular monitoring can help

Tick-borne encephalitis poses a serious threat to public health as the virus is transmitted not only by ticks but also through the consumption of raw milk and dairy products from infected animals. The study confirms that regular monitoring of farm animals can help in prevention and early identification of outbreaks.

The research was supported by grants from APVV (APVV-16-0518) and VEGA (VEGA 2/0126/22) and the TBFVnet project (2018-1-0659) funded by EEA and Norway Grants. The results of this study are an important step towards better protection of public health and more effective control of this serious disease.

The article is freely available at: https://doi.org/10.1016/j.ttbdis.2025.102444.

Contact persons:

Ela Rybárová, PR Manager, BMC SAV, v. v. i., tel.: +421 911 744 756

Dr. Boris Klempa, Head of the Department of Virus Ecology, Institute of Virology, BMC SAV, v. v. i., boris.klempa@savba.sk

Text: Dr. B. Klempa, BMC SAV, v. v. i.; E. Rybárová, BMC SAS

Photo: archive of J. Kerlik

Graphics: Dr. B. Klempa, BMC SAS

Prevalence of antibodies against tick-borne encephalitis in animals in Slovakia.