Scientific Rationale for Acaricide Treatment Periods in Russian Federation Regions Affected by Tick-Borne Viral Encephalitis

Introduction. Tick-borne viral encephalitis is reported in 35 countries across Eurasia. Due to climate change, which can affect the activity of the disease vector, it is necessary to update the timing of non-specific infection prevention measures.

Aim — retrospectively study changes in the calendar dates of visits to medical facilities in Russian regions by individuals affected by tick bites.

Materials and methods. Data was taken from the Reference Center for Monitoring Tick-borne Viral Encephalitis of the Irkutsk Anti-Plague Research Institute for 2008–2024 was used. Data on changes in average annual air temperatures in regions of the Russian Federation endemic for tick-borne viral encephalitis were obtained from the Statbase open data database.

Results. Analysis showed that from 2018–2024, temperatures increased by an average of 0.6°C compared to 2008–2017. Moreover, the first bites were registered, on average, in the third 10-day period of March (in 2018–2024, in the first ten-day period of April). The peak number of tick-borne injuries occurs in the 22^nd–24^th calendar weeks, and the first cases of tick-borne viral encephalitis are registered in the 21^st.4^th average calendar week. Taking these data into account, acaricidal treatments should begin in the 13^th–14^th calendar weeks (last week of March – 1^st week of April) for most Russian regions. Combined with mandatory repeat anti-tick treatments, this will minimize the number of tick-borne injuries and improve epidemiological stability with respect to tick-borne viral encephalitis throughout the epidemic season.

Conclusion. When planning acaricidal work, it is necessary to consider geographic differences in average annual air temperature, calendar dates of registration of the first cases of tick bites in the regions of the country, as well as the weather conditions of the current epidemic season.

Contribution:
Nikitin A.Ya. — concept and design of the study, data processing, writing the text; editing;
Yatsmenko E.V. — collection of materials, data processing;
Tolmacheva M.I. — data processing, editing, translation;
Sidorova E.A. — study concept and design, editing;
Prelovskaya M.A. — data processing; document preparation;
Balakhonov S.V. — concept and design of the study, editing.
All co-authors — approval of the final version of the article, responsibility for the integrity of all parts of the article.

Funding source. This study was not supported by any external sources of funding.

Conflict of interest. The authors declare no apparent or potential conflicts of interest related to the publication of this article.

Received: 16.12.2025 / Accepted: 04.02.2026 / Published: 10.04.2026

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