Vladimirov et al.
Quantifying the northward spread of ticks (Ixodida) as climate warms in northern Russia.
Atmosphere. 2021; 12:233. doi:10.3390/atmos2020233

Tronin et al.
Study of the relationship between the average annual temperature of atmospheric air and the number of tick-bitten humans in the north of European Russia.
Int. J. Environ. Res. Public Health. 2020; 17:8006. doi:10.3390/jierph17218006

The Arctic and neighboring northern regions are among the areas where climate change is very strong. The Republic of Sakhia (also known as Yakutia) in far north-eastern Russia is characterized by severely cold climate and low population density. 40% of the Republic is above the Arctic Circle and permafrost covers about 60% of the landscape. Climate change in Sakha includes rising annual air temperatures between 0.3°C and 0.6°C per decade since 1966, which has consequences for the distribution of taiga and forest ecosystems and an increased number of tick bites (mostly Ixodes persulcatus) and tick-borne diseases.

From 2000 to 2018, the number of reported tick bites has increased significantly (40-fold). While in 2000, only a very few tick bites were recorded in Yakutia, tick attacks were reported in 6 regions of the Republic in 2006, in 14 regions in 2013, and in 18 regions in 2015/16, also north of the polar circle. The analyses of the authors showed a strong relationship between the average temperature in the coldest month of the year and tick bite frequency.

Similar observations have been published for the Komi Republic, Arkhangelsk Oblast and Republic of Karelia in the north of European Russia. There is a strong correlation with the average annual air temperature and the long-period tick-bite incidence rate (TBIR) as well as a sharp rise in the incidence of TBE cases. Studies of the I. persulcatus tick’s ecology have shown that the development of the tick population requires the accumulated sum of air temperatures to be either 1400-1500 °C over the period with stable average daily temperatures exceeding 10 °C, or 1600 °C over the period with stable average daily temperatures exceeding 5 °C. The first tick bites on humans were recorded in truly Arctic regions of Komi Republic.

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