BackgroundThe increase in tick-borne encephalitis (TBE) incidence is observed in recent decades in a number of subarctic countries. The reasons of it are widely discussed in scientific publications. The objective of this study was to understand if the climate change in Arkhangelsk Oblast (AO) situated in the north of European subarctic zone of Russia has real impact on the northward expansion of Ixodid ticks and stipulates the increase in TBE incidence.MethodsThis study analyzes: TBE incidence in AO and throughout Russia, the results of Ixodid ticks collecting in a number of sites in AO, and TBE virus prevalence in those ticks, the data on tick bite incidence in AO, and meteorological data on AO mean annual air temperatures and precipitations.ResultsIt is established that in recent years TBE incidence in AO tended to increase contrary to its apparent decrease nationwide. In last 10 years, there was nearly 50-fold rise in TBE incidence in AO when compared with 1980–1989. Probably, the increase both in mean annual air temperatures and temperatures during tick active season resulted in the northward expansion of Ixodes Persulcatus, main TBE virus vector. The Ixodid ticks expansion is confirmed both by the results of ticks flagging from the surface vegetation and by the tick bite incidence in the population of AO locations earlier free from ticks. Our mathematical (correlation and regression) analysis of available data revealed a distinct correlation between TBE incidence and the growth of mean annual air temperatures in AO in 1990–2009.ConclusionNot ruling out other factors, we conclude that climate change contributed much to the TBE incidence increase in AO.

Climate change in the Russian Arctic is more pronounced than in any other part of the country. Between 1955 and 2000, the annual average air temperature in the Russian North increased by 1.2°C. During the same period, the mean temperature of upper layer of permafrost increased by 3°C. Climate change in Russian Arctic increases the risks of the emergence of zoonotic infectious diseases. This review presents data on morbidity rates among people, domestic animals and wildlife in the Russian Arctic, focusing on the potential climate related emergence of such diseases as tick-borne encephalitis, tularemia, brucellosis, leptospirosis, rabies, and anthrax.

No abstract

No abstract

Background: The causes of the recent rise of tick-borne encephalitis (TBE) incidence in Europe are discussed. Our objective was to estimate the impact of air temperature change on TBE incidence in the European part of the Russian Arctic. Methods: We analysed the TBE incidence in the Komi Republic (RK) over a 42-year period in relation to changes in local annual average air temperature, air temperature during the season of tick activity, tick abundance, TBE-prevalence in ticks, tick-bite incidence rate, and normalised difference vegetation index within the area under study. Results: In 1998–2011 in RK a substantial growth of TBE virus (TBEV) prevalence both in questing and feeding ticks was observed. In 1992–2011 there was 23-fold growth of the tick-bite incidence rate in humans, a northward shift of the reported tick bites, and the season of tick bites increased from 4 to 6 months. In 1998–2011 there was more than 6-fold growth of average annual TBE incidence compared with 1970–1983 and 1984–1997 periods. This resulted both from the northward shift of TBE, and its growth in the south. In our view it was related to local climate change as both the average annual air temperature, and the air temperature during the tick activity season grew substantially. We revealed in RK a strong correlation between the change in the air temperature and that in TBE incidence. The satellite data showed NDVI growth within RK, i.e. alteration of the local ecosystem under the influence of climate change. Conclusions: The rise in TBE incidence in RK is related considerably to the expansion of the range of Ixodes persulcatus. The territory with reported TBE cases also expanded northward. Climate change is an important driver of TBE incidence rate growth.