The impact of climatic factors on tick-related hospital visits and borreliosis incidence rates in European Russia

PLoS One. 2022 Jul 20;17(7):e0269846. doi: 10.1371/journal.pone.0269846. eCollection 2022.

Abstract

Tick-borne diseases are among the challenges associated with warming climate. Many studies predict, and already note, expansion of ticks' habitats to the north, bringing previously non-endemic diseases, such as borreliosis and encephalitis, to the new areas. In addition, higher temperatures accelerate phases of ticks' development in areas where ticks have established populations. Earlier works have shown that meteorological parameters, such as temperature and humidity influence ticks' survival and define their areas of habitat. Here, we study the link between climatic parameters and tick-related hospital visits as well as borreliosis incidence rates focusing on European Russia. We have used yearly incidence rates of borreliosis spanning a period of 20 years (1997-2016) and weekly tick-related hospital visits spanning two years (2018-2019). We identify regions in Russia characterized by similar dynamics of incidence rates and dominating tick species. For each cluster, we find a set of climatic parameters that are significantly correlated with the incidence rates, though a linear regression approach using exclusively climatic parameters to incidence prediction was less than 50% effective. On a weekly timescale, we find correlations of different climatic parameters with hospital visits. Finally, we trained two long short-term memory neural network models to project the tick-related hospital visits until the end of the century, under the RCP8.5 climate scenario, and present our findings in the evolution of the tick season length for different regions in Russia. Our results show that the regions with an expected increase in both tick season length and borreliosis incidence rates are located in the southern forested areas of European Russia. Oppositely, our projections suggest no prolongation of the tick season length in the northern areas with already established tick population.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Borrelia Infections*
  • Encephalitis, Tick-Borne* / epidemiology
  • Hospitals
  • Incidence
  • Ixodes*
  • Lyme Disease* / epidemiology
  • Russia / epidemiology
  • Tick-Borne Diseases* / epidemiology

Grants and funding

Financial support from the Academy of Finland Centre of Excellence program (grant no. 307331), Belmont Forum project Arctic Community Resilience to Boreal Environmental change: Assessing Risks from fire and disease (ACRoBEAR) via the Academy of Finland, decision number 334792, and Atmosphere and Climate Competence Center (ACCC) Academy of Finland flagship proposal is gratefully acknowledged. This study has been also conducted under the EMME-CARE project, which has been funded from the European Union’s Horizon 2020 Research and Innovation Programme (grant agreemend ID 856612). The funding bodies did not play any role in the study.