Ticks on the move—climate change-induced range shifts of three tick species in Europe: current and future habitat suitability for Ixodes ricinus in comparison with Dermacentor reticulatus and Dermacentor marginatus

Abstract

Tick-borne diseases are a major health problem worldwide and could become even more important in Europe in the future. Due to changing climatic conditions, ticks are assumed to be able to expand their ranges in Europe towards higher latitudes and altitudes, which could result in an increased occurrence of tick-borne diseases.There is a great interest to identify potential (new) areas of distribution of vector species in order to assess the future infection risk with vector-borne diseases, improve surveillance, to develop more targeted monitoring program, and, if required, control measures.Based on an ecological niche modelling approach we project the climatic suitability for the three tick species Ixodes ricinus, Dermacentor reticulatus and Dermacentor marginatus under current and future climatic conditions in Europe. These common tick species also feed on humans and livestock and are vector competent for a number of pathogens.For niche modelling, we used a comprehensive occurrence data set based on several databases and publications and six bioclimatic variables in a maximum entropy approach. For projections, we used the most recent IPCC data on current and future climatic conditions including four different scenarios of socio-economic developments.Our models clearly support the assumption that the three tick species will benefit from climate change with projected range expansions towards north-eastern Europe and wide areas in central Europe with projected potential co-occurrence.A higher tick biodiversity and locally higher abundances might increase the risk of tick-borne diseases, although other factors such as pathogen prevalence and host abundances are also important.

Climate Change Drives the Transmission and Spread of Vector-Borne Diseases: An Ecological Perspective

“…Climate change has an important impact on the transmission of vector-borne diseases, which in general will expand the climate-adaptive transmission zone of vector-borne diseases. In Europe, climate change is likely to expand ticks into higher latitudes and altitudes, thereby increasing the incidence of tick-borne diseases [ 46 ]. In South Africa, however, rising temperatures could decreases habitat suitability for some tick species (Acari: Ixodidae), which will decrease the occurrence of the related diseases [ 47 ].…”

First Expert Elicitation of Knowledge on Possible Drivers of Observed Increasing Human Cases of Tick-Borne Encephalitis in Europe

“…For example, a rise in temperature can increase the length of the tick questing season and, depending on the context, can also increase the numbers of susceptible ticks (larvae and nymphs) and the number of infected nymphs co-feeding on the same hosts, resulting in increased human infections [ 62 ]. Furthermore, a rise in temperature can increase the spread of ticks to areas with higher elevations (e.g., [ 63 , 64 ]) and may also drive changes in human behavior [ 65 ]. Theories explaining the consequences of climate change on tick-borne diseases in Europe, including TBE, are discussed in a recent review paper (and include effects on the intra-stage development of ticks, an extended transmission season, changes in the ecological balance of species abundance and interactions in the ecosystem, and climate-related range expansion of vectors, reservoir hosts, or human populations) [ 66 ].…”

Distribution of ticks in the Western Palearctic: an updated systematic review (2015–2021)

“…Ixodes ricinus and D. reticulatus received the greatest attention in terms of sampling efforts, representing 55% and 22.1% of the dataset, respectively. These species are considered among the most important in the Western Palearctic, and this importance has fuelled research into their distributions [ 12 ]. There are also spatial biases in terms of only a few countries representing the majority of records.…”

“…The incidence of tick-borne disease has mirrored the range expansion of their vectors [ 11 ]. Since these changes have direct veterinary and public health implications, there has been a growing interest in surveillance to determine the current distribution of these ticks, as well as mechanistic and correlative models to assess likely future changes [ 12 – 14 ].…”