Combining Climatic Projections and Dispersal Ability: A Method for Estimating the Responses of Sandfly Vector Species to Climate Change

Abstract

BackgroundIn the Old World, sandfly species of the genus Phlebotomus are known vectors of Leishmania, Bartonella and several viruses. Recent sandfly catches and autochthonous cases of leishmaniasis hint on spreading tendencies of the vectors towards Central Europe. However, studies addressing potential future distribution of sandflies in the light of a changing European climate are missing.MethodologyHere, we modelled bioclimatic envelopes using MaxEnt for five species with proven or assumed vector competence for Leishmania infantum, which are either predominantly located in (south-) western (Phlebotomus ariasi, P. mascittii and P. perniciosus) or south-eastern Europe (P. neglectus and P. perfiliewi). The determined bioclimatic envelopes were transferred to two climate change scenarios (A1B and B1) for Central Europe (Austria, Germany and Switzerland) using data of the regional climate model COSMO-CLM. We detected the most likely way of natural dispersal (“least-cost path”) for each species and hence determined the accessibility of potential future climatically suitable habitats by integrating landscape features, projected changes in climatic suitability and wind speed.Results and Relevance Results indicate that the Central European climate will become increasingly suitable especially for those vector species with a current south-western focus of distribution. In general, the highest suitability of Central Europe is projected for all species in the second half of the 21st century, except for P. perfiliewi. Nevertheless, we show that sandflies will hardly be able to occupy their climatically suitable habitats entirely, due to their limited natural dispersal ability. A northward spread of species with south-eastern focus of distribution may be constrained but not completely avoided by the Alps. Our results can be used to install specific monitoring systems to the projected risk zones of potential sandfly establishment. This is urgently needed for adaptation and coping strategies against the emerging spread of sandfly-borne diseases.

The Effect of Climate Change on the Potential Distribution of the European Phlebotomus Species

“…Our model finds, in contrast the results of Fischer et al (2011a), that the Benelux States may not be suitable for Phlebotomus species, because they don't favor the short, relatively cold and rainy summers (Kennewick et al, 2010). Fischer et al (2011a) expected no migration from southeastern direction, which is strengthened by our results. We found that to the end of the 2060's the expansion of P. ariasi and P. perniciosus to Central Europe is most likely among the studied species.…”

Climatic suitability of Aedes albopictus in Europe referring to climate change projections: comparison of mechanistic and correlative niche modelling approaches

“…Using the example of sandflies, it has been demonstrated that the dispersal of disease vectors on the continental scale can be evaluated by creating artificial cost surfaces that include several landscape features that are attributed with cost factors [44]. Consequently, the pathway with least costs for a species' dispersal can be considered as the most likely path of the species to move across landscapes.…”

The Health Effects of Climate Change in the WHO European Region

“…Originating in southeast Asia, Aedes albopictus is spreading globally and was reported in Albania in 1979 [97]. The mosquito is now established in southern parts of Europe [98,99] and can transmit not only Chikunguya, but also, among others, Dengue fever [100][101][102][103].…”

“…Observed and Projected Effects (6) Malaria in Portugal [89] Malaria in Germany [92] Malaria in Turkey [90] Aedes albopictus in Europe [98] Malaria in Spain [91] Recent and future Aedes albopictus suitability [99] WNF in Israel [93] Dengue in Europe [100] WNF in Hungary and Austria [94] Dengue in Europe [103] Chikungunya in Italy [96] Dengue and Chikungunya in Europe [101] Dengue in Madeira 2012 [102] Ticks transmit climate-sensitive infectious diseases including Crimean Congo hemorrhagic fever [108,109], Lyme borreliosis [110][111][112], tick-borne encephalitis [113][114][115][116][117][118][119][120] and Tularemia [121]. Several studies identified in the literature review do not report on climate change and tick-transmitted diseases, but instead describe changes in tick distribution, specifically in the United Kingdom [122], Slovenia [123], and the Czech Republic [124].…”