The effect of climate change on the potential distribution of the European Phlebotomus species and the parasite Leishmania infantum in 2011-2070. A climate envelope modeling approach

Aims: In the Mediterranean areas of Europe, leishmanisasis is one of the most emerging vector-borne diseases. Members of genus Phlebotomus are the primary vectors of the genus Leishmania. To track the human health effect of climate change it is a very important interdisciplinary question to study whether the climatic requirements and geographical distribution of the vectors of human pathogen organisms correlate with each other. Our study intended to explore the potential effects of ongoing climate change, in particular through a potential upward altitudinal and latitudinal shift of the distribution of the parasite Leishmania infantum, its vectors Phlebotomus ariasi, P. neglectus, P. perfiliewi, P. perniciosus, and P. tobbi, and some other sandfly species: P. papatasi, P. sergenti, and P. similis. Methods: By using a climate envelope modelling (CEM) method we modelled the current and future (2011-2070) potential distribution of 8 European sandfly species and L. infantum based on the current distribution using the REMO regional climate model. Results: We found that by the end of the 2060’s most parts of Western Europe can be colonized by sandfly species, mostly by P. ariasi and P. pernicosus. P. ariasi showed the greatest potential northward expansion. For all the studied vectors of L. infantum the entire Mediterranean Basin and South-Eastern Europe seemed to be suitable. L. infantum can affect the Eastern Mediterranean, without notable northward expansion. Our model resulted 1 to 2 months prolongation of the potentially active period of P. neglectus P. papatasi and P. perniciosus for the 2060’s in Southern Hungary. Conclusion: Our findings confirm the concerns that leishmanisais can become a real hazard for the major part of the European population to the end of the 21th century and the Carpathian Basin is a particularly vulnerable area.

Ornamental plants as climatic indicators of arthropod vectors

The importance and risk of vector-borne diseases (eg. leishmaniasis, West Nile Virus, Lyme borreliosis) is going to increase in the European temperate areas due to climate change. Our previous studies have shown that the potential distribution of Leishmania infantum and some Phlebotomus (sand fly) species – a parasite of leishmaniasis, and its vectors – may be expanded even to the southern coastline of the Baltic Sea by the end of the 21st century. The lowland areas of the Carpathian Basin and the main part of Hungary are projected to be suitable for the studied sand fly vectors in the near future. It is important to find some indicator plants to examine whether the sand flies are able to live in a certain climate at a certain time. We studied several Mediterranean and Sub-Mediterranean plant species, and we found that the aggregated distribution of three ligneous species (Juniperus oxycedrus L., Quercus ilex L. and Pinus brutia Ten.) shows high correlation with the union distribution of five sand flies (Phlebotomus ariasi Tonn., Ph. neglectus Tonn., Ph. perfiliewi Parrot, Ph. perniciosus Newst. and Ph. tobbi Adler, Theodor et Lourie). Since these Mediterranean species are highly tolerant of the edaphic characteristics of the planting site, they may prove to be good indicators. The present and upcoming climate of Hungary is seen to be suitable for the selected indicator plant species, and it draws attention to and verifies the potential of the expansion of sand flies, which has been proved by some recent observations of the vectors in Southern Hungary.

Európai lepkeszúnyog fajok potenciális elterjedése a 21. században

Leishmaniasis is a typical vectorial disease transmitted by Psycodidae vectors (Lutzomyans, Phlebotomus species). The worldwide observed 1,5-2 million new cases and 60,000 death caused by Leishmania parasites per year make leishmaniasis is one of the most important vectorial disease in the tropicals and warm temperate areas of the World. In the human environment dogs and cats are the most important hosts of the different leishmania agents. The different leishmania species cause symptomatically cutan or visceral disease forms, but many other type of the disease has recognised. Phlebotomus species are sensitive to climatic patterns, they require hight relative air humidity, mild winters and long and warm vegetation period, but the environmental requirements of the species naturally is not the same. Due to climate change in the near future the climate of Western and Central Europe could allow the colonisation of these highly populated areas with also the vectors and the parasites. Our aim was to analyse the environmental patterns of the current distribution area of 8 important sand flies (P. ariasi, P. perniciosus, P. perfiliewi, P. papatasi, P. tobbi, P. neglectus, P. similis and P. sergenti) using the 1960-1990 period’s climate as reference. Using climate envelope modeling we determined these climatic characters and using the REMO climate projection we created the recent and the near-future (2011-2040 and 2041-2070) potential distribution area of the sand flies. The current known area of many Phlebotomus species restricted either to the western or to the eastern Mediterranean Basin. We found that their climatic requirements are could not explain their segregation, it is maybe the consequence of their evolutionary history (geographical barriers and paleoclimatic history). By the end of the 2060’s most parts of Western Europe can be colonized by sand flies, mostly by P. ariasi and P. pernicosus. P. ariasi showed the greatest potential northward expansion. Our model resulted 1 to 2 months prolongation of the potentially active period of P. neglectus P. papatasi and P. perniciosus for the 2070’s in Southern Hungary. As the climate becomes drier and warmer, sand flies will occupy more and more parts of Hungary. Our findings confirm the concerns that leishmanisais can become a real hazard for the major part of the European population to the end of the 21th century and the Carpathian Basin is a particularly vulnerable area.

Klímaváltozás és az európai lepkeszúnyogok. Az areamodellezés módszertani kérdései

The future northward expansion of the arthropod vectors of leishmaniasis caused by climate change seems to be essential veterinary and medical problem. Our aim was to build and evaluate a Climate Envelope Model (CEM) to assess the potential effects of climate change on five European sandfly species. The studied species – Phlebotomus ariasi Tonn., P. neglectus Tonn., P. papatasi Scop., P. perfiliewi Parrot, P. perniciosus Newst., P. sergenti Parrot, P. similis Perfiliev, P. tobbi Adler, Theodor et Lourie – are important vectors of the parasite Leishmania infantum or other Leishmania species. The projections were based on REMO regional climate model with European domain. The climate data were available in a 25 km resolution grid for the reference period (1961-90) and two future periods (2011-40, 2041-70). The regional climate model was based on the IPCC SRES A1B scenario. Three types of climatic parameters were used for every month (averaged in the 30-years periods). The model was supported by VBORNET digital area database (distribution maps), ESRI ArcGIS 10 software’s Spatial Analyst module (modeling environment), PAST (calibration of the model with statistical method). Iterative model evaluation was done by summarizing two types of model errors based on an aggregated distribution. The results show that the best model results can be achieved by leaving 5-5 percentiles from the two extrema of the mean temperature, 2-2 percentiles from the two extrema of the minimum temperature, 0 percentile from the minimum of and 8 percentiles from the maximum of the precipitation.

Ornamental plants as climatic indicators of arthropod vectors

The importance and risk of vector-borne diseases (e.g., leishmaniasis, West Nile Virus, Lyme borreliosis) is going to increase in the European temperate areas due to climate change. Our previous studies have shown that the potential distribution of Leishmania infantum and some Phlebotomus (sand fly) species – a parasite of leishmaniasis, and its vectors – may be expanded even to the southern coastline of the Baltic Sea by the end of the 21st century. The lowland areas of the Carpathian Basin and the main part of Hungary are projected to be suitable for the studied sand fly vectors in the near future. It is important to find some indicator plants to examine whether the sand flies are able to live in a certain climate at a certain time. We studied several Mediterranean and Sub-Mediterranean plant species, and we found that the aggregated distribution of three ligneous species (Juniperus oxycedrus L., Quercus ilex L. and Pinus brutia Ten.) shows high correlation with the union distribution of five sand flies (Phlebotomus ariasi Tonn., Ph. neglectus Tonn., Ph. perfiliewi Parrot, Ph. perniciosus Newst. and Ph. tobbi Adler, Theodor et Lourie). Since these Mediterranean species are highly tolerant of the edaphic characteristics of the planting site, they may prove to be good indicators. The present and upcoming climate of Hungary is seen to be suitable for the selected indicator plant species, and it draws attention to and verifies the potential of the expansion of sand flies, which has been proved by some recent observations of the vectors in Southern Hungary.