Reflection of the Neogene–Quaternary phylogeography in the recent distribution limiting climatic factors of eight Mediterranean Phlebotomus species (Diptera: Psychodidae)

Geographical and Molecular Analysis of Haplotype Variations in Leishmania major Among Infected Iranian Phlebotomus papatasi

PURPOSE

Leishmania major is main causative agent and Phlebotomus papatasi is only proven vector of Zoonotic Cutaneous Leishmaniasis (ZCL) in Iran. Human leishmaniasis is mostly susceptible to climatic conditions and molecular variations of Leishmania parasites within sandflies.

METHODS

L. major was analyzed based on geographical, environmental, climatic changes and haplotype variations within P. papatasi. Molecular tools and different geographical aspects were employed using Arc-GIS software for mapping the geographic distribution of samples and other statistics tests. Fragments of ITS-rDNA, k-DNA, and microsatellite genes of Leishmania were used for PCR, RFLP, sequencing, and phylogenetic analyses.

RESULTS

Totally 81 out of 1083 female P. papatasi were detected with Leishmania parasites: 70 and five were L. major and L. turanica, respectively. Golestan and Fars provinces had the highest (13.64%) and lowest (4.55%) infection rates, respectively. The infection rate among female P. papatasi collected from gerbil burrows was significantly higher (15.15%) than animal shelters, yards, and inside houses (4.48%) (P < 0.0%). Microsatellite was more sensitive (22.72%) than k-DNA (18.8%) and ITS-rDNA (7.48%). More molecular variations of L. major were found in Isfahan province.

CONCLUSIONS

Arc-GIS software and other statistics tests were employed to find Leishmania positive and haplotype variations among sand flies. Geographical situations, altitude, climate, precipitation, humidity, temperature, urbanization, migrations, regional divergences, deforestation, global warming, genome instability, ecology, and biology of the sand flies intrinsically, and the reservoir hosts and neighboring infected locations could be reasons for increasing or decreasing the rate of Leishmania infection and haplotype variations.

Reconstructing the post-glacial spread of the sand fly Phlebotomus mascittii Grassi, 1908 (Diptera: Psychodidae) in Europe

Phlebotomine sand flies (Diptera: Phlebotominae) are the principal vectors of Leishmania spp. (Kinetoplastida: Trypanosomatidae). In Central Europe, Phlebotomus mascittii is the predominant species, but largely understudied. To better understand factors driving its current distribution, we infer patterns of genetic diversity by testing for signals of population expansion based on two mitochondrial genes and model current and past climate and habitat suitability for seven post-glacial maximum periods, taking 19 climatic variables into account. Consequently, we elucidate their connections by environmental-geographical network analysis. Most analyzed populations share a main haplotype tracing back to a single glacial maximum refuge area on the Mediterranean coasts of South France, which is supported by network analysis. The rapid range expansion of Ph. mascittii likely started in the early mid-Holocene epoch until today and its spread possibly followed two routes. The first one was through northern France to Germany and then Belgium, and the second across the Ligurian coast through present-day Slovenia to Austria, toward the northern Balkans. Here we present a combined approach to reveal glacial refugia and post-glacial spread of Ph. mascittii and observed discrepancies between the modelled and the current known distribution might reveal yet overlooked populations and potential further spread.

The changing distribution of Leishmania infantum Nicolle, 1908 and its Mediterranean sandfly vectors in the last 140 kys

The understanding of the effects of past climatic changes on the distribution of vector arthropods can strongly support the understanding of the future potential impact of anthropogenic climatic change on the geographical risk of vector-borne diseases. The zoogeographical patterns of the European sandfly vectors may suffer the continuously changing climate of the last 140 kys. The former range of L. infantum and six Phlebotomus species were modelled for the Last Interglacial, the Last Glacial Maximum and the Mid-Holocene Periods. It was found that the potential distribution of the parasite was much smaller in the Last Glacial Period L. infantum mainly could persist in the western shelves of the Mediterranean Sea. West and East Mediterranean sandfly species inhabited partly distinct refugia. The Apennine Peninsula, Sicily and the Iberian refugium formed a habitat chain along with the coastal areas of the West Mediterranean Basin. There was no direct connection between the Eastern and the Western sandfly refugia in the last 140 kys. The modelled distribution of sandfly taxa for the Middle Holocene Period can explain the relict populations of sandfly taxa in such Central European countries. The former genetic studies strongly confirm the existence of the modelled glacial refugees.