Phlebotomus (Adlerius) simici NITZULESCU, 1931: first record in Austria and phylogenetic relationship with other Adlerius species

Abstract

Background Phlebotomine sand flies are the principal vectors of Leishmania spp. (Kinetoplastida: Trypanosomatidae). Information on sand flies in Central Europe is scarce and, to date, in Austria, only Phlebotomus mascittii has been recorded. In 2018 and 2019, entomological surveys were conducted in Austria with the aim to further clarify sand fly distribution and species composition. Results In 2019, a Ph. simici specimen was trapped in Austria for the first time. Analyses of two commonly used marker genes, cytochrome c oxidase I (coxI) and cytochrome b (cytb), revealed high sequence identity with Ph. simici specimens from North Macedonia and Greece. Phylogenetic analyses showed high intraspecific distances within Ph. simici, thereby dividing this species into three lineages: one each from Europe, Turkey and Israel. Low interspecific distances between Ph. simici, Ph. brevis and an as yet unidentified Adlerius sp. from Turkey and Armenia highlight how challenging molecular identification within the Adlerius complex can be, even when standard marker genes are applied. Conclusion To our knowledge, this study reports the first finding of Ph. simici in Austria, representing the northernmost recording of this species to date. Moreover, it reveals valuable insights into the phylogenetic relationships among species within the subgenus Adlerius. Phlebotomus simici is a suspected vector of L. infantum and therefore of medical and veterinary importance. Potential sand fly expansion in Central Europe due to climatic change and the increasing import of Leishmania-infected dogs from endemic areas support the need for further studies on sand fly distribution in Austria and Central Europe in general. Graphic abstract

The changing epidemiology of human leishmaniasis in the non-endemic country of Austria between 2000 to 2021, including a congenital case

“…Sandfly populations are assumed to have been present in Central Europe since the end of the last glacial period, albeit in very small numbers [ 55 ]. In Austria, sandflies were first recorded in 2009 [ 56 ] and meanwhile, two species, Phlebotomus mascittii and Phlebotomus simici have been documented [ 57 , 58 ]. Vector competence for Leishmania species has been assumed, but still not proven for both species, thus it remains unclear, if these were involved in the transmission of the new presumably autochthonous case in 2017 and the published cases as of 1965 and 1989 [ 16 , 17 ].…”

“…Due to global warming, the conditions for sandfly development and reproduction have become more favorable, allowing for the vector populations to expand. Sandfly species have been detected at low densities also in more northern regions, up to Belgium and Germany [ 58 , 59 ]. According to simulations of global and regional climate models, temperatures across European land areas are predicted to rise this century by 1.2–8.5°C until 2071–2100, which is higher than the expected global average [ 60 ].…”

Phlebotomine sand fly survey in the Republic of Moldova: species composition, distribution and host preferences

“…Therefore, examination of representative specimens across its range is needed to reveal if these morphological and molecular differences reflect intraspecific geographical variation of local populations or the cryptic speciation within this taxon. The close relationship between P. balcanicus sequences from Eastern Europe (Romania and Serbia) and recently identified P. creticus needs further evaluation as well as the divergence of two lineages within the widely distributed P. simici , which has been recently recorded in Austria, suggesting possible northward spread in Europe [ 28 ]. An integrative approach deploying several molecular methods that study both DNA and proteins to complement the traditional morphological “golden standard” was recently successfully applied when describing Phlebotomus creticus , a novel species from the eastern Mediterranean [ 13 ], as well as studying sand fly fauna in East Africa [ 39 ].…”

Development and application of species ID and insecticide resistance assays, for monitoring sand flyLeishmaniavectors in the Mediterranean basin and in the Middle East

“…Particularly, P. simici exhibited an almost 2x-fold higher KDT than P. perfiliewi upon treatment with 0.75 μg/ml deltamethrin (mean KDT 59.4 vs 35.3 min). P. simici, a suspected L. infantum vector and among the most dominant species in our collections from the mainland of Greece, is well-established in the eastern Mediterranean basin and was recently recorded for the first time in Austria, raising concerns on its possible northward geographical expansion [49]. Even though we perceive that this is a time-consuming and technically difficult methodology, especially when in field conditions, it can potentially provide valuable information for effective sand fly control in relevant eco-epidemiological settings.…”