BackgroundDue to climate change, the geographical distribution of sand flies during the last decades has shifted northward from latitudes below 45°N in southern Europe to latitudes just above 50○N. Recent studies show that some phlebotomine sand flies were recorded in several parts of Germany and Belgium. In central Europe, some autochthone leishmaniasis cases are being recorded in regions traditionally regarded as leishmaniasis-free. An important challenge is to predict the geographical distribution of leishmaniasis vectors under new climatic conditions. In this study, we attempted to predict the current distribution of six leishmaniasis vectors in the Mediterranean basin and forecast species’ geographical shift under future climate scenarios using an ensemble ecological niche modeling approach. Species records were obtained from scientific surveys published in the research literature between 2006 and 2016. A series of climate metrics describing temperature and precipitation in the study area under two climatic scenarios were obtained from WorldClim database. A consensus model was derived from six varieties of modeling approaches (regression, machine learning and classification techniques) in order to ensure valid prediction of distribution of vectors under different climate scenarios.ResultsModel performance was generally high for the included species with a specificity (true negative rate) ranging from 81.03 to 96.52% (mean = 86.94%) and a sensitivity (true positive rate) ranging from 87.93 to 100% (mean = 96.98%). Our work evidenced the hypothesis of the widespread of Leishmania vectors under climate change scenarios. All of the studied species are prospected to gain new areas that are actually not suitable for vectors’ survival. Phlebotomine sand flies are prospected to invade extra-Mediterranean regions, especially western and central Europe.ConclusionsOur study confirmed the importance of environmental and climate factors on the distribution of leishmaniasis vectors and demonstrated the performance of ecological niche modeling in the prediction of the geographical spread of vector-borne diseases. Ecological niche modeling should be considered in the future as a valuable tool in addition to experimental laboratory studies for a better understanding of the biology of vector species.

A study was undertaken between November 2008 and March 2010, in the focus of cutaneous leishmaniasis of Central Tunisia, to evaluate the role of Psammomys obesus (n = 472) and Meriones shawi (n = 167) as reservoir hosts for Leishmania major infection. Prevalence of L. major infection was 7% versus 5% for culture ( p = not signifiant [NS]), 19% versus 16% for direct examination of smears ( p = NS), and 20% versus 33% ( p = NS) for Indirect Fluorescent Antibody Test among P. obesus and M. shawi, respectively. The peak of this infection was in winter and autumn and increased steadily with age for the both species of rodents. The clinical examination showed that depilation, hyper-pigmentation, ignition, and severe edema of the higher edge of the ears were the most frequent signs observed in the study sample (all signs combined: 47% for P. obesus versus 43% for M. shawi; p = NS). However, the lesions were bilateral and seem to be more destructive among M. shawi compared with P. obesus. Asymptomatic infection was *40% for both rodents. This study demonstrated that M. shawi plays an important role in the transmission and the emergence of Leishmania major cutaneous leishmaniasis in Tunisia.

BackgroundDuring a blood meal, female sand flies, vectors of Leishmania parasites, inject saliva into the host skin. Sand fly saliva is composed of a large variety of components that exert different pharmacological activities facilitating the acquisition of blood by the insect. Importantly, proteins present in saliva are able to elicit the production of specific anti-saliva antibodies, which can be used as markers for exposure to vector bites. Serological tests using total sand fly salivary gland extracts are challenging due to the difficulty of obtaining reproducible salivary gland preparations. Previously, we demonstrated that PpSP32 is the immunodominant salivary antigen in humans exposed to Phlebotomus papatasi bites and established that humans exposed to P. perniciosus bites do not recognize it.Methodology/Principal FindingsHerein, we have validated, in a large cohort of 522 individuals, the use of the Phlebotomus papatasi recombinant salivary protein PpSP32 (rPpSP32) as an alternative method for testing exposure to the bite of this sand fly. We also demonstrated that screening for total anti-rPpSP32 IgG antibodies is sufficient, being comparable in efficacy to the screening for IgG2, IgG4 and IgE antibodies against rPpSP32. Additionally, sera obtained from dogs immunized with saliva of P. perniciosus, a sympatric and widely distributed sand fly in Tunisia, did not recognize rPpSP32 demonstrating its suitability as a marker of exposure to P. papatasi saliva.Conclusions/SignificanceOur data indicate that rPpSP32 constitutes a useful epidemiological tool to monitor the spatial distribution of P. papatasi in a particular region, to direct control measures against zoonotic cutaneous leishmaniasis, to assess the efficiency of vector control interventions and perhaps to assess the risk of contracting the disease.

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