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Different approaches are being developed to improve the differentiation of Leishmania genus using biochemical and molecular methods. In this study, 11 independent polymorphic microsatellites were used for the typing of strains of L. infantum isolated in Sicily. Polymerase chain reaction was employed to amplify the microsatellites contained in 12 DNA regions selected from among more investigated loci. A total of 51 isolates of L. infantum from dogs were tested by using the same locus panel. The products were successively analysed using an automatic sequence detector (ABI PRISM 3130 AB), to discover relevant microsatellite polymorphisms. It was possible to discriminate between MON-1 and non-MON-1 groups. Moreover, the method permitted to distinguish various genotypes of L. infantum isolates within each zymodema. Model- and distance-based analyses of the data set showed comparable results. The frequency of heterozygosity in the alleles analysed varied extremely between the different groups of isolates. As the method exhibits a high level of discrimination, it is suitable for characterization of closely related strains in epidemiological studies.

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The geographical diffusion of leishmaniasis can depend on the factors limiting the distribution of sandfly vectors. In Sicily, as in all Mediterranean areas, sandflies are present almost all year round because the climate permits perpetuation of this vector's life cycle. Transmission can occurs in rural and domestic habitats through the bite of infected female phlebotomine sandflies. In Italy, the visceral form of leishmaniasis is commonly found, which is due exclusively to L. infantum. Two species of sandfly are considered the main vectors: Phlebotomus perniciosus and P. perfiliewi. Fluorescence resonance energy transfer technology was used to determine the parasite load in phlebotomine vectors, and the test was targeted on a 117-bp fragment of kinetoplast DNA minicircles. The assay was evaluated, focusing on analytical sensitivity, discriminatory power, and reliability of quantification. During 2005, a total of 1686 sandflies were trapped in various Sicilian provinces and in farms randomly selected using black light traps. We found 20, 30, and 16 sandflies positive for Leishmania for each kind of analyzed phlebotomine sandfly, respectively, corresponding to 6.5% for the gravid, 2.7% for the fed, and 6.3% for other groups. Previously the insects were identified on the basis of morphology and the most prevalent sandfly species were P. Sergentomyia minuta, P. perfiliewi, and P. perniciosus.