Multilocus microsatellite polymorphism analysis to characterize Leishmania infantum strains isolated in Sicily.

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.

Epidemiological surveillance of bluetongue in Sicily.

The authors describe the status of bluetongue (BT) since 13 October 2000, when the first outbreak was reported in Sicily. The results of the epidemiological surveillance programme, based on sentinel animals distributed over the entire region, are also given. In Sicily, the incidence of the disease is relatively low compared to some other areas in the Mediterranean Basin. Seventy-five outbreaks of the disease were recorded in the first three epidemics (October 2000 to May 2003). Overall morbidity was 13.25%, mortality 5.36% and the case fatality rate 41.49%. The Province of Catania seems to have been the worst affected; the incidence rate in August 2002 was 0.8%. The monthly incidence rate was calculated for sentinel animals of which the estimated total was 3 654, distributed in 63 areas. It is important to underline that in the period under consideration, a total of 2 382 animals was examined. During the surveillance period, which extended from September 2001 to May 2003, the incidence of BT peaked in September 2002, at 5.91% -/+ 0.979. The cumulative incidence rate from September 2001 to August 2002 and September 2002 to March 2003 was 4.53% -/+ 0.76 and 20.03% -/+ 1.85, respectively. The circulation of BT virus serotypes 2, 4, 9 and 16 is described, as revealed by seroconversion in sentinel animals.