Application of kDNA as a molecular marker to analyse Leishmania infantum diversity in Portugal.

Around the Mediterranean basin Leishmania infantum is an important parasite causing canine leishmaniasis and visceral and cutaneous clinical forms in both immunocompetent and immunocompromised humans. Efficient monitoring and evaluation of epidemiology with discriminatory molecular markers are required. We investigated the genetic diversity of L. infantum in Portugal by polymerase chain amplification and restriction fragment length polymorphism analysis of kinetoplastid DNA, as molecular marker. We analysed 120 Portuguese isolates of L. infantum plus 16 other non-Portuguese isolates (as a reference group) from humans, dogs and sand flies. The Portuguese population showed a high degree of polymorphism with a total of 13 profiles identified. The predominant profile was A, which was only detected in the Portuguese samples. The kinetoplastid DNA PCR-RFLP assay described here was suitable for use directly with biological samples and the profiles obtained were stable during long-term growth in vitro and in laboratory animals

Genetic structure and evolution of the Leishmania genus in Africa and Eurasia: what does MLSA tell us

Leishmaniasis is a complex parasitic disease from a taxonomic, clinical and epidemiological point of view. The role of genetic exchanges has been questioned for over twenty years and their recent experimental demonstration along with the identification of interspecific hybrids in natura has revived this debate. After arguing that genetic exchanges were exceptional and did not contribute to Leishmania evolution, it is currently proposed that interspecific exchanges could be a major driving force for rapid adaptation to new reservoirs and vectors, expansion into new parasitic cycles and adaptation to new life conditions. To assess the existence of gene flows between species during evolution we used MLSA-based (MultiLocus Sequence Analysis) approach to analyze 222 Leishmania strains from Africa and Eurasia to accurately represent the genetic diversity of this genus. We observed a remarkable congruence of the phylogenetic signal and identified seven genetic clusters that include mainly independent lineages which are accumulating divergences without any sign of recent interspecific recombination. From a taxonomic point of view, the strong genetic structuration of the different species does not question the current classification, except for species that cause visceral forms of leishmaniasis (L. donovani, L. infantum and L. archibaldi). Although these taxa cause specific clinical forms of the disease and are maintained through different parasitic cycles, they are not clearly distinct and form a continuum, in line with the concept of species complex already suggested for this group thirty years ago. These results should have practical consequences concerning the molecular identification of parasites and the subsequent therapeutic management of the disease

Evolutionary history of Leishmania killicki (synonymous Leishmania tropica) and taxonomic implications

Background: Leishmania (L.) killicki is responsible for the chronic cutaneous leishmaniasis. The taxonomic status of this parasite is still not well defined. It was suggested on one hand to include this taxon within L. tropica complex but also on the other hand to consider it as a distinct phylogenetic complex. The present work represents the more detailed study on the evolutionary history of L. killicki relative to L. tropica and the taxonomic implications. Methods: Thirty five L. killicki and 25 L. tropica strains isolated from humans and from several countries were characterized using the MultiLocus Enzyme Electrophoresis (MLEE) and the MultiLocus Sequence Typing (MLST) approaches. Results: The genetic and phylogenetic analyses strongly support that L. killicki belongs to L. tropica complex. The study suggests the emergence of L. killicki by a funder effect followed by an independent evolution from L. tropica, but does not validate the species status of this taxon. In this context, we suggest to call this taxon L. killicki (synonymous L. tropica) until further epidemiological and phylogenetic studies justify the L. killicki denomination. Conclusions: These findings provided taxonomic and phylogenetic informations on L. killicki and helped to better know the evolutionary history of this taxon

The isolation of Leishmania donovani mon-18, from an aids patient in Portugalpossible needle transmission

L'incidence des co-infections Leishmania/VIH augmente au Portugal depuis l'extension de l'infection VIH aux zones endémiques de kala-azar dans ce pays. Leishmania infantum MON-24, zymodème autochtone "dermo-trope", a déjà été isolé d'un cas de co-infection Leishmania/VIH au Portugal. Nous rapportons ici un cas similaire dû à L. donovani MON-18 chez un toxicomane portugais dont le mode de contamination pourrait s'expliquer par l'usage d'aiguilles ou de seringues contaminées. The spread of HIV infection into leishmaniasis endemic areas has increased the incidence of immunosupressed patients with kala-azar in Portugal.The dermotropic zymodeme MON-24 of Leishmania infantum has been already isolated from a Portuguese AIDS patient, as in some other Mediterranean countries.In this paper we report the isolation of L. donovani MON-18 from a drug addicted Portuguese patient with clinical visceral leishmaniasis and AIDS, that suggests a mechanically transmitted infection by the use of a shared needle or syringe.publishersversionpublishe

Présence simultanée chez le chien de deux zymodèmes du complexe Leishmania infantum

Jusqu'à présent, les prélèvements en vue de l'identification des Leishmania réalisés chez un même hôte et au même moment n'avaient pas permis de mettre en évidence plus d'un zymodème à la fois. Ainsi, sur le pourtour méditerranéen où circule L. infantum MON-1, c'est lui, et lui seul, que l'on isole habituellement de leishmanioses viscérales (LV) humaines, canines et vulpines, ainsi que des vecteurs Phlebotomus perniciosus et P. ariasi (1, 3, 4). Plus rarement, dans les leishmanioses cutanées (LC) ou dans certaines formes de LV, des parasites biochimiquement très proches (petits variants) sont isolés indépendamment (2, 3, 4, 5, 6, 7, 8). Exceptionnellement deux zymodèmes ont été isolés chez un même hôte mais à des périodes différentes. Ainsi Rioux et coll. (9) ont relaté la succession de L. infantum MON-1 et MON-29 au cours de deux épisodes de LC humaine survenus à trois ans d'intervalle. Il s'agissait d'une patiente âgée de 53 ans, domiciliée dans la proche banlieue de Montpellier. Ces zymodèmes se différencient par trois systèmes enzymatiques (G6PD, NP1, MDH) sur 15

Evolutionary and geographical history of the Leishmania donovani complex with a revision of current taxonomy.

Leishmaniasis is a geographically widespread severe disease, with an increasing incidence of two million cases per year and 350 million people from 88 countries at risk. The causative agents are species of Leishmania, a protozoan flagellate. Visceral leishmaniasis, the most severe form of the disease, lethal if untreated, is caused by species of the Leishmania donovani complex. These species are morphologically indistinguishable but have been identified by molecular methods, predominantly multilocus enzyme electrophoresis. We have conducted a multifactorial genetic analysis that includes DNA sequences of protein-coding genes as well as noncoding segments, microsatellites, restriction-fragment length polymorphisms, and randomly amplified polymorphic DNAs, for a total of approximately 18,000 characters for each of 25 geographically representative strains. Genotype is strongly correlated with geographical (continental) origin, but not with current taxonomy or clinical outcome. We propose a new taxonomy, in which Leishmania infantum and L. donovani are the only recognized species of the L. donovani complex, and we present an evolutionary hypothesis for the origin and dispersal of the species. The genus Leishmania may have originated in South America, but diversified after migration into Asia. L. donovani and L. infantum diverged approximately 1 Mya, with further divergence of infraspecific genetic groups between 0.4 and 0.8 Mya. The prevailing mode of reproduction is clonal, but there is evidence of genetic exchange between strains, particularly in Africa

Geographical distribution and epidemiological features of Old World Leishmania infantum and Leishmania donovani foci, based on the isoenzyme analysis of 2277 strains

A series of 2277 Leishmania strains from Old World visceral leishmaniasis foci, isolated between 1973 and 2008, were studied by isoenzyme analysis. The strains were obtained from humans, domestic and wild carnivores, rodents and phlebotomine sandflies, and came from 36 countries. In all, 60 different zymodemes were identified and clustered by a phenetic analysis into 3 different groups corresponding to the typically visceralizing species L. donovani (20 zymodemes, 169 strains), L. archibaldi (3 zymodemes, 46 strains) and L. infantum (37 zymodemes, 2,062 strains). The taxonomic position of these isoenzymatic groups is discussed in view of contradictory results obtained from recent molecular studie

Recurrent American Cutaneous Leishmaniasis

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