Comparative Expression Profiling of Leishmania: Modulation in Gene Expression between Species and in Different Host Genetic Backgrounds

The single-celled parasite Leishmania, transmitted by sand flies in more than 88 tropical and sub-tropical countries globally, infects man and other mammals, causing a spectrum of diseases called the leishmaniases. Over 12 million people are currently infected worldwide with 2 million new cases reported each year. The type of leishmaniasis that develops in the mammalian host is dependent on the species of infecting parasite and the immune response to infection (that can be influenced by host genetic variation). Our research is focused on identifying parasite factors that contribute to pathogenicity in the host and understanding how these might differ between parasite species that give rise to the different clinical forms of leishmaniasis. Molecules of this type might lead to new therapeutic tools in the longer term. In this paper, we report a comparative analysis of gene expression profiles in three Leishmania species that give rise to different types of disease, focusing on the intracellular stages that reside in mammalian macrophages. Our results show that there are only a small number of differences between these parasite species, with host genetics playing only a minor role in influencing the parasites' response to their intracellular habitat. These small changes may be significant, however, in determining the clinical outcome of infection

Multilocus Microsatellite Typing (MLMT) of Strains from Turkey and Cyprus Reveals a Novel Monophyletic L. donovani Sensu Lato Group

In eastern Mediterranean, leishmaniasis represents a major public health problem with considerable impact on morbidity and potential to spread. Cutaneous leishmaniasis (CL) caused by L. major or L. tropica accounts for most cases in this region although visceral leishmaniasis (VL) caused by L. infantum is also common. New foci of human CL caused by L. donovani complex strains were recently described in Cyprus and Turkey. Herein we analyzed Turkish strains from human CL foci in Çukurova region (north of Cyprus) and a human VL case in Kuşadasi. These were compared to Cypriot strains that were previously typed by Multilocus Enzyme Electrophoresis (MLEE) as L. donovani MON-37. Nevertheless, they were found genetically distinct from MON-37 strains of other regions and therefore their origin remained enigmatic. A population study was performed by Multilocus Microsatellite Typing (MLMT) and the profile of the Turkish strains was compared to previously analyzed L. donovani complex strains. Our results revealed close genetic relationship between Turkish and Cypriot strains, which form a genetically distinct L. infantum monophyletic group, suggesting that Cypriot strains may originate from Turkey. Our analysis indicates that the epidemiology of leishmaniasis in this region is more complicated than originally thought

A historical overview of the classification, evolution, and dispersion of Leishmania parasites and sandflies

Background The aim of this study is to describe the major evolutionary historical events among Leishmania, sandflies, and the associated animal reservoirs in detail, in accordance with the geographical evolution of the Earth, which has not been previously discussed on a large scale. Methodology and Principal Findings Leishmania and sandfly classification has always been a controversial matter, and the increasing number of species currently described further complicates this issue. Despite several hypotheses on the origin, evolution, and distribution of Leishmania and sandflies in the Old and New World, no consistent agreement exists regarding dissemination of the actors that play roles in leishmaniasis. For this purpose, we present here three centuries of research on sandflies and Leishmania descriptions, as well as a complete description of Leishmania and sandfly fossils and the emergence date of each Leishmania and sandfly group during different geographical periods, from 550 million years ago until now. We discuss critically the different approaches that were used for Leishmana and sandfly classification and their synonymies, proposing an updated classification for each species of Leishmania and sandfly. We update information on the current distribution and dispersion of different species of Leishmania (53), sandflies (more than 800 at genus or subgenus level), and animal reservoirs in each of the following geographical ecozones: Palearctic, Nearctic, Neotropic, Afrotropical, Oriental, Malagasy, and Australian. We propose an updated list of the potential and proven sandfly vectors for each Leishmania species in the Old and New World. Finally, we address a classical question about digenetic Leishmania evolution: which was the first host, a vertebrate or an invertebrate? Conclusions and Significance We propose an updated view of events that have played important roles in the geographical dispersion of sandflies, in relation to both the Leishmania species they transmit and the animal reservoirs of the parasites

Description de la femelle de Phlebotomus (Larroussius) chadlii Rioux, Juminer et Gibily, 1966 (Diptera : Psychodidae). D’après un exemplaire capturé aux environs du Kef (Tunisie)

La femelle de l’espèce Phlebotomus (Larroussius) chadlii Rioux, Juminer & Gibily, 1966, inconnue jusqu’à ce jour, est décrite à partir d’un exemplaire capturé au nord-ouest de la Tunisie, dans la région du Kef. Elle a pu être distinguée de P. ariasi par plusieurs caractères de la spermathèque : 1) chez P. chadlii, la partie évasée du conduit apparaît plus lisse et plus large que chez P. ariasi ; 2) chez P. chadlii cette partie représente les trois-quart du conduit alors que chez P. ariasi elle n’en forme que la moitié ; 3) chez P. chadlii, le col de la spermathèque est plus court que celui de P. ariasi. La base du conduit est compatible avec la grande taille de la valve pénienne de P. chadlii. Par ailleurs, l’attribution de cette femelle à l’espèce P. chadlii est soutenue par : 1) la présence de mâles P. chadlii dans la même localité, durant trois années successives ; 2) l’absence totale de P. ariasi dans cette région ; 3) la coexistence, dans la même station, de la femelle décrite, avec des mâles de P. chadlii

Description de la femelle de

La femelle de l’espèce Phlebotomus (Larroussius) chadlii Rioux, Juminer & Gibily, 1966, inconnue jusqu’à ce jour, est décrite à partir d’un exemplaire capturé au nord-ouest de la Tunisie, dans la région du Kef. Elle a pu être distinguée de P. ariasi par plusieurs caractères de la spermathèque : 1) chez P. chadlii, la partie évasée du conduit apparaît plus lisse et plus large que chez P. ariasi ; 2) chez P. chadlii cette partie représente les trois-quart du conduit alors que chez P. ariasi elle n’en forme que la moitié ; 3) chez P. chadlii, le col de la spermathèque est plus court que celui de P. ariasi. La base du conduit est compatible avec la grande taille de la valve pénienne de P. chadlii. Par ailleurs, l’attribution de cette femelle à l’espèce P. chadlii est soutenue par : 1) la présence de mâles P. chadlii dans la même localité, durant trois années successives ; 2) l’absence totale de P. ariasi dans cette région ; 3) la coexistence, dans la même station, de la femelle décrite, avec des mâles de P. chadlii

Identification of Lebanese dermotropic putative Leishmania archibaldi isolates by gp63 PCR-RFLP

Leishmania stocks isolated from cutaneous lesions in Lebanon were characterized by PCR methods. The stocks were typed as putative L. (L.) archibaldi (gp63 PCR-RFLP), belonging to 2 different genotypes (PCR-based schizodeme analysis). This constitutes the first report on the presence of L. (L.) archibaldi in the Middle East

Genomic polymorphism of Leishmania infantum; a relationship with clinical pleomorphism?

Leishmania infantum is the etiological agent of visceral (VL) and a cutaneous form (CL) of leishmaniasis around the Mediterranean Basin. In order to document the parasite genetic background corresponding to this clinical diversity, chromosome size polymorphism was analysed in 32 French isolates (18 CL and 14 VL) originating from the Cévennes and the Pyrénées Orientales (PO), and corresponding to zymodemes MON-1 and MON-29. Five chromosomes bearing tandemly repeated genes encoding for important antigens (gp63, PSA-2 and K39) or key metabolic functions (mini-exon and rDNA) were studied. Significant size variation (100-270 kbp) was observed for chromosomes bearing mini-exon, PSA-2 and rDNA genes, which involved variation in copy number of corresponding genes. The two other chromosomes showed smaller size-variation and did not involve dosage of gp63 and K39 genes. Chromosomal size showed correlation with geography and clinical origin: (i) chromosome 2 (mini-exon) was found to be significantly smaller in the PO; (ii) chromosomes 12 (PSA-2) and 27 (rDNA) were significantly smaller in the strictly cutaneous MON-29 isolates. Gene rearrangements and their synergistic effects on the phenotypic expression of the parasite are discussed

Molecular epidemiology and diagnosis of Leishmania: what have we learnt from genome structure, dynamics and function?

This paper reviews our exploration of the dynamics of the Leishmania genome and its contribution to epidemiology and diagnosis. We used as a model Peruvian populations of L. (Viannia) braziliensis and L. (V.) peruviana, 2 species very close phylogenetically, but phenotypically very different in biotope and pathology. We initially focused on karyotype analysis. Our data showed that chromosomes were subject to a fast rate of evolution, and were sensitive indicators of genetic drift. Therefore, molecular karyotyping appeared an adequate tool for monitoring (i) emergence of close species, (ii) ecogeographical differentiation at the intraspecific level, and (iii) strain 'fingerprinting'. Chromosome size variation was mostly due to the number of tandemly repeated genes (rDNA, mini-exon, gp63, and cysteine proteinase genes), and could involve the deletion of unique genes (L. (V.) braziliensis-specific gp63 families). Considering the importance of these genes in parasitism, their rearrangement might have functional implications: adaptation to different environments and pleomorphic pathogenicity. Our knowledge of genome structure and dynamics was used to develop new polymerase chain reaction (PCR) techniques. Amplification of gp63 genes followed by cleavage with restriction enzymes and study of restriction fragment length polymorphism (gp63 PCR-RFLP) allowed the discrimination of all species tested, even directly in biopsies with 95% sensitivity (compared with PCR amplification of kinetoplast deoxyribonucleic acid). At the intra-specific level, RFLP was also observed and corresponded to mutations in major immunogen domains of gp63. These seem to be under strong selection pressure, and the technique should facilitate addressing how the host's immune pressure may modulate parasite population structure. Altogether, gp63 PCR-RFLP represents a significant operational improvement over the other techniques for molecular epidemiology and diagnosis: it combines sensitivity, discriminatory power and prognostic value

Identification of Leishmania donovani as a cause of cutaneous leishmaniasis in Sudan

International audienceEight patients with cutaneous ulcers were referred to the Institute of Endemic Diseases, Khartoum, Sudan, from June 2000 to March 2002 for the diagnosis of suspected cutaneous leishmaniasis (CL). Diagnosis was confirmed parasitotogically by both positive Giemsa-stained smears and successful culture of Leishmania promastigotes in NNN medium. The eight parasite isolates were shown to belong to the Leishmania donovani complex by kDNA PCR. Isoenzyme typing of three isolates revealed that they were identical to the L. donovani MON-82 reference strain, and the gp63 PCR-RFLP profile showed similar patterns to a reference strain of MON-82. CL is endemic in most regions of Sudan and has been reported previously as being caused by L. major MON-74. The results of this study suggest that L. donovani is also a cause of CL in Sudan and that further study of isolates from Sudanese patients with cutaneous ulcers is warranted to ascertain whether L. donovani or L. major is the causative agent. (c) 2007 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved