Multiple hybrid genotypes of Leishmania (viannia) in a focus of mucocutaneous Leishmaniasis. Am J Trop Med Hyg

Department of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.
The American journal of tropical medicine and hygiene (Impact Factor: 2.7). 04/2007; 76(3):573-8.
Source: PubMed


The principal agent of mucocutaneous leishmaniasis (MCL) is the South American protozoan parasite Leishmania (Viannia) braziliensis. This organism is generally considered to be clonal, that is, it does not to undergo genetic exchange. Nevertheless, apparent hybrids between several Leishmania species have been reported in the New World and the Old World. When we characterized isolates of Leishmania (Viannia) from a single focus of cutaneous leishmaniasis (CL) and MCL, we found a remarkable phenotypic and genotypic diversity, with 12 zymodemes and 20 microsatellite genotypes. Furthermore, 26 of the 59 isolates were L. braziliensis/L. peruviana phenotypic hybrids that displayed 7 different microsatellite genotypes. A hybrid genotype was the only organism isolated from 4 patients with MCL. Thus hybrids must be included among the potential agents of MCL. Despite the propensity for clonality, hybrids are also an important feature of Leishmania (Viannia) and may give rise to epidemiologically important emergent genotypes.

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    • "In Leishmania and Trypanosoma cruzi, interspecies (or inter-DTU) hybridization occurs only sporadically (e.g. Nolder et al. 2007; Roellig et al. 2013), although highly successful genotypes can result (Lewis et al. 2011). However, those studies that evaluate intraspecies/intra-DTU diversity , as with Giardia, almost invariably find evidence for widespread genetic exchange (Rougeron et al. 2009, 2011; Ocana-Mayorga et al. 2011; Ramirez et al. 2012; Rogers et al. 2014). "
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    ABSTRACT: The debate around the frequency and importance of genetic exchange in parasitic protozoa is now several decades old. Recently, fresh assertions have been made that predominant clonal evolution explains the population structures of several key protozoan pathogens. Here we present an alternative perspective. On the assumption that much apparent clonality may be an artefact of inadequate sampling and study design, we review current research to define why sex might be so difficult to detect in protozoan parasite populations. In doing so we contrast laboratory models of genetic exchange in parasitic protozoa with natural patterns of genetic diversity and consider the fitness advantage of sex at different evolutionary scales. We discuss approaches to improve the accuracy of efforts to characterise genetic exchange in the field. We also examine the implications of the first population genomic studies for the debate around sex and clonality in parasitic protozoa and discuss caveats for the future.This article is protected by copyright. All rights reserved.
    Molecular Ecology 07/2014; 23(17). DOI:10.1111/mec.12872 · 6.49 Impact Factor
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    • "This is the case of L. braziliensis and L. peruviana. Both species co-circulate in some regions of Peru, but only L. braziliensis can potentially cause severe mucocutaneous complications [23]. We observed several sequence variations in the calmodulin intergenic spacer that allow a distinction between these two closely related species belonging to the Viannia sub-genus (Additional file 1). "
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    ABSTRACT: Human leishmaniasis is a neglected disease caused by parasites of the genus Leishmania. Clinical aspects of this disease can vary significantly, reflecting the wide range of parasites in the genus Leishmania. Knowing accurately the Leishmania species infecting humans is important for clinical case management and evaluation of epidemiological risk. Calmodulin is an essential gene in trypanosomatids that modulates the calcium metabolism in various cellular activities. Despite its strong conservation in trypanosomatids, it has been recently observed that its untranslated regions (UTR) diverge among species. In this study we analyzed the sequences and the absolute dinucleotide frequency of the intergenic spacer of the calmodulin gene (containing both, 3[prime] and 5[prime]UTR) in nine reference Leishmania species and ten clinical isolates obtained from patients with cutaneous leishmaniasis. We show that the short calmodulin intergenic spacers exhibit features that make them interesting for applications in molecular characterization and phylogenetic studies of Leishmania. Dendrograms based on sequence alignments and on the dinucleotide frequency indicate that this particular region of calmodulin gene might be useful for species typing between the Leishmania and Viannia subgenera. Mutations and composition of the calmodulin intergenic spacer from Leishmania species might have taxonomic value as parameters to define if an isolate is identical to a certain species or belongs to one of the two current subgenera.
    Parasites & Vectors 01/2014; 7(1):35. DOI:10.1186/1756-3305-7-35 · 3.43 Impact Factor
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    • "Robust coalescent Bayesian dating suggest that this genotype emerged approximately 23 000 ± 12 000 years ago and followed by population expansion, broadly corresponding with the earliest human migration into the Americas [19]. Emergent genotypes have been reported in other parasites such as Plasmodium and Leishmania[46-48] as a strong signal of recombination. When a detailed analyses of the number of domestic and peridomestic/sylvatic genotypes was observed among the polymorphic genes (Figure 1). "
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    ABSTRACT: Chagas disease is a systemic pathology caused by Trypanosoma cruzi. This parasite reveals remarkable genetic variability, evinced in six Discrete Typing Units (DTUs) named from T. cruzi I to T. cruzi VI (TcI to TcVI). Recently newly identified genotypes have emerged such as TcBat in Brazil, Colombia and Panama associated to anthropogenic bats. The genotype with the broadest geographical distribution is TcI, which has recently been associated to severe cardiomyopathies in Argentina and Colombia. Therefore, new studies unraveling the genetic structure and natural history of this DTU must be pursued. We conducted a spatial and temporal analysis on 50 biological clones of T. cruzi I (TcI) isolated from humans with different clinical phenotypes, triatomine bugs and mammal reservoirs across three endemic regions for Chagas disease in Colombia. These clones were submitted to a nuclear Multilocus Sequence Typing (nMLST) analysis in order to elucidate its genetic diversity and clustering. After analyzing 13 nuclear housekeeping genes and obtaining a 5821 bp length alignment, we detected two robust genotypes within TcI henceforth named TcIDOM (associated to human infections) and a second cluster associated to peridomestic and sylvatic populations. Additionaly, we detected putative events of recombination and an intriguing lack of linkage disequilibrium. These findings reinforce the emergence of an enigmatic domestic T. cruzi genotype (TcIDOM), and demonstrates the high frequency of recombination at nuclear level across natural populations of T. cruzi. Therefore, the need to pursue studies focused on the diferential virulence profiles of TcI strains. The biological and epidemiological implications of these findings are herein discussed.
    BMC Genetics 09/2013; 14(1):96. DOI:10.1186/1471-2156-14-96 · 2.40 Impact Factor
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