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ABSTRACT: During 2002-2009, 466 cases of cutaneous leishmaniasis (CL) were reported from Jenin District, Palestine, affecting both genders. The average annual incidence was 23 cases per 100000 inhabitants, increasing with age in children. Most cases presented a single lesion, generally on the face. Diagnosis and species identification was done by applying internal transcribed spacer 1 (ITS1) RFLP analysis to 47 isolates, of which 44 (93.6%) were Leishmania tropica and 3 (6.4%) were L. major. RFLP analysis was also performed on 256 skin tissue scrapings spotted onto filter papers, showing that 138 (53.9%) were positive, of which 50.7% were infected with L. tropica, 17.4% with L. major and 2.9% with L. donovani s.l., and 29.0% could not be identified. This is the first report from Palestine on human CL caused by L. infantum. Nine of the strains of L. tropica were subjected to multilocus enzyme electrophoresis, six of which belonged to the zymodeme MON-137 and three to a new zymodeme (MON-307). This separation was corroborated by excreted factor serotyping. This observation modifies the classical epidemiological view of CL in Palestine. Jenin District is an active focus of CL caused by L. tropica, where Phlebotomus sergenti, the putative vector, is abundant. These data suggest that CL is a zoonotic infection, but an animal reservoir has not been found.
Transactions of the Royal Society of Tropical Medicine and Hygiene 07/2012; 106(9):554-62. · 2.16 Impact Factor
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Manu Vanaerschot,
Saskia Decuypere,
Tim Downing,
Hideo Imamura,
Olivia Stark,
Simonne De Doncker,
Syamal Roy,
Bart Ostyn,
Louis Maes,
Basudha Khanal,
Marleen Boelaert, Gabriele Schönian,
Matthew Berriman,
François Chappuis,
Jean-Claude Dujardin,
Shyam Sundar,
Suman Rijal
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ABSTRACT: The current standard to assess pentavalent antimonial (SSG) susceptibility of Leishmania is a laborious in vitro assay of which the result has little clinical value because SSG-resistant parasites are also found in SSG-cured patients. Candidate genetic markers for clinically relevant SSG-resistant parasites identified by full genome sequencing were here validated on a larger set of clinical strains. We show that 3 genomic locations suffice to specifically detect the SSG-resistant parasites found only in patients experiencing SSG treatment failure. This finding allows the development of rapid assays to monitor the emergence and spread of clinically relevant SSG-resistant Leishmania parasites.
The Journal of Infectious Diseases 06/2012; 206(5):752-5. · 6.41 Impact Factor
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ABSTRACT: Cutaneous leishmaniasis (CL) is a major public health problem in Libya. The objective of this study was to investigate, for the first time, epidemiological features of CL outbreaks in Libya including molecular identification of parasites, the geographical distribution of cases and possible scenarios of parasite transmission.
We studied 450 patients that came from 49 areas distributed in 12 districts in north-west Libya. The patients' ages ranged from 9 months to 87 years (median age 25 years); 54% of the cases were males. Skin scrapings spotted on glass slides were collected for molecular identification of causative agent. The ribosomal internal transcribed spacer 1 (ITS1) was amplified and subsequently characterized by restriction fragment length polymorphism (RFLP) analysis. In total, 195 samples were successfully identified of which 148 (75.9%) were Leishmania major, and 47 (24.1%) Leishmania tropica. CL cases infected with L. major were found in all CL areas whereas L. tropica cases came mainly from Al Jabal Al Gharbi (46.4%), Misrata (17.8%) and Tarhuna districts (10.7%). A trend of seasonality was noticed for the infections with L. major which showed a clear peak between November and January, but was less pronounced for infections by L. tropica.
The first molecular study on CL in Libya revealed that the disease is caused by L. major and L. tropica and the epidemiological patterns in the different foci were the same as in other Mediterranean foci of CL.
PLoS Neglected Tropical Diseases 06/2012; 6(6):e1700. · 4.69 Impact Factor
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Evi Gouzelou,
Christos Haralambous,
Ahmad Amro,
Andreas Mentis,
Francine Pratlong,
Jean-Pierre Dedet,
Jan Votypka,
Petr Volf,
Seray Ozensoy Toz,
Katrin Kuhls, Gabriele Schönian,
Ketty Soteriadou
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ABSTRACT: New foci of human CL caused by strains of the Leishmania donovani (L. donovani) complex have been recently described in Cyprus and the Çukurova region in Turkey (L. infantum) situated 150 km north of Cyprus. Cypriot strains were typed by Multilocus Enzyme Electrophoresis (MLEE) using the Montpellier (MON) system as L. donovani zymodeme MON-37. However, multilocus microsatellite typing (MLMT) has shown that this zymodeme is paraphyletic; composed of distantly related genetic subgroups of different geographical origin. Consequently the origin of the Cypriot strains remained enigmatic.
The Cypriot strains were compared with a set of Turkish isolates obtained from a CL patient and sand fly vectors in south-east Turkey (Çukurova region; CUK strains) and from a VL patient in the south-west (Kuşadasi; EP59 strain). These Turkish strains were initially analyzed using the K26-PCR assay that discriminates MON-1 strains by their amplicon size. In line with previous DNA-based data, the strains were inferred to the L. donovani complex and characterized as non MON-1. For these strains MLEE typing revealed two novel zymodemes; L. donovani MON-309 (CUK strains) and MON-308 (EP59). A population genetic analysis of the Turkish isolates was performed using 14 hyper-variable microsatellite loci. The genotypic profiles of 68 previously analyzed L. donovani complex strains from major endemic regions were included for comparison. Population structures were inferred by combination of bayesian model-based and distance-based approaches. MLMT placed the Turkish and Cypriot strains in a subclade of a newly discovered, genetically distinct L. infantum monophyletic group, suggesting that the Cypriot strains may originate from Turkey.
The discovery of a genetically distinct L. infantum monophyletic group in the south-eastern Mediterranean stresses the importance of species genetic characterization towards better understanding, monitoring and controlling the spread of leishmaniasis in this region.
PLoS Neglected Tropical Diseases 02/2012; 6(2):e1507. · 4.69 Impact Factor
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Manu Vanaerschot,
Saskia Decuypere,
Tim Downing,
Hideo Imamura,
Olivia Stark,
Simonne De Doncker,
Syamal Roy,
Bart Ostyn,
Louis Maes,
Basudha Khanal,
Marleen Boelaert, Gabriele Schönian,
Matthew Berriman,
François Chappuis,
Jean-Claude Dujardin,
Shyam Sundar,
Suman Rijal
The Journal of Infectious Diseases 01/2012; 29(3). · 6.41 Impact Factor
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Tim Downing,
Hideo Imamura,
Saskia Decuypere,
Taane G Clark,
Graham H Coombs,
James A Cotton,
James D Hilley,
Simonne de Doncker,
Ilse Maes,
Jeremy C Mottram,
Mike A Quail,
Suman Rijal,
Mandy Sanders, Gabriele Schönian,
Olivia Stark,
Shyam Sundar,
Manu Vanaerschot,
Christiane Hertz-Fowler,
Jean-Claude Dujardin,
Matthew Berriman
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ABSTRACT: Visceral leishmaniasis is a potentially fatal disease endemic to large parts of Asia and Africa, primarily caused by the protozoan parasite Leishmania donovani. Here, we report a high-quality reference genome sequence for a strain of L. donovani from Nepal, and use this sequence to study variation in a set of 16 related clinical lines, isolated from visceral leishmaniasis patients from the same region, which also differ in their response to in vitro drug susceptibility. We show that whole-genome sequence data reveals genetic structure within these lines not shown by multilocus typing, and suggests that drug resistance has emerged multiple times in this closely related set of lines. Sequence comparisons with other Leishmania species and analysis of single-nucleotide diversity within our sample showed evidence of selection acting in a range of surface- and transport-related genes, including genes associated with drug resistance. Against a background of relative genetic homogeneity, we found extensive variation in chromosome copy number between our lines. Other forms of structural variation were significantly associated with drug resistance, notably including gene dosage and the copy number of an experimentally verified circular episome present in all lines and described here for the first time. This study provides a basis for more powerful molecular profiling of visceral leishmaniasis, providing additional power to track the drug resistance and epidemiology of an important human pathogen.
Genome Research 12/2011; 21(12):2143-56. · 13.61 Impact Factor
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Tim Downing,
Olivia Stark,
Manu Vanaerschot,
Hideo Imamura,
Mandy Sanders,
Saskia Decuypere,
Simonne de Doncker,
Ilse Maes,
Suman Rijal,
Shyam Sundar,
Jean-Claude Dujardin,
Matthew Berriman, Gabriele Schönian
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ABSTRACT: The species of the Leishmania donovani species complex cause visceral leishmaniasis, a debilitating infectious disease transmitted by sandflies. Understanding molecular changes associated with population structure in these parasites can help unravel their epidemiology and spread in humans. In this study, we used a panel of standard microsatellite loci and genome-wide SNPs to investigate population-level diversity in L. donovani strains recently isolated from a small geographic area spanning India, Bihar and Nepal, and compared their variation to that found in diverse strains of the L. donovani complex isolates from Europe, Africa and Asia. Microsatellites and SNPs could clearly resolve the phylogenetic relationships of the strains between continents, and microsatellite phylogenies indicated that certain older Indian strains were closely related to African strains. In the context of the anti-malaria spraying campaigns in the 1960s, this was consistent with a pattern of episodic population size contractions and clonal expansions in these parasites that was supported by population history simulations. In sharp contrast to the low resolution provided by microsatellites, SNPs retained a much more fine-scale resolution of population-level variability to the extent that they identified four different lineages from the same region one of which was more closely related to African and European strains than to Indian or Nepalese ones. Joining results of in vitro testing the antimonial drug sensitivity with the phylogenetic signals from the SNP data highlighted protein-level mutations revealing a distinct drug-resistant group of Nepalese and Indian L. donovani. This study demonstrates the power of genomic data for exploring parasite population structure. Furthermore, markers defining different genetic groups have been discovered that could potentially be applied to investigate drug resistance in clinical Leishmania strains.
Infection, genetics and evolution: journal of molecular epidemiology and evolutionary genetics in infectious diseases 11/2011; 12(1):149-59. · 3.22 Impact Factor
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Vanessa Adaui,
Ilse Maes,
Tine Huyse,
Frederik Van den Broeck,
Michael Talledo,
Katrin Kuhls,
Simonne De Doncker,
Louis Maes,
Alejandro Llanos-Cuentas, Gabriele Schönian,
Jorge Arevalo,
Jean-Claude Dujardin
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ABSTRACT: In order to understand the epidemiological dynamics of antimonial (Sb(V)) resistance in zoonotic tegumentary leishmaniasis and its link with treatment outcome, we analyzed the population structure of 24 Peruvian Leishmania braziliensis clinical isolates with known in vitro antimony susceptibility and clinical phenotype by multilocus microsatellite typing (14 microsatellite loci). The genetic variability in the Peruvian isolates was high and the multilocus genotypes were strongly differentiated from each other. No correlation was found between the genotypes and in vitro drug susceptibility or clinical treatment outcome. The finding of a polyphyletic pattern among the Sb(V)-resistant L. braziliensis might be explained by (i) independent events of drug resistance emergence, (ii) sexual recombination and/or (iii) other phenomena mimicking recombination signals. Interestingly, the polyphyletic pattern observed here is very similar to the one we observed in the anthroponotic Leishmania donovani (Laurent et al., 2007), hereby questioning the role of transmission and/or chemotherapeutic drug pressure in the observed population structure.
Infection, genetics and evolution: journal of molecular epidemiology and evolutionary genetics in infectious diseases 08/2011; 11(8):1873-80. · 3.22 Impact Factor
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ABSTRACT: The evolutionary history of Leishmania chagasi, the aetiological agent of visceral leishmaniasis in South America has been widely debated. This study addresses the problem of the origin of L. chagasi, its timing and demography with fast evolving genetic markers, a suite of Bayesian clustering algorithms and coalescent modelling. Here, using 14 microsatellite markers, 450 strains from the Leishmania donovani complex, we show that the vast majority of the Central and South American L. chagasi were nested within the Portuguese Leishmania infantum clade. Moreover, L. chagasi allelic richness was half that of their Old World counterparts. The bottleneck signature was estimated to be about 500 years old and the settlement of L. chagasi in the New World, probably via infected dogs, was accompanied by a thousand-fold population decrease. Visceral leishmaniasis, lethal if untreated, is therefore one more disease that the Conquistadores brought to the New World.
Infection, genetics and evolution: journal of molecular epidemiology and evolutionary genetics in infectious diseases 07/2011; 11(5):1091-5. · 3.22 Impact Factor
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ABSTRACT: Leishmania infantum (syn. L. chagasi) is the causative agent of visceral leishmaniasis (VL) in the New World (NW) with endemic regions extending from southern USA to northern Argentina. The two hypotheses about the origin of VL in the NW suggest (1) recent importation of L. infantum from the Old World (OW), or (2) an indigenous origin and a distinct taxonomic rank for the NW parasite. Multilocus microsatellite typing was applied in a survey of 98 L. infantum isolates from different NW foci. The microsatellite profiles obtained were compared to those of 308 L. infantum and 20 L. donovani strains from OW countries previously assigned to well-defined populations. Two main populations were identified for both NW and OW L. infantum. Most of the NW strains belonged to population 1, which corresponded to the OW MON-1 population. However, the NW population was much more homogeneous. A second, more heterogeneous, population comprised most Caribbean strains and corresponded to the OW non-MON-1 population. All Brazilian L. infantum strains belonged to population 1, although they represented 61% of the sample and originated from 9 states. Population analysis including the OW L. infantum populations indicated that the NW strains were more similar to MON-1 and non-MON-1 sub-populations of L. infantum from southwest Europe, than to any other OW sub-population. Moreover, similarity between NW and Southwest European L. infantum was higher than between OW L. infantum from distinct parts of the Mediterranean region, Middle East and Central Asia. No correlation was found between NW L. infantum genotypes and clinical picture or host background. This study represents the first continent-wide analysis of NW L. infantum population structure. It confirmed that the agent of VL in the NW is L. infantum and that the parasite has been recently imported multiple times to the NW from southwest Europe.
PLoS Neglected Tropical Diseases 06/2011; 5(6):e1155. · 4.69 Impact Factor
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ABSTRACT: We report paired strains of Leishmania parasites, one from the viscera and the other from skin lesions that were isolated from three patients with visceral leishmaniasis and disseminated cutaneous leishmaniasis that were co-infected with human immunodeficiency virus. The causative parasites were characterized by polymerase chain reaction-restriction length polymorphism of the ribosomal DNA internal transcribed spacer 1 and by a panel of multilocus microsatellite markers. We demonstrated that the causative agent was Leishmania donovani in all cases, irrespective of the phenotype of the disease. The paired strains from viscera and skin lesions of the same patients showed genetic identity across the 14 microsatellite markers investigated. These findings demonstrate that the skin lesions in these human immunodeficiency virus-positive patients with visceral leishmaniasis were caused by dissemination of viscerotropic L. donovani parasites as a consequence of severe immunosuppression. However, in all three patients, rapid clearance of the skin lesions was observed after antimonial therapy.
The American journal of tropical medicine and hygiene 06/2011; 84(6):906-12. · 2.59 Impact Factor
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ABSTRACT: Ten polymorphic microsatellite markers were used to analyse 25 strains of Leishmania major collected from cutaneous leishmaniasis cases in different endemic areas in Iran. Nine of the markers were polymorphic, revealing 21 different genotypes. The data displayed significant microsatellite polymorphism with rare allelic heterozygosity. Bayesian statistic and distance based analyses identified three genetic clusters among the 25 strains analysed. Cluster I represented mainly strains isolated in the west and south-west of Iran, with the exception of four strains originating from central Iran. Cluster II comprised strains from the central part of Iran, and cluster III included only strains from north Iran. The geographical distribution of L. major in Iran was supported by comparing the microsatellite profiles of the 25 Iranian strains to those of 105 strains collected in 19 Asian and African countries. The Iranian clusters I and II were separated from three previously described populations comprising strains from Africa, the Middle East and Central Asia whereas cluster III grouped together with the Central Asian population. The considerable genetic variability of L. major might be related to the existence of different populations of Phlebotomus papatasi and/or to differences in reservoir host abundance in different parts of Iran.
Microbes and Infection 05/2011; 13(11):937-42. · 3.10 Impact Factor
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ABSTRACT: Cutaneous leishmaniasis caused by Leishmania aethiopica is rarely encountered outside disease-endemic areas and there have been no clinical trials evaluating its pharmacotherapy. We describe the treatment of cutaneous leishmaniasis caused by L. aethiopica using liposomal amphothericin B in an immunocompromised traveler returning from Eritrea.
The American journal of tropical medicine and hygiene 05/2011; 84(5):692-4. · 2.59 Impact Factor
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ABSTRACT: In 2004, an outbreak of kala-azar (KA) occurred for the first time in Libo Kemkem district, in the highland area of northwest Ethiopia. In order to track the possible origins of the outbreak parasites, we have investigated 19 strains of Leishmania donovani that were collected during (n = 6) and after (n = 13) the outbreak by using 14 highly polymorphic microsatellite markers. Unique microsatellite profiles were obtained for all strains from Libo Kemkem. When compared to those of L. donovani strains from different Ethiopian, Kenyan and Sudanese foci, by genetic distance and Bayesian clustering model analyses, most strains from Libo Kemkem grouped with strains from: (i) Humera and Metema in the lowlands and Belessa in the highland of Ethiopia, and (ii) Sudan, at different hierarchal levels. The strains from Libo Kemkem district were assigned at least to three genetically distinct clusters (A, B1 and B2) of which only one, cluster B2, consisted exclusively of strains from Libo Kemkem. The fact that most of the outbreak strains were found to be related to strains from well-known KA foci in northwest Ethiopia and Sudan might suggest multiple introductions of L. donovani strains from these foci into Libo Kemkem district.
Microbes and Infection 03/2011; 13(6):595-601. · 3.10 Impact Factor
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Dmitriy A Kovalenko,
Shavkat A Razakov,
Evgeny N Ponirovsky,
Alon Warburg,
Rokhat M Nasyrova,
Valentina I Ponomareva,
Aziza A Fatullaeva,
Abdelmajeed Nasereddin,
Eyal Klement,
Mohammad Z Alam,
Lionel F Schnur,
Charles L Jaffe, Gabriele Schönian,
Gad Baneth
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ABSTRACT: The Namangan Region in the Pap District, located in Eastern Uzbekistan is the main focus of visceral leishmaniasis (VL) in Uzbekistan. In total, 28 cases of human VL were registered during 2006-2008 in this region. A study on the epidemiology of VL in this area was carried out in 2007-2008 in the villages of Chodak, Oltinkan, Gulistan and Chorkesar located at elevations of 900-1200 above sea level.
A total of 162 dogs were tested for Leishmania infection. Blood was drawn for serology and PCR. When clinical signs of the disease were present, aspirates from lymph nodes and the spleen were taken. Forty-two dogs (25.9%) had clinical signs suggestive of VL and 51 (31.5%) were sero-positive. ITS-1 PCR was performed for 135 dogs using blood and tissue samples and 40 (29.6%) of them were PCR-positive. Leishmanial parasites were cultured from lymph node or spleen aspirates from 10 dogs.Eight Leishmania strains isolated from dogs were typed by multi-locus microsatellite typing (MLMT) and by multilocus enzyme electrophoretic analysis (MLEE), using a 15 enzyme system. These analyses revealed that the strains belong to the most common zymodeme of L. infantum, i.e., MON-1, and form a unique group when compared to MON-1 strains from other geographical regions.
The data obtained through this study confirm the existence of an active focus of VL in the Namangan region of Uzbekistan. The fact that L. infantum was the causative agent of canine infection with typical clinical signs, and also of human infection affecting only infants, suggests that a zoonotic form of VL similar in epidemiology to Mediterranean VL is present in Uzbekistan.
Parasites & Vectors 01/2011; 4:58. · 2.94 Impact Factor
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ABSTRACT: Leishmania is notable for a large number of described species. Molecular phylogenies of Leishmania have increasingly suggested that the number of species could be too large. A recent phylogenetic analysis of the heat-shock protein 70 gene (hsp70) by Fraga and colleagues supports the existence of only eight medically relevant species compared to 17 species as defined by multilocus enzyme electrophoresis. Whether a revised classification system should be introduced for Leishmania is discussed.
Trends in Parasitology 10/2010; 26(10):466-9. · 5.14 Impact Factor
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ABSTRACT: The aim of the study was to assess the 7SL RNA PCR followed by restriction fragment length polymorphism (RFLP) and reverse dot blot (RDB) assays for use in identification of Old World Leishmania species. Species-specific RFLP patterns were obtained for Leishmania major, Leishmania tropica and the Leishmania donovani complex when the 7SL RNA PCR product was digested with the restriction enzyme BsuRI, an isoschizomer of HaeIII. For the RDB assay, biotin-labelled 7SL RNA amplicons were hybridized to Leishmania genus-specific and species-specific oligonucleotide probes immobilized onto a membrane. The Old World Leishmania species could be distinguished by using five probes: one that was a genus-specific probe and hybridized to all Leishmania species (Lc), two that were specific for L. major (Lm1 and Lm2), one that was specific for L. tropica (Lt) and one that detected both L. major and L. tropica (Lmt). The PCR-RDB was 10 times more sensitive than 7SL PCR and can detect <1 parasite. In addition, the identification of species was easier and more reliable than with 7SL PCR-RFLP. 7SL PCR-RFLP detected parasites in 50 of 57 clinical samples, whereas PCR-RDB detected 53 and 55 were detected by amplification of kinetoplast (k) DNA. The 7SL RNA PCR has proven useful for direct diagnosis of Old World leishmaniasis, especially when combined with the RBD assay for species identification.
Tropical Medicine & International Health 08/2010; 15(8):872-80. · 2.80 Impact Factor
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ABSTRACT: Parasites' evolution in response to parasite-targeted control strategies, such as vaccines and drugs, is known to be influenced by their population genetic structure. The aim of this study was to describe the population structure of Ethiopian strains of Leishmania donovani derived from different areas endemic for visceral leishmaniasis (VL) as a prerequisite for the design of effective control strategies against the disease.
Sixty-three strains of L. donovani newly isolated from VL cases in the two main Ethiopian foci, in the north Ethiopia (NE) and south Ethiopia (SE) of the country were investigated by using 14 highly polymorphic microsatellite markers. The microsatellite profiles of 60 previously analysed L. donovani strains from Sudan, Kenya and India were included for comparison. Multilocus microsatellite typing placed strains from SE and Kenya (n = 30) in one population and strains from NE and Sudan (n = 65) in another. These two East African populations corresponded to the areas of distribution of two different sand fly vectors. In NE and Sudan Phlebotomus orientalis has been implicated to transmit the parasites and in SE and Kenya P. martini. The genetic differences between parasites from NE and SE are also congruent with some phenotypic differences. Each of these populations was further divided into two subpopulations. Interestingly, in one of the subpopulations of the population NE we observed predominance of strains isolated from HIV-VL co-infected patients and of strains with putative hybrid genotypes. Furthermore, high inbreeding irreconcilable from strict clonal reproduction was found for strains from SE and Kenya indicating a mixed-mating system.
This study identified a hierarchical population structure of L. donovani in East Africa. The existence of two main, genetically and geographically separated, populations could reflect different parasite-vector associations, different ecologies and varying host backgrounds and should be further investigated.
PLoS Neglected Tropical Diseases 01/2010; 4(11):e889. · 4.69 Impact Factor
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ABSTRACT: Three major forms of human disease, cutaneous leishmaniasis, visceral leishmaniasis and mucocutaneous leishmaniasis, are caused by several leishmanial species whose geographic distribution frequently overlaps. These Leishmania species have diverse reservoir hosts, sand fly vectors and transmission patterns. In the Old World, the main parasite species responsible for leishmaniasis are Leishmania infantum, L. donovani, L. tropica, L. aethiopica and L. major. Accurate, rapid and sensitive diagnostic and identification procedures are crucial for the detection of infection and characterization of the causative leishmanial species, in order to provide accurate treatment, precise prognosis and appropriate public health control measures.
High resolution melt analysis of a real time PCR product from the Internal Transcribed Spacer-1 rRNA region was used to identify and quantify Old World Leishmania in 300 samples from human patients, reservoir hosts and sand flies. Different characteristic high resolution melt analysis patterns were exhibited by L. major, L. tropica, L. aethiopica, and L. infantum. Genotyping by high resolution melt analysis was verified by DNA sequencing or restriction fragment length polymorphism. This new assay was able to detect as little as 2-4 ITS1 gene copies in a 5 microl DNA sample, i.e., less than a single parasite per reaction.
This new technique is useful for rapid diagnosis of leishmaniasis and simultaneous identification and quantification of the infecting Leishmania species. It can be used for diagnostic purposes directly from clinical samples, as well as epidemiological studies, reservoir host investigations and vector surveys.
PLoS Neglected Tropical Diseases 01/2010; 4(1):e581. · 4.69 Impact Factor
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ABSTRACT: A multilocus microsatellite typing (MLMT) approach based on the analysis of 15 independent loci has been developed for the discrimination of strains belonging to different Viannia species. Thirteen microsatellite loci were isolated de novo from microsatellite-enriched libraries for both Leishmania braziliensis and L. guyanensis. Two previously identified markers, AC01 and AC16, were modified and added to our marker set. Markers were designed to contain simple dinucleotide repeats flanked by the minimal possible number of nucleotides in order to allow variations in repeat numbers to be scored as size variations of the PCR products. The 15 markers in total were amplified for almost all of the strains of Viannia tested; one marker did not amplify from the two L. peruviana strains included in the study. When 30 strains of L. braziliensis, 21 strains of L. guyanensis, and 2 strains of L. peruviana were tested for polymorphisms, all strains except two strains of L. guyanensis had individual MLMT types. Distance-based analysis identified three main clusters. All strains except one strain of L. guyanensis grouped together. Two clusters consisted of strains of L. braziliensis according to their geographical origins. The two strains of L. peruviana grouped together with strains of L. braziliensis from Peru and the adjacent Brazilian state of Acre. MLMT has proven capable of individualizing strains even from the same areas of endemicity and of detecting genetic structures at different levels. MLMT is thus applicable for epidemiological and population genetic studies of strains within the subgenus Viannia.
Journal of clinical microbiology 08/2009; 47(9):2818-25. · 4.16 Impact Factor
