Iso-enzymatic variability of Leishmania infantum in Spain

Typing of Leishmania isolates from vectors and leporids of the Madrid (Spain) outbreak

In 2009, a large outbreak of leishmaniasis, associated with environmental changes, was declared near Madrid (Spain), in which Phlebotomus perniciosus was the vector, whereas the main reservoirs were hares and rabbits. Analysis of isolates from humans, vectors and leporids from the focus identified the Leishmania infantum ITS-Lombardi genotype. However, multilocus enzyme electrophoresis (MLEE), the reference technique for Leishmania typing, and sequencing of the hsp70 gene, a commonly used marker, were not performed. In the present study, 19 isolates from P. perniciosus (n = 11), hares (n = 5) and rabbits (n = 3) from the outbreak area, all characterized as ITS-Lombardi in previous studies, were analysed by MLEE and hsp70 sequencing. The hsp70 results confirmed that all the analysed strains are L. infantum. However, by MLEE, 4 different zymodemes of L. infantum were identified based on variable mobilities of the NP1 enzyme: MON-34 (NP1100, n = 11), MON-80 (NP1130, n = 6), MON-24 (NP1140, n = 1) and MON-331 (NP1150, n = 1). The relative frequency of these zymodemes does not correspond to their usual occurrence in Spain. Moreover, MON-34 and MON-80 were found in P. perniciosus, hares and rabbits for the first time. These findings continue to provide insights into the outbreak and call for further studies with a higher number of strains.

The Sporadic cutaneous leishmaniasis due to Leishmania infantum in Morocco: A presumably trend towards endemicity

In Morocco, cutaneous leishmaniasis (CL) is an endemic disease; it is considered a major public health problem caused by three species Leishmaniamajor, Leishmaniatropica, and the dermotropic variant MON-24 of Leishmaniainfantum. This species has three incriminated vectors named; Phlebotomus ariasi, Phlebotomus longicuspis and Phlebotomus perniciosus, with the dog as reservoir.The main aim of this review is to elucidate the current epidemiological pattern of CL due to L.infantum and to investigate the factors facilitating its propagation throughout the country. Therefore, the number of CL cases due to L.infantum, their repartition; the distribution of L.infantum vectors, as well as the factors affecting their abundance and spread were investigated. We showed a wide extension of this form of CL, from the north of Morocco to the Saharan areas, as well as an increase of reported cases. This extension of the disease has been accompanied by a juxtaposed spread and a high abundance of confirmed vectors of L. infantum, which are present in almost all bioclimatic zones. In this review, we have highlighted the impact of climate: temperature, humidity, precipitation; vegetation and human activities on the geographical expansion of L. infantum vectors. These abiotic and biotic factors constitute favorable conditions for the increase of vector populations, and their introduction into areas where they did not exist before, and subsequently raise the risk of introduction of this form of cutaneous leishmaniasis into previously free areas. To conclude, CL by L.infantum, traditionally evolving as a sporadic form, is changing to an endemic mode, which seeks more epidemiological studies, and more attention from the health authorities when implementing control programs.

Autochthonous and imported tegumentary leishmaniasis in Catalonia (Spain): Aetiological evolution in the last four decades and usefulness of different typing approaches based on biochemical, molecular and proteomic markers

Leishmaniasis is a transmissible disease caused by Leishmania protozoa. Spain is endemic for both visceral and cutaneous leishmaniasis, the autochthonous aetiological agent being Leishmania infantum. Around the world, the L. donovani complex is associated with visceral symptoms, while any species of the Leishmania or Viannia subgenera affecting human can produce tegumentary forms. In a context of growing numbers of imported cases, associated with globalisation, the aim of this study was to analyse the aetiological evolution of human tegumentary leishmaniasis in a region of Spain (Catalonia). Fifty-six Leishmania strains, isolated from 1981 to 2018, were analysed using MLEE, gene sequencing (hsp70, rpoIILS, fh and ITS2) and MALDI-TOF. The utility of these different analytical methods was compared. The results showed an increase in leishmaniasis over the two last decades, particularly imported cases, which represented 39% of all cases studied. Leishmania infantum, L. major, L. tropica, L. braziliensis, L. guyanensis and L. panamensis were identified. The combination of molecular and enzymatic methods allowed the identification of 29 different strain types (A to AC). Strain diversity was higher in L. (Viannia), whilst the different L. major types were relatable with geo-temporal data. Among the autochthonous cases, type C prevailed throughout the studied period (39%). Minor types generally appeared within a short time interval. While all the techniques provided identical identification at the species complex level, MALDI-TOF and rpoIILS or fh sequencing would be the most suitable identification tools for clinical practice, and the tandem hsp70-ITS2 could substitute MLEE in the epidemiological field.

Exploiting genetic polymorphisms in metabolic enzymes for rapid screening of Leishmania infantum genotypes

Background

Leishmania infantum is the aetiological agent of visceral leishmaniasis (VL) and cutaneous leishmaniasis (CL). Numerous strains and/or zymodemes have been identified and characterized by multilocus enzyme electrophoresis (MLEE). MLEE is considered the reference method for L. infantum parasite typing and it is based upon enzyme electrophoretic mobility analysis from promastigote cultures. However, the MLEE technique is cumbersome, time-consuming and does not detect silent genetic mutations or nucleotide changes that give rise to amino acid changes that do not alter electrophoretic mobility. As a result of these difficulties, many DNA-based typing methods have been developed over the past few years. However, relative to the enzymes utilized in MLEE analysis, we observed a shortage of DNA sequences available in the GenBank database or an absolute lack of sequences belonging to specific zymodemes. The aims of the present study were to (i) implement the number of sequences coding for metabolic enzymes used in MLEE; (ii) identify polymorphisms that characterize L. infantum zymodemes most prevalent in the Mediterranean basin; and (iii) exploit these polymorphisms to develop a rapid screening test that would give results comparable with existing MLEE typing.

Results

Partial sequences of seven metabolic enzyme genes (malic enzyme, 6-phosphogluconate dehydrogenase, mitochondrial isocitrate dehydrogenase, glucose-6-phosphate isomerase, glucose-6-phosphate dehydrogenase, phosphoglucomutase and mannose phosphate isomerase) were obtained from 11 L. infantum strains. The comparison of these sequences with those obtained from GenBank allowed for the identification of a few polymorphisms that could distinguish several zymodemes. In particular, the polymorphism 390T>G in the malic enzyme gene has been exploited to develop a high-resolution melt (HRM)-based assay to rapidly differentiate the genotype 390T, associated with zymodemes MON-1, MON-72 and MON-201, evidencing a partial agreement between genotyping results and MLEE. The assay has been successfully applied to L. infantum clinical isolates and clinical samples.

Conclusions

A HRM-based assay for rapid identification of genotypes associated with the most common L. infantum zymodemes in the Mediterranean basin has been developed and its potential application in epidemiological research for L. infantum population screening, without parasite isolation and culturing, has been demonstrated.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-3143-7) contains supplementary material, which is available to authorized users.

Clinical management of canine leishmaniosis versus human leishmaniasis due to Leishmania infantum: Putting "One Health" principles into practice

The initiative One World, "One Health" tries to rapidly detect emerging or reemerging human and animal infectious diseases and prevent epidemiological situations such as deforestation, some agricultural practices or the appearance of new foci of leishmaniosis due to Leishmania infantum with alternative reservoirs. With this objective in mind, we here consider leishmaniosis in the Mediterranean basin and compare its current clinical management from two perspectives: that of a veterinarian specialized in infectious and parasitic diseases, and that of a physician specialized in infectious tropical diseases. We thus prepared a list of 10 key questions from epidemiology to control of the disease in both species: dogs and humans. This issue requires a concise and clear response to help animal and human health clinicians to improve their clinical management and understanding of this important zoonosis. Our ultimate aim is to update and bring together the information available backed by sound scientific evidence.

Genome wide comparison of Ethiopian Leishmania donovani strains reveals differences potentially related to parasite survival

Leishmania donovani is the main cause of visceral leishmaniasis (VL) in East Africa. Differences between northern Ethiopia/Sudan (NE) and southern Ethiopia (SE) in ecology, vectors, and patient sensitivity to drug treatment have been described, however the relationship between differences in parasite genotype between these two foci and phenotype is unknown. Whole genomic sequencing (WGS) was carried out for 41 L. donovani strains and clones from VL and VL/HIV co-infected patients in NE (n = 28) and SE (n = 13). Chromosome aneuploidy was observed in all parasites examined with each isolate exhibiting a unique karyotype. Differences in chromosome ploidy or karyotype were not correlated with the geographic origin of the parasites. However, correlation between single nucleotide polymorphism (SNP) and geographic origin was seen for 38/41 isolates, separating the NE and SE parasites into two large groups. SNP restricted to NE and SE groups were associated with genes involved in viability and parasite resistance to drugs. Unique copy number variation (CNV) were also associated with NE and SE parasites, respectively. One striking example is the folate transporter (FT) family genes (LdBPK_100390, LdBPK_100400 and LdBPK_100410) on chromosome 10 that are single copy in all 13 SE isolates, but either double copy or higher in 39/41 NE isolates (copy number 2-4). High copy number (= 4) was also found for one Sudanese strain examined. This was confirmed by quantitative polymerase chain reaction for LdBPK_100400, the L. donovani FT1 transporter homolog. Good correlation (p = 0.005) between FT copy number and resistance to methotrexate (0.5 mg/ml MTX) was also observed with the haploid SE strains examined showing higher viability than the NE strains at this concentration. Our results emphasize the advantages of whole genome analysis to shed light on vital parasite processes in Leishmania.

Multilocus microsatellite typing of Leishmania infantum isolates in monitored Leishmania/HIV coinfected patients

Background

Leishmania infantum is the main etiological agent of both visceral and cutaneous clinical forms of leishmaniasis in the Mediterranean area. Leishmania/HIV coinfection in this area is characterized by a chronic course and frequent recurrences of clinical episodes. The present study using Multilocus Microsatellite Typing (MLMT) analysis, a highly discriminative tool, aimed to genetically characterize L. infantum isolates taken from monitored Leishmania/HIV coinfected patients presenting successive clinical episodes.

Methods

In this study, by the analysis of 20 microsatellite loci, we studied the MLMT profiles of 25 L. infantum isolates from 8 Leishmania/HIV coinfected patients who had experienced several clinical episodes. Two to seven isolates per patient were taken before and after treatment, during clinical and non-clinical episodes, with time intervals of 6 days to 29 months. Genetic diversity, clustering and phenetic analyses were performed.

Results

MLMT enabled us to study the genetic characteristics of the 25 L. infantum isolates, differentiating 18 genotypes, corresponding to a genotypic diversity of 0.72. Fifteen genotypes were unique in the total sample set and only 3 were repeated, 2 of which were detected in different patients. Both clustering and phylogenetic analyses provided insights into the genetic links between the isolates; in five patients isolates showed clear genetic links: either the genotype was exactly the same or only slightly different. In contrast, the isolates of the other three patients were dispersed in different clusters and some could be the result of mixing between populations.

Conclusions

Our data indicated a great MLMT variability between isolates from coinfected patients and no predominant genotype was observed. Despite this, almost all clinical episodes could be interpreted as a relapse rather than a reinfection. The results showed that diverse factors like an intrapatient evolution over time or culture bias could influence the parasite population detected in the patient, making it difficult to differentiate between relapse and reinfection.

Visceral leishmaniasis and HIV coinfection in the Mediterranean region

Visceral leishmaniasis is hypoendemic in Mediterranean countries, where it is caused by the flagellate protozoan Leishmania infantum. VL cases in this area account for 5%–6% of the global burden. Cases of Leishmania/HIV coinfection have been reported in the Mediterranean region, mainly in France, Italy, Portugal, and Spain. Since highly active antiretroviral therapy was introduced in 1997, a marked decrease in the number of coinfected cases in this region has been reported. The development of new diagnostic methods to accurately identify level of parasitemia and the risk of relapse is one of the main challenges in improving the treatment of coinfected patients. Clinical trials in the Mediterranean region are needed to determine the most adequate therapeutic options for Leishmania/HIV patients as well as the indications and regimes for secondary prophylaxis. This article reviews the epidemiological, diagnostic, clinical, and therapeutic aspects of Leishmania/HIV coinfection in the Mediterranean region.

Molecular typing of Leishmania infantum isolates from a leishmaniasis outbreak in Madrid, Spain, 2009 to 2012

Leishmaniasis is endemic in south-west Europe. Recent data point to the spread and (re-)emergence of this disease in previously endemic and non-endemic European countries. A recent example is the urban community outbreak of cutaneous and visceral leishmaniasis in the south-west of Madrid autonomous community, Spain, which began on 1 July 2009. A total of 446 cases associated to this outbreak were reported up to 31 December 2012. We show molecular typing data for 73 Leishmania infantum isolates obtained from January 2008 to July 2012 from different areas of Madrid, including those affected by the outbreak. Seven different genotypes were identified by combining data from two targets: the ribosomal internal transcribed spacers (ITS)-1 and -2 and the haspb (k26) gene. The results contribute to a better understanding of the parasite population circulating in the region, and indicate that most of the outbreak-associated isolates (22/31) were infected by parasites with the same combined genotype. Additional data from 82 L. infantum isolates typed as either MON-1 or MON-24 by isoenzyme analysis indicate that far from concluding that the outbreak was caused by a 'new' emerging genotype, further molecular typing-based surveillance studies are required to better understand the epidemiology of leishmaniasis in the region.

Fatal visceral leishmaniasis, with massive bone-marrow infection, in an immunosuppressed but HIV-negative Spanish patient, after the initiation of treatment with meglumine antimoniate

Although visceral leishmaniasis is often fatal in the developing world, Leishmania-attributable deaths in Europe are relatively rare and nowadays almost always linked to HIV infection. In Spain, however, a HIV-negative man with a history of chronic obstructive pulmonary disease and prednisone treatment was recently hospitalized because of hypotension and asthenia. Although the patient was afebrile, a bone-marrow aspirate, collected after thrombo- and leuco-cytopenia had been observed, was found to contain huge numbers of amastigotes. A course of antileishmanial treatment with meglumine antimoniate was initiated but the patient went into refractory shock and died within 6 h. The significance of this case, in terms of the routine investigation and treatment of immunosuppressed patients who may have leishmaniasis, is discussed.

Characterization of the biology and infectivity of Leishmania infantum viscerotropic and dermotropic strains isolated from HIV+ and HIV- patients in the murine model of visceral leishmaniasis

BACKGROUND

Leishmaniasis is a group of diseases with a variety of clinical manifestations. The form of the disease is highly dependent on the infective Leishmania species and the immunological status of the host. The infectivity of the parasite strain also plays an important role in the progression of the infection. The aim of this work is to understand the influence of the natural infectivity of Leishmania strains in the outcome of visceral leishmaniasis.

METHODS

In this study we have characterized four strains of L. infantum in terms of molecular typing, in vitro cultivation and differentiation. Two strains were isolated from HIV+ patients with visceral leishmaniasis (Bibiano and E390M), one strain was isolated from a cutaneous lesion in an immunocompetent patient (HL) and another internal reference strain causative of visceral leishmaniasis (ST) also from an immunocompetent patient was used for comparison. For this objective, we have compared their virulence by in vitro and in vivo infectivity in a murine model of visceral leishmaniasis.

RESULTS

Molecular typing unraveled a new k26 sequence attributed to MON-284 zymodeme and allowed the generation of a molecular signature for the identification of each strain. In vitro cultivation enabled the production of promastigotes with comparable growth curves and metacyclogenesis development. The HL strain was the most infective, showing the highest parasite loads in vitro that were corroborated with the in vivo assays, 6 weeks post-infection in BALB/c mice. The two strains isolated from HIV+ patients, both belonging to two different zymodemes, revealed different kinetics of infection.

CONCLUSION

Differences in in vitro and in vivo infectivity found in the murine model were then attributed to intrinsic characteristics of each strain. This work is supported by other studies that present the parasite's inherent features as factors for the multiplicity of clinical manifestations and severity of leishmaniasis.

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 studies.

Canine Leishmania infantum enzymatic polymorphism: a review including 1023 strains of the Mediterranean area, with special reference to Algeria

This bibliographic review reports the isoenzyme polymorphism of 1023 Leishmania infantum strains isolated from dogs that have been characterized by multilocus enzyme electrophoresis in the Leishmania Reference Centre of Montpellier, or in other laboratories, to which this typification technique has already been transferred. Between 1981 and 2010, a total of 12 zymodemes were identified around the Mediterranean basin: MON-1, MON-24, MON-34, MON-72, MON-77, MON-80, MON-98, MON-105, MON-108, MON-199, MON-199 var NP1130 and MON-281, of which 6 were present in Algeria. The zymodeme MON-1 was predominant (86.5% of the strains). The dog was confirmed as the main reservoir of L. infantum MON-1, while the reservoir of the other zymodemes has not yet been identified. The enzymatic polymorphism is relatively high in Algeria and in Spain in contrast to other Mediterranean countries. The reasons for this polymorphism are discussed.

Leishmania infantum: Lipophosphoglycan intraspecific variation and interaction with vertebrate and invertebrate hosts

Interspecies variations in lipophosphoglycan (LPG) have been the focus of intense study over the years due its role in specificity during sand fly-Leishmania interaction. This cell surface glycoconjugate is highly polymorphic among species with variations in sugars that branch off the conserved Gal(β1,4)Man(α1)-PO(4) backbone of repeat units. However, the degree of intraspecies polymorphism in LPG of Leishmania infantum (syn. Leishmania chagasi) is not known. In this study, intraspecific variation in the repeat units of LPG was evaluated in 16 strains of L. infantum from Brazil, France, Algeria and Tunisia. The structural polymorphism in the L. infantum LPG repeat units was relatively slight and consisted of three types: type I does not have side chains; type II has one β-glucose residue that branches off the disaccharide-phosphate repeat units and type III has up to three glucose residues (oligo-glucosylated). The significance of these modifications was investigated during in vivo interaction of L. infantum with Lutzomyia longipalpis, and in vitro interaction of the parasites and respective LPGs with murine macrophages. There were no consequential differences in the parasite densities in sand fly midguts infected with Leishmania strains exhibiting type I, II and III LPGs. However, higher nitric oxide production was observed in macrophages exposed to glucosylated type II LPG.

Genetic diversity of human zoonotic leishmaniasis in Iberian Peninsula

Leishmaniasis caused by Leishmania (Leishmania) infantum is a zoonotic disease endemic in South Europe, from Portugal to the Middle East. The aim of the present study was to investigate the genetic diversity of L. infantum parasites in Iberian Peninsula. Twenty-four L. infantum strains isolated from immunocompetent patients with leishmaniasis from several localities of Portugal and Spain were studied. The use of kinetoplast DNA-PCR-restriction fragment length polymorphism as a molecular marker revealed intra-specific variation. No association was found between genotype and clinical form of the disease or patients age group. Two main clusters were identified with this marker: (i) zymodeme MON-1 strains and (ii) non-MON-1 strains. However, no association was found between strains variability and geographical distribution suggesting that parasite populations of different regions in the Iberian Peninsula are homogenous.

Cutaneous leishmaniasis (Leishmania tropica) in a German tourist after travel to Greece

We report on a German tourist returning from vacations in Southern Greece with cutaneous leishmaniasis (CL) presenting as multiple erythematosquamous lesions caused by Leishmania tropica (zymodeme MON-57). In spite of its endemicity, only few data are available on the incidence and current distribution of CL in Greece, which may allow for an assessment of the risk for travelers.

Differentiation and gene flow among European populations of Leishmania infantum MON-1

BACKGROUND

Leishmania infantum is the causative agent of visceral and cutaneous leishmaniasis in the Mediterranean region, South America, and China. MON-1 L. infantum is the predominating zymodeme in all endemic regions, both in humans and dogs, the reservoir host. In order to answer important epidemiological questions it is essential to discriminate strains of MON-1.

METHODOLOGY/PRINCIPAL FINDINGS

We have used a set of 14 microsatellite markers to analyse 141 strains of L. infantum mainly from Spain, Portugal, and Greece of which 107 strains were typed by MLEE as MON-1. The highly variable microsatellites have the potential to discriminate MON-1 strains from other L. infantum zymodemes and even within MON-1 strains. Model- and distance-based analysis detected a considerable amount of structure within European L. infantum. Two major monophyletic groups-MON-1 and non-MON-1-could be distinguished, with non-MON-1 being more polymorphic. Strains of MON-98, 77, and 108 were always part of the MON-1 group. Among MON-1, three geographically determined and genetically differentiated populations could be identified: (1) Greece; (2) Spain islands-Majorca/Ibiza; (3) mainland Portugal/Spain. All four populations showed a predominantly clonal structure; however, there are indications of occasional recombination events and gene flow even between MON-1 and non-MON-1. Sand fly vectors seem to play an important role in sustaining genetic diversity. No correlation was observed between Leishmania genotypes, host specificity, and clinical manifestation. In the case of relapse/re-infection, only re-infections by a strain with a different MLMT profile can be unequivocally identified, since not all strains have individual MLMT profiles.

CONCLUSION

In the present study for the first time several key epidemiological questions could be addressed for the MON-1 zymodeme, because of the high discriminatory power of microsatellite markers, thus creating a basis for further epidemiological investigations.

The relationship between leishmaniasis and AIDS: the second 10 years

To date, most Leishmania and human immunodeficiency virus (HIV) coinfection cases reported to WHO come from Southern Europe. Up to the year 2001, nearly 2,000 cases of coinfection were identified, of which 90% were from Spain, Italy, France, and Portugal. However, these figures are misleading because they do not account for the large proportion of cases in many African and Asian countries that are missed due to a lack of diagnostic facilities and poor reporting systems. Most cases of coinfection in the Americas are reported in Brazil, where the incidence of leishmaniasis has spread in recent years due to overlap with major areas of HIV transmission. In some areas of Africa, the number of coinfection cases has increased dramatically due to social phenomena such as mass migration and wars. In northwest Ethiopia, up to 30% of all visceral leishmaniasis patients are also infected with HIV. In Asia, coinfections are increasingly being reported in India, which also has the highest global burden of leishmaniasis and a high rate of resistance to antimonial drugs. Based on the previous experience of 20 years of coinfection in Europe, this review focuses on the management of Leishmania-HIV-coinfected patients in low-income countries where leishmaniasis is endemic.

HIV-1/parasite co-infection and the emergence of new parasite strains

HIV-1 and parasitic infections co-circulate in many populations, and in a few well-studied examples HIV-1 co-infection is known to amplify parasite transmission. There are indications that HIV-1 interacts significantly with many other parasitic infections within individual hosts, but the population-level impacts of co-infection are not well-characterized. Here we consider how alteration of host immune status due to HIV-1 infection may influence the emergence of novel parasite strains. We review clinical and epidemiological evidence from five parasitic diseases (malaria, leishmaniasis, schistosomiasis, trypanosomiasis and strongyloidiasis) with emphasis on how HIV-1 co-infection alters individual susceptibility and infectiousness for the parasites. We then introduce a simple modelling framework that allows us to project how these individual-level properties might influence population-level dynamics. We find that HIV-1 can facilitate invasion by parasite strains in many circumstances and we identify threshold values of HIV-1 prevalence that allow otherwise unsustainable parasite strains to invade successfully. Definitive evidence to test these predicted effects is largely lacking, and we conclude by discussing challenges in interpreting available data and priorities for future studies.

Leishmaniasis in Portugal: enzyme polymorphism of Leishmania infantum based on the identification of 213 strains

This study reports isoenzyme polymorphism of Leishmania strains isolated in different regions of Portugal between 1982 and 2005. A total of 213 strains were obtained from cases of visceral and cutaneous leishmaniasis isolated from immunocompetent patients (adults and children) and immunocompromised adults, as well as from dogs and sandflies. Four zymodemes were identified: MON-1, MON-24, MON-29 and MON-80. Zymodeme MON-1 was identified in 96.7% of the strains, predominating in both immunocompetent and immunocompromised human patients, and it was the only zymodeme isolated from dogs. Isoenzyme diversity in HIV-infected patients was higher than in the immunocompetent group, in which all the strains from visceral leishmaniasis were MON-1. The domestic dog was confirmed as the reservoir host of zoonotic leishmaniasis in Portugal and Phlebotomus perniciosus and Phlebotomus ariasi as vectors. The overall low enzyme polymorphism observed in the Portuguese foci contrasts with the neighbouring foci in Spain.

Studies on the CPA cysteine peptidase in the Leishmania infantum genome strain JPCM5

Background

Visceral leishmaniasis caused by members of the Leishmania donovani complex is often fatal in the absence of treatment. Research has been hampered by the lack of good laboratory models and tools for genetic manipulation. In this study, we have characterised a L. infantum line (JPCM5) that was isolated from a naturally infected dog and then cloned. We found that JPCM5 has attributes that make it an excellent laboratory model; different stages of the parasite life cycle can be studied in vitro, it is accessible to genetic manipulation and it has retained its virulence. Furthermore, the L. infantum JPCM5 genome has now been fully sequenced.

Results

We have further focused our studies on LiCPA, the L. infantum homologue to L. mexicana cysteine peptidase CPA. LiCPA was found to share a high percentage of amino acid identity with CPA proteins of other Leishmania species. Two independent LiCPA-deficient promastigote clones (ΔLicpa) were generated and their phenotype characterised. In contrast to L. mexicana CPA-deficient mutants, both clones of ΔLicpa were found to have significantly reduced virulence in vitro and in vivo. Re-expression of just one LiCPA allele (giving ΔLicpa::CPA) was sufficient to complement the reduced infectivity of both ΔLicpa mutants for human macrophages, which confirms the importance of LiCPA for L. infantum virulence. In contrast, in vivo experiments did not show any virulence recovery of the re-expressor clone ΔLicpaC1::CPA compared with the CPA-deficient mutant ΔLicpaC1.

Conclusion

The data suggest that CPA is not essential for replication of L. infantum promastigotes, but is important for the host-parasite interaction. Further studies will be necessary to elucidate the precise roles that LiCPA plays and why the re-expression of LiCPA in the ΔLicpa mutants complemented the gene deletion phenotype only in in vitro and not in in vivo infection of hamsters.

Comparison of molecular markers for strain typing of Leishmania infantum

The epidemiology of Leishmania infantum, the etiological agent of visceral leishmaniasis, is changing rapidly; hence powerful typing tools are required in order to monitor the parasite populations spreading and to adapt adequate control measures. We compared here the resolving power of four molecular methods at the zymodeme level: PCR-RFLP analysis of kDNA minicircles (kDNAPCR-RFLP) and antigen genes (cysteine proteinase b and major surface protease, cpb- and gp63PCR-RFLP), multilocus microsatellite typing (MLMT) and random amplification of polymorphic DNA (RAPD) were applied to samples of 25 L. infantum MON-1 strains obtained from different hosts (HIV+ patients, HIV- patients and dogs) coming from three Spanish foci: Madrid, Mallorca and Ibiza. While RAPD was not sufficiently resolving, the other three methods allowed genotyping within the zymodeme. KDNAPCR-RFLP and MLMT were the most discriminatory and appeared the most adequate for strain fingerprinting. In an eco-geographical context, cpbPCR-RFLP, MLMT and kDNAPCR-RFLP were all informative: they showed here a similar picture, with the existence of cluster(s) of isolates from the islands and other one(s) of mixed composition (Madrid and the islands). None of the markers revealed an association with the host type or the clinical form. In general, there was a significant correlation between each pair of distances calculated from the cpb, microsatellite and kDNA data, respectively, but visual inspection of the trees revealed a better congruence between cpb and microsatellite trees. The methods used here are complementary and each adapted to answer specific epidemiological questions. Their choice should be the result of a compromise between the required resolving power, the genetic features of the respective markers and the technical aspects.

Leishmania chagasi/infantum: further investigations on Leishmania tropisms in atypical cutaneous and visceral leishmaniasis foci in Central America

In Central America, apparently genetically identical Leishmania chagasi/infantum parasites cause cutaneous (CL) and visceral leishmaniasis (VL), the latter being more frequent in young children. The present study investigated if there were pathology-related differences in virulence between Honduran CL and VL strains using Mediterranean L. infantum strains as a reference. Macrophage infectivity and serum sensitivity, properties thought to be associated with virulence, were similar between CL and VL strains from both regions. Attention focused on the genome organisation of genes for two candidate virulence factors: Leishmania mitogen activated protein kinase (LMPK) and cysteine proteinase b (Cpb). Interestingly, the Mediterranean strains exhibited restriction enzyme polymorphisms associated with tropism for both LMPK and Cpb genes whereas no differences were observed for the Honduran strains. We also report relative genetic homogeneity of the Honduran strains as compared to the Mediterranean strains and discuss it in terms of the probable origin for the Central American L. chagasi/infantum.