Moroccan Leishmania infantum: genetic diversity and population structure as revealed by multi-locus microsatellite typing

Genetic Diversity and Population Structure of Leishmania infantum in Morocco as Revealed by Multilocus Sequence Typing (MLST) Approach

Leishmania infantum is endemic in Morocco, and it causes both visceral (VL) and cutaneous leishmaniasis (CL). In this study, the multilocus sequence typing (MLST) approach was used to investigate the phylogeny and population structure of Leishmania infantum strains isolated from CL and VL patients and the canine reservoir in different leishmaniasis endemic foci in Morocco. For this purpose, eight loci (pgm, alat, me, fh, g6pd, pgd, gpi and cytb) were amplified in 40 samples, out of which 31 were successfully sequenced. The genetic diversity analysis detected a high degree of intraspecific genetic variability among the studied strains. The phylogenetic and the haplotype analyses showed that most of the strains from the same geographical areas clustered together. The recombination among Leishmania infantum strains was revealed through a splits tree analysis and the number of recombination events. Moreover, the assessment of the gene flow between Leishmania infantum and Leishmania tropica through phylogenetic analysis and haplotype diversity in two endemic foci where the two species were sympatric showed no genetic exchange between the two species.

Distribution and Ecology of Phlebotomine Sand Flies (Diptera: Psychodidae) in Endemic and Nonendemic Area of Leishmaniasis in Northern Morocco

Northern Morocco is endemic for cutaneous and visceral leishmaniasis. Our entomological investigations aim to evaluate the risk of Leishmania transmission by determining the species composition, the density, and seasonal fluctuation of sand fly populations in endemic and nonendemic areas of leishmaniasis in Tetouan province (North-Western Morocco). Using Sticky-paper traps, 8,370 specimens were collected between May and November 2015 in two localities: peri-urban area of Tetouan city, where leishmaniasis is endemic and that of the Oued Laou village where no cases of leishmaniasis have been recorded. Six sand fly species were identified. The genus Phebotomus was represented by five species: Phlebotomus ariasi, Phlebotomus. longicuspis, Phlebotomus perniciosus, Phlebotomus kazeruni, and Phlebotomus sergenti, while the genus Sergentomyia was represented by only one species Sergentomyia minuta. Phlebotomus perniciosus was dominant in the nonendemic area (47%) while Phlebotomus sergenti was dominant in the endemic area (51%). The spatio-temporal distribution of sand fly populations is discussed according to biotic and abiotic variables. Seasonal fluctuation in sand fly density showed a bimodal pattern for the subgenus Larroussius and a unimodal pattern for the subgenus Paraphlebotomus in Tetouan city. But, in Oued Laou village, a unimodal density distribution for species of the Larroussius subgenus and a bimodal seasonal distribution for species of the subgenus Paraphlebotomus were identified. We affirm the coexistence, in the study area, of vectors of both cutaneous and visceral leishmaniasis, namely P. ariasi, P. longicuspis and P. perniciosus vectors of Leishmania infantum and P. sergenti vector of L. tropica. However, the geographic distribution, the specific abundance, and the activity reveal significant differences between endemic and nonendemic areas in the region.

Potential distributions of phlebotomine sandfly vectors of human visceral leishmaniasis caused by Leishmania infantum in Morocco

Zoonotic visceral leishmaniasis is a common vector-borne systemic disease caused by Leishmania infantum (Kinetoplastida: Trypanosomatidae). In Morocco the situation is complex: many sandfly species have been collected in areas in which the disease is endemic, but only Phlebotomus ariasi, Phlebotomus perniciosus and Phlebotomus longicuspis (Diptera: Psychodidae) have been confirmed to have vectorial roles. The objective of the present study was to ascertain the potential distribution of L. infantum and its vectors in Morocco, using ecological niche modelling. Vector records were obtained from field collections of the Laboratory team and from previously published entomological observations. Epidemiological data for L. infantum modelling were obtained from Moroccan Ministry of Health reports. The jackknife test indicated that the bioclimatic variables with the greatest influence on model development for all species were annual precipitation and precipitation in the driest quarter of the year. MaxEnt model representations for sandfly species that act as vectors of L. infantum showed the widespread geographic distribution of these species in Morocco, specifically in northern and central Morocco, where foci of visceral leishmaniasis are found. The ecological niche modelling points out areas in which the probability of occurrence of these species is higher. This information should be considered as a starting point for further research to fully elucidate the ecology and epidemiology of these species, as well as of the pathogens they transmit.

Emerging and Re-Emerging Leishmaniases in the Mediterranean Area: What Can Be Learned from a Retrospective Review Analysis of the Situation in Morocco during 1990 to 2010?

In Morocco, cutaneous and visceral leishmaniases represent a public health concern. In this opinion paper, we propose to highlight chosen elements that have governed the drastic increase in the incidence of leishmaniases recorded in Morocco during the period between 1990 to 2010 in order to guide the prediction of the expansion of diseases and epidemic events. We highlight that the dispersion of the zoonotic cutaneous leishmaniasis (ZCL) form, caused by the Leishmania major parasite, appears to be closely related to that of its arthropod vector density, which is sensitive to changes in climate. The dissemination of anthroponotic cutaneous leishmaniasis (ACL) was related to an increase in human travel and local tourism during the studied decades. These are linked to economic expansion and infrastructure development. Interestingly, the main ACL foci are spatially aligned with the highways, and their occurrence was synchronized with the building of transportation infrastructure. During the above-mentioned decades, the zoonotic visceral leishmaniasis (ZVL) caused by Leishmania infantum has expanded from its historical northern territories, dispersing outwards in all directions. This spread follows the emergence of hamlets and villages connecting with major cities.

Genetic tools discriminate strains of Leishmania infantum isolated from humans and dogs in Sicily, Italy

BACKGROUND

Leishmaniasis is one of the most important vector-borne diseases and it represents a serious world health problem affecting millions of people. High levels of Leishmania infections, affecting both humans and animals, are recognized among Italian regions. Among these, Sicily has one of the highest prevalence of Leishmania infection.

METHODOLOGY/PRINCIPAL FINDINGS

Seventy-eight Leishmania strains isolated from human and animal samples across Sicily, were analyzed for the polymorphic k26-gene and genotypes were assigned according to the size of the PCR products. A multilocus microsatellite typing (MLMT) approach based on the analysis of 11 independent loci was used to investigate populations structure and genetic diversity of the isolated strains. Six L. infantum reference strains were included in the analysis for comparison. Bayesian clustering analysis of microsatellite data showed that all the isolated strains clustered in two genetically distinct populations, corresponding to human and canine isolates respectively. A further subdivision was observed between the two main groups, giving a good correlation between human strains and their geographic origin, conversely canine population showed a great genetic variability diffused in the territory.

CONCLUSIONS/SIGNIFICANCE

Among the 78 Leishmania isolates, K26 analysis detected 71 samples (91%) as MON-1 zymodeme, confirming it as the predominant strain in Mediterranean area and 7 human samples (9%) as non-MON-1. MLMT gives important insights into the epidemiology of leishmaniases and allows characterization of different strains to a higher resolution than possible with zymodeme typing. Two main populations presented a strong correlation respect to the different hosts, exhibiting a co-circulation of two distinct populations of L. infantum. The population found in infected humans exhibited a correlation with geographic origin. These clusters could represent a geographically restricted population of strains with the same or related genotypes. This study can contribute to an understanding of Leishmania epidemiology, including the spread of reservoirs and sand fly vectors in the different foci of infection, characterizing parasites within the different hosts.

Multilocus microsatellite typing (MLMT) reveals host-related population structure in Leishmania infantum from northeastern Italy

Background

Visceral leishmaniasis (VL) caused by Leishmania infantum is an ongoing health problem in southern Europe, where dogs are considered the main reservoirs of the disease. Current data point to a northward spread of VL and canine leishmaniasis (CanL) in Italy, with new foci in northern regions previously regarded as non-endemic.

Methodology/Principal findings

Multilocus microsatellite typing (MLMT) was performed to investigate genetic diversity and population structure of L. infantum on 55 samples from infected humans, dogs and sand flies of the E-R region between 2013 and 2017. E-R samples were compared with 10 L. infantum samples from VL cases in other Italian regions (extra E-R) and with 52 strains within the L. donovani complex. Data displayed significant microsatellite polymorphisms with low allelic heterozygosity. Forty-one unique and eight repeated MLMT profiles were recognized among the L. infantum samples from E-R, and ten unique MLMT profiles were assigned to the extra E-R samples. Bayesian analysis assigned E-R samples to two distinct populations, with further sub-structuring within each of them; all CanL samples belonged to one population, genetically related to Mediterranean MON-1 strains, while all but one VL cases as well as the isolate from the sand fly Phlebotomus perfiliewi fell under the second population. Conversely, VL samples from other Italian regions proved to be genetically similar to strains circulating in dogs.

Conclusions/Significance

A peculiar epidemiological situation was observed in northeastern Italy, with the co-circulation of two distinct populations of L. infantum; one population mainly detected in dogs and the other population detected in humans and in a sand fly. While the classical cycle of CanL in Italy fits well into the data obtained for the first population, the population found in infected humans exhibits a different cycle, probably not involving a canine reservoir. This study can contribute to a better understanding of the population structure of L. infantum circulating in northeastern Italy, thus providing useful epidemiologic information for public health authorities.

Visceral leishmaniasis is a sand fly-borne disease caused by protozoan parasites of the genus Leishmania. Leishmania infantum is the only parasitic species circulating in Italy and dogs are considered the main reservoirs of the disease. In this study, 55 L. infantum strains obtained from humans, dogs and sand flies from the Emiliana-Romagna (E-R) region, northeastern Italy, were assessed using multilocus microsatellite typing, a tool applied for population genetic studies. Results were compared with those obtained from 10 samples of visceral leishmaniasis cases occurring in other Italian regions and with 52 strains of the L. donovani complex from other foci of leishmaniasis. Our genetic analysis revealed that canine and human L. infantum strains from the E-R region were separated in two distinct populations; all samples obtained from dogs belonged to one population, while all but one human samples as well as a sand fly sample fell under another population. Samples from patients with visceral leishmaniasis from other Italian regions proved to be genetically similar to strains circulating in dogs. Our findings raise questions on the role of dogs as main reservoirs for human visceral leishmaniasis in the investigated area of northeastern Italy.

Genetic polymorphism in Leishmania infantum isolates from human and animals determined by nagt PCR-RFLP

BACKGROUND

Leishmania infantum is the causative agent of human visceral leishmaniasis (VL) and sporadic human cutaneous leishmaniasis (CL) in the Mediterranean region. The genetic variation of the Leishmania parasites may result in different phenotypes that can be associated with the geographical distribution and diversity of the clinical manifestations. The main objective of this study was to explore the genetic polymorphism in L. infantum isolates from human and animal hosts in different regions of Morocco.

METHODS

The intraspecific genetic variability of 40 Moroccan L. infantum MON-1 strains isolated from patients with VL (n = 31) and CL (n = 2) and from dogs (n = 7) was evaluated by PCR-RFLP of nagt, a single-copy gene encoding N-acetylglucosamine-1-phosphate transferase. For a more complete analysis of L. infantum polymorphism, we included the restriction patterns of nagt from 17 strains available in the literature and patterns determined by in-silico digestion of three sequences from the GenBank database.

RESULTS

Moroccan L. infantum strains presented a certain level of genetic diversity and six distinct nagt-RFLP genotypes were identified. Three of the six genotypes were exclusively identified in the Moroccan population of L. infantum: variant M1 (15%), variant M2 (7.5%), and variant M3 (2.5%). The most common genotype (65%), variant 2 (2.5%), and variant 4 (7.5%), were previously described in several countries with endemic leishmaniasis. Phylogenetic analysis segregated our L. infantum population into two distinct clusters, whereas variant M2 was clearly distinguished from both cluster I and cluster II. This distribution highlights the degree of genetic variability among the Moroccan L. infantum population.

CONCLUSION

The nagt PCR-RFLP method presented here showed an important genetic heterogeneity among Moroccan L. infantum strains isolated from human and canine reservoirs with 6 genotypes identified. Three of the six Moroccan nagt genotypes, have not been previously described and support the particular genetic diversity of the Moroccan L. infantum population reported in other studies.

Spatiotemporal and molecular epidemiology of cutaneous leishmaniasis in Libya

Background

Cutaneous leishmaniasis (CL) is a major public health problem in Libya. In this paper, we describe the eco-epidemiological parameters of CL during the armed conflict period from January 2011 till December 2012. Current spatiotemporal distributions of CL cases were explored and projected to the future using a correlative modelling approach. In addition the present results were compared with our previous data obtained for the time period 1995–2008.

Methodology/Principal findings

We investigated 312 CL patients who presented to the Dermatology Department at the Tripoli Central Hospital and came from 81 endemic areas distributed in 10 districts. The patients presented with typical localized lesions which appeared commonly on the face, arms and legs. Molecular identification of parasites by a PCR-RFLP approach targeting the ITS1 region of the rDNA was successful for 81 patients with two causative species identified: L. major and L. tropica comprised 59 (72.8%) and 22 (27.2%) cases, respectively. Around 77.3% of L. tropica CL and 57.7% of L. major CL caused single lesions. Five CL patients among our data set were seropositive for HIV. L. tropica was found mainly in three districts, Murqub (27.3%), Jabal al Gharbi (27.3%) and Misrata (13.7%) while L. major was found in two districts, in Jabal al Gharbi (61%) and Jafara (20.3%). Seasonal occurrence of CL cases showed that most cases (74.2%) admitted to the hospital between November and March, L. major cases from November till January (69.4%), and L. tropica cases mainly in January and February (41%). Two risk factors were identified for the two species; the presence of previously infected household members, and the presence of rodents and sandflies in patient’s neighborhoods. Spatiotemporal projections using correlative distribution models based on current case data and climatic conditions showed that coastal regions have a higher level of risk due to more favourable conditions for the transmitting vectors.

Conclusion

Future projection of CL until 2060 showed a trend of increasing incidence of CL in the north-western part of Libya, a spread along the coastal region and a possible emergence of new endemics in the north-eastern districts of Libya. These results should be considered for control programs to prevent the emergence of new endemic areas taking also into consideration changes in socio-economical factors such as migration, conflicts, urbanization, land use and access to health care.

Cutaneous leishmaniasis (CL) is a skin infection caused by a single-celled parasite that is transmitted by the bite of a phlebotomine sandfly. CL is the most common form of leishmaniasis characterized by localized lesions in the skin and mucous membranes. The disease is prevalent in all countries around the Mediterranean Basin. In this paper, we describe spatiotemporal and eco-epidemiological parameters of CL in Libya. Moreover, we explored current spatiotemporal distributions of CL cases and explored the future projection of the disease. Our study indicates the presence of higher risk of CL in the coastal regions of Libya. Future projection until 2060 showed a trend of increasing incidence of CL in the north-western part of Libya, a spread along the coastal region and a possible emergence of new endemics in the north-eastern districts of Libya. These scenarios should be considered by health authorities in order to develop appropriate intervention strategies and plan effective control programs.

Urbanization of human visceral leishmaniasis in Morocco

Human visceral leishmaniasis one of the seven most neglected tropical diseases in the world. In Morocco, HVL is widespread in all regions; but it is more common in the northern part with sporadic cases observed in the South.

During the period between 2004 and 2013, the most affected Moroccan provinces were Taounate province, with 220 cases (16.09% of all cases), followed by Chefchaouen with 13.17% and Taza with 10.46% of the total cases. Children < 5 years old are the most affected age group, most cases registered were male.

Geographic distribution of HVL showed predominance in rural areas but we noted that it's opening to be urban.

Epidemiological characteristics of visceral leishmaniasis in Morocco (1990-2014): an update

Leishmaniases are parasitic diseases frequent in the Mediterranean Basin. Visceral leishmaniasis (VL) is a notifiable parasitic disease that increased in incidence in Morocco over the past few years and has recently emerged in several new foci, causing a public health problem in Morocco. The aim of this study is to describe the spatio-temporal distribution of VL in Morocco between 1990 and 2014 period in order to highlight important features and trends of VL and its epidemiology and to assess whether the activity of the unit reflects the situation of the disease at the national level and whether it could constitute an indicator of public health relevance. Two thousand four hundred and twenty one cases were reported in Morocco between 1990 and 2014 with an average annual reported incidence rate of 0.4 cases per 100.000 inhabitants. Before 1996 the average annual incidence of VL was 50 cases on average. After this date the number of cases increased and then remained stable with around 100-150 cases per year. Children whose age varies between 1 and 4 years old are the most affected with 1327 (74%) of total cases; nevertheless the adult starts to be affected by the disease. In 2000, 65% of positive cases of VL are concentrated at both northern regions: Taza-Al Hoceima- Taounate with 45% of cases, Tanger- Tetouan mainly represented by Chefchaoun with 20% of cases. The Fez-Boulemane region located in the center recorded 12% of cases. Throughout the years the map VL distribution has been progressively changed and spatial spread of the disease to the center is noted in 2007. 2014 has been marked by an even greater extension of the disease to the center and south of Morocco. Nationally in 2014, 34 of 75 provinces and prefectures are affected compared to 2000, when 22 out of 82 provinces and prefectures were affected. Leishmania infantum was identified the causative agent based on species- specific PCR-Lei70 assay. VL remains a sporadically endemic parasitic disease in Morocco with a progressive extension of its range of distribution. Such a situation would relate to the geographical succession of Phlebotomine sand fly vectors, the difficulty of actions against the canine population reservoirs of L. infantum and unfavorable socio-economic factors.

Intraspecific genetic variability in a population of Moroccan Leishmania infantum revealed by PCR-RFLP of kDNA minicircles

In Morocco, Leishmania infantum is the main etiologic agent of human and canine visceral leishmaniasis (VL). This species has been proven to be an opportunistic agent in HIV+ patients and is also responsible of sporadic cutaneous leishmaniasis (CL).This work aims to evaluate the genetic variability of Moroccan L. infantum strains based on PCR-RFLP analysis of the kinetoplastid DNA (kDNA) minicircles. A total of 75 DNA samples extracted from positive Giemsa-stained smears (n=32) and from L. infantum cultures (n=43) was studied. The samples have been taken from VL patients infected (n=7) or not (n=56) by HIV, patients with CL (n=2) and finally from infected dogs (n=10). An hypervariable region of kDNA was amplified using the primers MC1 and MC2; the PCR products were digested separately by a panel of nine restriction enzymes. The presence or absence of restriction fragments was scored in a binary matrix and the SplitsTree4 software was used for the construction of a Neighbor-Net network. Moroccan L. infantum population showed an important level of variability with the identification of 6 genotypes. For each genotype a PCR product was sequenced, confirming the presence of all the expected restriction sites. The predominant profile was the genotype B. A new genotype, named Q was detected for the first time, whereas the four other genotypes (G, K, N and O) were reported sporadically in the Mediterranean basin. The Neighbor-Net network segregates our L. infantum population into 3 clusters: Cluster I includes genotype B, cluster II grouping the genotypes O, Q and G and finally the cluster III contains the genotype N. The kDNA-PCR-RFLP assay is suitable for use directly on biological samples; it reveals an important degree of genetic variability among L. infantum strains even those belonging to the same zymodeme what is of great epidemiological interest.

New epidemiological aspects of visceral and cutaneous leishmaniasis in Taza, Morocco

Background

Leishmaniasis is considered among the main endemic diseases in Morocco. However, further knowledge about epidemiological aspects of this disease is needed in several provinces to plan control and preventive strategies to tackle the disease. The present study aims to determine the epidemiological aspect of cutaneous and visceral leishmaniasis in Taza Province from 2007–2014 and to identify the circulating species in this province.

Results

The temporal study from 2007 to 2014 showed that the number of cutaneous leishmaniasis cases increased since 2010. During the period of study, most leishmaniasis cases were detected in both urban and rural areas with 34% of cases detected in two urban localities, Bab Zitouna and Bab tété with 297 and 106 cases, respectively. The molecular study of cutaneous leishmaniasis showed the presence of non-sporadic Leishmania infantum and Leishmania tropica in this province. Regarding visceral leishmaniasis, Leishmania infantum is the species that has been identified.

Conclusions

The epidemio-molecular study of leishmaniasis in Taza Province showed the coexistence of two species of Leishmania in the same foci. They also indicated that CL due to Leishmania infantum is more prevalent than reported in the literature. These results will be helpful for the implementation of control strategies by targeting dogs that constitute a reservoir of Leishmania infantum.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-016-1910-x) contains supplementary material, which is available to authorized users.

Genetic Diversity and Population Structure of Leishmania infantum from Southeastern France: Evaluation Using Multi-Locus Microsatellite Typing

In the south of France, Leishmania infantum is responsible for numerous cases of canine leishmaniasis (CanL), sporadic cases of human visceral leishmaniasis (VL) and rare cases of cutaneous and muco-cutaneous leishmaniasis (CL and MCL, respectively). Several endemic areas have been clearly identified in the south of France including the Pyrénées-Orientales, Cévennes (CE), Provence (P), Alpes-Maritimes (AM) and Corsica (CO). Within these endemic areas, the two cities of Nice (AM) and Marseille (P), which are located 150 km apart, and their surroundings, concentrate the greatest number of French autochthonous leishmaniasis cases. In this study, 270 L. infantum isolates from an extended time period (1978–2011) from four endemic areas, AM, P, CE and CO, were assessed using Multi-Locus Microsatellite Typing (MLMT). MLMT revealed a total of 121 different genotypes with 91 unique genotypes and 30 repeated genotypes. Substantial genetic diversity was found with a strong genetic differentiation between the Leishmania populations from AM and P. However, exchanges were observed between these two endemic areas in which it seems that strains spread from AM to P. The genetic differentiations in these areas suggest strong epidemiological structuring. A model-based analysis using STRUCTURE revealed two main populations: population A (consisting of samples primarily from the P and AM endemic areas with MON-1 and non-MON-1 strains) and population B consisting of only MON-1 strains essentially from the AM endemic area. For four patients, we observed several isolates from different biological samples which provided insight into disease relapse and re-infection. These findings shed light on the transmission dynamics of parasites in humans. However, further data are required to confirm this hypothesis based on a limited sample set. This study represents the most extensive population analysis of L. infantum strains using MLMT conducted in France.

In the south of France, the parasite Leishmania infantum is responsible for diseases that primarily affect dogs but can also impact humans. Several endemic areas have been clearly identified in the south of France including the Pyrénées-Orientales, Cévennes (CE), Provence (P), Alpes-Maritimes (AM) and Corsica (CO). In this study, 270 L. infantum isolates from four endemic areas, AM, P, CE and CO, were assessed using Multi-Locus Microsatellite Typing (MLMT), a tool applied for population genetic studies. MLMT revealed a strong genetic differentiation between the Leishmania populations from AM and P with exchanges observed between these two endemic areas. For four patients, the occurrence of disease relapses and re-infections was examined. These findings shed light on the transmission dynamics of parasites in humans. This study represents the most extensive population analysis of L. infantum isolates using MLMT conducted in France.

Spatial relations among environmental factors and phlebotomine sand fly populations (Diptera: Psychodidae) in central and southern Morocco

Phlebotomine sand flies (Diptera: Psychodidae, Phlebotominae) are of considerable public health importance because of their ability to transmit several human parasites, mainly as vectors of Leishmania spp. Over the past decade, the epidemiological situation of cutaneous leishmaniasis (CL) has significantly increased with its geographic expansion to previously free areas and the emergence of overlapping foci of cutaneous leishmaniasis and visceral leishmaniasis (VL) in several provinces of Morocco. A total of 15,313 specimens was collected during this entomological survey. The genera Phlebotomus (57.38%) and Sergentomyia (42.62%) were identified. Sergentomyia minuta (22.01%) was the most prevalent species, followed by S. fallax (18.21%), Phlebotomus perniciosus (14.35%), P. papatasi (14.06%), P. sergenti (12.85%), P. longicuspis (10.74%), P. ariasi (2.68%), S. dreyfussi (1.53%), P. alexandri (1.31%), P. bergeroti (1.14%), S. christophersi (0.62%), S. africana (0.25%), P. chabaudi (0.14%), P. chadlii (0.05%), and P. kazeruni (0.04%). We aimed to determine current distribution of leishmaniases vectors, their ecological characteristics, and the significance of the predominant species at any bioclimate stage, altitude range, and soil texture in terms of the risk of leishmaniasis transmission.

Species composition of phlebotomine sand fly fauna in an area with sporadic cases of Leishmania infantum human visceral leishmaniasis, Morocco

Visceral and cutaneous leishmaniases are the main endemic vector-born diseases in Morocco. Human visceral leishmaniasis (HVL), by Leishmania infantum, currently presents a significant health problem throughout the country and may constitute factor for death, especially among children with less than 15 years old. In the past, HVL has been basically absent or at least sporadic in Marrakesh-Tensift-Al Haouz region; however it became significant during the last decade. An entomological survey and a retrospective study on L. infantum HVL cases had been carried out to assess the risk of the disease apparition in this region. 7046 sand flies (Diptera: Psychodidae) were collected and studied from twelve localities within Marrakesh-Tensift-Al Haouz region. The result shows the presence of ten sand fly species, 58.76% from the genus Phlebotomus and 41.24% from genus Sergentomyia. A further analysis indicates that Phlebotomus perniciosus, Phlebotomus longicuspis and Phlebotomus ariasi species, incriminated vectors of L. infantum, are dominant (35.56%), so, we describe their spatial (according to altitude and biotopes) and temporal (seasonal activity) distribution in study area.

Multilocus microsatellite typing of Leishmania and clinical applications: a review

Microsatellite markers have been used for Leishmania genetic studies worldwide, giving useful insight into leishmaniasis epidemiology. Understanding the geographic distribution, dynamics of Leishmania populations, and disease epidemiology improved markedly with this tool. In endemic foci, the origins of antimony-resistant strains and multidrug treatment failures were explored with multilocus microsatellite typing (MLMT). High genetic variability was detected but no association between parasite genotypes and drug resistance was established. An association between MLMT profiles and clinical disease manifestations was highlighted in only three studies and this data needs further confirmation. At the individual level, MLMT provided information on relapse and reinfection when multiple leishmaniasis episodes occurred. This information could improve knowledge of epidemiology and guide therapeutic choices for active chronic visceral leishmaniasis, the disease form in some HIV-positive patients.

Multilocus Microsatellite Typing reveals intra-focal genetic diversity among strains of Leishmania tropica in Chichaoua Province, Morocco

In Morocco, cutaneous leishmaniasis (CL) caused by Leishmania (L.) tropica is a major public health threat. Strains of this species have been shown to display considerable serological, biochemical, molecular biological and genetic heterogeneity; and Multilocus Enzyme Electrophoresis (MLEE), has shown that in many countries including Morocco heterogenic variants of L. tropica can co-exist in single geographical foci. Here, the microsatellite profiles discerned by MLMT of nine Moroccan strains of L. tropica isolated in 2000 from human cases of CL from Chichaoua Province were compared to those of nine Moroccan strains of L. tropica isolated between 1988 and 1990 from human cases of CL from Marrakech Province, and also to those of 147 strains of L. tropica isolated at different times from different worldwide geographical locations within the range of distribution of the species. Several programs, each employing a different algorithm, were used for population genetic analysis. The strains from each of the two Moroccan foci separated into two phylogenetic clusters independent of their geographical origin. Genetic diversity and heterogeneity existed in both foci, which are geographically close to each other. This intra-focal distribution of genetic variants of L. tropica is not considered owing to in situ mutation. Rather, it is proposed to be explained by the importation of pre-existing variants of L. tropica into Morocco.

Molecular detection and identification of Leishmania infection in naturally infected sand flies in a focus of cutaneous leishmaniasis in northern Morocco

Background

Cutaneous leishmaniasis is an infectious disease caused by various species of the flagellate protozoan Leishmania. During the past 20 years, cutaneous leishmaniasis has emerged as a major public health threat in Morocco. The main objective of this study was to study the occurrence of Leishmania infection in vectors and to identify sand fly blood meal sources in an endemic locality of cutaneous leishmaniasis within Sefrou province, where the vectors of leishmaniasis were still unknown.

Methods

2650 sand flies were collected using CDC miniature light traps and identified morphologically. The identified sand flies were tested for Leishmania infection by nested PCR. The source of blood meal of 10 freshly engorged females: 6 Phlebotomus longicuspis and 4 Phlebotomus sergenti, was determined using the Cyt b sequence.

Results

The collected sand flies consisted of 10 species, seven of which belonged to the genus Phlebotomus and three to the genus Sergentomyia. The most abundant species was P. longicuspis, accounting for 72% of the total sand flies collected. In females of three P. longicuspis and four P. sergenti, Leishmania infantum and Leishmania tropica DNA was detected, respectively.

The source of blood meal of engorged females showed that all sand flies tested fed on humans.

Conclusions

We report for the first time the natural infection of P. longicuspis with L. infantum in Morocco. The high frequency of this species in this region, in addition to its anthropophilic character make P. longicuspis the putative vector of L. infantum in this cutaneous leishmaniasis focus where L. tropica is confirmed as the causative agent of the disease and P. sergenti as its vector. The presence of L. infantum, and its presumed vector in this area, makes this a site of high risk of visceral leishmaniasis, mostly because of the proximity of a focus of human and canine visceral leishmaniasis.