New epidemiological pattern of cutaneous leishmaniasis in two pre-Saharan arid provinces, southern Morocco

Entomological, parasitological and molecular investigations in a new focus of cutaneous leishmaniasis in Youssoufia region, Morocco

BACKGROUND AND AIMS

Leishmaniasis is a neglected tropical infection caused by Leishmania parasite that affect human and animal. In Morocco, the cutaneous leishmaniasis has spread substantially to the new areas. The surveillance limited to active foci may underestimate the occurrence of cutaneous leishmaniasis (CL). This study aims to investigate the local transmission of CL in rural districts of Youssoufia province, central Morocco, as a potential focus of CL.

METHODS

For this purpose, parasitological, molecular and entomological investigations were carried out in this area. Data collection concerns potential vectors and human cases. Thus, 402 patients were examined for suspected leishmaniasis lesions in three localities of the province of Youssoufia. In these same localities, 983 sand flies were collected by CDC light traps and sticky paper during one-night per month during 6 months. These sand flies were all identified morphologically using the Moroccan identification key.

RESULTS

The results showed that among the 25 skin lesions detected in a population of 402 individuals, 18 were confirmed by kDNA nested PCR as CL positive patients, of which only 25% were positive by direct examination. Leishmania tropica and Leishmania major were identified as causative agents of CL in the study area. Direct parasitological examination showed a low sensitivity (27.78%), especially for L. major, although its specificity was evaluated at 100%. Regarding entomological results, both genera of the Moroccan sand fly were collected in the study area: Genus/Phlebotomus (75.28%) and Sergentomyia (24.72%). Phlebotomus (P) papatasi, the proven vector of L. major, was the most abundant species (33.98%), followed by Paralongicollum sergenti (22.58%), the confirmed vector of L. tropica; while Sergentomyia (S) minuta, P. longicuspis, S. fallax and P. kazeruni were collected with, respectively, 17.60%, 16.99%, 7.12% and 1.73%.

CONCLUSION

This study constitutes the first report of CL in the study areas, as well as the coexistence of L. tropica and L. major in these rural localities. Local transmission of CL is highly probable, as indicated by the prevalence of the two proven vectors of L. major and L. tropica. To control the spread of this disease, our results suggest the use of highly sensitive molecular methods to detect CL cases in potential leishmaniasis foci, which will improve surveillance.

A comparative genomics approach reveals a local genetic signature of Leishmania tropica in Morocco

In Morocco, cutaneous leishmaniasis (CL) caused by Leishmania (L.) tropica is an important health problem. Despite the high incidence of CL in the country, the genomic heterogeneity of these parasites is still incompletely understood. In this study, we sequenced the genomes of 14 Moroccan isolates of L. tropica collected from confirmed cases of CL to investigate their genomic heterogeneity. Comparative genomics analyses were conducted by applying the recently established Genome Instability Pipeline (GIP), which allowed us to conduct phylogenomic and principal components analyses (PCA), and to assess genomic variations at the levels of the karyotype, gene copy number, single nucleotide polymorphisms (SNPs) and small insertions/deletions (INDELs) variants. Read-depth analyses revealed a mostly disomic karyotype, with the exception of the stable tetrasomy of chromosome 31. In contrast, we identified important gene copy number variations across all isolates, which affect known virulence genes and thus were probably selected in the field. SNP-based cluster analysis of the 14 isolates revealed a core group of 12 strains that formed a tight cluster and shared 45.1 % (87 751) of SNPs, as well as two strains (M3015, Ltr_16) that clustered separately from each other and the core group, suggesting the circulation of genetically highly diverse strains in Morocco. Phylogenetic analysis, which compared our 14 L. tropica isolates against 40 published genomes of L. tropica from a diverse array of locations, confirmed the genetic difference of our Moroccan isolates from all other isolates examined. In conclusion, our results indicate potential regional variations in SNP profiles that may differentiate Moroccan L. tropica from other L. tropica strains circulating in endemic countries in the Middle East. Our report paves the way for future research with a larger number of strains that will allow correlation of diverse phenotypes (resistance to treatments, virulence) and origins (geography, host species, year of isolation) to defined genomic signals such as gene copy number variations or SNP profiles that may represent interesting biomarker candidates.

Population Genetic Structure of Phlebotomus sergenti (Diptera: Psychodidae) Collected in Four Regions of Morocco Based on the Analysis of Cyt b and EF-1α Genes

Phlebotomus (Ph.) sergenti is the main vector of Leishmania (L.) tropica (Trypanosomatida: Trypanosomatidae), the causative agent of anthroponotic cutaneous leishmaniasis in Morocco. This species has an extended geographical distribution, wider than that of the parasite. The main objective of our study was to analyze the genetic diversity of Ph. sergenti collected in four foci in Morocco: Taza, Foum Jemâa, El Hanchane, and Ouarzazate. We studied a set of diversity and population structure indices by sequencing two markers; nuclear EF-1α and mitochondrial Cyt b from 175 individual sand flies. Our results showed a considerable degree of intraspecific polymorphism with a high number of haplotypes identified in both genes. Many polymorphic sites detected in the Cyt b sequences (SCyt b = 45) indicate that it is the most polymorphic marker showing a distinct distribution of haplotypes according to their geographical origin, whereas the EF-1α marker showed no geographical isolation. Analysis by Tajima's D and Fu's Fs tests revealed a possible recent expansion of the populations, especially with the EF-1α marker, showing significant values in Taza and Ouarzazate sequences. The present study revealed significant genetic diversity within Ph. sergenti populations in Morocco. The results warrant further research using a combination of more than two markers including mitochondrial and non-mitochondrial markers, which may provide more information to clarify the genetic status of Ph. sergenti.

Determinants of anthroponotic cutaneous leishmaniasis by case-control study in Morocco

Leishmaniasis is endemic in Morocco where both cutaneous and visceral forms coexist. To date, anthroponotic cutaneous leishmaniasis (ACL) determinants remain poorly investigated in Morocco. However, the disease risk factors identification is vital to determine the specific preventive process. In this aim, a case-control study was conducted in the main active ACL foci in central Morocco. Epidemiological data were extracted from bulletins, registers and annual reports of the regional direction of Health offices. The socioeconomic and environmental data were collected from epidemiological surveys, completed by a questionnaire intended for accessible positive population and control people selected from the cases' entourage. The study included 258 cases and 395 controls. Our results showed that many socioeconomic factors were associated with ACL in Morocco such as the rural habitation (OR = 4.163; 95% CI: 2.91-5.96), movement to endemic area (OR = 4.53; 95% CI: 3.03-6.77), provenance from leishmaniasis foci (in Essaouira focus OR = 5.34; 95% CI: 1.19-24.03) and poverty. In addition, environmental factors like proximity of vegetation (OR = 2.45; 95% CI: 1.14-5.25), poor domestic hygiene, particularly the absence of sewage system/waste management (OR = 1.63; 95% CI: 1.35-1.96), and presence of animals (OR = 2.67; 95% CI: 1.14-5.25) increase the risk of ACL in Morocco. Except for Matrimonial status (married people, OR = 4.11; 95% CI: 1.80-9.41), there is however no significant association of the disease with the other socio-demographic factors in the study area (p>0.05). These several risk factors must be taken in consideration to prevent this disease through multidisciplinary collaboration and community participation.

Environmental, Climatic, and Parasite Molecular Factors Impacting the Incidence of Cutaneous Leishmaniasis Due to Leishmania tropica in Three Moroccan Foci

Cutaneous leishmaniasis (CL) occurring due to Leishmania tropica is a public health problem in Morocco. The distribution and incidence of this form of leishmaniasis have increased in an unusual way in the last decade, and the control measures put in place are struggling to slow down the epidemic. This study was designed to assess the impact of climatic and environmental factors on CL in L. tropica foci. The data collected included CL incidence and climatic and environmental factors across three Moroccan foci (Foum Jemaa, Imintanout, and Ouazzane) from 2000 to 2019. Statistical analyses were performed using the linear regression model. An association was found between the occurrence of CL in Imintanout and temperature and humidity (r² = 0.6076, df = (1.18), p-value = 3.09 × 10⁻⁵; r² = 0.6306, df = (1.18), p-value = 1.77 × 10⁻⁵). As a second objective of our study, we investigated the population structure of L.tropica in these three foci, using the nuclear marker internal transcribed spacer 1 (ITS1). Our results showed a low-to-medium level of geographic differentiation among the L.tropica populations using pairwise differentiation. Molecular diversity indices showed a high genetic diversity in Foum Jemaa and Imintanout; indeed, 29 polymorphic sites were identified, leading to the definition of 13 haplotypes. Tajima’s D and Fu’s F test statistics in all populations were not statistically significant, and consistent with a population at drift–mutation equilibrium. Further analysis, including additional DNA markers and a larger sample size, could provide a more complete perspective of L. tropica’s population structure in these three regions. In addition, further research is needed to better understand the impact of climatic conditions on the transmission cycle of Leishmania, allowing both for the development of effective control measures, and for the development of a predictive model for this parasitosis.

Tissue tropism: Is it an intrinsic characteristic of Leishmania species?

The genus Leishmania comprises a wide range of species, some of which are pathogenic to humans and each of which has a different tissue preference, resulting in one of the three clinical forms of human leishmaniasis: visceral, cutaneous, or mucocutaneous. Although, all pathogenic species are deposited intradermally in the mammalian host upon an infectious sand fly bite, only the viscerotropic strains can leave the skin and reach the internal organs. We assume that Leishmania tissue tropism is not only the result of Leishmania genetic determinism but is also governed by the interaction of the parasite with different vectorial and human host elements. To shed light on these elements and key steps determining the course of the infection, we describe throughout this review the disease's progression from the early stages of infection taking place in the skin to the late stages succeeding in the parasite's visceral dissemination. Hence, we address the question of Leishmania tropism, through providing relevant hypotheses and answers gathered from the literature.

Independent Circulation of Leishmania major and Leishmania tropica in Their Respective Sandfly Vectors for Transmission of Zoonotic and Chronic Cutaneous Leishmaniasis Co-Existing in a Mixed Focus of Central Tunisia

Zoonotic cutaneous leishmaniasis (ZCL) and chronic cutaneous leishmaniasis (CCL) are known to overlap in Central Tunisia. Sandflies were collected using sticky traps and CDC light-traps set in rodent burrows at the ecotones surrounding the village, in houses, and in animal shelters during July–October 2017, 2018, and 2019. A total of 17,175 sandflies were collected during the three sandfly seasons and identified morphologically to species level. Of a total of 18 sandfly species reported in Tunisia, 16 were identified in this mixed focus of ZCL and CCL. Except for the rocky mountainous areas, Phlebotomus papatasi was the most abundant sandfly species in all biotopes. In the mountainous areas, Phlebotomus sergenti is the most abundant sandfly species belonging to the genus Phlebotomus. Female sandflies were tested for the presence of Leishmania species by PCR. The overall infection prevalence of sandflies with Leishmania major and Leishmania tropica was 0.42% and 0.065%, respectively. The sequencing of PCR-amplified ITS1 products showed that L. major is the predominant species in all biotopes and transmitted mostly by P. papaptasi followed by Phlebotomus longicuspis and Sergentomyia species. Leishmania tropica was detected in Phlebotomus sergenti and in Phlebotomus longicuspis collected in bedrooms and in the ecotone of rocky mountainous areas. Our results provided strong evidence that the proximity of human settlements to biotopes of rodent reservoir hosts of L. major and of L. tropica resulted into the cocirculation of both Leishmania species leading to a mixed focus of ZCL and CCL. The epidemiology of leishmaniases in North Africa is highly complex by the high diversity of sandfly vectors and their associated Leishmania species, leading to a mixed form of cutaneous leishmaniasis. It is of major epidemiological importance to point to the risk of spillover from rural to urban areas leading to the anthroponization of cutaneous leishmaniasis. Therefore, efficient control to reduce the indoor abundance of sandfly vectors in order to reduce the incidence of leishmaniases is urgently needed.

Genotypic and phylogenic analyses of cutaneous leishmaniasis in Al Ahsa, Eastern Saudi Arabia during the coronavirus disease 2019 pandemic: First cases of Leishmania tropica with the predominance of Leishmania major

During the coronavirus disease 2019 lockdown period, a surge in sandflies and cutaneous leishmaniasis (CL) cases was observed in Al-Ahsa, Saudi Arabia. Skin punch biopsies were obtained from 100 patients clinically diagnosed with CL in Al-Ahsa who had no travel history in the last 6 months. Impression smears were used following a three-step polymerase chain reaction (PCR) protocol using genus-specific primers targeting kDNA and ITS1. Leishmania speciation was determined by ITS1 PCR/nested PCR-restriction fragment length polymorphism and sequencing. A phylogenetic tree was constructed. The associated patient characteristics were analyzed. Using internal transcribed spacer one (ITS1)-PCR/nested PCR, 98 cases were considered true-positive CL. Leishmania major was the predominant species, and Leishmania tropica was identified in three cases. Microscopy had poor sensitivity and perfect specificity. Direct ITS1-PCR missed nine cases. Sex, residence, and treatment outcome were significantly associated with the occurrence of Leishmania; distribution of skin lesion(s) and treatment outcome were significantly associated with Leishmania genotype. This is the first time that L. tropica was identified as a cause of CL in human in Al-Ahsa, in addition to the predominant zoonotic species, L. major. We recommend using ITS1-nested PCR for negative cases by ITS1-PCR. Further exploration of Leishmania transmission dynamics in vectors and reservoir animals is essential for designing effective preventive measures.

A Review on Climate, Air Pollution, and Health in North Africa

PURPOSE OF REVIEW

The aim of this review is to summarize and provide clear insights into studies that evaluate the interaction between air pollution, climate, and health in North Africa.

RECENT FINDINGS

Few studies have estimated the effects of climate and air pollution on health in North Africa. Most of the studies highlighted the evidence of the link between climate and air pollution as driving factors and increased mortality and morbidity as health outcomes. Each North African country prioritized research on a specific health factor. It was observed that the health outcome from each driving factor depends on the studied area and data availability. The latter is a major challenge in the region. As such, more studies should be led in the future to cover more areas in North Africa and when more data are available. Data availability will help to explore the applicability of different tools and techniques new to the region. This review explores studies related to climate and air pollution, and their possible impacts on health in North Africa. On one hand, air quality studies have focused mainly on particulate matter exceedance levels and their long-term exposure impacts, namely, morbidity and mortality. The observed differences between the various studies are mainly due to the used exposure-response function, the studied population, background emissions, and natural emission from the Sahara Desert that characterize the region. On the other hand, climate studies have focused primarily on the impact of heat waves, vector-borne disease, and mental disorders. More than half of these studies have been on leishmaniasis disease. The review revealed unbalanced and insufficient research on health impacts from air pollution episodes and climate extremes across the region.

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.

Transmission patterns of Leishmania tropica around the Mediterranean basin: Could Morocco be impacted by a zoonotic spillover?

Cutaneous leishmaniasis (CL) due to Leishmania tropica is a neglected tropical disease characterized by a wide geographical distribution in the Mediterranean basin and is endemic in several of its countries. In addition, the vector Phlebotomus sergenti is abundantly present all around the basin. Its transmission cycle is still subject to debate. In some countries, the presence of an animal reservoir has been confirmed. In Morocco, CL due to L. tropica has risen since the 1980s and has spread widely to become the most abundant form of leishmaniasis in the territory. However, the anthroponotic transmission is so far the only recognized mode, despite recordings of L. tropica infection in animal hosts. In this review article, we assess the situation of CL due to L. tropica in the Mediterranean basin with a focus on Morocco and gather knowledge about any potential zoonotic transmission in the country. A concomitant zoonotic transmission could explain the persistence of the disease in areas where human protective measures combined with vector management did not help reduce the disease burden.

Cutaneous leishmaniasis (CL) due to Leishmania tropica is a neglected tropical disease still considered to be anthroponotic in Morocco despite evidence of zoonotic transmission in other endemic countries of the Mediterranean basin. Its high incidence in the country makes it necessary to investigate whether or not a potential concomitant zoonotic transmission exists alongside the anthroponotic one. Moreover, several reports of natural animal infection have been noted in the country. In this paper, we review how CL due to L. tropica is present around the Mediterranean basin, with a particular focus on the Moroccan foci, and try to unveil the existence of a zoonotic transmission in the area. A deep understanding of the transmission patterns of L. tropica in the region is necessary for the implementation of effective control measures and a better assessment of the disease burden. In addition, the complexity of this neglected disease requires more fundamental and applied research to unveil potential factors involved in its spread.

Changes in the microbiological diagnosis and epidemiology of cutaneous leishmaniasis in real-time PCR era: A six-year experience in a referral center in Barcelona

Background

Leishmaniasis is a neglected disease caused by different species of the protozoa Leishmania spp. Cutaneous lesions are the most common clinical manifestation. This disease is prevalent in tropical and subtropical areas, including the Mediterranean basin. In Spain, Leishmania (L.) infantum is the only endemic species, but imported cases are often diagnosed. Different classical parasitological methods can be performed for cutaneous leishmaniasis (CL) diagnosis; but currently molecular techniques serve as a relevant tool for the detection and characterization of Leishmania parasites. We aimed to evaluate clinical and epidemiological characteristics of CL diagnosed patients by real-time PCR in a tertiary hospital over a six-year period.

Methodology/Principal findings

Clinical, epidemiological and microbiological data were retrospectively collected and analyzed. In our study, CL was confirmed in 59 (31.4%) out of 188 patients by real-time PCR, showing an increase over recent years: 11 cases of CL between 2014 and 2016 and 48 between 2017 and 2019. Real-time PCR was performed on skin swabs and/or biopsies samples, with a positivity of 38.5% and 26.5%, respectively. Results were 100% concordant when biopsy and skin swab were performed simultaneously. L. (L.) infantum was the most frequent species detected (50%), followed by L. (L.) major (45%) and Viannia subgenus (5%), which were detected only in imported cases. L. (L.) major was almost entirely detected in travelers/migrants from Morocco. Multiple and atypical skin lesions were more common in imported cases than in autochthonous cases (44.4% vs. 21.8%).

Conclusions/Significance

An increase in both autochthonous and imported CL cases has been observed in past years in our hospital. Molecular techniques assist in improving CL diagnosis and characterization of the Leishmania species, mainly in imported cases.

Leishmaniasis is a neglected disease caused by different species of the genus Leishmania. This disease is prevalent in tropical and subtropical areas, including the Mediterranean basin. In Spain, the only endemic species is L. (L) infantum, although there are cases of imported leishmaniasis due to travel and migration of people from other endemic areas. Cutaneous lesions are the most common clinical form, but L. (L) infantum can also cause mucosal or visceral involvement. Although microscopic diagnosis and skin biopsy specimens are still used in routine diagnosis for cutaneous leishmaniasis, they are time-consuming and invasive, respectively. Currently, molecular techniques, such as real-time PCR, are very sensitive tools for the detection and identification of Leishmania parasites. In addition, the skin swab sample seems to be a non-invasive alternative for the diagnosis of cutaneous leishmaniasis. In the present work, we describe the clinical characteristics of 59 patients diagnosed by real-time PCR of cutaneous leishmaniasis, as well as the molecular epidemiology of the causative species. We show that there has been an increase in cutaneous leishmaniasis cases, both autochthonous and imported cases, over the study period. The presence of Leishmania species other than L. (L) infantum is also highlighted.

The role of sampling by cotton swab in the molecular diagnosis of cutaneous leishmaniasis

An appreciated sampling technique is essential for achieving optimum results from diagnostic tests of cutaneous leishmaniasis (CL); conventional sampling methods, such as skin biopsy and dermal scrapping, are painful for the patients and require qualified staff and hospital facilities, while swabbing is patient-friendly more comfortable than invasive traditional techniques and can be carried out under field conditions. The aim of this study is to evaluate a non-invasive sampling method (swab) in the cutaneous leishmaniasis diagnosis, compared to microscopic examination. The recruitment of 205 patients was done during 3 years in six regions known as endemic CL foci in the south-east, the centre, the south-west and the north of Morocco. The results showed that molecular detection of the nuclear marker ITS1 on swab materials is to be less sensitive than microscopic examination, and the difference was statistically significant (p-value = .036). Thereafter, 55 patients were randomly selected to compare the results of two molecular techniques (ITS1-PCR and nested KDNA-PCR), performed both on swab and on stained smears used for microscopic examination; ITS1-PCR results from stained smears reached 87% positivity against 65,2% for cotton swab; and it was statistically significant (p-value = .019); on the other hand for the KDNA marker, results from cotton swab reached 93% of positivity against 91% for stained smears; and statistically the difference was not significant (p-value = .5113). One can presume that rubbing over the lesion with cotton swab implies a low parasitic load collection, but the choice of the amplification target greatly influences the results obtained from cotton swab; on top of that swab remains useful in the cases of patients with multiples lesions or the latter are located in sensitive places difficult to reach with an invasive method such as the eyelids, the lips or other mucous areas.

Cartography and Epidemiological Study of Leishmaniasis Disease in Sefrou Province (2007-2010), Central North of Morocco

Increasing cases of leishmaniasis disease have been reported during recent years in Sefrou Province, Central North of Morocco. This study presents the epidemiological profile of the provincial population, aims at analyzing the epidemiological profile, and in particular, spatiotemporal follow-up of all cases of leishmaniasis. It is a retrospective analysis of leishmaniasis cases recorded between 2007 and 2010. The data were analyzed by SPSS software (version 20). Over a four-year period, from 2007 to 2010, there were 62 cases of leishmaniasis, 93.12% of cases of cutaneous leishmaniasis and 6.87% of visceral leishmaniasis. The case number of leishmaniasis in the Province of Sefrou varies between 0.165% and 0.0018%. For each type of leishmaniasis, the female sex was the most affected compared to the male sex. This difference cannot be considered statistically significant (χ2 = 0.083, p value = 0.77). For cutaneous leishmaniasis, all age groups were affected with a large percentage: patients aged 0–9 years with 63.11% followed by the age group [10–19] with 24.18%. Visceral leishmaniasis mainly has affected the infant population [0–9] with 83.33%. We have not observed any association between the age classes and the leishmaniasis type (χ2 = 6.20, p value = 0.4). From a spatial point of view, the majority of cases of leishmaniasis was reported in El Menzel region (67 cases) followed by Sefrou (64 cases) and Tazouta (38 cases). There is a statistically significant relationship between the type of leishmaniasis and the studied regions (χ2 = 52; p value <0.001). The study of the epidemiological profile of leishmaniasis cases may be useful in enlightening health authorities to develop screening, treatment, and control strategies to reduce the incidence rate of the disease. Other research studies can be conducted to the dynamics of the vectors of sandflies and their ecology.

Possible introduction of Leishmania tropica to urban areas determined by epidemiological and clinical profiles of patients with cutaneous leishmaniasis in Casablanca (Morocco)

Leishmaniases are a group of infectious diseases caused by protozoan Leishmania parasites and are transmitted by the bites of infected phlebotomine sandflies. The heterogeneity of these diseases is influenced by both parasitic properties and host factors. Cutaneous leishmaniasis (CL) is a major public health problem in Morocco, where the geographical expansion of CL (particularly CL caused by Leishmania tropica), the heterogeneous appearance of lesions and the difficulty in diagnosing CL contribute to late diagnosis of CL and delayed treatment of patients. Therefore, the main objective of this study was to describe the epidemiological and clinical profiles of patients with CL diagnosed in Casablanca (Morocco), which is a non-endemic area for CL. A cross-sectional study was conducted between 2010 and 2016, during which epidemiological and clinical data were collected from patients that met the inclusion criteria through an information sheet. Then, samples were obtained from each patient for parasitological and molecular diagnosis, and only patients with positive polymerase chain reaction and genotyping results were included in the study. Overall, 106 cases of CL were genotyped, of which 61 (57.5%) were caused by L. tropica, 38 (35.9%) by L. major and 7 (6.6%) by L. infantum. While all age groups were affected, CL cases wherein L. tropica was the causative agent were most frequently diagnosed in children aged 0–9 years (p = 0.005), whereas those caused by L. major were more frequently diagnosed in elderly patients (p = 0.004). Multivariate logistic regression analysis showed that two clinical variables were significantly associated with CL caused by L. tropica: lesion size (p = 0.002) and occurrence of lesion on the face (p = 0.005). Furthermore, the results of our survey highlighted the association of Leishmania infection when travelling to endemic areas. The high number of endemic foci where patients with CL were infected with L. tropica illustrated the tendency of this form to spread and generate epidemics, exposing young people to a greater degree to the disease. The epidemic status of CL caused by L. tropica in Morocco and the increased movement of the population from rural to urban areas indicate a possible introduction of this species to urban areas.

Leishmania Spp-Host Interaction: There Is Always an Onset, but Is There an End?

For a long time Leishmaniasis had been considered as a neglected tropical disease. Recently, it has become a priority in public health all over the world for different aspects such as geographic spread, number of population living at risk of infection as well as the potential lethality and/or the development of disfiguring lesions in the, respectively, visceral and tegumentary forms of the disease. As a result, several groups have been bending over this issue and many valuable data have been published. Nevertheless, parasite-host interactions are still not fully known and, consequently, we do not entirely understand the infection dynamics and parasite persistence. This knowledge may point targets for modulation or blockage, being very useful in the development of measures to interfere in the course of infection/ disease and to minimize the risks and morbidity. In the present review we will discuss some aspects of the Leishmania spp-mammalian host interaction in the onset of infection and after the clinical cure of the lesions. We will also examine the information already available concerning the parasite strategy to evade immune response mainly at the beginning of the infection, as well as during the parasite persistence. This knowledge can improve the conditions of treatment, follow-up and cure control of patients, minimizing the potential damages this protozoosis can cause to infected individuals.

Leishmaniasis in Northern Morocco: Predominance of Leishmania infantum Compared to Leishmania tropica

In Morocco, Leishmania infantum species is the main causative agents of visceral leishmaniasis (VL). However, cutaneous leishmaniasis (CL) due to L. infantum has been reported sporadically. Moreover, the recent geographical expansion of L. infantum in the Mediterranean subregion leads us to suggest whether the nonsporadic cases of CL due to this species are present. In this context, this review is written to establish a retrospective study of cutaneous and visceral leishmaniasis in northern Morocco between 1997 and 2018 and also to conduct a molecular study to identify the circulating species responsible for the recent cases of leishmaniases in this region. Data concerning leishmaniases cases were collected from the Epidemiology and Disease Control Directorate from 1997 to 2018. Human samples obtained from peripheral laboratories were examined using PCR-ITS1 method. The ITS1 products were subjected to digestion with the restriction endonuclease Mn1-I. Between 1997 and 2018, a total of 1,255 cases of cutaneous and visceral leishmaniasis were recorded in Tangier-Tetouan-Al Hoceima Region, i.e., 1.56% of the reported cases in Morocco (1,255/80,299). Concerning the geographical study covering the period 2007-2018, 79.5% (105/132) of the sectors were affected by leishmaniases. The molecular results showed that Humans were found to be infected with the L. infantum species with a high infection rate compared to L. tropica infection. Moreover, molecular characterization using ITS1 PCR-RFLP showed that the density of L. infantum was significantly higher (n = 68/81; 84%) than that of L. tropica (n = 13/81; 16%) (P-value 9.894e-10). While regarding visceral leishmaniasis, L. infantum was the only species responsible of this form. These findings of this study showed the emergence of L. infantum in Morocco and suggest that this species might be more prevalent than previously thought. Furthermore, the molecular determination of L. infantum will be helpful for control strategies by taking into consideration the reservoir of this species.

Accuracy of a Rapid Diagnostic Test Based on Antigen Detection for the Diagnosis of Cutaneous Leishmaniasis in Patients with Suggestive Skin Lesions in Morocco

In rural areas in Morocco, diagnosing cutaneous leishmaniasis (CL) can be challenging. We evaluated the accuracy of a rapid diagnostic test (RDT) based on antigen detection, CL Detect Rapid Test^™ (Inbios International Inc., Seattle, WA), in this setting. We consecutively recruited patients with new skin ulcers in nine primary health centers. We took a dental broach sample for the RDT and two other tissue samples by scraping the border and center of the lesion with a scalpel and smearing it on a slide. We duplicated each smear by pressing a clean slide against it and processed the slides by microscopy, polymerase chain reaction (PCR) internal transcribed spacer 1, and kDNA minicircle PCR. In a subgroup with positive PCR, the Leishmania species was identified using PCR-restriction fragment length polymorphism and PCR-sequencing of hsp70 genes. A participant with positive microscopy and/or PCR was considered a confirmed CL case. We computed sensitivity (Se) and specificity (Sp) of the RDT compared with this reference standard (ClinicalTrials.gov registration: NCT02979002). Between December 2016 and July 2017, we included 219 patients, 50% of them were under 18 years old. Rapid diagnostic test Se was 68% [95% confidence interval (CI): 61–74], Sp 94% [95% CI: 91–97], positive predictive value 95% [95% CI: 92–98], and negative predictive value 64% [95% CI: 58–70]. Despite its low Se, this novel RDT is a useful addition to clinical management of CL in Morocco, especially in isolated localities. Rapid diagnostic test–positive lesions can be treated as CL; but when RDT negative, microscopy should be done in a second step. The Se of the RDT can probably be optimized by improving the sampling procedure.

Risk factors and prediction analysis of cutaneous leishmaniasis due to Leishmania tropica in Southwestern Morocco

Cutaneous leishmaniasis is currently a serious public health problem in northern Africa, especially in Morocco. The causative parasite is transmitted to a human host through the bite of infected female sandflies of the genus Phlebotomus. The objective of the present study is to characterize the causative organisms and to predict the risk of cutaneous leishmaniasis (CL) cases in six provinces in southwestern Morocco, based on the spatial distribution of cases in relation to environmental factors and other risk factors such as socio-economic status and demographics. A molecular study was carried out using ITS1 PCR-RFLP method of the ribosomal DNA of Leishmania. An epidemiological study on CL cases was reported between 2000 and 2016 in this current investigation in six provinces in southwestern Morocco. Statistical analysis was performed using a linear regression model to identify the impact as well as the interaction between all predictor variables on the distribution of CL in the studied provinces. The forecast Holt-Winters (HW) method was used to describe the trend and seasonality of CL cases. The ITS1-PCR- RFLP analysis revealed the presence of Leishmania tropica in all studied provinces. The spatial distribution of CL cases documented in all studied provinces during the sixteen years showed a heterogeneous pattern and fluctuation trend with an average prevalence of 9.92 per 100,000 inhabitants. In addition, the forecast HW model predicts continued variability of trend and seasonality of CL cases in the upcoming years. This study confirmed the importance of socioeconomic factors, in particular poverty and the vulnerability rate, on distribution and emergence of CL. This study revealed a relationship between increasing risk of CL occurrence due to Leishmania tropica, as well as the distribution and emergence thereof, and socioeconomic factors in the investigated area.

Molecular identification of Leishmania infection in the most relevant sand fly species and in patient skin samples from a cutaneous leishmaniasis focus, in Morocco

BACKGROUND

Cutaneous leishmaniasis (CL) is an infectious disease caused by various species of Leishmania and transmitted by several species of sand flies. CL is among the most neglected tropical diseases, and it has represented a major health threat over the past 20 years in Morocco. The main objectives of this study were to identify relevant sand fly species and detect Leishmania infection in the most prevalent species and patient skin samples in Taza, a focus of CL in North-eastern Morocco.

METHODOLOGY AND FINDING

A total of 3672 sand flies were collected by CDC miniature light traps. Morphological identification permitted the identification of 13 species, namely 10 Phlebotomus species and 3 Sergentomyia species. P. longicuspis was the most abundant species, comprising 64.08% of the total collected sand flies, followed by P. sergenti (20.1%) and P. perniciosus (8.45%). Using nested-kDNA PCR, seven pools of P. sergenti were positive to Leishmania tropica DNA, whereas 23 pools of P. longicuspis and 4 pools of P. perniciosus tested positive for Leishmania infantum DNA. The rates of P. longicuspis and P. perniciosus Leishmania infection were 2.51% (23/915) and 7.27% (4/55), respectively, whereas the infection prevalence of P. sergenti was 3.24%. We also extracted DNA from lesion smears of 12 patients suspected of CL, among them nine patients were positive with enzymatic digestion of ITS1 by HaeIII revealing two profiles. The most abundant profile, present in eight patients, was identical to L. infantum, whereas L. tropica was found in one patient. The results of RFLP were confirmed by sequencing of the ITS1 DNA region.

CONCLUSION

This is the first molecular detection of L. tropica and L. infantum in P. sergenti and P. longicuspis, respectively, in this CL focus. Infection of P. perniciosus by L. infantum was identified for the first time in Morocco. This study also underlined the predominance of L. infantum and its vector in this region, in which L. tropica has been considered the causative agent of CL for more than 20 years.