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.

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.

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.