Descriptive and Geometric Morphometry of the Wings of Phlebotomus sergenti Populations in Central Morocco.

Background: Phlebotomus sergenti, the proven vector of Leishmania tropica, the causative agent of anthroponotic cutaneous leishmaniasis, is widely distributed in Morocco. Previous works using molecular markers (Internal Transcribed Spacer 2 rDNA and Cytochrome B mtDNA) hypothesized the existence of multiple closely related populations of sand fly species (cryptic species) that would exhibit distinct vectorial capacities. This work studies morphotypic diversity using traditional and geometric morphometry analyses carried out on Ph. sergenti's wings from central Morocco, where active L. tropica transmission occurs for 30 years. Methods: Descriptive characteristics (size and shape) of the right wings were measured in Ph. sergenti's specimens collected from fourteen stations in central Morocco. Both traditional and geometric morphometry methods were used to analyse geographic variations in Ph. sergenti wing's size and shape. Results: These analyses support the existence of distinct Ph. sergenti populations, enlightening significant phenotypic variations of Ph. sergenti's wings, regarding their size and shape, depending on geographic origin. In addition, traditional and geometric morphometric analyses of the wing's length, centroid size, ß, ɵ, and γ distances allowed clear discrimination of Ph. sergenti sub-populations. Conclusion: These data pinpoint the adaptative ability of Ph. sergenti to local environmental conditions. Additional studies are now required to further shed light on the genetic structure of Ph. sergenti populations in Morocco.

Population Genetics of Phlebotomus papatasi from Endemic and Nonendemic Areas for Zoonotic Cutaneous Leishmaniasis in Morocco, as Revealed by Cytochrome Oxidase Gene Subunit I Sequencing.

Zoonotic cutaneous leishmaniasis (ZCL) caused by Leishmania major Yakimoff & Shokhor and transmitted by Phlebotomus papatasi (Scopoli) is a public health concern in Morocco. The disease is endemic mainly in pre-Saharan regions on the southern slope of the High Atlas Mountains. The northern slope of the High Atlas Mountains and the arid plains of central Morocco remain non-endemic and are currently considered high risk for ZCL. Here we investigate and compare the population genetic structure of P. papatasi populations sampled in various habitats in historical foci and non-endemic ZCL areas. A fragment of the mtDNA cytochrome oxidase I (CO1) gene was amplified and sequenced in 59 individuals from 10 P. papatasi populations. Haplotype diversity was probed, a median-joining network was generated (FST) and molecular variance (AMOVA) were analyzed. Overall, we identified 28 haplotypes with 32 distinct segregating sites, of which seven are parsimony informative. The rate of private haplotypes was high; 20 haplotypes (71.4%) are private ones and exclusive to a single population. The phylogenetic tree and the network reconstructed highlight a genetic structuration of these populations in two well defined groups: Ouarzazate (or endemic areas) and Non-Ouarzazate (or nonendemic areas). These groups are separated by the High Atlas Mountains. Overall, our study highlights differences in terms of population genetics between ZCL endemic and non-endemic areas. To what extent such differences would impact the transmission of L. major by natural P. papatasi population remains to be investigated.

Thirty years of cutaneous leishmaniasis in Tadla-Azilal focus, Morocco.

Cutaneous leishmaniasis (CL) due to Leishmania tropica is a major health problem in Tadla-Azilal focus, Morocco, where the first case was registered, here, in one locality named Tanant in 1987. So far, CL remains endemic and largely widespread. The objective of this study was to analyze the current eco-epidemiological situation after thirty years of active transmission. Data used are the official ones, obtained from the Moroccan Ministry of Health. Between 1998 and 2015, 5518 CL cases were registered in three provinces; Azilal, Béni Mellal and Fquih Ben Salah. CL has spread, from the historical focus in Azilal along two axes; one to the Northeastern Mountains and the other to the Northwestern plains. CL infected both genders and all ages, with large number of women (53%) and children (75% had <9 years old). More interestingly, age range at risk was larger within females than males, and this difference was more pronounced in Fquih Ben Salah where the disease had newly emerged. Similarly, age ranges at risk were larger and fluctuated significantly each year particularly in new emerging areas in Béni Mellal and Fquih Ben Salah. All these variations may testify, at least in part, to the process of acquiring immunity. Altitude structured CL spatiotemporal distribution. CL was more prevalent in two altitudes ranges; 400-500 m and 800-900 m. The situation and duration of period of diagnostic of CL varied largely according to the altitude. These different scenarios could be related to the seasonal dynamics of vector populations.

Wing size and shape variation of Phlebotomus papatasi (Diptera: Psychodidae) populations from the south and north slopes of the Atlas Mountains in Morocco.

The wing shape and size morphology of populations of the medically important phlebotomine sand fly, Phlebotomus papatasi, were examined in two endemic (south of the Atlas Mountains) and nonendemic (north of the Atlas Mountains) foci of cutaneous leishmaniasis by using geometric morphometrics in Morocco. Although it is present in all of Morocco, P. papatasi is the main vector of Leishmania major in only southern part of the Atlas Mountains. There are four major mountain ranges that serve as geographical barriers for species distribution in the study area and at least four gaps were recognized among these barriers. We found statistically significant differences in wing shape morphology between southern and northern populations. Analysis clearly recognized two main groups of populations on both sides of the mountains. The graphical depiction of Principal Component Analysis (PCA) and Canonical Variates Analysis (CVA) confirmed our morphometric study suggesting that the difference in wing morphology between the populations indicates that the population of P. papatasi shows phenotypic plasticity in the study area. According to centroid size analyses, which were used as measures of wing size differences among different sites, the north population of P. papatasi had relatively larger wings than the south population.

Genetic structure of Phlebotomus (Larroussius) ariasi populations, the vector of Leishmania infantum in the western Mediterranean: epidemiological implications.

In recent years there has been growing interest in analyzing the geographical variations between populations of different Phlebotomus spp. by comparing the sequences of various genes. However, little is known about the genetic structure of Phlebotomus ariasi. In this study, we were able to sequence a fragment of the mitochondrial Cyt b gene in 133 sandflies morphologically identified as P. ariasi and proceeding from a wide geographical range covering 35 locations in 11 different regions from five countries. The intra-specific diversity of P. ariasi is high, with 45 haplotypes differing from each other by one to 26 bases and they are distributed in two mitochondrial lineages, one limited geographically to Algeria and the other widely dispersed across Mediterranean countries. The Algerian lineage is characterized by having 13 fixed polymorphisms and is made up of one sole haplotype. The European/Moroccan P. ariasi lineage is characterized by being made up of a great diversity of haplotypes (44) which display some geographical structuring. This could be one of the multiple factors involved in the epidemiological heterogeneity of the foci of leishmaniasis. Phlebotomus chadlii is the sister group of European/Moroccan P. ariasi. The separation of the Algerian haplotype, H45, from the rest of the specimens, European/Moroccan P. ariasi and P. chadlii, is well supported by the bootstrap analysis.

The epidemic threshold of vector-borne diseases with seasonality: the case of cutaneous leishmaniasis in Chichaoua, Morocco.

Cutaneous leishmaniasis is a vector-borne disease transmitted to humans by sandflies. In this paper, we develop a mathematical model which takes into account the seasonality of the vector population and the distribution of the latent period from infection to symptoms in humans. Parameters are fitted to real data from the province of Chichaoua, Morocco. We also introduce a generalization of the definition of the basic reproduction number R (0) which is adapted to periodic environments. This R (0) is estimated numerically for the epidemic in Chichaoua; approximately 1.94. The model suggests that the epidemic could be stopped if the vector population were reduced by a factor approximately 3.76.