Leishmaniasis in Tunisia: History and New Insights into the Epidemiology of a Neglected Disease

In Tunisia, both cutaneous (CL) and visceral leishmaniases (VL) are historical diseases that have been described since the nineteenth century. Cutaneous form is more prevalent than the visceral one. It is caused by three taxa (Leishmania major, Leishmania infantum, and Leishmania killicki synonymous Leishmania tropica) and six zymodemes (MON-1, MON-8, MON-24, MON-25, MON-80, and MON-317). Among these dermotropic zymodemes, sand flies vectors and reservoir hosts were identified for only three ones. Transmission cycles of L. infantum MON-24 and MON-80 and L. killicki MON-317 are still unknown. Zoonotic CL is largely distributed and covers mainly the sub-arid and arid bioclimatic stages. Nevertheless, it has recently spread to the humid and sub-humid stages in northern Tunisia. Sporadic and chronic CL are less prevalent with limited geographical distribution. Visceral leishmaniasis (VL) is mainly infantile that affects children of <13 years. It is caused by the single taxon L. infantum. Transmission cycle of this parasite is zoonotic but not well elucidated. Three zymodemes are responsible for the genesis of VL (MON-1, MON-24 and MON-80). Only the transmission cycle of L. infantum MON-1 is identified. Geographically, VL is mainly distributed in the humid, sub-humid, and semi-arid bioclimatic stages of the country. Despite the large progress of knowledge in the ecoepidemiology of leishmaniases in Tunisia, many parameters of the transmission cycles of these taxa are still unknown and need further investigations to identify them

Evolutionary history of Leishmania killicki (synonymous Leishmania tropica) and taxonomic implications

Background: Leishmania (L.) killicki is responsible for the chronic cutaneous leishmaniasis. The taxonomic status of this parasite is still not well defined. It was suggested on one hand to include this taxon within L. tropica complex but also on the other hand to consider it as a distinct phylogenetic complex. The present work represents the more detailed study on the evolutionary history of L. killicki relative to L. tropica and the taxonomic implications. Methods: Thirty five L. killicki and 25 L. tropica strains isolated from humans and from several countries were characterized using the MultiLocus Enzyme Electrophoresis (MLEE) and the MultiLocus Sequence Typing (MLST) approaches. Results: The genetic and phylogenetic analyses strongly support that L. killicki belongs to L. tropica complex. The study suggests the emergence of L. killicki by a funder effect followed by an independent evolution from L. tropica, but does not validate the species status of this taxon. In this context, we suggest to call this taxon L. killicki (synonymous L. tropica) until further epidemiological and phylogenetic studies justify the L. killicki denomination. Conclusions: These findings provided taxonomic and phylogenetic informations on L. killicki and helped to better know the evolutionary history of this taxon

Cystic echinococcosis in slaughtered animals in Ha’il, Northwestern Saudi Arabia

Meat inspection records of two slaughterhouses were used to determine the prevalence Echinococcus granulosus infection among slaughtered animals in Ha’il province, North-western Saudi Arabia. Records showed that from January to December 2015, 149514 animals were examined (126642 sheep, 4347 cattle and 18525 camels). The prevalence of E. granulosus was 7.89% (95% CI ＝ 7.74-8.04), 2.76% (95% CI ＝ 2.30-3.30) and 0.51% (95% CI ＝ 0.41-0.62) in sheep, cattle and camels respectively. Hydatid cyst was found strictly in liver and lung. A total of 440 hydatid cysts from sheep were assessed for their fertility and viability: thus, 66.59% were fertile, 12.5% were sterile and 20.90% were purulent or calcified. Among the fertile cysts the protoscoleces were viable in 59.38% of them. In conclusion, the prevalence of slaughtered animal cystic echinococcosis in North-western Saudi Arabia is lower compared to those reported in other regions of the country. Nevertheless, control of stray dog population, deworming of dogs and proper disposal of infected viscera remain crucial to curtail the problem

Blood meal analysis of culicoides (Diptera: ceratopogonidae) in central Tunisia.

To evaluate the host preferences of Culicoides species (Diptera: Ceratopogonidae) in Central Tunisia, we identified the source of blood meals of field collected specimens by sequencing of the cytochrome b (cyt b) mitochondrial locus and Prepronociceptine single copy nuclear gene. The study includes the most common and abundant livestock associated species of biting midges in Tunisia: C. imicola, C. jumineri, C. newsteadi, C. paolae, C. cataneii, C. circumscriptus, C. kingi, C. pseudojumineri, C. submaritimus, C. langeroni, C. jumineri var and some unidentified C. species. Analysis of cyt b PCR products from 182 field collected blood-engorged females' midges revealed that 92% of them fed solely on mammalian species, 1.6% on birds, 2.4% on insects and 0.8% on reptiles. The blast results identified the blood origin of biting midges to the species level with exact or nearly exact matches (≥98%). The results confirm the presence of several Culicoides species, including proven vectors in Central Tunisia. Blood meal analyses show that these species will indeed feed on bigger mammals, thereby highlighting the risk that these viruses will be able to spread in Tunisia

Cutaneous leishmaniasis in northwestern Saudi Arabia: identification of sand fly fauna and parasites

Abstract Background Cutaneous leishmaniasis (CL) is a vector-borne disease transmitted by the bite of an infected sand fly. This disease is highly prevalent in Saudi Arabia where Leishmania major and L. tropica are the etiological agents. In the region of Hail, northwestern of Saudi Arabia, the incidence is about 183 cases/year. However, the epidemiology of the disease in this area is not well understood. Thus, an epidemiological survey was conducted in 2015–2016 to identify the circulating parasite and the sand fly fauna in the region of Hail. Skin lesion scrapings were collected from suspected patients with CL. Methods The diagnosis was made by microscopic examination of Giemsa-stained smear and PCR. The parasite was identified by PCR and sequencing of the single copy putative translation initiation factor alpha subunit gene. Sand fly specimens were collected and identified morphologically. Total DNA was extracted from the abdomen of female specimens and Leishmania DNA was detected by PCR. Results Among the 57 examined patients, 37 were positive for CL. The identification of the parasite has revealed the single species Leishmania major. The 384 sand flies were collected belonged to two genera (Phlebotomus and Sergentomyia), six sub-genera and six species. Phlebotomus papatasi, Ph. kazeruni and Sergentomyia clydei were the dominant species. Leishmania DNA was detected in two females of Ph. papatasi two of Ph. kazeruni and one specimen of Sergentomyia clydei. Conclusions Leishmania major is confirmed to be the etiological agent of cutaneous leishmaniasis in northwestern Saudi Arabia. The molecular detection of Leishmania DNA in Ph. papatasi and Ph. kazeruni supports the potential role of these two species in the transmission of Leishmania. Further epidemiological studies are needed to prove their role and to evaluate the burden of CL in the study region

First report of Leishmania (L) killicki Rioux, Lanotte & Pratlong, 1986 in Libya.

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Analytical sensitivity of cyt <i>b</i> gene PCR amplification (359 bp) (A). Analytical sensitivity of <i>PNOC</i> gene PCR amplification (333 bp) (B).

<p>Lanes 1–10, 9-fold dilutions of human genomic DNA; Lane 11, negative control. MW, Molecular Weight marker (100-bp DNA ladder)</p

Unexpected co-detection of promastigote and amastigote Leishmania forms in a human cutaneous lesion: implications for leishmaniasis physiopathology and treatment

International audienceCutaneous leishmaniasis pathogenicity depends on the survival and replication of the parasitic protozoa in the form of non-motile amastigotes inside macrophages. Here, we report the unprecedented observation of both Leishmania major amastigote and promastigote forms (the latter is normally detected only in the mid gut of the insect vector or in vitro culture) in a cutaneous lesion of a 6-year-old boy. This finding suggests that modifications of the skin lesion environment, such as maceration and changes in pH or temperature, could promote the in situ transformation of Leishmania amastigotes into promastigotes. This observation raises questions about the physiopathology of cutaneous leishmaniasis and the influence of micro-environmental changes on the efficiency of topical treatments

Localization of farms in Central Tunisia.

<p><u>Farm A</u> is located in Khniss and reprented by a black circle with blue border. <u>Farm B, C, D</u> are located in Bir zira and showed by a black triangle with orange border. <u>Farm E and F are</u> identified by a black triangle with orange border also. <u>Farm G i</u>s located in Jemmel and signified by a black square with a blue border. <u>Farm H</u> is showed by a lozenge with a yellow border. <u>Farm N</u> is situated in Mahdia and showed by a white circle with black border.</p