Laboratory of Parasitology and Vector-Borne-Diseases, Institut Pasteur du Maroc, Casablanca, Morocco.
Molecular Genetics and Immunophysiopathology Research Team, Health and Environment Laboratory, Hassan II University of Casablanca, Aïn Chock Faculty of Sciences, Morocco.
PLoS Negl Trop Dis. 2018 Mar 2;12(3):e0006315. doi: 10.1371/journal.pntd.0006315. eCollection 2018 Mar.
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.
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.
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.
皮肤利什曼病（CL）是一种由各种利什曼原虫引起的传染病，由几种沙蝇传播。CL 是最被忽视的热带病之一，在过去 20 年里，它一直是摩洛哥东北部一个重点地区的主要健康威胁。本研究的主要目的是确定相关的沙蝇种类，并在 Taza（摩洛哥东北部一个 CL 重点地区）最常见的物种和患者皮肤样本中检测到利什曼原虫感染。
使用 CDC 微型灯诱捕器共收集了 3672 只沙蝇。形态学鉴定允许鉴定出 13 种，即 10 种嗜人按蚊和 3 种白蛉。P. longicuspis 是最丰富的物种，占总采集沙蝇的 64.08%，其次是 P. sergenti（20.1%）和 P. perniciosus（8.45%）。使用嵌套 kDNA PCR，7 个 P. sergenti 虫群对利什曼原虫 DNA 呈阳性，而 23 个 P. longicuspis 虫群和 4 个 P. perniciosus 虫群对利什曼原虫婴儿 DNA 呈阳性。P. longicuspis 和 P. perniciosus 的利什曼原虫感染率分别为 2.51%（23/915）和 7.27%（4/55），而 P. sergenti 的感染率为 3.24%。我们还从 12 名疑似 CL 的患者的病变涂片上提取了 DNA，其中 9 名患者经 HaeIII 酶切 ITS1 呈阳性，显示出两种图谱。在 8 名患者中最丰富的图谱与 L. infantum 相同，而在 1 名患者中发现了 L. tropica。ITS1 DNA 区域的测序证实了 RFLP 的结果。
这是首次在该 CL 重点地区的 P. sergenti 和 P. longicuspis 中分别检测到 L. tropica 和 L. infantum 的分子检测。在摩洛哥，首次发现 P. perniciosus 感染 L. infantum。本研究还强调了 L. infantum 及其媒介在该地区的优势，在该地区，L. tropica 已被认为是 CL 的病原体 20 多年。
