Evolutionary Ecology Group, Biology Department, University of Antwerp, Antwerp, Belgium.
Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic.
Parasit Vectors. 2020 Nov 17;13(1):580. doi: 10.1186/s13071-020-04450-2.
Ethiopia is affected by human leishmaniasis caused by several Leishmania species and transmitted by a variety of sand fly vectors of the genus Phlebotomus. The sand fly fauna in Ethiopia is highly diverse and some species are closely related and similar in morphology, resulting in difficulties with species identification that requires deployment of molecular techniques. DNA barcoding entails high costs, requires time and lacks reference sequences for many Ethiopian species. Yet, proper species identification is pivotal for epidemiological surveillance as species differ in their actual involvement in transmission cycles. Recently, protein profiling using MALDI-TOF mass spectrometry has been introduced as a promising technique for sand fly identification.
In our study, we used an integrative taxonomic approach to identify most of the important sand fly vectors of leishmaniasis in Ethiopia, applying three complementary methods: morphological assessment, sequencing analysis of two genetic markers, and MALDI-TOF MS protein profiling.
Although morphological assessment resulted in some inconclusive identifications, both DNA- and protein-based techniques performed well, providing a similar hierarchical clustering pattern for the analyzed species. Both methods generated species-specific sequences or protein patterns for all species except for Phlebotomus pedifer and P. longipes, the two presumed vectors of Leishmania aethiopica, suggesting that they may represent a single species, P. longipes Parrot & Martin. All three approaches also revealed that the collected specimens of Adlerius sp. differ from P. (Adlerius) arabicus, the only species of Adlerius currently reported in Ethiopia, and molecular comparisons indicate that it may represent a yet undescribed new species.
Our study uses three complementary taxonomical methods for species identification of taxonomically challenging and yet medically import Ethiopian sand flies. The generated MALDI-TOF MS protein profiles resulted in unambiguous identifications, hence showing suitability of this technique for sand fly species identification. Furthermore, our results contribute to the still inadequate knowledge of the sand fly fauna of Ethiopia, a country severely burdened with human leishmaniasis.
埃塞俄比亚受到由几种利什曼原虫引起的人类利什曼病的影响，并由各种属的沙蝇传播。埃塞俄比亚的沙蝇动物群非常多样化，有些物种在形态上非常相似，这导致了物种鉴定的困难，需要使用分子技术。DNA 条形码需要高昂的成本，需要时间，并且缺乏许多埃塞俄比亚物种的参考序列。然而，正确的物种鉴定对于流行病学监测至关重要，因为不同物种在实际参与传播周期方面存在差异。最近，使用 MALDI-TOF 质谱的蛋白质谱分析已被引入作为沙蝇鉴定的一种有前途的技术。
在我们的研究中，我们使用综合分类学方法来鉴定埃塞俄比亚最重要的利什曼病沙蝇传播媒介，应用了三种互补的方法：形态评估、两种遗传标记的测序分析和 MALDI-TOF MS 蛋白质谱分析。
尽管形态评估导致了一些不确定的鉴定结果，但 DNA 和蛋白质基技术都表现良好，为分析的物种提供了相似的层次聚类模式。两种方法都为除 Phlebotomus pedifer 和 P. longipes 之外的所有物种生成了物种特异性的序列或蛋白质模式，这两种物种被认为是 Leishmania aethiopica 的传播媒介，这表明它们可能代表一个单一的物种，即 P. longipes Parrot & Martin。所有三种方法还表明，收集到的 Adlerius sp. 标本与埃塞俄比亚目前唯一报告的 Adlerius 物种 P. (Adlerius) arabicus 不同，分子比较表明它可能代表一个尚未描述的新物种。
我们的研究使用三种互补的分类学方法来鉴定埃塞俄比亚具有分类挑战性且具有医学重要性的沙蝇。生成的 MALDI-TOF MS 蛋白质谱产生了明确的鉴定结果，因此表明该技术适合沙蝇物种鉴定。此外，我们的研究结果有助于增加对埃塞俄比亚沙蝇动物群的认识，该国严重受到人类利什曼病的困扰。
