Identification of French Guiana sand flies using MALDI-TOF mass spectrometry with a new mass spectra library

Phlebotomine sand flies are insects that are highly relevant in medicine, particularly as the sole proven vectors of leishmaniasis. Accurate identification of sand fly species is an essential prerequisite for eco-epidemiological studies aiming to better understand the disease. Traditional morphological identification is painstaking and time-consuming, and molecular methods for extensive screening remain expensive. Recent studies have shown that matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a promising tool for rapid and cost-effective identification of arthropod vectors, including sand flies. The aim of this study was to validate the use of MALDI-TOF MS for the identification of Northern Amazonian sand flies. We constituted a MALDI-TOF MS reference database comprising 29 species of sand flies that were field-collected in French Guiana, which are expected to cover many of the more common species of the Northern Amazonian region, including known vectors of leishmaniasis. Carrying out a blind test, all the sand flies tested (n = 157) with a log (score) threshold greater than 1.7 were correctly identified at the species level. We confirmed that MALDI-TOF MS protein profiling is a useful tool for the study of sand flies, including neotropical species, known for their great diversity. An application that includes the spectra generated here will be available to the scientific community in the near future via an online platform.

白蛉（Phlebotomine sand flies）是一类具有重要医学价值的昆虫，作为利什曼病唯一经证实的传播媒介而广受关注。精准鉴定沙蝇物种，是开展生态流行病学研究以深入解析该疾病的必要前提。传统形态学鉴定方法耗时费力，而用于大规模筛查的分子检测手段仍成本高昂。已有研究表明，基质辅助激光解吸电离飞行时间质谱（matrix-assisted laser desorption and ionization time-of-flight mass spectrometry，MALDI-TOF MS）是一种可实现节肢动物媒介（包括沙蝇）快速、低成本鉴定的极具应用前景的工具。本研究旨在验证基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）用于北亚马逊地区沙蝇鉴定的有效性。我们构建了一套MALDI-TOF MS参考数据库，收录了在法属圭亚那野外采集的29种沙蝇；该数据库覆盖了北亚马逊地区多数常见沙蝇物种，其中包含已知的利什曼病传播媒介。通过盲法测试，所有log（得分）阈值大于1.7的受试沙蝇（n=157）均实现了准确的物种级鉴定。本研究证实，MALDI-TOF MS蛋白谱分析是开展沙蝇研究的有效工具，尤其适用于以物种多样性丰富著称的新热带区沙蝇类群。包含本研究生成的质谱图谱的应用程序，将于近期通过在线平台向科研界开放。