Abstract Chagas disease, caused by the parasite Trypanosoma cruzi, is widespread in Latin America, where the disease remains one of the major public health problems. This condition is mostly transmitted by triatomines which are haematophagous insects all their life. With 154 species described in the world, the correct determination of the species involved in the transmission is crucial to develop efficient control strategies. This can be achieved by taxonomic keys (available only for adult stages, nymphal instars must be reared), or by molecular techniques. Both are time and/or money consuming, showing the needs of new identification tools, especially for nymphal instars which are the most frequently found on the field. Visible and near-infrared spectroscopy (VIS-NIR), used successfully these last years in various organisms’ determination, was applied on a sample of three species from Bolivia: Triatoma infestans, Triatoma sordida and Triatoma guasayana. The spectrum of the dorsal part of the head from nymphal instars and adult stages was taken for each specimen of each species. Different methods of pre-processing and selection of variables (wavelengths) were tested to find the best model of classification for the three species. Each model was evaluated by different indices: accuracy, specificity, and F1 score. The comparison of the performance of each model evidenced that the best results were obtained when using a short spectrum (400–2000 ​nm) without pre-processing. A total of 32 components were retained by tuning, and 933 wavelengths were kept by the backward feature selection algorithm. Applying it on a new sample of insects, this model showed a global accuracy of 97.2% (95.0–98.6). The F1 score was greater than 0.95, and the specificity greater than 0.94 for all the species. For the first time, a tool is available to quickly identify and with a high accuracy nymphal instars and adults of triatomines.

中文翻译：

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使用可见光和近红外光谱法识别恰加斯病媒介

摘要 由寄生虫克氏锥虫引起的南美锥虫病在拉丁美洲很普遍，该病仍然是主要的公共卫生问题之一。这种情况主要是由终生吸血昆虫的triatomines传播的。世界上描述了 154 种物种，正确确定参与传播的物种对于制定有效的控制策略至关重要。这可以通过分类学密钥（仅适用于成虫阶段，若虫龄期必须饲养）或分子技术来实现。两者都耗费时间和/或金钱，表明需要新的识别工具，特别是对于野外最常见的若虫龄期。可见光和近红外光谱 (VIS-NIR)，近年来成功用于各种生物体的测定，应用于来自玻利维亚的三个物种的样本：Triatoma infestans、Triatoma sordida 和 Triatoma guasayana。对于每个物种的每个标本，从若虫龄和成虫阶段获取头部背部的光谱。测试了不同的预处理方法和变量（波长）选择，以找到三种物种的最佳分类模型。每个模型都通过不同的指标进行评估：准确性、特异性和 F1 分数。每个模型的性能比较表明，在不进行预处理的情况下使用短光谱（400-2000 nm）时获得了最佳结果。通过调谐总共保留了32个分量，通过反向特征选择算法保留了933个波长。将其应用于新的昆虫样本，该模型显示出 97.2% 的全局准确率 (95. 0–98.6）。F1评分大于0.95，所有物种的特异性大于0.94。这是第一次有一种工具可以快速和高精度地识别三叶虫的若虫幼虫和成虫。