Utilização da espectroscopia com análise multivariada na identificação de diferentes DTUs do Trypanosoma cruzi em Triatoma brasiliensis infectados experimentalmente

Abstract

The Trypanosoma cruzi infection is a public health problem and it is substancial that its diagnosis be performed quickly and efficiently. However, the techniques applied on the diagnosis of T. cruzi infection present low sensitivity and specificity regarding the entomological and epidemiological surveillance of the parasite. Considering this problem, the biospectroscopy with the use of ATR-FTIR was used in this study to evaluate its efficiency in the identification of the experimental infection of Triatoma brasiliensis by different DTUs of T. cruzi. The standardization of the calibration model included the use of fourth and fifth instars of T. brasiliensis, which were infected with different DTUs of the parasite (TcI, TcII, TcIII or mixed infection) at a concentration of 40,000 parasites / ml of blood. Followed 15 and 30 days after infection (DAI), infrared spectra were collected from the abdomen of each insect; 30 DAI, intestinal wastes were collected and later used for kDNA analysis. The standardization of the calibration model showed that the application of the mild-infrared using the ATR-FTIR distinguished the triatomines that were not infected and experimentally infected with T. cruzi. In addition, the technique was able to identify the DTUs used, separating the 5 distinct groups only with the exploratory data analysis through the application of Principal Component Analysis (PCA), which differentially identified protein clusters, nucleic acids and to a lesser extent, lipids. The kDNA analysis confirmed 92.5% of the infected insects, while the ATR-FTIR correctly identified all samples. Thus, biospectroscopy applied with the use of ATR-FTIR was efficient in the identification of the T. brasiliensis infection by T. cruzi, and could be used as a diagnostic tool for the future, assisting in the entomological surveillance of the infection by this parasite.