Mass spectrometric analysis of nematodes Dirofilaria and Ascaris using MALDI-TOF MS

Accurate species-level identification of parasitic nematodes of medical and veterinary importance remains a pressing challenge in modern parasitology. Traditional morphological methods are often insufficiently informative when dealing with closely related species, damaged specimens, or objects with incomplete preservation of diagnostic features. Molecular genetic approaches, despite their high accuracy, require considerable time and material costs, which limits their application in routine diagnostics. In this regard, the use of MALDI-TOF mass spectrometry—a method based on the detection of species-specific protein profiles—represents a promising direction. This technique has already proven itself in microbiology and is being actively introduced into parasitology. The aim of this study was to analyze the protein mass spectrometric profiles of four species of parasitic nematodes ( Dirofilaria immitis , Dirofilaria repens , Ascaris suum , and Ascaris lumbricoides ) and to evaluate the informativeness of MALDI-TOF MS for their comparative characterization and species differentiation. In this study, mass spectrometric profiles of four nematode representatives were analyzed. Reproducible spectra were obtained for each species in the m/z range of 2000–20000, in which both components common to closely related taxa and variable components were identified. Interspecies differences were manifested in the distribution of signals, the frequency of detection of individual peaks, and their intensities. The application of multivariate analysis methods—cluster analysis and principal component analysis (PCA)—demonstrated the grouping of spectral profiles according to the species identity of the samples. The most pronounced separation was observed between representatives of the genera Ascaris and Dirofilaria, reflecting substantial differences in their protein composition. The obtained results confirm the high differentiating potential of MALDI-TOF MS for the characterization of parasitic nematodes. The generated spectral data can be used to expand reference libraries and improve helminth identification algorithms, which in the future will enable the implementation of this method into laboratory diagnostic practice.