Visceral leishmaniasis is a reemerging neglected tropical disease with limitations for its diagnosis, including low concentration of antibodies in the serum of asymptomatic patients and cross-reactions. In this context, this work proposes an electrochemical immunosensor for the diagnosis of visceral leishmaniasis in a more sensitive way that is capable of avoiding cross-reaction with Chagas disease (CD). Crude Leishmania infantum antigens tested in the enzyme-linked immunosorbent assay (ELISA) were methodologically standardized to best engage to the sensor. The antibodies anti-Trypanosoma cruzi and anti-Leishmania sp. Present in serum from patients with diverse types of CD or leishmaniasis were chosen. A screen-printed carbon electrode modified with gold nanoparticles was the best platform to guarantee effective adsorption of all antigens so that the epitope of specific recognition for leishmaniasis occurred efficiently and without cross-reaction with the evaluated CD. The current peaks reduced linearly after the recognition, and still were able to notice the discrimination between different kinds of diseases (digestive, cardiac, undetermined Chagas/acute and visceral chronic leishmaniasis). Comparative analyses with ELISA were performed with the same groups, and a low specificity (44%) was verified due to cross-reactions (high number of false positives) on ELISA tests, while the proposed immunosensor presented high selectivity and specificity (100%) without any false positives or false negatives for the serum samples from isolated patients with different types of CD and visceral leishmaniasis. Furthermore, the biosensor was stable for 5 days and presented a detection limit of 200 ng mL−1.

Knowing that ticks have bioactive molecules in their saliva which modulate hemostatic and immunomodulatory activities in humans, we carried out a systematic search for biomolecules present in tick saliva with great pharmacological potential. We evaluated studies published in the last ten years. Following the recommendations of the Prisma tool, primary and secondary studies of a systematic nature were selected, with no language or country restriction. Studies that included arthropods other than ticks and studies in which the use of saliva had no pharmacological application were excluded. For searches, we used the following databases: MEDLINE®/PubMed®, Web of Science, LILACS, EMBASE, Cochrane and SCOPUS. The methodological quality was performed using the tools available in Joanna Briggs, always with two or more independent evaluators. The generated data were tabulated and summarized through qualitative narrative analysis. The methodology selected 19 articles that met the eligibility criteria. The saliva of hard ticks, found in the Americas, is more promising when used in experimental studies with human cells. The elucidation of the biomolecules was possible, with evasin and serpine being the biomolecules with the most evident pharmacological potential for anti-inflammatory action. In the selected studies, we found only experimental studies, with no pre-clinical or clinical studies, making methodological qualification difficult; in some studies, with the biomolecule Evasin and Serpin, the need for elucidation of these biomolecules in question was suggested. Thus, we found evidence that the saliva of American hard ticks is the most studied for pharmacological applications of anti-inflammatory and immunomodulatory action.