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.

Visceral leishmaniasis is an endemic protozoonosis observed in over 60 countries, with over 500 000 new cases recorded annually. Although the diagnostic procedure of its symptomatic forms is well established, for asymptomatic patients, who represent about 85% of those infected, there is no consensus on the best method for its identification. Recent studies have presented molecular techniques as viable identification methods, with good sensitivity and specificity indices in asymptomatic individuals. Therefore, we aimed to use molecular methods to assess their effectiveness in identifying the presence of asymptomatic infection by Leishmania infantum (L. infantum) individuals from endemic regions of Brazil. Screening was performed by real-time polymerase chain reaction (qPCR) and confirmed by sequencing the cytochrome B gene. Of the 127 samples [from 608 blood donors who had participated in a previous study, of which 34 were positive by the enzyme-linked immunosorbent assay (ELISA) rK39] tested by qPCR, 31 (24.4%) were positive. In the sequencing of 10 qPCR-positive samples, five were identified as L. infantum. Complimentary samples of the ELISA rK39 and conventional PCR showed only reasonable and low agreement with qPCR, respectively. The qPCR confirmed the presence of infection in five of the 10 sequenced samples, ELISA confirmed three, and the conventional PCR confirmed none.

SARS-CoV-2 (COVID-19) infection is responsible for causing a disease with a wide spectrum of clinical presentations. Predisposition to thromboembolic disease due to excessive inflammation is also attributed to the disease. The objective of this study was to characterize the clinical and laboratory aspects of hospitalized patients, in addition to studying the pattern of serum cytokines, and associate them with the occurrence of thromboembolic events. Methodology: A retrospective cohort study with 97 COVID-19 patients hospitalized from April to August 2020 in the Triângulo Mineiro macro-region was carried out. A review of medical records was conducted to evaluate the clinical and laboratory aspects and the frequency of thrombosis, as well as the measurement of cytokines, in the groups that presented or did not present a thrombotic event. Results: There were seven confirmed cases of thrombotic occurrence in the cohort. A reduction in the time of prothrombin activity was observed in the group with thrombosis. Further, 27.8% of all patients had thrombocytopenia. In the group that had thrombotic events, the levels of IL1b, IL-10, and IL2 were higher (p < 0.05). Conclusions: In the studied sample, there was an increase in the inflammatory response in patients with thrombotic events, confirmed by the increase in cytokines. Furthermore, in this cohort, a link was observed between the IL-10 percentage and an increased chance of a thrombotic event.