Triatomines (Hemiptera: Heteroptera: Reduviidae) are hematophagous insects, well-known for their vectorial role in transmitting Trypanosoma cruzi Chagas (Kinetoplastida: Trypanosomatidae) parasites, the etiological agent of Chagas disease. Trapping these insects would limit human-triatomine interaction and, thus, control the disease. In this context, there is a critical need for effective lures to control triatomines. Through double-choice bioassays, we investigated the preference of Triatoma infestans Klug, T. pallidipennis Stal, and Rhodnius prolixus Stal triatomines for: (a) volatiles from fermented products (various fermentation types and substrates) and (b) commercial insect lures. Furthermore, we identified the chemical composition of these volatiles through headspace collection using Solid Phase Micro Extraction coupled with Gas Chromatograph-Mass Spectrometer (HS-SPME-GC-MS). Volatiles from lactic fermentation and certain fermented fruits, along with commercial lures, attracted triatomines, while other products exhibited possible repellent or dislodging properties. These findings hold promise for the control of triatomines and, ultimately, Chagas disease.

Chagas disease is a parasitic infection caused by the protozoan Trypanosoma cruzi. One of the complications of the disease is the infection of the central nervous system (CNS), as it can result from either the acute phase or by reactivation during the chronic phase, exhibiting high mortality in immunocompromised patients. This systematic review aimed to determine clinical and paraclinical characteristics of patients with Chagas disease in the CNS. Articles were searched from PubMed, Scopus and LILACS until January 2023. From 2325 articles, 59 case reports and 13 case series of patients with Chagas in the CNS were retrieved from which 138 patients were identified. In this population, 77% of the patients were male, with a median age of 35 years old, from which most of them came from Argentina and Brazil. Most of the individuals were immunocompromised from which 89% were HIV-positive, and 54 patients had an average of 48 cells per mm3 CD4+ T cells. Motor deficits and seizures were the most common manifestation of CNS compromise. Furthermore, 90 patients had a documented CNS lesion by imaging from which 89% were supratentorial and 86% were in the anterior/middle cranial fossa. The overall mortality was of 74%. Among patients who were empirically treated with anti-toxoplasma drugs, 70% died. This review shows how Chagas disease in the CNS is a devastating complication requiring prompt diagnosis and treatment to improve patients’ outcomes.

The prevalence rate of coinfection Chagas disease (CD) and HIV in Brazil is between 1.3 and 5%. Serological tests for detecting CD use total antigen, which present cross reactivity with other endemic diseases, such as leishmaniasis. It is urge the use of a specific test to determinate the real prevalence of T. cruzi infection in people living with HIV AIDS (PLWHA). Here, we evaluated the prevalence of T. cruzi infection in a cohort of 240 PLWHA living in urban area from São Paulo, Brazil. Enzyme Linked Immunosorbent Assay, using epimastigote alkaline extract antigen from T. cruzi (ELISA EAE), returned a 2.0% prevalence. However by Immunoblotting, using trypomastigote excreted-secreted antigen (TESA Blot) from T. cruzi, we detected a prevalence of 0.83%. We consider that the real prevalence of T. cruzi-infection in PLWHA is 0.83%, lower than reported in literature; this is due to TESA Blot specificity, probably excluding false positives for CD immunodiagnosis. Our results demonstrate a real need to apply diagnostic tests with high sensitivity and specificity that can help assess the current status of CD/HIV coinfection in Brazil in order to stratify the effective risk of reactivation and consequently decreasing mortality.

Chagas disease (CD) is a neglected tropical disease caused by the intracellular protozoan Trypanosoma cruzi that remains a serious public health issue affecting more than 6 million people worldwide. The available treatment includes 2 nitro derivatives, benznidazole (BZ) and nifurtimox, that lack in efficacy in the later chronic phase and when administered against the several naturally resistant parasite strains and present several side-effects, demanding new therapeutic options. One strategy is based on repurposing by testing drugs already used for other illness that may share similar targets. In this context, our previous data on imatinib (IMB) and derivatives motivated the screening of 8 new IMB analogues. Our findings showed that all except 1 were active against bloodstream trypomastigotes reaching drug concentration capable of inducing a 50% of parasite lysis (EC50) values < 12 μm after 2 h while BZ was inactive. After 24 h, all derivatives were more potent than BZ, exhibiting EC50 values 1.5–5.5 times lower. Against intracellular forms, 7 out of 8 derivatives presented high activity, with EC50 values ≤ BZ. LS2/89 stood out as one of the most promising, reaching EC90 values of 1.68 and 4.9 μm on intracellular and trypomastigote forms, respectively, with the best selectivity index (>60) towards the proliferative forms. Physicochemical parameters as well as the absorption, distribution, metabolism, excretion and toxicity properties were predicted to be acceptable and with good chance of a favourable oral bioavailability. The promising results motivate further studies such as in vivo and combinatory assays aiming to contribute for a novel safer and effective therapy for CD.

From a systematic review framework, we analysed the clinical evidence on the effectiveness and safety of monotherapy and combination chemotherapy for Chagas disease (ChD) treatment. The research protocol was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and patient, intervention, comparison and outcome strategy. Only randomized controlled trials (RCT) were retrieved from Embase, Medline, Scopus and Web of Science databases. Diagnostic tools, treatment protocols, seroconversion rates and adverse events were investigated. Fifteen RCT mainly concentrated in endemic countries were identified. ChD diagnosis was mainly based on haemagglutination, immunofluorescence, enzyme-linked immunosorbent assay and polymerase chain reaction. Benznidazole (BNZ), nifurtimox, fosravuconazole, posaconazole, allopurinol and thioctic acid were the identified drugs. The best negative seroconversion results (100, 96, 94 and 91.3%) were, respectively, based on BNZ (5 mg kg day−1, 200 mg day−1, 150 mg day−1 and 2.5 mg kg−1) administration for 60 days. Negative seroconversion was not achieved with allopurinol (300 mg day−1 for 60 days). Adverse reactions ranged from 5 to 73% in patients receiving antiparasitic chemotherapy. Treatment discontinuation (1.5–57%) was mainly associated with gastrointestinal, cutaneous and neurological manifestations. Current RCT-based evidence indicates that BNZ is the most viable option for ChD treatment. However, new protocols need to be developed to mitigate side effects and increase patient adherence to antiparasitic chemotherapy. Therefore, shorter regimens, lower concentrations and treatments combining BNZ with posaconazole, fosravuconazole or ravuconazole may be viable to ensure comparable efficacy to BZN-based monotherapy, contributing to reduce dose- and time-dependent toxicity reactions.

Congenital transmission of Chagas disease plays an important role in endemic countries because it is not a diagnosis that is encountered frequently in prenatal care. Due to limited information regarding congenital transmission of Trypanosoma cruzi in Mexico, the present study aimed to investigate protozoan infectivity and modulation of immune responses in human placental explants infected with T. cruzi Ia Mexican strains. The Inc-5 strain showed increased infectivity and modulated IL-1β, IL-10 and TLR-4, decreasing their expression after 24 h of infection. Both strains (Inc-5 and Ninoa) stimulated the production of TNF-α and decreased IL-6 levels 96 h after infection. An important detachment of the syncytiotrophoblast caused by infection with T. cruzi was observed after 24 h of infection. In this study, ex vivo infection of human placental villi was performed to better understand interactions involving parasitic T. cruzi and human placental tissue. It was concluded that the strains of TcIa present parasitism in placental tissue, modulation of the innate immune system of the placenta, and cause intense detachment of the syncytiotrophoblast, a fact that may be more associated with abortion and premature birth events than the congenital transmission itself, justifying the low rate of this transmission mechanism by this genotype.

Chagas disease is a potentially life-threatening protozoan infection affecting around 8 million people, for which only chemotherapies with limited efficacy and severe adverse secondary effects are available. The aetiological agent, Trypanosoma cruzi, displays varied cell invading tactics and triggers different host cell signals, including the Wnt/β-catenin pathway. Poly(ADP-ribose) (PAR) can be synthetized by certain members of the poly(ADP-ribose) polymerase (PARP) family: PARP-1/-2 and Tankyrases-1/2 (TNKS). PAR homoeostasis participates in the host cell response to T. cruzi infection and TNKS are involved in Wnt signalling, among other pathways. Therefore, we hypothesized that TNKS inhibitors (TNKSi) could hamper T. cruzi infection. We showed that five TNKSi (FLALL9, MN64, XAV939, G007LK and OULL9) diminished T. cruzi infection of Vero cells. As most TNKSi did not affect the viability of axenically cultivated parasites, our results suggested that TNKSi were interfering with parasite–host cell signalling. Infection by T. cruzi induced nuclear translocation of β-catenin, as well as upregulation of TNF-α expression and secretion. These changes were hampered by TNKSi. Further signals should be monitored in this model and in vivo. As a TNKSi has entered cancer clinical trials with promising results, our findings encourage further studies aiming at drug repurposing strategies.

Drug combinations have been evaluated for Chagas disease in an attempt to improve efficacy and safety. In this line, the objective of this work is to assess the effects of treatment with nitro drugs combinations using benznidazole (BZ) or nifurtimox (NFX) plus the sulfone metabolite of fexinidazole (fex-SFN) in vitro and in vivo on Trypanosoma cruzi infection. The in vitro interaction of fex-SFN and BZ or NFX against infected H9c2 cells by the Y strain was classified as an additive (0.5⩾ΣFIC<4), suggesting the possibility of a dose reduction in the in vivo T. cruzi infection. Next, the effect of combining suboptimal doses was assessed in an acute model of murine T. cruzi infection. Drug combinations led to a faster suppression of parasitemia than monotherapies. Also, the associations led to higher cure levels than those in the reference treatment BZ 100 mg day−1 (57.1%) (i.e. 83.3% with BZ/fex-SFN and 75% with NFX/fex-SFN). Importantly, toxic effects resulting from the associations were not observed, according to weight gain and hepatic enzyme levels in the serum of experimental animals. Taken together, this study is a starting point to explore the potential effects of nitro drugs combinations in preclinical models of kinetoplastid-related infections.

Biomarkers (coming from host or parasite) to monitor Chagas disease (CD) progression as well as the therapeutic response in chronic CD are critically needed, since seronegativization, which may be considered the best indicator of therapeutic cure, takes several years to be observed in adults. Several molecules have been suggested as biomarkers for CD, however, they have to be validated. Taking advantage of mouse models of Trypanosoma cruzi infection, we investigated changes in the degradation profile of fibronectin in plasma. The degradation profile of fibronectin was different in the acute phase compared to the chronic phase of the infection. Fibronectin fragments of approximately 150, 100, 40 and 30 kDa were identified. Furthermore, those degradation profiles correlated with acute parasitaemia as well as with cardiac parasite burden and tissue damage during the infection. The usefulness of fibronectin degradation as a biomarker for therapeutic response following drug treatment and immunotherapeutic vaccination also was evaluated and a decreased fibronectin degradation profile was observed upon benznidazole or a vaccine candidate treatment.

Chagas disease is a serious parasitic infection caused by Trypanosoma cruzi. Unfortunately, the current chemotherapeutic tools are not enough to combat the infection. The aim of this study was to evaluate the trypanocidal activity of benznidazole-loaded microparticles during the acute phase of Chagas infection in an experimental murine model. Microparticles were prepared by spray-drying using copolymers derived from esters of acrylic and methacrylic acids as carriers. Dissolution efficiency of the formulations was up to 3.80-fold greater than that of raw benznidazole. Stability assay showed no significant difference (P > 0.05) in the loading capacity of microparticles for 3 years. Cell cultures showed no visible morphological changes or destabilization of the cell membrane nor haemolysis was observed in defibrinated human blood after microparticles treatment. Mice with acute lethal infection survived 100% after 30 days of treatment with benznidazole microparticles (50 mg kg−1 day−1). Furthermore, no detectable parasite load measured by quantitative polymerase chain reaction and lower levels of T. cruzi-specific antibodies by enzyme-linked immunosorbent assay were found in those mice. A significant decrease in the inflammation of heart tissue after treatment with these microparticles was observed, in comparison with the inflammatory damage observed in both infected mice treated with raw benznidazole and untreated infected mice. Therefore, these polymeric formulations are an attractive approach to treat Chagas disease.

The prevalence of Chagas disease has decreased in the Americas region due to vector control measures. However, non-vectorial transmission through blood transfusions and organ transplantation has gained importance in recent years. Screening among blood and organ donors are essential to reduce Trypanosoma cruzi transmission and could provide information to estimate population prevalence. We conducted a cross-sectional study on the prevalence of immunoglobulin G (IgG) antibodies against T. cruzi in healthy blood donors, solid organ donors and heart transplant recipients from 2012 to 2019. We found a total of 99 357 IgG T. cruzi results during the study period. The cumulative seroprevalence in healthy blood donors was 0.13% (95% confidence interval (CI) 0.10–0.15), in organ donors was 0.53% (95% CI 0.06–1.92) and in heart transplant recipients was 3.03 (95% CI 0.07–15.75). Seroprevalence trend in healthy blood donors showed annual increase between 2012 and 2015, decreasing in the following years. No trend was seen in organ donors neither heart recipients. Adjusted rates did not show difference by sex and age among blood donors. No significant increases in seroprevalence T. cruzi were found during the study period. T. cruzi transmission remains low.

VmCT1 is an antimicrobial peptide (AMP) isolated from the venom of the scorpion Vaejovis mexicanus with antimicrobial, anticancer and antimalarial activities, which the rational design with Arg-substitution has yielded AMPs with higher antimicrobial activity than VmCT1. Chagas is a neglected tropical disease, becoming the development of new antichagasic agents is urgent. Thus, we aimed to evaluate the antichagasic effect of VmCT1 and three Arg-substituted analogues, as well their action mechanism. Peptides were tested against the epimastigote, trypomastigote, amastigote forms of Trypanossoma cruzi Y strain and against LLC-MK2 mammalian cells. The mechanism of action of these peptides was evaluated by means of flow cytometry and scanning electron microscopy. VmCT1 presented activity against all three forms of T. cruzi, with EC50 against trypomastigote forms of 1.37 μmol L−1 and selectivity index (SI) of 58. [Arg]3-VmCT1, [Arg]7-VmCT1 and [Arg]11-VmCT1 also showed trypanocidal effect, but [Arg]11-VmCT1 had the best effect, being able to decrease the EC50 against trypomastigote forms to 0.8 μmol L−1 and increase SI to 175. Necrosis was cell death pathway of VmCT1, as well [Arg]7-VmCT1 and [Arg]11-VmCT1, such as observed by membrane damage in flow cytometry analyses and scanning-electron-microscopy. In conclusion, [Arg]11-VmCT1 revealed promising as a candidate for new antichagasic therapeutics.

Chagas disease (CD) is a neglected disease and endemic in Brazil. In the Brazilian Northeast Region, it affects millions of people. Therefore, it is necessary to identify the spatiotemporal trends of CD mortality in the Northeast of Brazil. This ecological study was designed, in which the unit of analysis was the municipality of the Brazilian northeast. The data source was the Information System of Mortality. It was calculated relative risk from socioeconomic characteristics. Mortality rates were smoothed by the Local Empirical Bayes method. Spatial dependency was analysed by the Global and Local Moran Index. Scan spatial statistics were also used. A total of 11 287 deaths by CD were notified in the study. An expressive parcel of this number was observed among 70-year-olds or more (n = 4381; 38.8%), no schooling (n = 4381; 38.8%), mixed-race (n = 4381; 62.3%), male (n = 6875; 60.9%). It was observed positive spatial autocorrelation, mostly in municipalities of the state of Bahia, Piauí (with high-high clusters), and Maranhão (with low-low clusters). The spatial scan statistics has presented a risk of mortality in 24 purely spatial clusters (P < 0.05). The study has identified the spatial pattern of CD mortality mostly in Bahia and Piauí, highlighting priority areas in planning and control strategies of the health services.

In previous studies, we have identified several families of 5-nitroindazole derivatives as promising antichagasic prototypes. Among them, 1-(2-aminoethyl)-2-benzyl-5-nitro-1,2-dihydro-3H-indazol-3-one, (hydrochloride) and 1-(2-acetoxyethyl)-2-benzyl-5-nitro-1,2-dihydro-3H-indazol-3-one (compounds 16 and 24, respectively) have recently shown outstanding activity in vitro over the drug-sensitive Trypanosoma cruzi CL strain (DTU TcVI). Here, we explored the activity of these derivatives against the moderately drug-resistant Y strain (DTU TcII), in vitro and in vivo. The outcomes confirmed their activity over replicative forms, showing IC50 values of 0.49 (16) and 5.75 μm (24) towards epimastigotes, 0.41 (16) and 1.17 μm (24) against intracellular amastigotes. These results, supported by the lack of toxicity on cardiac cells, led to better selectivities than benznidazole (BZ). Otherwise, they were not as active as BZ in vitro against the non-replicative form of the parasite, i.e. bloodstream trypomastigotes. In vivo, acute toxicity assays revealed the absence of toxic events when administered to mice. Moreover, different therapeutic schemes pointed to their capability for decreasing the parasitaemia of T. cruzi Y acute infected mice, reaching up to 60% of reduction at the peak day as monotherapy (16), 79.24 and 91.11% when 16 and 24 were co-administered with BZ. These combined therapies had also a positive impact over the mortality, yielding survivals of 83.33 and 66.67%, respectively, while untreated animals reached a cumulative mortality of 100%. These findings confirm the 5-nitroindazole scaffold as a putative prototype for developing novel drugs potentially applicable to the treatment of Chagas disease and introduce their suitability to act in combination with the reference drug.

Trypanosoma cruzi, the etiological agent of Chagas disease, releases factors, including antigens from the trans-sialidase (TS) superfamily, which modulate the host immune responses. Tc13 antigens belong to group IV of TSs and are characterized by C-terminal EPKSA repeats. Here, we studied the effect of the Tc13 antigen from the Tulahuén strain, Tc13Tul, on primary cultures of splenocytes from naïve BALB/c mice. Recombinant Tc13Tul increased the percentage of viable cells and induced B (CD19+) lymphocyte proliferation. Tc13Tul stimulation also induced secretion of non-specific IgM and interferon-γ (IFN-γ). The same effects were induced by Tc13Tul on splenocytes from naïve C3H/HeJ mice. In vivo administration of Tc13Tul to naïve BALB/c mice increased non-specific IgG in sera. In addition, in vitro cultured splenocytes from Tc13Tul-inoculated mice secreted a higher basal level of non-specific IgM than controls and the in vitro Tc13Tul stimulation of these cells showed an enhanced effect on IgM and IFN-γ secretion. Our results indicate that Tc13Tul may participate in the early immunity in T. cruzi infection by favouring immune system evasion through B-cell activation and non-specific Ig secretion. In contrast, as IFN-γ is an important factor involved in T. cruzi resistance, this may be considered a Tc13Tul effect in favour of the host.

Transmission of Trypanosma cruzi (Kinetoplastida: Trypanosomatidae) occurs when feces/urine of infected triatomines come into contact with mucous membranes or damaged skin, and this occurs mainly when insects defecate while feeding on the host. Thus, the vector competence of the triatomines is associated with their feeding and excretion/defecation behavior. This work studied for the first time the effect of T. cruzi infection on feeding and excretion/defecation patterns of Triatoma infestans (Hemiptera: Reduviidae). Uninfected and infected fifth-instar nymphs were fed ad libitum and their feeding behavior and defecations were registered during and after feeding. The feeding pattern did not show differences between the experimental groups. However, the infected nymphs began to defecate earlier, defecated in greater quantity and there was a greater proportion of defecating individuals compared to uninfected nymphs. These results show that T. cruzi affected the excretion/defecation pattern of T. infestans in a way that would increase the probability of contact between infective feces and the mammalian host.

Levamisole (Lms) is an anthelminthic drug with immunomodulatory activity. Chagas disease (CD) is caused by Trypanosoma cruzi and there is very low access to the drugs available, benznidazole (Bz) and nifurtimox, both far from ideal. In a drug-repurposing strategy to test potential activity as antiparasitic and immunomodulatory agent for CD, Lms was assayed on acute T. cruzi murine infection, alone and in co-administration with Bz. During protocol standardization, 100 and 10 mpk of Bz given for five consecutive days resulted in parasitaemia suppression and 100% animal survival only with the highest dose. Flow cytometry showed that both optimal (100 mpk) and suboptimal (10 mpk) doses of Bz equally decreased the plasma levels of cytokines commonly elevated in this acute infection model. Lms alone (10–0.5 mpk) did not decrease parasitaemia nor mortality rates. Co-administration was investigated using the suboptimal dose of Bz and different doses of Lms. While Bz 10 mpk did not alter parasitaemia, the combo partially reduced it but only slightly promoted animal survival. This effect could be related to Th1-response modulation since interleukin-6 and interferon-γ were higher after treatment with the combo.