Insights of potential trypanocidal effect of the synthetic derivative (2E)-1-(4-aminophenyl)-3-(2,4-dichlorophenyl)prop-2-en-1-one: in vitro assay, MEV analysis, quantum study, molecular docking, molecular dynamics, MPO analysis, and predictive ADMET.

This study aims to evaluate the antitrypanosomiasis activity of a synthetic dichloro-substituted aminochalcone via in vitro assays against infected cell cultures, as well as a theoretical characterization of pharmacokinetics and pharmacodynamics against the protein targets of the evolutionary cycle of T. cruzi. The in vitro evaluation of parasite proliferation inhibition was performed via cytotoxicity analysis on mammalian host cells, effect on epimastigote and trypomastigote forms, and cell death analysis, while computer simulations characterized the electronic structure of (2E)-1-(4-aminophenyl)-3-(2,4-dichlorophenyl)prop-2-en-1-one (DCl), the mechanism of action against the proteins of the evolutionary cycle of T. cruzi: Cruzain, Trypanothione reductase, TcGAPDH, and CYP51 by molecular docking and dynamics and predictive pharmacokinetics by MPO-based ADMET. The in vitro tests showed that the DCl LC50 in order of 178.9 ± 23.9 was similar to the BZN, evidencing the effectiveness of chalcone against Trypomastigotes. Molecular docking and dynamics simulations suggest that DCl acts on the active site of the CYP51 receptor, with hydrogen interactions that showed a high degree of occupation, establishing a stable complex with the target. MPO analysis and ADMET prediction tests suggest that the compound presents an alignment between permeability and hepatic clearance, although it presents low metabolic stability. Chalcone showed stable pharmacodynamics against the CYP51 target, but can form reactive metabolites from N-conjugation and C = C epoxidation, as an indication of controlled oral dose, although the estimated LD50 rate > 500 mg/kg is a indicative of low incidence of lethality by ingestion, constituting a promising therapeutic strategy.

Mortality risk score for patients with Chagas cardiomyopathy and pacemaker.

BACKGROUND: Prognosis of Chronic Chagasic Cardiomyopathy (CCC) patients depends on functional and clinical factors. Bradyarrhythmia requiring pacemaker is a common complication. Prognosis of these patients is poorly studied, and mortality risk factors are unknown. We aimed to identify predictors of death and to define a risk score for mortality in a large cohort of CCC patients with pacemaker. METHODS: It was an observational, unicentric and prospective study. The endpoint was all-cause mortality. Cox regression was used to identify predictors of death and to define a risk score. Bootstrapping method was used to internal score validation. RESULTS: We included 555 patients and after a mean follow-up of 3.7±1.5 years, 100 (18%) deaths occurred. Predictors of death were: right ventricular dysfunction (HR [hazard ratio] 2.24; 95%CI 1.41-3.53; P = 0.001); heart failure class III or IV (HR 2.16; 95% confidence interval [95%CI] 1.16-4.00; P = 0.014); renal disease (HR 2.14; 95%CI 1.24-3.68; P = 0.006); left ventricular end-systolic diameter > 44mm (HR 1.97; 95%CI 1.26-3.05; P = 0.003); atrial fibrillation (HR 1.94; 95%CI 1.25-2.99; P = 0.003) and cardiomegaly on X-ray (HR 1.87; 95%CI 1.10-3.17; P = 0.020). The score identified patients with: low (0-20 points), intermediate (21-30 points) and high risk (>31points). The optimism-corrected C-statistic of the predictive model was 0.751 (95% CI 0.696-0.806). Internal validation with bootstrapping revealed a calibration slope of 0.946 (95% CI 0.920-0.961), reflecting a small degree of over-optimism and C-statistic of 0.746 (95% CI 0.692-0.785). CONCLUSIONS: This study identified predictors of mortality in CCC patients with pacemaker defining a simple, validated and specific risk score.

A woman in her seventies with fever and convulsions. / En kvinne i 70-årene med feber og krampeanfall.

Background: Chagas encephalitis is a rare but severe manifestation of reactivation in patients with chronic Chagas disease. Case presentation: A woman in her seventies who was immunosuppressed after a heart transplant due to Chagas disease was admitted with convulsions, headache and visual disturbances. She developed fever, confusion and repeated convulsions. Pleocytosis was found in spinal fluid. Wet-mount microscopy of spinal fluid revealed motile Trypanosoma cruzi trypomastigotes, and multiple trypomastigotes were seen on a Giemsa-stained smear, confirming reactivation of Chagas disease with meningoencephalitis. Despite benznidazole treatment, she deteriorated, exhibiting pharyngeal paralysis, aphasia and increasing somnolence. Brain CT showed pathology consistent with Chagas encephalitis. Nifurtimox was given as an adjunctive treatment. After a week of treatment, the patient began to improve. She completed 60 days of benznidazole and had regained normal cognitive and neurological function on subsequent follow-up. She had no signs of myocarditis reactivation. Interpretation: Chronic Chagas disease is common among Latin American immigrants in Europe. Reactivation with myocarditis after a heart transplant is well known, while encephalitis is a rare manifestation. We report on a case of Chagas encephalitis in an immunosuppressed patient. Microscopy of parasites in spinal fluid revealed the diagnosis. The WHO provided antiparasitic medications, and despite a severe prognosis, the patient made a full recovery.

Design, synthesis and identification of novel molecular hybrids based on naphthoquinone aromatic hydrazides as potential trypanocide and leishmanicidal agents.

In pursuit of potential agents to treat Chagas disease and leishmaniasis, we report the design, synthesis, and identification novel naphthoquinone hydrazide-based molecular hybrids. The compounds were subjected to in vitro trypanocide and leishmanicidal activities. N'-(1,4-Dioxo-1,4-dihydronaphthalen-2-yl)-3,5-dimethoxybenzohydrazide (13) showed the best performance against Trypanosoma cruzi (IC50 1.83 µM) and Leishmania amazonensis (IC50 9.65 µM). 4-Bromo-N'-(1,4-dioxo-1,4-dihydronaphthalen-2-yl)benzohydrazide (16) exhibited leishmanicidal activity (IC50 12.16 µM). Regarding trypanocide activity, compound 13 was low cytotoxic to LLC-MK2 cells (SI = 95.28). Furthermore, through molecular modeling studies, the cysteine proteases cruzain, rhodesain and CPB2.8 were identified as the potential biological targets.

Chagas Disease: Comparison of Therapy with Nifurtimox and Benznidazole in Indigenous Communities in Colombia.

Background: For indigenous people in Colombia, high infection rates with Chagas disease (CD) are known. Methods: In 2018 and 2020, nine villages were screened for CD. CD-positive patients could enter a drug observed treatment. While, in 2018, Benznidazole (BNZ) was provided as the first-line drug by the government, nifurtimox (NFX) was administered in 2020. Results: Of 121 individuals treated with BNZ, 79 (65%) suffered from at least one adverse event (AE). Of 115 treated with NFX, at least one AE occurred in 96 (84%) patients. In 69% of BNZ cases, the side effects did not last longer than one day; this applied to 31% of NFX cases. Excluding extreme outlier values, average duration of AEs differed highly significantly: BNZ (M = 0.7, SD = 1.4) and NFX (M = 1.7, SD = 1.5, p < 0.001). Using an intensity scale, AEs were highly significantly more severe for NFX (M = 2.1, SD = 0.58) compared to BZN (M = 1.1, SD = 0.38), p < 0.001. When analyzing the duration in relation to the intensity, the burden of AEs caused by NFX was significantly more pronounced. Dropouts (n = 2) due to AEs were in the NFX-group only. Conclusions: Side effects caused by BNZ were significantly fewer, as well as milder, shorter in duration, and more easily treatable, compared to NFX.

Emerging Trends in Left Ventricular Thrombus: A Comprehensive Review of Non-Ischemic and Ischemic Cardiopathies, Including Eosinophilic Myocarditis, Chagas Cardiomyopathy, Amyloidosis, and Innovative Anticoagulant Approaches.

This comprehensive review explores the intricate aspects of left ventricular thrombus (LVT), a potential complication in both ischemic and non-ischemic cardiomyopathies. It provides a thorough understanding of left ventricular thrombus, revealing its uncommon incidence in the general population (7 cases per 10,000 patients), predominantly linked to ischemic heart diseases (ICMs) at an 80% prevalence rate. Diagnostic tools, notably transthoracic echocardiography (TTE) and cardiac magnetic resonance imaging (CMR), demonstrate varying sensitivity but remain indispensable in specific clinical contexts related to LVT as non-invasive diagnostic modalities. A detailed comparison between ICM patients and those with non-ischemic cardiomyopathy (NICM) who have left ventricular thrombus reveals subtle distinctions with significant clinical implications. This analysis underscores the importance of these imaging techniques in distinguishing between the two conditions. Additionally, we explored the occurrence of LVT in specific non-ischemic cardiomyopathies, including Takotsubo syndrome, hypertrophic cardiomyopathy, eosinophilic myocarditis, Chagas disease, cardiac amyloidosis, and several other conditions. The article further delves into anticoagulation strategies, thoroughly examining their impact on LVT regression and patient outcomes. Pharmacological interventions, with a focus on direct oral anticoagulants, emerge as promising alternatives; however, there is insufficient information on their efficiency and safety, especially in NICM population. In conclusion, this review highlights the complex nature of LVT, incorporating a range of etiopathogenic factors, diagnostic complexities, and evolving therapeutic approaches. It emphasizes the pressing need for ongoing research in this field.

Insecticidal activity of fluralaner (Exzolt®) administered to Gallus gallus domesticus against triatomines (Hemiptera, Reduviidae, Triatominae).

BACKGROUND: Triatoma infestans, Triatoma brasiliensis, Triatoma pseudomaculata and Rhodnius prolixus are vectors of Trypanosoma cruzi, the etiological agent of Chagas disease. Chickens serve as an important blood food source for triatomines. This study aimed to assess the insecticidal activity of fluralaner (Exzolt®) administered to chickens against triatomines (R. prolixus, T. infestans, T. brasiliensis and T. pseudomaculata). METHODS: Twelve non-breed chickens (Gallus gallus domesticus) were randomized based on weight into three groups: negative control (n = 4); a single dose of 0.5 mg/kg fluralaner (Exzolt®) (n = 4); two doses of 0.5 mg/kg fluralaner (Exzolt®) (n = 4). Nymphs of 3rd, 4th and 5th instars of R. prolixus, T. infestans, T. brasiliensis and T. pseudomaculata (all n = 10) were allowed to feed on chickens before treatment, and at intervals of 1, 7, 14, 21, 28, 35 and 56 days after treatment, with insect mortality determined. RESULTS: Treatment with two doses of fluralaner showed higher insecticidal efficacy against R. prolixus, T. infestans and T. brasiliensis compared to the single-dose treatment. Similar insecticidal efficacy was observed for T. pseudomaculata for one and two doses of fluralaner. Insecticidal activity of fluralaner (Exzolt®) against triatomine bugs was noted up to 21 and 28 days after treatment with one and two doses of fluralaner, respectively. CONCLUSIONS: The results demonstrate that treatment of chickens with fluralaner (Exzolt®) induces insecticidal activity against triatomines for up to 28 days post-treatment, suggesting its potential use as a control strategy for Chagas disease in endemic areas.

In the fed state, autophagy plays a crucial role in assisting the insect vector Rhodnius prolixus mobilize TAG reserves under forced flight activity.

Autophagy is a cellular degradation pathway mediated by highly conserved autophagy-related genes (Atgs). In our previous work, we showed that inhibiting autophagy under starvation conditions leads to significant physiological changes in the insect vector of Chagas disease Rhodnius prolixus; these changes include triacylglycerol (TAG) retention in the fat body, reduced survival and impaired locomotion and flight capabilities. Herein, because it is known that autophagy can be modulated in response to various stimuli, we further investigated the role of autophagy in the fed state, following blood feeding. Interestingly, the primary indicator for the presence of autophagosomes, the lipidated form of Atg8 (Atg8-II), displayed 20%-50% higher autophagic activation in the first 2 weeks after feeding compared to the third week when digestion was complete. Despite the elevated detection of autophagosomes, RNAi-mediated suppression of RpAtg6 and RpAtg8 did not cause substantial changes in TAG or protein levels in the fat body or the flight muscle during blood digestion. We also found that knockdown of RpAtg6 and RpAtg8 led to modest modulations in the gene expression of essential enzymes involved in lipid metabolism and did not significantly stimulate the expression of the chaperones BiP and PDI, which are the main effectors of the unfolded protein response. These findings indicate that impaired autophagy leads to slight disturbances in lipid metabolism and general cell proteostasis. However, the ability of insects to fly during forced flight until exhaustion was reduced by 60% after knockdown of RpAtg6 and RpAtg8. This change was accompanied by TAG and protein increases as well as decreased ATP levels in the fat body and flight muscle, indicating that autophagy during digestion, i.e., under fed conditions, is necessary to sustain high-performance activity.

Signatures of CD4+ T and B cells are associated with distinct stages of chronic chagasic cardiomyopathy.

Introduction: Chagas disease is a neglected parasitic disease caused by Trypanosoma cruzi. While most patients are asymptomatic, around 30% develop Chronic Chagasic Cardiomyopathy (CCC). Methods: Here, we employed high-dimensional flow cytometry to analyze CD4+ T and B cell compartments in patients during the chronic phase of Chagas disease, presenting the asymptomatic and mild or moderate/severe cardiac clinical forms. Results: Effector CD27-CD4+ T cells were expanded in both CCC groups, and only mild CCC patients showed higher frequencies of effector memory and T follicular helper (Tfh) cells than healthy donors (CTL) and asymptomatic patients. Unsupervised analysis confirmed these findings and further revealed the expansion of a specific subpopulation composed of Tfh, transitional, and central memory CD4+ T cells bearing a phenotype associated with strong activation, differentiation, and exhaustion in patients with mild but not moderate/severe CCC. In contrast, patients with mild and moderate/severe CCC had lower frequencies of CD4+ T cells expressing lower levels of activation markers, suggesting resting status, than CTL. Regarding the B cell compartment, no alterations were found in naïve CD21-, memory cells expressing IgM or IgD, marginal zone, and plasma cells in patients with Chagas disease. However, expansion of class-switched activated and atypical memory B cells was observed in all clinical forms, and more substantially in mild CCC patients. Discussion: Taken together, our results showed that T. cruzi infection triggers changes in CD4+ T and B cell compartments that are more pronounced in the mild CCC clinical form, suggesting an orchestrated cellular communication during Chagas disease. Conclusion: Overall, these findings reinforce the heterogeneity and complexity of the immune response in patients with chronic Chagas disease and may provide new insights into disease pathology and potential markers to guide clinical decisions.

Conformational analysis and spectroscopic properties of antichagasic nifurtimox.

Considering the health relevance of Chagas' disease, recent research efforts have focused on developing more efficient drug delivery systems containing nifurtimox (NFX). This paper comprehensively investigates NFX through conformational analysis and spectroscopic characterization. Using a conformer-rotamer ensemble sampling tool (CREST-xtb), five distinct conformers of NFX were sampled within a 3.0 kcal mol-1 relative energy window. Subsequently, such structures were used as inputs for geometry optimization by density functional theory (DFT) at B3LYP-def2-TZVP level of theory. Notably, harmonic vibrational frequencies were calculated to establish an in-depth comparison with experimental results and existing literature for the NFX or similar molecules and functional groups, thereby achieving a widely reasoned assignment of the mid-infrared band absorptions for the first time. Moreover, UV-VIS spectra of NFX were obtained in several solvents, enabling the determination of the molar absorptivity coefficient for the two electronic transitions observed for NFX. Among the aprotic solvents, a bathochromic effect was observed in the function of the dielectric constants. Furthermore, a hypochromic effect was observed when the drug was dissolved in protic solvents. These findings offer crucial support for new drug delivery systems containing NFX while demonstrating the potential of spectrophotometric studies in establishing quality control assays for NFX drug products.

Apparent absence of Trypanosoma cruzi in Mexican free-tailed bats (Tadarida brasiliensis) from Texas, USA.

The Mexican free-tailed bat (Tadarida brasiliensis) is one of the most abundant mammals in North America. Mexican free-tailed bats have a wide geographic range stretching from northern South America to the western United States. Bats are theorized to be the original hosts for Trypanosoma cruzi -the causative agent of Chagas disease- and can serve as a source of infection to triatomine insect vectors that feed upon them. Chagas disease is a neglected tropical disease across the Americas where triatomines are present, including the southern United States, where Texas reports this highest number of locally-acquired human cases. To learn more about the role of bats in the ecology of Chagas disease in Texas, we surveyed a colony of Mexican free-tailed bats from Brazos County, Texas, for T. cruzi using carcasses salvaged after an extreme weather event. A total of 283 Mexican free-tailed bats collected in February 2021 were dissected and DNA from the hearts and kidneys was used for T. cruzi detection via qPCR. None of the bat hearts or kidneys tested positive for T. cruzi; this sample size affords 95% confidence that the true prevalence of T. cruzi in this population does not exceed 1%. Future sampling of multiple bat species as well as migrant and resident colonies of Mexican free-tailed bats across different times of the year over a broader geographic range would be useful in learning more about the role of bats in the ecology of Chagas disease in Texas.

Variety is the spice: the role of morphological variation of Triatoma infestans (Hemiptera, Reduviidae) at a macro-scale§.

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi (Chagas, 1909). One of the primary vectors of T. cruzi in South America is Triatoma infestans (Klug, 1834). This triatomine species is distributed across a huge latitudinal gradient, inhabiting domiciliary , peridomiciliary , and wild environments. Its wide geographic distribution provides an excellent opportunity to study the relationships between environmental gradients and intraspecific morphological variation. In this study, we investigated variations in wing size and shape in T. infestans across six ecoregions. We aimed to address the following questions: How do wing size and shape vary on a regional scale, does morphological variation follow specific patterns along an environmental or latitudinal gradient, and what environmental factors might contribute to wing variation? Geometric morphometric methods were applied to the wings of 162 females belonging to 21 T. infestans populations, 13 from Argentina (n = 105), 5 from Bolivia (n = 42), and 3 from Paraguay (n = 15). A comparison of wing centroid size across the 21 populations showed significant differences. Canonical Variate Analysis (CVA) revealed significant differences in wing shape between the populations from Argentina, Bolivia, and Paraguay, although there was a considerable overlap, especially among the Argentinian populations. Well-structured populations were observed for the Bolivian and Paraguayan groups. Two analyses were performed to assess the association between wing size and shape, geographic and climatic variables: multiple linear regression analysis (MRA) for size and Partial Least Squares (PLS) regression for shape. The MRA showed a significant general model fit. Six temperature-related variables, one precipitation-related variable, and the latitude showed significant associations with wing size. The PLS analysis revealed a significant correlation between wing shape with latitude, longitude, temperature-related, and rainfall-related variables. Wing size and shape in T. infestans populations varied across geographic distribution. Our findings demonstrate that geographic and climatic variables significantly influence T. infestans wing morphology.

Chronic Chagas Disease in the US.

This JAMA Insights provides recommendations for Chagas disease screening, diagnosis, and management in the US.

In vitro and In vivo Biological Activity of Two Aryloxy-naphthoquinones in Mice Infected with Trypanosoma cruzi Strains.

BACKGROUND: Chagas disease, a condition caused by Trypanosoma cruzi, is an endemic disease in Latin American countries that affects approximately eight million people worldwide. It is a continuing public health problem. As nifurtimox and benznidazole are the two pharmacological treatments currently used to treat it, the present research proposes new therapeutic alternatives. Previous studies conducted on naphthoquinone derivatives have found interesting trypanocidal effects on epimastigotes, with the molecules 2-phenoxy-1,4-naphthoquinone (IC50= 50 nM and SI < 250) and 2-(3-nitrophenoxy)-naphthalene-1,4-dione (IC50= 20 nM y SI=625) presenting the best biological activity. METHOD: The present study evaluated the efficacy of in vitro, ex vivo and in vivo models of two aryloxyquinones, 2-phenoxy-1,4-naphthoquinone (1) and 2-(3-nitrophenoxy)-naphthalene-1,4- dione (2), against two Mexican T. cruzi strains in both their epimastigote and blood Trypomastigote stage. Both compounds were evaluated against T. cruzi using a mouse model (CD1) infected with Mexican isolates of T. cruzi, nifurtimox and benznidazole used as control drugs. Finally, the cytotoxicity of the two compounds against the J774.2 mouse macrophage cell line was also determined. RESULT: The in vitro and in vivo results obtained indicated that both quinones were more active than the reference drugs. Compound 1 presents in vivo activity, showing up to 40% parasite reduction after 8 h of administration, a finding which is 1.25 times more effective than the results obtained using nifurtimox. CONCLUSION: These are encouraging results for proposing new naphthoquinone derivatives with potential anti-T. cruzi activity.

First Report of Seropositivity to Trypanosoma cruzi in Mexican Afro-Descendants from Guerrero and Oaxaca States.

Mexican Afro-descendant is a population poorly studied in many aspects, between them the infectious diseases that they suffer. This population is mainly found in the country's Pacific (Oaxaca and Guerrero states) and Atlantic (Veracruz) coast. In these regions, a diversity of triatomine vectors of the Chagas disease is found. Also, all the genotypes of Trypanosoma cruzi DTUs have been reported. That is why the present study aimed to study the presence of antibodies against T. cruzi and cardiac pathology associated with the Chagas disease in the Mexican Afro-descendant population of Guerrero and Oaxaca. ELISA, Western blot, and recombinant antigen's ELISA were used to evaluate the seropositivity of these communities. Furthermore, an electrocardiographic study and evaluation of risk factors associated with T. cruzi infection in the Oaxaca and Guerrero populations were conducted. 26.77% of the analyzed population was positive for two serological tests. These percentages are higher than the previously reported for the mestizo population in similar studies. Electrocardiographic results showed cardiac disorder associated with the Chagas disease in the population. Also, risk factors were identified associated with the men's activities in the outdoor working areas.

New drug discovery strategies for the treatment of benznidazole-resistance in Trypanosoma cruzi, the causative agent of Chagas disease.

INTRODUCTION: Benznidazole, the drug of choice for treating Chagas Disease (CD), has significant limitations, such as poor cure efficacy, mainly in the chronic phase of CD, association with side effects, and parasite resistance. Understanding parasite resistance to benznidazole is crucial for developing new drugs to treat CD. AREAS COVERED: Here, the authors review the current understanding of the molecular basis of benznidazole resistance. Furthermore, they discuss the state-of-the-art methods and critical outcomes employed to evaluate the efficacy of potential drugs against T. cruzi, aiming to select better compounds likely to succeed in the clinic. Finally, the authors describe the different strategies employed to overcome resistance to benznidazole and find effective new treatments for CD. EXPERT OPINION: Resistance to benznidazole is a complex phenomenon that occurs naturally among T. cruzi strains. The combination of compounds that inhibit different metabolic pathways of the parasite is an important strategy for developing a new chemotherapeutic protocol.

Structural investigation of Trypanosoma cruzi Akt-like kinase as drug target against Chagas disease.

According to the World Health Organization, Chagas disease (CD) is the most prevalent poverty-promoting neglected tropical disease. Alarmingly, climate change is accelerating the geographical spreading of CD causative parasite, Trypanosoma cruzi, which additionally increases infection rates. Still, CD treatment remains challenging due to a lack of safe and efficient drugs. In this work, we analyze the viability of T. cruzi Akt-like kinase (TcAkt) as drug target against CD including primary structural and functional information about a parasitic Akt protein. Nuclear Magnetic Resonance derived information in combination with Molecular Dynamics simulations offer detailed insights into structural properties of the pleckstrin homology (PH) domain of TcAkt and its binding to phosphatidylinositol phosphate ligands (PIP). Experimental data combined with Alpha Fold proposes a model for the mechanism of action of TcAkt involving a PIP-induced disruption of the intramolecular interface between the kinase and the PH domain resulting in an open conformation enabling TcAkt kinase activity. Further docking experiments reveal that TcAkt is recognized by human inhibitors PIT-1 and capivasertib, and TcAkt inhibition by UBMC-4 and UBMC-6 is achieved via binding to TcAkt kinase domain. Our in-depth structural analysis of TcAkt reveals potential sites for drug development against CD, located at activity essential regions.

The use of peptides for immunodiagnosis of human Chagas disease.

Chagas disease, caused by the protozoa Trypanosoma cruzi, continues to be a serious public health problem in Latin America, worsened by the limitations in its detection. Given the importance of developing new diagnostic methods for this disease, the present review aimed to verify the number of publications dedicated to research on peptides that demonstrate their usefulness in serodiagnosis. To this end, a bibliographic survey was conducted on the PubMed platform using the keyword "peptide" or "epitope" combined with "Chagas disease" or "Trypanosoma cruzi"; "diagno*" or "serodiagnosis" or "immunodiagnosis", without period restriction. An increasing number of publications on studies employing peptides in ELISA and rapid tests assays was verified, which confirms the expansion of research in this field. It is possible to observe that many of the peptides tested so far originate from proteins widely used in the diagnosis of Chagas, and many of them are part of commercial tests developed. In this sense, as expected, promising results were obtained for several peptides when tested in ELISA, as many of them exhibited sensitivity and specificity values above 90%. Furthermore, some peptides have been tested in several studies, confirming their diagnostic potential. Despite the promising results observed, it is possible to emphasize the need for extensive testing of peptides, using different serological panels, in order to confirm their potential. The importance of producing an effective assay capable of detecting the clinical stages of the disease, as well as new immunogenic antigens that enable new serological diagnostic tools for Chagas disease, is evident.

Presence of Trypanosoma cruzi TcI and Trypanosoma dionisii in sylvatic bats from Yucatan, Mexico.

BACKGROUND: Chagas disease is caused by Trypanosoma cruzi, whose genetic structure is divided into six discrete typing units (DTUs) known as TcI-TcVI. In the Yucatan Peninsula, Mexico, information regarding the DTUs circulating in wild mammals is scarce, while this is important knowledge for our understanding of T. cruzi transmission dynamics. METHODS: In the current study, we sampled wild mammals in a sylvatic site of the Yucatan Peninsula and assessed their infection with T. cruzi by PCR. Then, for infected mammals, we amplified and sequenced nuclear and mitochondrial T. cruzi genetic markers for DTU identification. RESULTS: In total, we captured 99 mammals belonging to the orders Chiroptera, Rodentia and Didelphimorphia. The prevalence of infection with T. cruzi was 9% (9/99; 95% CI [5, 16]), and we identified TcI in a Jamaican fruit bat, Artibeus jamaicensis. Moreover, we fortuitously identified Trypanosoma dionisii in another Jamaican fruit bat and detected an unidentified Trypanosoma species in a third specimen. While the latter discoveries were not expected because we used primers designed for T. cruzi, this study is the first to report the identification of T. dionisii in a bat from Yucatan, Mexico, adding to a recent first report of T. dionisii in bats from Veracruz, and first report of this Trypanosoma species in Mexico. CONCLUSION: Further research is needed to enhance our knowledge of T. cruzi DTUs and Trypanosoma diversity circulating in wildlife in Southeastern Mexico.

A recombinant chimeric antigen constructed with B-cell epitopes from Mycobacterium leprae hypothetical proteins is effective for the diagnosis of leprosy.

The diagnosis if leprosy is difficult, as it requires clinical expertise and sensitive laboratory tests. In this study, we develop a serological test for leprosy by using bioinformatics tools to identify specific B-cell epitopes from Mycobacterium leprae hypothetical proteins, which were used to construct a recombinant chimeric protein, M1. The synthetic peptides were obtained and showed good reactivity to detect leprosy patients, although the M1 chimera have showed sensitivity (Se) and specificity (Sp) values higher than 90.0% to diagnose both paucibacillary (PB) and multibacillary (MB) leprosy patients, but not those developing tegumentary or visceral leishmaniasis, tuberculosis, Chagas disease, malaria, histoplasmosis and aspergillosis, in ELISA experiments. Using sera from household contacts, values for Se and Sp were 100% and 65.3%, respectively. In conclusion, our proof-of-concept study has generated data that suggest that a new recombinant protein could be developed into a diagnostic antigen for leprosy.