Cruzi Antibodies Research Articles

Comparison of Four Chimeric Antigens and Commercial Serological Assays for the Diagnosis of Trypanosoma cruzi Infection

Chagas disease (CD), a neglected tropical disease caused by Trypanosoma cruzi, is a significant public health issue particularly in Latin America, affecting millions worldwide. Diagnosis is a challenge owing to the genetic diversity of T. cruzi and the complexities involved in selecting antigens for the detection of anti–T. cruzi antibodies. This study evaluated four chimeric recombinant antigens (IBMP-8.1, IBMP-8.2, IBMP-8.3, and IBMP-8.4) designed to enhance diagnostic accuracy by addressing assay variability. We compared the diagnostic performance of these chimeric antigens using indirect ELISA as a diagnostic platform, with three commercial serological assays in Brazil, analyzing 100 serum samples from individuals with confirmed CD and 86 from non-infected controls. The results revealed that all assays and antigens demonstrated an area under the receiver operating characteristic curve of 100%, signifying their exceptional ability to distinguish between CD-positive and CD-negative samples. Notably, the chimeric antigens achieved 100% sensitivity, specificity, accuracy, and kappa index, equaling or surpassing the commercial assays. This research highlights the efficacy of IBMP chimeric antigens as reliable diagnostic tools for CD, suggesting their potential integration into commercial diagnostic platforms to enhance the accuracy and reliability of CD detection.

A guide for the generation of repositories of clinical samples for research on Chagas disease.

Chagas disease, caused by the parasite Trypanosoma cruzi, affects over 6 million people, mainly in Latin America. Two different clinical phases, acute and chronic, are recognised. Currently, 2 anti-parasitic drugs are available to treat the disease (nifurtimox and benznidazole), but diagnostic methods require of a relatively complex infrastructure and trained personnel, limiting its widespread use in endemic areas, and the access of patients to treatment. New diagnostic methods, such as rapid tests (RDTs) to diagnose chronic Chagas disease, or loop-mediated isothermal amplification (LAMP), to detect acute infections, represent valuable alternatives, but the parasite's remarkable genetic diversity might make its implementation difficult. Furthermore, determining the efficacy of Chagas disease treatment is complicated, given the slow reversion of serological anti-T. cruzi antibody reactivity, which may even take decades to occur. New biomarkers to evaluate early therapeutic efficacy, as well as diagnostic tests able to detect the wide variety of circulating genotypes, are therefore, urgently required. To carry out studies that address these needs, high-quality and traceable samples from T. cruzi-infected individuals with different geographical backgrounds, along with associated clinical and epidemiological data, are necessary. This work describes the framework for the creation of such repositories, following standardised and uniform protocols, and considering the ethical, technical, and logistic aspects of the process. The manual can be adapted according to the resources of each laboratory, to guarantee that samples are obtained in a reproducible way, favouring the exchange of data among different work groups, and their generalizable evaluation and analysis. The main objective of this is to accelerate the development of new diagnostic methods and the identification of biomarkers for Chagas disease.

Tumor-Suppressive Cross-Linking of Anti-T. cruzi Antibodies in Acute Lymphoblastic Leukemia.

Parasites have been associated with possible anticancer activity, including Trypanosoma cruzi, which has been linked to inhibiting the growth of solid tumors. To better understand this antitumor effect, we investigated the association of anti-T. cruzi antibodies with B cells of the acute lymphoblastic leukemia (ALL) SUPB15 cell line. The antibodies were generated in rabbits. IgGs were purified by affinity chromatography. Two procedures (flow cytometry (CF) and Western blot(WB)) were employed to recognize anti-T. cruzi antibodies on SUPB15 cells. We also used CF to determine whether the anti-T. cruzi antibodies could suppress SUPB15 cells. The anti-T. cruzi antibodies recognized 35.5% of the surface antigens of SUPB15. The complement-dependent cytotoxicity (CDC) results demonstrate the cross-suppression of anti-T. cruzi antibodies on up to 8.4% of SUPB15 cells. For the WB analysis, a band at 100 kDa with high intensity was sequenced using mass spectrometry, identifying the protein as nucleolin. This protein may play a role in the antitumor effect on T. cruzi. The anti-T. cruzi antibodies represent promising polyclonal antibodies that have the effect of tumor-suppressive cross-linking on cancer cells, which should be further investigated.

Seroprevalence of Chagas disease at the Instituto Nacional de Cardiología Ignacio Chávez from 2004 to 2010

Different pathogens can cause dilated cardiomyopathy, one of them is Trypanosoma cruzi protozoan. T.cruzi-chronic infection causes chronic Chagasic cardiomyopathy and affects the sinus node and the conduction systembelow the bundle of His; besides, it shows excellent arrhythmogenic potential because of ventricular arrhythmias. Knowingthe clinical characteristics and performing serological tests to diagnose chronic Chagasic cardiomyopathy is essential. The serological diagnosis for searching the antibodies is based on the phase, which can be a predictor for the development of dilated cardiomyopathy. In this work, the objective was to describe the frequency of dilated cardiomyopathy in patients with T. cruzi positive serology. A total of 961 patients who were medically and clinically diagnosed with dilated cardiomyopathy were studied. Of these, 128 were diagnosed with chronic Chagasic cardiomyopathy and had positive serology for T. cruzi with two serological tests. The clinical findings were obtained from the results of the electrocardiograms and were taken from the patient's clinical histories. In conclusion, complete blockage of the right branch of the bundle of His (44.2%) is one of the primary conduction disorders in the patients studied. Regarding seroprevalence, 14% of patients diagnosed with dilated cardiomyopathy had anti-T. cruzi antibodies.

Evaluation of chimeric recombinant antigens for the serodiagnosis of Trypanosoma cruzi in dogs: a promising tool for Chagas disease surveillance

BackgroundChagas disease (CD), a neglected parasitic disease caused by Trypanosoma cruzi, poses a significant health threat in Latin America and has emerged globally because of human migration. Trypanosoma cruzi infects humans and over 100 other mammalian species, including dogs, which are important sentinels for assessing the risk of human infection. Nonetheless, the serodiagnosis of T. cruzi in dogs is still impaired by the absence of commercial tests. In this study, we investigated the diagnostic accuracy of four chimeric recombinant T. cruzi IBMP antigens (IBMP-8.1, IBMP-8.2, IBMP-8.3, and IBMP-8.4) for detecting anti-T. cruzi antibodies in dogs, using latent class analysis (LCA).Methods We examined 663 canine serum samples, employing indirect ELISA with the chimeric antigens. LCA was utilized to establish a latent variable as a gold standard for T. cruzi infection, revealing distinct response patterns for each antigen.Results The IBMP (Portuguese acronym for the Molecular Biology Institute of Paraná) antigens achieved area under the ROC curve (AUC) values ranging from 90.9% to 97.3%. The highest sensitivity was attributed to IBMP-8.2 (89.8%), while IBMP-8.1, IBMP-8.3, and IBMP-8.4 achieved 73.5%, 79.6%, and 85.7%, respectively. The highest specificity was observed for IBMP-8.4 (98.6%), followed by IBMP-8.2, IBMP-8.3, and IBMP-8.1 with specificities of 98.3%, 94.4%, and 92.7%, respectively. Predictive values varied according to prevalence, indicating higher effectiveness in endemic settings.Conclusions Our findings underscore the remarkable diagnostic performance of IBMP-8.2 and IBMP-8.4 for the serodiagnosis of Trypanosoma cruzi in dogs, representing a promising tool for the diagnosis of CD in dogs. These chimeric recombinant antigens may not only enhance CD surveillance strategies but also hold broader implications for public health, contributing to the global fight against this neglected tropical disease.Graphical

Post-therapeutic cure criterion in chronic Chagas disease using Trypanosoma cruzi chimeric proteins.

Chagas disease (CD) is a neglected disease caused by Trypanosoma cruzi Chagas, 1909. Causative treatment can be achieved with two drugs: benznidazole or Nifurtimox. There are some gaps that hinder progress in eradicating the disease. There is no test that can efficiently assess cure control after treatment. Currently, the decline in anti-T. cruzi antibody titres is assessed with conventional serological tests, which can take years. However, the search for new markers of cure must continue to fill this gap. The present study aimed to evaluate the decline in serological titres using chimeric proteins after treatment with benznidazole in chronic patients diagnosed with CD. It was a prospective cross-sectional cohort study between 2000 and 2004 of T. cruzi-positive participants from the Añatuya region (Argentina) treated with benznidazole. Serum samples from ten patients were collected before treatment (day zero) and after the end of treatment (2, 3, 6, 12, 24 and 36 months). For the detection of anti-T. cruzi antibodies, an indirect ELISA was performed using two chimeric recombinant proteins (IBMP-8.1 and IBMP-8.4) as antigens. The changes in reactivity index within the groups before and after treatment were evaluated using the Friedman test. All participants experienced a decrease in serological titres after treatment with benznidazole, especially IBMP-8.1. However, due to the small number of samples and the short follow-up period, it is premature to conclude that this molecule serves as a criterion for sustained cure. Further studies are needed to validate tests based on these or other biomarkers to demonstrate parasitological cure.

Trypanosoma Cruzi antibody screening in North Texas client owned dogs

Despite multiple screening efforts to identify exposures to Trypanosoma cruzi, in dogs across southern USA, no published studies could be found involving client owned dogs in the North Texas Metroplex area. Therefore, a limited screen was conducted for client owned dogs, seeking routine or preventative care, from participating veterinary practices in the greater Dallas-Fort Worth (DFW) Metroplex from 2019 to 2021. Participants, with owner consent, ranged in age, breed, and length of time at recorded residence. Ninety-nine samples were acquired from participating veterinary practices, initially assessed with the Chagas StatPak, and positive samples were confirmed with IFA (indirect fluorescent antibody test) at the Texas Veterinary Medical Diagnostic Lab (TVMDL), College Station, Texas. Six samples were positive with the StatPak and only two were confirmed positive with IFA. Both animals were senior (10 and 8 years) with no owner reports of previous cardiac issues. The results appear reasonable within the context of previous studies and the seropositivity rate of 2% (n = 99) for client owned dogs included in this study are lower than previously reported rates for shelter dogs from the North Texas area.

Abstract 31 Chagas Disease Screening in Pregnancy: Lessons from Screening Maternal Donors from Publicly Banked Umbilical Cord Blood

Abstract Introduction Screening for Chagas disease in the perinatal setting has the dual benefit of identifying cases in young adults, for whom treatment can reduce morbidity, and providing the opportunity for early intervention in the case of vertical transmission to infants. North Carolina (NC) has experienced substantial growth in populations from Chagas-endemic regions; however, routine perinatal Trypanosoma cruzi antibody screening is not performed in the state. However, T. cruzi antibody screening is performed on all mothers donating their baby’s cord blood to the Carolina Cord Blood Bank (CCBB), an FDA-licensed public cord blood bank in NC. Objectives We aim to identify the prevalence of positive T. cruzi screening serology within a large cohort of maternal cord blood donors in NC. Methods This is a retrospective review of positive screening serology for T. cruzi in all maternal donors of their baby’s cord blood to the CCBB in NC from 7/1/2007–05/31/2023. Screening serology was performed using a chemiluminescent microparticle immunoassay for the qualitative detection of antibodies to T. cruzi. Results Among 26,698 cord blood donations screened over 16 years, 45 samples (0.17%) had a positive T. cruzi antibody screen. Of the 3,787 donations from patients self-identifying as Hispanic or Latino (14% of the cohort), 15 (0.4%) had a positive screen. The prevalence of a positive T. cruzi screen in donated cord blood was 1.7 per 1,000 cord blood donations. Discussion Our data highlight the prevalence of Chagas disease in a non-endemic region and suggest that targeted screening may be a feasible screening strategy for the state. They also demonstrate an additional value to maternal health for donors to public cord blood banks. Further evaluation is needed to determine if these patients had confirmatory testing and whether they were linked to care.

Chagas disease prevalence among migrants from El Salvador in Milan: a cross- sectional study of an often-overlooked population

Background Chagas disease (CD) is considered to be highly endemic in El Salvador, where its prevalence is estimated to be 1.3–3.7%. Although more than 40,000 migrants from El Salvador are currently living in Europe (particularly in Spain and Italy), there are few data regarding the prevalence of CD in this population. The aim of this study was to evaluate the prevalence of CD among Salvadorans living in Italy. Methods A cross-sectional serological survey of CD among Salvadorans living in the metropolitan area of Milan was carried out between October 2017 and December 2019. The participants’ blood samples were tested for Trypanosoma cruzi antibodies using two different serological assays. The collected demographic data included their biological sex, province of origin, the type of housing in their country of origin, and family history of CD. Results Of the 384 subjects who voluntarily participated in the study, five (1.3%, most coming from La Paz) were positive to both serological assays and therefore conclusively diagnosed as having CD. Five other subjects had discrepant serological results but were not positive to a third assay. Three of the five subjects with a diagnosis of CD completed medical staging, one of whom had chronic disease (digestive and cardiac involvement). Conclusions The prevalence of CD among Salvadorans living in Milan is similar to that estimated by the WHO in 2010. Although they are often overlooked in CD surveys, Salvadoran migrants should be included in CD control programs in countries in which the disease is not endemic.

Effectiveness of the repurposed drug isotretinoin in an experimental murine model of Chagas disease

Benznidazole and nifurtimox are the drugs currently used for the treatment of Chagas disease, however its side effects may affect patient adherence. In the search for new alternative therapies, we previously identified isotretinoin (ISO), an FDA-approved drug widely used for the treatment of severe acne through a drug repurposing strategy. ISO shows a strong activity against Trypanosoma cruzi parasites in the nanomolar range, and its mechanism of action is through the inhibition of T. cruzi polyamine and amino acid transporters from the Amino Acid/Auxin Permeases (AAAP) family. In this work, a murine model of chronic Chagas disease (C57BL/6 J mice), intraperitoneally infected with T. cruzi Nicaragua isolate (DTU TcI), were treated with different oral administrations of ISO: daily doses of 5 mg/kg/day for 30 days and weekly doses of 10 mg/kg during 13 weeks. The efficacy of the treatments was evaluated by monitoring blood parasitemia by qPCR, anti-T. cruzi antibodies by ELISA, and cardiac abnormalities by electrocardiography. No parasites were detected in blood after any of the ISO treatments. The electrocardiographic study of the untreated chronic mice showed a significant decrease in heart rate, while in the treated mice this negative chronotropic effect was not observed. Atrioventricular nodal conduction time in untreated mice was significantly longer than in treated animals. Mice treated even with ISO 10 mg/kg dose every 7 days, showed a significant reduction in anti-T. cruzi IgG levels. In conclusion, the intermittent administration of ISO 10 mg/kg would improve myocardial compromise during the chronic stage.

A multicenter comparative study of the performance of four rapid immunochromatographic tests for the detection of anti-Trypanosoma cruzi antibodies in Brazil.

Diagnosis of Trypanosoma cruzi (T. cruzi) infection in the chronic phase of Chagas disease (CD) is performed by serologic testing. Conventional tests are currently used with very good results but require time, laboratory infrastructure, and expertise. Rapid diagnostic tests (RDTs) are an alternative as the results are immediate and do not require specialized knowledge, making them suitable for epidemiologic studies and promising as a screening tool. Nevertheless, few studies conducted comparative evaluations of RDTs to validate the results and assess their performance. In this study, we analyzed four trades of rapid tests (OnSite Chagas Ab Combo Rapid Test-United States, SD Bioline Chagas AB-United States, WL Check Chagas-Argentina, and TR Chagas Bio-Manguinhos-Brazil) using a panel of 190 samples, including sera from 111 infected individuals, most of whom had low T. cruzi antibody levels. An additional 59 samples from uninfected individuals and 20 sera from individuals with other diseases, mainly visceral leishmaniasis, were included. All tests were performed by three independent laboratories in a blinded manner. Results showed differences in sensitivity from 92.8 to 100%, specificity from 78.5 to 92.4%, and accuracy from 90.5 to 95.3% among the four assays. The results presented here show that all four RDTs have high overall diagnostic ability. However, WL Check Chagas and TR Chagas Bio-Manguinhos were considered most suitable for use in screening studies due to their high sensitivity combined with good performance. Although these two RDTs have high sensitivity, a positive result should be confirmed with other tests to confirm or rule out reactivity/positivity, especially considering possible cross-reactivity with individuals with leishmaniasis or toxoplasmosis.

Development and Application of an Assay to Evaluate the Anti-Parasitic Effect of Humoral Responses against Trypanosoma cruzi

Mounting a balanced and robust humoral immune response is of utmost importance for reducing the infectivity of Trypanosoma cruzi. While the role of such a response in controlling the infection is well known, there is a lack of tools that can be used to quickly evaluate it. We developed a serum parasite inhibition assay (to evaluate changes in the parasite infection after exposing infective T. cruzi trypomastigotes to serum samples from infected patients). It is based on Vero cells as the hosts and the Tulahuen β-galactosidase parasite strain, genetically engineered to be quantifiable by spectrophotometry. In parallel, we developed an in-house ELISA to correlate the anti-T. cruzi antibody titres of the clinical samples with their observed anti-parasitic effect in the serum parasite inhibition assay. Serum samples from chronically T. cruzi-infected patients significantly inhibited parasite invasion in a titre-dependant manner, regardless of the patient's clinical status, compared to samples from the non-infected controls. In addition, there was a clear correlation between the reactivity of the samples to the whole-parasite lysates by ELISA and the inhibitory effect. The results of this work confirm the previously described anti-parasitic effect of the serum of individuals exposed to T. cruzi and present a framework for its large-scale evaluation in further studies. The serum parasite inhibition assay represents a reproducible way to evaluate the intensity and anti-parasitic effect of humoral responses against T. cruzi, which could be applied to the evaluation of candidate antigens/epitopes in the design of Chagas disease vaccine candidates.

Anti-Trypanosoma cruzi antibody profiling in patients with Chagas disease treated with benznidazole assessed by genome phage display.

There have been significant improvements in Chagas disease therapy and it is now widely accepted that most patients with chronic disease might benefit from therapy. However, there are challenges to monitor drug efficacy and cure for these patients, which are important impediments for current and future therapies. Trypanosoma cruzi-PCR is highly variable while IgG seroconversion takes decades yielding variable results depending on the antigen(s) used for the assay. We used the genomic phage display (gPhage) platform to perform a pairwise comparison of antigens and epitopes recognized by twenty individual patients with chronic Chagas disease before and after treatment with benznidazole. In total, we mapped 54,473 T. cruzi epitopes recognized by IgG from individual patients (N = 20) before benznidazole treatment. After treatment, the number of epitopes recognized by all patients was significantly smaller (21,254), a reduction consistent with a decrease in anti-T. cruzi antibodies. Most of these epitopes represent distinct fragments from the same protein and could, therefore, be grouped into 80 clusters of antigens. After three years of treatment with benznidazole, we observed a 64% reduction in the number of clusters of antigens recognized by patients (59 clusters before versus 21 clusters after treatment). The most abundant antigenic clusters recognized by patients correspond to the surface antigen CA-2 (B13) followed by the microtubule associated antigen, which highlights the value of these epitopes in Chagas disease diagnosis. Most importantly, quantitative pairwise comparison of gPhage data allowed for the prediction of patient response to treatment based on PCR status. Here, we compiled a list of antigens and epitopes preferentially recognized by Chagas disease patients before and after benznidazole treatment. Next, we observed that gPhage data correlated with patient PCR-status and could, therefore, predict patient response to treatment. Moreover, gPhage results suggest that overall, independent of PCR status, treatment led to a reduction in the presence of T. cruzi-specific antibody levels and the number of antigens and epitopes recognized by these patients. The gPhage platform use of unbiased library of antigens, which is different from conventional serological assays that rely on predetermined antigens, is a contribution for the development of novel diagnostic tools for Chagas disease.

Western blot using Trypanosoma cruzi chimeric recombinant proteins for the serodiagnosis of chronic Chagas disease: A proof-of-concept study.

Chagas disease (CD) is caused by Trypanosoma cruzi. The chronic phase of CD is characterized by the presence of IgG anti-T. cruzi antibodies; and diagnosis is performed by serological methods. Because there is no reliable test that can be used as a reference test, WHO recommends the parallel use of two different tests for CD serodiagnosis. If results are inconclusive, samples should be subjected to a confirmatory test, e.g., Western blot (WB) or PCR. PCR offers low sensitivity in the chronic phase, whereas few confirmatory tests based on the WB method are commercially available worldwide. Therefore, new diagnostic tools should be evaluated to fill the gap in CD confirmatory tests. In recent years, four chimeric recombinant antigens (IBMP-8.1, IBMP-8.2, IBMP-8.3 and IBMP-8.4) have been evaluated in phase I, II and III studies using ELISA, liquid microarray and immunochromatography with 95-100% accuracy. Given the high diagnostic performance of these antigens, the present study investigated the ability of these molecules to diagnose chronic CD using a WB testing platform. In this study, we analyzed the diagnostic potential of four chimeric antigens using 40 T. cruzi-positive, 24-negative, and three additional positive samples for visceral leishmaniasis (i.e., potentially cross-reactive) using WB as the diagnostic platform. Checkerboard titration with different dilutions of antigens, conjugated antigens, and serum samples was performed to standardize all assays. All IBMP antigens achieved 100% sensitivity, specificity, and accuracy, with the exception of IBMP-8.3, which had 100% specificity despite lack of significance, but lower sensitivity (95%) and accuracy (96.9%). No cross-reactivity was observed in samples positive for leishmaniasis. The present phase I (proof-of-concept) study demonstrated the high diagnostic potential of these four IBMP antigens to discriminate between T. cruzi-positive and -negative samples, making them candidates for phase II and confirmatory testing with WB.

Electrochemical impedance biosensor for Chagas Disease diagnosis in clinical samples

Chagas disease (CD) is one of the main neglected tropical diseases, diagnosed mainly by serological tests performed in centralized laboratories, which severely limits the clinical management of the disease in communities with scarce resources. Herein, an electrochemical impedance biosensor for the detection of CD was developed for the first time using a cruzipain-based sensor surface. The protein, highly immunogenic and isolated from Trypanosoma cruzi, was immobilized over the surface of gold disc electrodes modified with 11-mercaptoundecanoic (MUA) and 6-mercapto-1-hexanol (MCH) self-assembled monolayers (SAMs). Reproducible sensor surfaces, yielding 38 ± 3% coverage as measured by Surface Plasmon Resonance, were obtained by amide coupling of 120 μg/mL cruzipain onto 1/10 MUA/MCH SAMs for 30 min. Under optimized operational conditions, the impedimetric immunosensor recognized specific interactions for anti-T. cruzi antibodies in 1/800 diluted human serum patient samples. The charge transfer resistance of the biosensors increases by ∼18% in the presence of the positive samples, whereas the negative samples give rise to a negligible increase of around 6%. An excellent selectivity to clinical samples from patients infected with T. cruzi was obtained. The clear signal difference obtained for positive and negative clinical samples highlights the applicability of the sensors for the point-of-care diagnosis of CD.

Chronic Chagas Disease-the Potential Role of Reinfections in Cardiomyopathy Pathogenesis.

Chagas disease is a neglected anthropozoonosis of global importance with significant cardiovascular-associated mortality. This review focuses on the Trypanosoma cruzi reinfections' role in chronic Chagas cardiomyopathy pathogenesis. We discuss and summarize the available data related to pathology, pathogenesis, diagnosis, and treatment of reinfections. Reinfections influence the genetic and regional diversity of T. cruzi, tissue tropism, modulation of the host's immune system response, clinical manifestations, the risk for congenital infections, differences in diagnostics performances, response to antiparasitic therapy, and the natural history of the disease. Animal models suggest that reinfections lead to worse outcomes and increased mortality, while other studies showed an association between reinfections and lower parasitemia levels and subsequent infection protection. In some regions, the human risk of reinfections is 14% at 5years. Evidence has shown that higher anti-T. cruzi antibodies are correlated with an increased rate of cardiomyopathy and death, suggesting that a higher parasite exposure related to reinfections may lead to worse outcomes. Based on the existing literature, reinfections may play a role in developing and exacerbating chronic Chagas cardiomyopathy and are linked to worse outcomes. Control efforts should be redirected to interventions that address structural poverty for the successful and sustainable prevention of Chagas disease.

Persistence of Trypanosoma cruzi vector-borne transmission among school-age children in the Bolivian Chaco documented by 24-month longitudinal serosurveillance.

Chagas disease represents a major public health concern in several Latin American countries, including Bolivia. We present a longitudinal serosurvey for Trypanosoma cruzi antibodies among a cohort of 120 school-age children from rural communities in the Bolivian Chaco at three time points between 2017 and 2019. Serum samples extracted from dry blood spots collected on filter paper were tested for T. cruzi antibodies by enzyme-linked immunosorbent assay and rapid diagnostic test. T. cruzi antibodies were detected in 7/120 (5.8%), 8/120 (6.7%) and 11/120 (9.2%) samples in 2017, 2018 and 2019, respectively. An average incidence of 1.76 per 100 person-years was observed. Our findings support the persistence of vector-borne T. cruzi transmission in this area, highlighting the need for strengthening multidisciplinary efforts against Chagas disease.

Insights from the use of erythropoietin in experimental Chagas disease

In addition to the long-established role in erythropoiesis, erythropoietin (Epo) has protective functions in a variety of tissues, including the heart. This is the most affected organ in chronic Chagas disease, caused by the protozoan Trypanosoma cruzi. Despite seven million people being infected with T. cruzi worldwide, there is no effective treatment preventing the disease progression to the chronic phase when the pathological involvement of the heart is often observed. Chronic chagasic cardiomyopathy has a wide variety of manifestations, like left ventricular systolic dysfunction, dilated cardiomyopathy, and heart failure. Since Epo may help maintain cardiac function by reducing myocardial necrosis, inflammation, and fibrosis, this study aimed to evaluate whether the Epo has positive effects on experimental Chagas disease. For that, we assessed the earlier (acute phase) and also the later (chronic phase) use of Epo in infected C57BL/6 mice. Blood cell count, biochemical parameters, parasitic load, and echocardiography data were evaluated. In addition, histopathological analysis was carried out. Our data showed that Epo had no trypanocide effect nor did it modify the production of anti-T. cruzi antibodies. Epo-treated groups exhibited parasitic burden much lower in the heart compared to blood. No pattern of hematological changes was observed combining infection with treatment with Epo. Chronic Epo administration reduced CK-MB serum activity from d0 to d180, irrespectively of T. cruzi infection. Likewise, echocardiography and histological results indicate that Epo treatment is more effective in the chronic phase of experimental Chagas disease. Since treatment is one of the greatest challenges of Chagas disease, alternative therapies should be investigated, including Epo combined with benznidazole.

Presence of Anti-T. cruzi Antibodies in Inhabitants and Dogs of Two Rural Settlements in the Sierra de Los Tuxtlas, Veracruz, Mexico.

The aim of this study was to identify the risk factors associated with house infestation by Triatoma dimidiata as well as with Trypanosoma cruzi infection in humans and owned dogs in two rural communities from the municipality of Catemaco, Veracruz, Mexico. One hundred and 16 human blood samples and 34 dog blood samples were collected. The presence of anti-T. cruzi antibodies was determined using four different ELISA assays. Moreover, reactive ELISA sera from humans and dogs were processed by indirect immunofluorescence (IFI) to confirm the presence of anti-T. cruzi antibodies. Serologic tests for T. cruzi infection showed a prevalence of 5.1% (6/116) in humans and of 50% (17/34) in owned dogs. The presence of animals (dogs, chickens and wild animals), as well as some characteristics of house construction were identified as risk factors for infestation and infection. Complementary studies must be carried out to allow a better understanding of the transmission dynamics in the state of Veracruz, Mexico, and the implementation of adequate control programs.

Evaluation of Four Biomarkers in Patients Chronically Infected with Trypanosoma cruzi and Their Relationship with Disease Progression.

This study evaluated four biomarkers of inflammation or fibrosis as progression indicators for heart disease in patients with Chagas disease. We compared values of these markers at the time of the first sample collection of blood (first time point) and at the time of the last collection of blood (second time point) for 103 individuals positive for Trypanosoma cruzi antibodies. They were split into two clinical groups: 52 individuals with the indeterminate form of the disease at the first time point and 51 controls that already had either cardiac involvement (N = 25) or megaviscera (megaesophagus and/or megacolon; N = 26) at that time. All individuals had an electrocardiogram performed both at the first and second time point (mean time between time points: 11 years). All samples were blind tested for galectin-3, brain natriuretic peptide (NT-proBNP), lysyl oxidase-like protein 2 (LOXL2), and troponin. Differences in concentrations between samples were analyzed using the months between samples as the covariate. This analysis showed that values for all markers, except troponin biomarkers had a significative increase at the second time point for the 91 patients without progression. A similar result was obtained for NT-proBNP and LOXL2 with sera from 12 patients that progressed with cardiac disease. The single marker that showed a significative difference between groups (P = 0.01) was galectin-3. We concluded that galectin-3 was the only marker with a prognostic value in relation to the progression or worsening of heart disease in patients with Chagas disease.