Chagas Disease Infection Research Articles

Machine learning for predicting Chagas disease infection in rural areas of Brazil.

Chagas disease is a severe parasitic illness that is prevalent in Latin America and often goes unaddressed. Early detection and treatment are critical in preventing the progression of the illness and its associated life-threatening complications. In recent years, machine learning algorithms have emerged as powerful tools for disease prediction and diagnosis. In this study, we developed machine learning algorithms to predict the risk of Chagas disease based on five general factors: age, gender, history of living in a mud or wooden house, history of being bitten by a triatomine bug, and family history of Chagas disease. We analyzed data from the Retrovirus Epidemiology Donor Study (REDS) to train five popular machine learning algorithms. The sample comprised 2,006 patients, divided into 75% for training and 25% for testing algorithm performance. We evaluated the model performance using precision, recall, and AUC-ROC metrics. The Adaboost algorithm yielded an AUC-ROC of 0.772, a precision of 0.199, and a recall of 0.612. We simulated the decision boundary using various thresholds and observed that in this dataset a threshold of 0.45 resulted in a 100% recall. This finding suggests that employing such a threshold could potentially save 22.5% of the cost associated with mass testing of Chagas disease. Our findings highlight the potential of applying machine learning to improve the sensitivity and effectiveness of Chagas disease diagnosis and prevention. Furthermore, we emphasize the importance of integrating socio-demographic and environmental factors into neglected disease prediction models to enhance their performance.

Strasseriolides display in vitro and in vivo activity against trypanosomal parasites and cause morphological and size defects in Trypanosoma cruzi.

Neglected diseases caused by kinetoplastid parasites are a health burden in tropical and subtropical countries. The need to create safe and effective medicines to improve treatment remains a priority. Microbial natural products are a source of chemical diversity that provides a valuable approach for identifying new drug candidates. We recently reported the discovery and bioassay-guided isolation of a novel family of macrolides with antiplasmodial activity. The novel family of four potent antimalarial macrolides, strasseriolides A-D, was isolated from cultures of Strasseria geniculata CF-247251, a fungal strain obtained from plant tissues. In the present study, we analyze these strasseriolides for activity against kinetoplastid protozoan parasites, namely, Trypanosoma brucei brucei, Leishmania donovani and Trypanosoma cruzi. Compounds exhibited mostly low activities against T. b. brucei, yet notable growth inhibition and selectivity were observed for strasseriolides C and D in the clinically relevant intracellular T. cruzi and L. donovani amastigotes with EC50 values in the low micromolar range. Compound C is fast-acting and active against both intracellular and trypomastigote forms of T. cruzi. While cell cycle defects were not identified, prominent morphological changes were visualized by differential interference contrast microscopy and smaller and rounded parasites were visualized upon exposure to strasseriolide C. Moreover, compound C lowers parasitaemia in vivo in acute models of infection of Chagas disease. Hence, strasseriolide C is a novel natural product active against different forms of T. cruzi in vitro and in vivo. The study provides an avenue for blocking infection of new cells, a strategy that could additionally contribute to avoid treatment failure.

Validation of the NAT Chagas IVD Kit for the Detection and Quantification of Trypanosoma cruzi in Blood Samples of Patients with Chagas Disease.

In the absence of validated biomarkers to control the cure of Chagas disease, PCR-based diagnosis is being used as the main tool for an early indication of therapeutic failure. However, since it is considered a technique of complex reproducibility, mainly due to difficulties in establishing accurate controls to guarantee the quality of the reaction, the use of PCR for Chagas disease diagnosis is restricted to specialized centers. In an effort to disseminate the molecular diagnosis of Chagas disease and its applications, new diagnostic kits based on qPCR have been made available in the market in recent years. Here, we show the results of the validation of the NAT Chagas kit (Nucleic Acid Test for Chagas Disease) for the detection and quantification of T. cruzi in blood samples of patients suspected of Chagas disease infection. The kit, composed of a TaqMan duplex reaction targeting the T. cruzi satellite nuclear DNA and an exogenous internal amplification control, presented a reportable range from 104 to 0.5 parasite equivalents/mL and a limit of detection (LOD) of 0.16 parasite equivalents/mL of blood. In addition, the NAT Chagas kit detected T. cruzi belonging to all six discrete typing units (DTUs-TcI to TcVI), similarly to the in-house real-time PCR performed with commercial reagents, which has been selected as the best performance assay in the international consensus for the validation of qPCR for Chagas disease. In the clinical validation presented here, the kit showed 100% sensitivity and 100% specificity when compared to the consensus in-house real-time PCR assay. Thus, the NAT Chagas kit, which is produced entirely in Brazil under the international standards of good manufacturing practices (GMP), appears as an excellent alternative to enable the molecular diagnosis of Chagas disease in public and private diagnostic centers, as well as to facilitate the monitoring of patients under etiological treatment participating in clinical trials.

Murine colon organoids as a novel model to study Trypanosoma cruzi infection and interactions with the intestinal epithelium.

Chagas disease (CD) is a life-threatening illness caused by the parasite Trypanosoma cruzi (T. cruzi). With around seven million people infected worldwide and over 50,000 deaths per year, CD is a major public health issue in Latin America. The main route of transmission to humans is through a triatomine bug (vector-borne), but congenital and oral transmission have also been reported. The acute phase of CD presents mild symptoms but may develop into a long-lasting chronic illness, characterized by severely impaired cardiac, digestive, and neurological functions. The intestinal tissue appears to have a key role during oral transmission and chronic infection of CD. In this immune-privileged reservoir, dormant/quiescent parasites have been suggested to contribute to disease persistence, infection relapse, and treatment failure. However, the interaction between the intestinal epithelium and T. cruzi has not been examined in depth, in part, due to the lack of in vitro models that approximate to the biological and structural complexity of this tissue. Therefore, to understand the role played by the intestinal tissue during transmission and chronic infection, physiological models resembling the organ complexity are needed. Here we addressed this issue by establishing and characterizing adult stem cell-derived colonoid infection models that are clinically relevant for CD. 3D and 2D systems of murine intestinal organoids infected with T. cruzi Dm28c (a highly virulent strain associated with oral outbreaks) were analyzed at different time points by confocal microscopy. T. cruzi was able to invade and replicate in intestinal epithelial primary cells grown as intact organoids (3D) and monolayers (2D). The permissiveness to pathogen infection differed markedly between organoids and cell lines (primate and intestinal human cell lines). So far, this represents the first evidence of the potential that these cellular systems offer for the study of host-pathogen interactions and the discovery of effective anti-chagasic drugs.

Outbreak of Chagas disease in Brazil: Validation of a molecular diagnostic method

Chagas disease (CD), caused by the protozoan Trypanosoma cruzi (T. cruzi), affects millions of people worldwide. Polymerase Chain Reaction (PCR) and real-time quantitative PCR (qPCR) have been used as tools to monitor parasitic levels in the bloodstream of individuals exposed to infection, thus enabling the monitoring of relapses and the effectiveness of therapy, for example. The aim of this study was to evaluate the TcSAT-IAM system, developed by our research group, on samples from patients with suspected Chagas disease infection. Initially, primer systems were developed for the detection of the nuclear DNA (SAT-DNA) from T. cruzi (TcSAT-IAM). The Cruzi system, predicted in the literature, and TcSAT-IAM were then evaluated in relation to their analytical sensitivity, specificity and efficiency. Afterwards, the applicability of the qPCR technique using both systems (separately) for the diagnosis of acute CD was evaluated in samples from 77 individuals exposed to the outbreak that occurred in Pernambuco-Brazil, relating the results obtained to those of the classical diagnostic methods recommended for this stage of the infection. TcSAT-IAM and Cruzi had a detection limit of 1 fg of target DNA (0,003 parasites). Thirty-eight cases were recorded, 28 by laboratory criteria and 10 by clinical and epidemiological criteria. Blood samples from 77 subjects were submitted to qPCR by both systems, reaching an agreement of 89.61% between them. After analyzes between systems and diagnostic criteria, the TcSAT-IAM showed sensitivity and specificity of 52.36% (CI 37.26–67.52) and 92.31% (CI 79.68–97.35), respectively, accuracy of 72.73% and moderate agreement. The TcSAT-IAM showed an accuracy of 72.58% and 75% in relation to parasitological and serological tests (IgM anti-T. cruzi), respectively. Therefore, quantitative PCR should be incorporated into the diagnosis of suspected acute cases of Chagas disease.

Chagas disease in the context of the 2030 agenda: global warming and vectors.

The 2030 Agenda for Sustainable Development is a plan of action for people, planet and prosperity. Thousands of years and centuries of colonisation have passed the precarious housing conditions, food insecurity, lack of sanitation, the limitation of surveillance, health care programs and climate change. Chagas disease continues to be a public health problem. The control programs have been successful in many countries in reducing transmission by T. cruzi; but the results have been variable. WHO makes recommendations for prevention and control with the aim of eliminating Chagas disease as a public health problem. Climate change, deforestation, migration, urbanisation, sylvatic vectors and oral transmission require integrating the economic, social, and environmental dimensions of sustainable development, as well as the links within and between objectives and sectors. While the environment scenarios change around the world, native vector species pose a significant public health threat. The man-made atmosphere change is related to the increase of triatomines’ dispersal range, or an increase of the mobility of the vectors from their sylvatic environment to man-made constructions, or humans getting into sylvatic scenarios, leading to an increase of Chagas disease infection. Innovations with the communities and collaborations among municipalities, International cooperation agencies, local governmental agencies, academic partners, developmental agencies, or environmental institutions may present promising solutions, but sustained partnerships, long-term commitment, and strong regional leadership are required. A new world has just opened up for the renewal of surveillance practices, but the lessons learned in the past should be the basis for solutions in the future.

Electrochemical sensing of trypanosome- and flavivirus-related neglected tropical diseases

Virus infections and parasitic diseases that are often found in tropical countries represent a large burden on societies in those regions but are unfortunately rarely studied by electrochemistry. These neglected tropical diseases (NTDs) are a concerning issue, especially in developing nations because a challenged healthcare system often negatively affects the economy. Besides the exploration of new treatment strategies, the development of early diagnostic methods is crucial to attenuate negative impacts related to NTDs. This review highlights the most recent developments of electrochemical biosensing efforts for five NTDs, Chagas disease, leishmaniasis, sleeping sickness, dengue fever and Zika virus infection, which affect a number of Latin American, African, and Asian countries. Special focus is placed on the design and fabrication of genosensors and immunosensors, designed as innovative and promising diagnostic tools with the potential of being integrated into portable systems to advance the development of point-of-care devices.

Ten-year follow-up of the largest oral Chagas disease outbreak. Laboratory biomarkers of infection as indicators of therapeutic failure

Trypanosoma cruzi uses various mechanisms of infection to access humans. Since 1967, food contaminated with metacyclic trypomastigotes has triggered several outbreaks of acute infection of Chagas disease by oral transmission. Follow-up studies to assess the effectiveness of anti-parasitic treatment of oral outbreaks are rather scarce. Here, we report a 10-year laboratory follow-up using parasitological, serological, and molecular tests of 106 individuals infected in 2007 of the largest known outbreak of orally transmitted Chagas disease, which occurred in Caracas city, Venezuela. Before treatment (2007), specific IgA, IgM and IgG, were found in 71% (75/106), 90% (95/106) and 100% (106/106), respectively, in addition to 21% (9/43) parasitemia, Complement Mediated Lysis (CML) in 98% (104/106) and 79% (34/43) parasitic DNA for PCR. Blood culture detected parasitemia up to 18 months post-treatment in 6% (6/106) of the patients. In 2017, the original number of cases in the follow-up decreased by 46% and due to the country's economic situation, not all the trials could be carried out in the entire population. During follow-up, IgA and IgM disappeared promptly, with IgM persisting in 19% (20/104) of the patients three years after treatment. The anti-T. cruzi IgG remained positive 10 years later in 41% (20/49) of the individuals evaluated. CML remained positive seven years later in 79% (65/82) of the cases. PCR positive cases decreased after treatment but progressively recovered, being positive in 69% (32/46) of the individuals evaluated in 2017. The group of children (under 18 years of age) showed the highest PCR positivity with 76% (26/34) of the cases, but their parasitic load tended to diminish, while in adults the parasitic load regained their initial values. The simultaneous evaluation of serological tests and PCR of the patients allowed us to separate patients among responders and non-responders to the anti-parasitic treatment, and this information prompted us to apply a second anti-parasitic treatment in the group of non-responders. In this population not subjected to the like lihood of re-infection, adult patients were more likely to be non-responders when compared to children. These results suggest that rigorous laboratory follow-up with T. cruzi infectious biomarkers is essential to detect cases of parasite persistence.

Emerging infectious disease and transfusion-transmitted infection

Hepatitis B, hepatitis C and HIV infections are well-known infectious diseases caused by blood products, but recently there have been almost no reports. In 2011, hepatitis E virus (HEV) antibody test was covered by insurance in Japan, and certain numbers of transfusion-transmitted HEV were reported, and five cases were recognized in 2019. As the Japanese Red Cross has started to examine individual NAT of HEV for all blood donors since August 2020, and the number of transfusion-transmitted HEV will decrease. In addition, Trypanosoma cruzi antibody test for selective blood donors has been examined since August 2016, and the risk of Chagas disease infection by blood transfusion will be decreased. In the future, it is important for protecting against the transfusion-transmitted infection to inspect bacterial tests and know the information of emerging infectious disease occurring overseas. When the emerging infectious diseases such as DENV (dengue virus), WNV (West Nile virus), Zika (Zika virus) and CHIKV (chikungunya virus) occur in Japan, it is necessary to stimulate countermeasures and prepare what kind of tests should be performed for blood donors or criteria for blood donation.

Diferencias de género en la interacción entre consumo de tabaco y alcohol con la presión arterial elevada.

En diferentes regiones de Latinoamérica la infección por T. cruzi y Leishmania se superponen, por lo cual se reportan infecciones mixtas circulantes, debido a esto; deben realizarse pruebas diagnósticas específicas para evitar reacciones cruzadas entre estas dos patologías. Objetivo: Determinar patrones de fluorescencia que permitan la diferenciación entre Leishmaniasis, enfermedad de Chagas e infección mixta empleando epimastigotes de T. cruzi. Metodología: Se empleó la técnica de Inmunofluorescencia Indirecta utilizando epimastigotes de T. cruzi (TcV autóctono) como antígeno figurado frente a un panel de muestras de suero codificados como A, B, C y D correspondientes a pacientes con infección por: Leishmaniasis (A), Infección mixta por Leishmania y Chagas(B), Enfermedad de Chagas (C) y sin ninguna de las dos infecciones (D). Resultados: En los cuatro paneles de muestras se observaron diferentes patrones de intensidad de fluorescencia a nivel de membrana y núcleo de los epimastigotes de T. cruzi (TcV autóctono). Conclusiones: La técnica de Inmunofluorescencia (IFI) con antígenos de epimastigotes de T. cruzi a demostrado utilidad en la diferenciación entre enfermedad de Chagas, Leishmaniasis y/o infecciones mixtas por ambos parásitos en aquellas zonas donde la coexistencia de ambas es habitual.

Benznidazole as Prophylaxis for Chagas Disease Infection Reactivation in Heart Transplant Patients: A Case Series in Brazil.

Background—Patients with Chagas cardiomyopathy (CC) have high mortality, and CC is a common indication for heart transplantation (HTx) in endemic countries. Chagas disease reactivation (CDR) is common after transplantation and is likely to cause adverse outcomes unless detected and treated appropriately. This study reviews our experiences with HTx among patients with CC, and the use of benznidazole (BZ) before transplantation. Methods—During the 18-year period from 1996 through 2014, 70 of 353 patients who underwent HTx (19.8%) had CC, and 53 patients met the inclusion criteria. The effectiveness of prophylactic treatment with BZ (dose of 5 mg/kg/day, two times per day, for at least four weeks and for a maximum of eight weeks) was determined based on the observed reduction in the incidence of CDR during the post-HTx period. Results—Prophylactic therapy was administered to 18/53 patients (34.0%). During the follow-up period, the incidence rate of CDR in our study was 34.0% (18/53). Based on logistic regression analysis, only prophylaxis (OR = 0.12; CI 0.02–0.76; p = 0.025) was considered to protect against CDR. Conclusion—Our study suggests that the use of BZ may reduce the incidence of CDR in patients undergoing HTx and warrants further investigation in a prospective, randomized trial.

Chagas Disease Infection Prevalence and Vector Exposure in a High-Risk Population of Texas Hunters.

Chagas disease, caused by the vector-borne parasite Trypanosoma cruzi, remains one of the most significant neglected tropical diseases affecting the Americas. Identifying high-risk populations is important for understanding Chagas disease transmission and directing public health resources. We recently hypothesized that Texas hunters may be at an elevated risk for contracting Chagas disease because of opportunities for vector exposure and contact with blood of infected reservoirs. To assess their unique exposure risks, we conducted a statewide screening program of Texas hunters. A total of 885 study participants were interviewed and tested for T. cruzi infection; 18 screened positive on a rapid, point-of-care test; however, none were found positive through confirmatory testing. We did find a high prevalence of reported direct contact with wildlife blood as well as triatomine and other arthropod disease vectors. This large-scale screening program represents a novel approach to better understand the vector-borne disease risk in this unique population.

Seroprevalence of Trypanosoma cruzi infection among at-risk blood donors in Japan.

Chagas disease is caused by Trypanosoma cruzi and is endemic in Latin America. In nonendemic countries, including Japan, Chagas disease is primarily a problem in the context of transfusion transmission. Approximately 250,000 immigrants from Latin America reside in Japan, and many of those individuals serve as active blood donors. This study surveyed the seroprevalence of T. cruzi infection among at-risk blood donors in Japan, defined as those who themselves (or whose mothers) were born (or raised) in Latin America, or those with a travel history to Latin America. Blood samples were obtained from at-risk donors in two periods, 2004-2012 and 2013-2016. Collected samples were tested for T. cruzi antibodies using both an enzyme-linked immunosorbent assay and a chemiluminescent immunoassay. Samples that tested positive in both assays were additionally tested by polymerase chain reaction, and look-back investigation was conducted when necessary. Of 18,484 samples obtained from 18,076 at-risk donors, 3 (1:6,025, 0.017%) donors showed seroreactivity by enzyme-linked immunosorbent assay and chemiluminescent immunoassay. All antibody-positive donors were born in Latin America. One of them also was positive for T. cruzi DNA. Eleven previous donations from this donor were subjected to look-back investigation, and five recipients were tested. All five recipients tested negative for T. cruzi antibodies. Seroprevalence of T. cruzi was 0.017% among at-risk donors in Japan. Transfusion-transmitted infection of Chagas disease has not been confirmed to date. Screening for T. cruzi antibodies by targeting at-risk donors is an appropriate strategy for ensuring blood safety in Japan.

Examination of antigenic proteins of Trypanosoma cruzi to fabricate an epitope-based subunit vaccine by exploiting epitope mapping mechanism

Chagas disease is a protozoan parasitic disease caused by Trypanosoma cruzi. This injurious disease spread by the circulation of the blood sucking triatomine insects and transmitted to humans. Chagas disease is endemic in Latin America and also known as American trypanosomasis. Currently, 7 million people are infected by T. cruzi infection and about 22,000 death cases were reported per year throughout the Americas. Various immunization approaches against T. cruzi infection have been examined and some of the developed vaccine showed efficacy in animal models but there is no effective and safe vaccines for humans have been developed yet. Since, the drug resistance is increasing day by day because the developed drug (nifurtimox and benznidazole) to control T. cruzi infection, failed to activate a prodrug and still no drug and vaccine have been established. To control the infection of chagas disease, here in this study we use immunoinformatics method to design multi-epitope subunit vaccine against T. cruzi infection. Moreover, on the basis of immunogenicity B and T cell epitopes were evaluated. The allergenicity, antigenicity was predicted to ensure the safety of vaccine constructs whereas, the physiochemical property showing the stable nature of final vaccine model. Further, molecular docking was performed to optimize the interaction between TLR-2 and TLR-4 (receptor) and vaccine model (ligand) complex. Molecular dynamics simulation was performed to evaluate the energy minimization; RMSD and RMSF plot which confirm the stability of TLR-2 and TLR-4 (receptor) present on immune cells and vaccine model (ligand) complex. This study needed the experimental validation for the safety and immunogenic behavior of designed vaccine protein and it may be helpful in future to control T. cruzi infection.

Input of NAcGlc6SO3 epitopes (sulfotopes) present in Trypanosoma cruzi glycoproteins, and their specific antibodies, in the infection and immune pathogenesis of experimental Chagas disease

Background: Trypanosoma cruzi, the causative agent of Chagas disease contains a major antigen, cruzipain (Cz). The C-terminal domain (C-T) of this glycoprotein bears N-linked high mannose type sulfated oligosaccharide chains and is responsible for most antibodies in natural and experimental infections. Mice immunization with C-T has shown that sulfate moieties of Cz molecule are targets for specific immune responses and responsible for cardiac ultrastructural abnormalities in absence of infection. Methods & Materials: After the molecular characterization of these sufotopes, BALB/c mice were immunized with Cz/C-T, prior and after desulfation treatment, and with NAcGlc6SO3-BSA, to be further sublethally challenged with trypomastigotes to investigate whether they are involved in immunepathogenesis and/or infection of experimental Chagas disease. Results: C-T-immunized mice showed low IL-4 levels and elevated IFN-γ concentration by capture ELISA using C-T as stimulus and a cytokines profile compatible with a mixed response showing: Th2 tendency with excessively high IFNγ and raised IL-17 levels. By contrast, dC-T-immunized-mice presented undetectable IL-4 levels, low IFN-γ level and a cytokines profile like that of control but with a significantly elevated IL-10 value. In addition, ultrastructural cardiac alterations and main immunorecognition of fibrils and mitochondria were observed in C-T-immunized mice both confronted with polyclonal anti-Cz and myosin adsorbed anti-Cz sera. After sublethal challenge, elevated parasitaemias were observed. Mortality was 20 and 80% in C-T and dC-T immunized mice, respectively and mice from dC-T group that survived presented severe muscle alterations. BSA-NAcGlc6SO3-immunized mice mounted a predominant IgG1and IgG2b immune response followed by IgG2a, demonstrating the immunodominance of the sulfotope and a vigorous mice memory T cells response, similarly to C-T-immunized mice. After sublethal infection, mice immunized with the sulfotope displayed excessively elevated parasitemias, similar IFN-γ levels and significant lower mortality percentage than those from BSA-NAcGlc control group. Furthermore, mice treated by passive transference of sulfate-specific IgGs purified from sera of BSA-NAcGlc6SO3-immunized mice, exhibited ultrastructural alterations in cardiac tissue. After challenge, those treated with sulfate-specific IgGs presented higher parasitemias than controls Conclusion: Altogether, these findings have demonstrated that sulfotopes and their specific antibodies display a dual role, participating in the host-tissue immunopathogenicity of experimental Chagas disease and favoring the infection by T. cruzi.

3-pyridyl inhibitors with novel activity against Trypanosoma cruzi reveal in vitro profiles can aid prediction of putative cytochrome P450 inhibition

Using high throughput, high-content imaging, a proprietary library was screened against intracellular Trypanosoma cruzi amastigotes to identify compounds with novel activity against the parasite. Five inhibitors were discovered, which did not clear all of the parasites from 3T3 host cells following 48 hours exposure, and were identified as putative T. cruzi cytochrome P450 (TcCYP51) inhibitors. TcCYP51 inhibitors are not favourable for the drug discovery pipeline for treatment of Chagas Disease infection due to clinical and pre-clinical failures. To determine if there were in vitro inhibitory characteristics of these compounds that could aid the prediction of TcCYP51 inhibition further profiling using imaging and fluorescence based assays was undertaken. It was determined that in vitro profiles, coupled with analysis of chemical structure, could support the early prediction of putative TcCYP51 activity and thus enable early de-prioritisation of these compounds from progression through the drug discovery pipeline.

Comprehensive analysis of three TYK2 gene variants in the susceptibility to Chagas disease infection and cardiomyopathy.

Tyrosine kinase 2 (TYK2) is a member of the Janus kinases family implicated in the signal transduction of type I interferons and several interleukins. It has been described that genetic mutations within TYK2 lead to multiple deleterious effects in the immune response. In this work, we have analyzed three functional independent variants from the frequency spectrum on the TYK2 gene (common and low-frequency variants) suggested to reduce the function of the gene in mediating cytokine signaling and the susceptibility to infections by Trypanosoma cruzi and/or the development of Chagas cardiomyopathy in the Colombian population. A total of 1,323 individuals from a Colombian endemic region for Chagas disease were enrolled in the study. They were classified as seronegative (n = 445), seropositive asymptomatic (n = 336), and chronic Chagas Cardiomyopathy subjects (n = 542). DNA samples were genotyped using TaqMan probes. Our results showed no statistically significant differences between the allelic frequencies of the three analyzed variants when seropositive and seronegative individuals were compared, therefore these variants were not associated with susceptibility to Chagas disease. Moreover, when Chagas cardiomyopathy patients were compared to asymptomatic patients, no significant associations were found. Previous reports highlighted the association of this gene in immune-related disorders under an autoimmunity context, but not predisposing patients to infectious diseases, which is consistent with our findings. Therefore, according to our results, TYK2 gene variants do not seem to play an important role in Chagas disease susceptibility and/or chronic Chagas cardiomyopathy.

Trypanosoma cruzi serinecarboxipeptidase is a sulfated glycoprotein and a minor antigen in human Chagas disease infection.

In this work, the presence of sulfated N-glycans was studied in a high-mannose-type glycoprotein of Trypanosoma cruzi with serinecarboxipeptidase (TcSCP) activity. The immune cross-reactivity between purified SCP and Cruzipain (Cz) was evidenced using rabbit sera specific for both glycoproteins. Taking advantage that SCP co-purifies with Cz from Concanavalin-A affinity columns, the Cz-SCP mixture was desulfated, ascribing the cross-reactivity to the presence of sulfate groups in both molecules. Therefore, knowing that Cz is a sulfated glycoprotein, with antigenic sulfated epitopes (sulfotopes), SCP was excised from SDS-PAGE and the N-glycosydic chains were analyzed by UV-MALDI-TOF-MS, confirming the presence of short-sulfated high-mannose-type oligosaccharidic chains. Besides, the presence of sulfotopes was analyzed in lysates of the different parasite stages demonstrating that a band with apparent molecular weight similar to SCP was highly recognized in trypomastigotes. In addition, SCP was confronted with sera of infected people with different degrees of cardiac dysfunction. Although most sera recognized it in different groups, no statistical association was found between sera antibodies specific for SCP and the severity of the disease. In summary, our findings demonstrate (1) the presence of sulfate groups in the N-glycosidic short chains of native TcSCP, (2) the existence of immune cross-reactivity between Cz and SCP, purified from epimastigotes, (3) the presence of common sulfotopes between both parasite glycoproteins, and (4) the enhanced presence of sulfotopes in trypomastigotes, probably involved in parasite-host relationship and/or infection. Interestingly, we show for the first time that SCP is a minor antigen recognized by most of chronic Chagas disease patient's sera.

Chagas Disease Infection among Migrants at the Mexico/Guatemala Border.

Chagas disease results in the largest burden, in terms of disability-adjusted-life-years, of any parasitic disease in the Americas. Monitoring Chagas disease among migrants is critical to controlling its spread and to serving the needs of the migrant community. Therefore, we determined the prevalence and correlates of Chagas disease in regional and international migrant populations at the Mexico/Guatemala border. Data were collected as part of a larger study of human immunodeficiency virus (HIV) and migration. Participants were a sample of recent regional and international migrants who used an illicit substance or had recent problem drinking. Trypanosoma cruzi infection was classified as testing positive on two different enzyme-linked immunosorbent assays (ELISAs). Interviewer-administered surveys captured sociodemographics, migration history, Chagas disease knowledge, and access to care. We enrolled 389 recent migrants, and the prevalence of Chagas disease was 3.1%. Only 19% of the participants reported having ever heard of the disease and less than 1% had been previously tested. Trypanosoma cruzi-positive participants were more likely to have been born in a rural area or town than a city (92% yes versus 59% no, P = 0.02) and have recently lived in a house with a makeshift roof (33% yes versus 8% no, P < 0.01), walls (42% yes versus 13% no, P < 0.01), or floor (50% yes versus 21% no, P < 0.02), or cinderblock walls (92% yes versus 63% no, P = 0.04). With migration rapidly changing the distribution of Chagas disease, more work needs to be done to create targeted surveillance programs and provide access to affordable treatment among Latin American migrants.

Early polymerase chain reaction detection of Chagas disease reactivation in heart transplant patients

Heart transplantation is a valuable therapeutic option for Chagas disease patients with severe cardiomyopathy. During patient follow-up, the differential diagnosis between cardiac transplant rejection and Chagas disease infection reactivation remains a challenging task, which hinders rapid implementation of the appropriate treatment. Herein we investigate whether polymerase chain reaction (PCR) strategies could facilitate early detection of Trypanosoma cruzi (T cruzi) in transplanted endomyocardial biopsies (EMBs). In this study we analyzed 500 EMB specimens obtained from 58 chagasic cardiac transplant patients, using PCR approaches targeted to nuclear (rDNA 24Sα) and kinetoplastid (kDNA) markers, and compared the efficiency of these approaches with that of other tests routinely used. T cruzi DNA was detected in 112 EMB specimens derived from 39 patients (67.2%). The first positive result occurred at a median 1.0 month post-transplant. Conventional histopathologic, blood smear and hemoculture analyses showed lower sensitivity and higher median time to the first positive result. Patient follow-up revealed that 31 of 39 PCR-positive cases presented clinical reactivation of Chagas disease at different time-points after transplantation. PCR techniques showed considerable sensitivity (0.82) and specificity (0.60), with area under the receiver operating characteristic (ROC) curves of 0.708 (p = 0.001). Moreover, PCR techniques anticipated the clinical signs of Chagas disease reactivation by up to 36 months, with a median time of 6 months and an average of 9.1 months. We found a good association between the PCR diagnosis and the clinical signs of the disease, indicating that the PCR approaches used herein are suitable for early diagnosis of Chagas disease reactivation, with high potential to assist physicians in treatment decisions. For this purpose, an algorithm is proposed for surveillance based on the molecular tests.