Chagas' Disease

Purinergic ecto-enzymes participate in the thromboregulation in acute in mice infection by Trypanosoma cruzi

Coagulation disorders have been described in Chagas disease with thrombocytopenia as an important event. Several mechanisms may be related to this pathogenesis, such as enzymes of the purinergic system, purine, and receptors involved in the regulation and modulation of physiological events related to hemostasis. Therefore, the aim of this study was to evaluate the activities of E-NTPDase, E-5'nucleotidase, and ecto-adenosine deaminase (E-ADA) in platelets of mice experimentally infected by Trypanosoma cruzi. Twelve female mice were used, divided into two groups (n = 6): uninfected and infected. Mice of infected group were intraperitoneally inoculated with 10⁴ trypomastigotes of T. cruzi (strain Y). On day 12 post-infection (PI), blood samples were collected for quantitation and separation of platelets. A significant reduction in the number of platelets of infected mice (P < 0.05) was observed. The activities of E-NTPDase (ATP and ADP substrates), E-5'nucleotidase, and E-ADA in platelets increased significantly (P < 0.05) in mice infected by T. cruzi compared with uninfected animals. A negative correlation (P < 0.01)was observed between the number of platelets and ATP hydrolysis (r = -0.64), and ADP hydrolysis (r = -0.69) by E-NTPDase. Therefore, there is a response from the purinergic system activating ecto-enzymes in platelets of mice T. cruzi infected, as a compensatory effect of thrombocytopenia.

Cardiac manifestations of parasitic diseases

The heart may be affected directly or indirectly by a variety of protozoa and helminths. This involvement may manifest in different ways, but the syndromes resulting from impairment of the myocardium and pericardium are the most frequent. The myocardium may be invaded by parasites that trigger local inflammatory response with subsequent myocarditis or cardiomyopathy, as occurs in Chagas disease, African trypanosomiasis, toxoplasmosis, trichinellosis and infection with free-living amoebae. In amoebiasis and echinococcosis, the pericardium is the structure most frequently involved with consequent pericardial effusion, acute pericarditis, cardiac tamponade or constrictive pericarditis. Chronic hypereosinophilia due to helminth infections, especially filarial infections, has been associated with the development of tropical endomyocardial fibrosis, a severe form of restrictive cardiomyopathy. Schistosomiasis-associated lung vasculature involvement may cause pulmonary hypertension (PH) and cor pulmonale Tropical pulmonary eosinophilia, which is characterised by progressive interstitial fibrosis and restrictive lung disease, may lead to PH and its consequences may occur in the course of filarial infections. Intracardiac rupture of an Echinococcus cyst can cause membrane or secondary cysts embolisation to the lungs or organs supplied by the systemic circulation. Although unusual causes of cardiac disease outside the endemic areas, heart involvement by parasites should be considered in the differential diagnosis especially of myocardial and/or pericardial diseases of unknown aetiology in both immunocompetent and immunocompromised individuals. In this review, we updated and summarised the current knowledge on the major heart diseases caused by protozoan and metazoan parasites, which either involve the heart directly or otherwise influence the heart adversely.

S. mansoni-T. cruzi co-infection modulates arginase-1/iNOS expression, liver and heart disease in mice

Although Schistosoma species and Trypanosoma cruzi share common endemic areas, co-infections by these parasites remains overlooked. By using a murine model of S. mansoni and T. cruzi co-infection, we investigated if and to what extent these infections might interact to change the pathological outcomes typically observed when the host is infected by a single parasite species. Swiss mice were randomized into four groups: uninfected (NI) and those infected by S. mansoni (SM), T. cruzi (TC) or co-infected (SM + TC). After 120 days of S. mansoni infection, T. cruzi was concurrently inoculated and the infection occurred for 30 days. Taken together, we identified that the overlap of Th2 (schistosomiasis) and Th1 (Chagas disease) immunological patterns changes the host resistance against both pathogens. Beyond impairing the control of granulomatous inflammation, T. cruzi parasitemia and parasitism in co-infected animals, the Th2 inflammatory response against S. mansoni elicits the activation of the arginase-1 pathway to the detriment of inducible oxide nitric synthase (iNOS) expression and nitric oxide (NO) production, contributing to the liver damage, with minor effects on heart pathology.

Antiparasitic Treatment Induces an Improved CD8+ T Cell Response in Chronic Chagasic Patients

Chagas disease is a chronic infection caused by Trypanosoma cruzi, an intracellular protozoan parasite. Chronic chagasic patients (CCPs) have dysfunctional CD8⁺ T cells that are characterized by impaired cytokine production, high coexpression of inhibitory receptors, and advanced cellular differentiation. Most patients diagnosed in the chronic phase of Chagas disease already exhibit heart involvement, and there is no vaccination that protects against the disease. Antiparasitic treatment is controversial as to its indication for this stage of the disease. There is a lack of biological markers to evaluate the effectiveness of antiparasitic treatment, and little is known about the effect of the treatment on CD8⁺ T cells. Thus, the aim of the current study was to analyze the early effects of antiparasitic treatment on CD8⁺ T cells from CCPs with asymptomatic clinical forms of disease. To evaluate the CD8⁺ T cell subsets, expression of inhibitory receptors, and functionality of T cells in CCPs, PBMCs were isolated. The results showed that treatment of CCPs with the asymptomatic form of the disease induces an increase in the frequency of CD8⁺ central memory T cells and terminal effector T cells, a decrease in the coexpression of inhibitory receptors, an improved Ag-specific CD8⁺ T cell response exhibited by the individual production of IFN-γ or IL-2, and a multifunctional CD8⁺ T cell profile of up to four functions (IFN-γ⁺IL-2⁺Perforin⁺Granzyme B⁺). These findings suggest that, in CCPs, antiparasitic treatment improved the quality of Ag-specific CD8⁺ T cell responses associated with a decrease in inhibitory receptor coexpression, which could serve as biomarkers for monitoring the effectiveness of antiparasitic treatment.

Seroprevalence of five neglected parasitic diseases among immigrants accessing five infectious and tropical diseases units in Italy: a cross-sectional study

OBJECTIVE

This multicentre cross-sectional study aims to estimate the prevalence of five neglected tropical diseases (Chagas disease, filariasis, schistosomiasis, strongyloidiasis and toxocariasis) among immigrants accessing health care facilities in five Italian cities (Bologna, Brescia, Florence, Rome, Verona).

METHODS

Individuals underwent a different set of serological tests, according to country of origin and presence of eosinophilia. Seropositive patients were treated and further followed up.

RESULTS

A total of 930 adult immigrants were enrolled: 477 men (51.3%), 445 women (47.9%), eight transgender (0.8%); median age was 37.81 years (range 18-80 years). Most of them had come from the African continent (405/930, 43.5%), the rest from East Europe, South America and Asia, and 9.6% (89/930) were diagnosed with at least one of the infections under study. Seroprevalence of each specific infection varied from 3.9% (7/180) for Chagas disease to 9.7% (11/113) for toxocariasis. Seropositive people were more likely to be 35-40 years old and male, and to come from South East Asia, sub-Saharan Africa or South America.

CONCLUSIONS

The results of our study confirm that neglected tropical diseases represent a substantial health problem among immigrants and highlight the need to address this emerging public health issue.

Comparison and validation of two computational models of Chagas disease: A thirty year perspective from Venezuela

BACKGROUND

Mathematical models can help aid public health responses to Chagas disease. Models are typically developed to fulfill a particular need, and comparing outputs from different models addressing the same question can help identify the strengths and weaknesses of the models in answering particular questions, such as those for achieving the 2020 goals for Chagas disease.

METHODS

Using two separately developed models (PHICOR/CIDMA model and Princeton model), we simulated dynamics for domestic transmission of Trypanosoma cruzi (T. cruzi). We compared how well the models targeted the last 9 years and last 19 years of the 1968-1998 historical seroprevalence data from Venezuela.

RESULTS

Both models were able to generate the T. cruzi seroprevalence for the next time period within reason to the historical data. The PHICOR/CIDMA model estimates of the total population seroprevalence more closely followed the trends seen in the historic data, while the Princeton model estimates of the age-specific seroprevalence more closely followed historic trends when simulating over 9 years. Additionally, results from both models overestimated T. cruzi seroprevalence among younger age groups, while underestimating the seroprevalence of T. cruzi in older age groups.

CONCLUSION

The PHICOR/CIDMA and Princeton models differ in level of detail and included features, yet both were able to generate the historical changes in T. cruzi seroprevalence in Venezuela over 9 and 19-year time periods. Our model comparison has demonstrated that different model structures can be useful in evaluating disease transmission dynamics and intervention strategies.

Cardiac rehabilitation program in patients with Chagas heart failure: a single-arm pilot study

INTRODUCTION

The benefit of a cardiac rehabilitation (CR) program for patients with Chagas heart failure (CHF) remains unclear. Therefore, we aimed to investigate the effects of CR for CHF patients.

METHODS

A single-arm pilot study, including 12 patients with CHF, was performed. Patients participated in an 8-month physical exercise intervention, comprising aerobic, strength, and stretching exercises (3 times per week, 60 minutes per session). Nutritional and pharmaceutical counseling were also performed. Functional capacity (cardiopulmonary exercise test), muscle respiratory strength (manovacuometry), and body composition (anthropometry and skinfolds) were evaluated at baseline, and after 4 and 8 months of intervention. Cardiac function (echocardiography), biomarkers (lipid profile, glucose, and glycated hemoglobin) and quality of life (Minnesota Living with Heart Failure Questionnaire) were assessed at baseline and at the end of the intervention.

RESULTS

Seven of 12 patients included in the study completed the 8-month follow-up period. Only 2 moderate adverse events occurred during the exercise training. Functional capacity improved after 4 months of CR, while left ventricular ejection fraction (LVEF) and respiratory strength improved after 8 months. Patients with right ventricular (RV) dysfunction at baseline exhibited an improvement in functional capacity after 4 months, and improvements in left ventricular (LV) diastolic pressure, respiratory strength, and quality of life at the end of follow-up. Conversely, those with normal baseline RV function demonstrated LVEF increases that were not observed in patients with RV dysfunction.

CONCLUSIONS

CR was feasible, safe, and has important clinical benefits for patients with CHF, specifically for cardiac function and muscle respiratory strength.

Anti-trypanosomatid drug discovery: an ongoing challenge and a continuing need

The WHO recognizes human African trypanosomiasis, Chagas disease and the leishmaniases as neglected tropical diseases. These diseases are caused by parasitic trypanosomatids and range in severity from mild and self-curing to near invariably fatal. Public health advances have substantially decreased the effect of these diseases in recent decades but alone will not eliminate them. In this Review, we discuss why new drugs against trypanosomatids are required, approaches that are under investigation to develop new drugs and why the drug discovery pipeline remains essentially unfilled. In addition, we consider the important challenges to drug discovery strategies and the new technologies that can address them. The combination of new drugs, new technologies and public health initiatives is essential for the management, and hopefully eventual elimination, of trypanosomatid diseases from the human population.

Simvastatin Attenuates Endothelial Activation through 15-Epi-Lipoxin A4 Production in Murine Chronic Chagas Cardiomyopathy

Current treatments for chronic Chagas cardiomyopathy, a disease with high mortality rates and caused by the protozoan Trypanosoma cruzi, are unsatisfactory. Myocardial inflammation, including endothelial activation, is responsible for the structural and functional damage seen in the chronic phase. The clinical efficacy of benznidazole could be improved by decreasing chronic inflammation. Statins, which have anti-inflammatory properties, may improve the action of benznidazole. Here, the action of simvastatin in a murine model of chronic Chagas cardiomyopathy and the link with the production of the proresolving eicosanoid 15-epi-lipoxin A4, produced by 5-lipoxygenase, are evaluated. Simvastatin decreased the expression of the adhesion molecules E-selectin, intracellular adhesion molecule type 1 (ICAM-1), and vascular cell adhesion molecule type 1 (VCAM-1) in T. cruzi-infected mice. However, when this drug was administered to 5-lipoxygenase-deficient mice, the anti-inflammatory effect was not observed unless exogenous 15-epi-lipoxin A4 was administered. Thus, in chronic Chagas disease, 5-epi-lipoxin A4 induced by simvastatin treatment could improve the pathophysiological condition of patients by increasing the trypanocidal action of benznidazole.

Desing and synthesis of potent anti-Trypanosoma cruzi agents new thiazoles derivatives which induce apoptotic parasite death

Chagas disease, caused by the kinetoplastid protozoan parasite Trypanosoma cruzi, remains a relevant cause of illness and premature death and it is estimated that 6 million to 7 million people are infected worldwide. Although chemotherapy options are limited presenting serious problems, such as low efficacy and high toxicity. T. cruzi is susceptible to thiazoles, making this class of compounds appealing for drug development. Previously, thiazoles resulted in an increase in anti-T. cruzi activity in comparison to thiosemicarbazones. Here, we report the structural planning, synthesis and anti-T. cruzi evaluation of new thiazoles derivatives (3a-m and 4a-m), designed from molecular hybridization associated with non-classical bioisosterism. By varying substituents attached to the phenyl and thiazole rings, substituents were observed to retain, enhance or greatly increase their anti-T. cruzi activity, in comparison to the corresponding thiosemicarbazones. In most cases, electron-withdrawing substituents, such as bromine, 3,4-dichloro and nitro groups, greatly increased antiparasitic activity. Specifically, new thiazoles were identified that inhibit the epimastigote proliferation and were toxic for trypomastigotes without affecting macrophages viability. These compounds were also evaluated against cruzain. However, inhibition of this enzyme was not observed, suggesting that the compounds work through another mechanism. In addition, examination of T. cruzi cell death showed that these molecules induce apoptosis. In conclusion, except for compounds 3h and 3k, all thiazoles derivatives evaluated exhibited higher cytotoxic activity against the trypomastigote forms than the reference medicament benznidazole, without affecting macrophages viability. Compounds 4d and 4k were highlights, CC50 = 1.2 e 1.6 μM, respectively. Mechanistically, these compounds do not inhibit the cruzain, but induce T. cruzi cell death by an apoptotic process, being considered a good starting point for the development of new anti-Chagas drug candidates.

Trypanocidal Activity of Quinoxaline 1,4 Di-N-oxide Derivatives as Trypanothione Reductase Inhibitors

Chagas disease or American trypanosomiasis is a worldwide public health problem. In this work, we evaluated 26 new propyl and isopropyl quinoxaline-7-carboxylate 1,4-di-N-oxide derivatives as potential trypanocidal agents. Additionally, molecular docking and enzymatic assays on trypanothione reductase (TR) were performed to provide a basis for their potential mechanism of action. Seven compounds showed better trypanocidal activity on epimastigotes than the reference drugs, and only four displayed activity on trypomastigotes; T-085 was the lead compound with an IC₅₀ = 59.9 and 73.02 µM on NINOA and INC-5 strain, respectively. An in silico analysis proposed compound T-085 as a potential TR inhibitor with better affinity than the natural substrate. Enzymatic analysis revealed that T-085 inhibits parasite TR non-competitively. Compound T-085 carries a carbonyl, a CF₃, and an isopropyl carboxylate group at 2-, 3- and 7-position, respectively. These results suggest the chemical structure of this compound as a good starting point for the design and synthesis of novel trypanocidal derivatives with higher TR inhibitory potency and lower toxicity.

Microbial control of arthropod-borne disease

Arthropods harbor a diverse array of microbes that profoundly influence many aspects of host biology, including vector competence. Additionally, symbionts can be engineered to produce molecules that inhibit pathogens. Due to their intimate association with the host, microbes have developed strategies that facilitate their transmission, either horizontally or vertically, to conspecifics. These attributes make microbes attractive agents for applied strategies to control arthropod-borne disease. Here we discuss the recent advances in microbial control approaches to reduce the burden of pathogens such as Zika, Dengue and Chikungunya viruses, and Trypanosome and Plasmodium parasites. We also highlight where further investigation is warranted.

Nonsteroidal anti-inflammatory is more effective than anti-oxidant therapy in counteracting oxidative/nitrosative stress and heart disease in T. cruzi-infected mice

We compared the relevance of ibuprofen, vitamins C and E to control oxidative/nitrosative stress and heart disease in mice infected by Trypanosoma cruzi. Swiss mice were randomized into five groups: control, uninfected; infected without treatment; and infected treated with vitamins C, E or ibuprofen. Animals were inoculated with 2000 trypomastigote forms of T. cruzi. After 20 days, infected mice presented reduced vitamin C and E tissue levels, high cytokines (interferon gamma, tumour necrosis factor-α, interleukin 10 and chemokine ligand 2), prostaglandin F2α (PGF2α ) and nitric oxide (NO) cardiac production, intense myocarditis and reactive tissue damage, which was directly correlated with the intensity of the inflammatory infiltrate and the degree of pathological cardiac remodelling. Vitamins C and E supplementation were irrelevant to counteract reactive tissue damage and myocarditis in infected animals. Conversely, ibuprofen reduced tissue levels of cytokines, PGF2α and NO, as well as lipid and protein oxidation, antioxidant enzyme activity and the cardiac damage, without interfering with heart parasitism. Our results do not support the applicability of vitamin C and E supplementation in the management of acute Chagas cardiomyopathy. By controlling the inflammatory infiltrate, anti-inflammatory-based therapy proved to be a more rational strategy than a direct antioxidant therapy in attenuating oxidative/nitrosative stress and cardiac damage.

Molecular identification and genotyping of Trypanosoma cruzi DNA in autochthonous Chagas disease patients from Texas, USA

The parasitic protozoan Trypanosoma cruzi, the causative agent of Chagas disease, is widely distributed throughout the Americas, from the southern United States (US) to northern Argentina, and infects at least 6 million people in endemic areas. Much remains unknown about the dynamics of T. cruzi transmission among mammals and triatomine vectors in sylvatic and peridomestic eco-epidemiological cycles, as well as of the risk of transmission to humans in the US. Identification of T. cruzi DTUs among locally-acquired cases is necessary for enhancing our diagnostic and clinical prognostic capacities, as well as to understand parasite transmission cycles. Blood samples from a cohort of 15 confirmed locally-acquired Chagas disease patients from Texas were used for genotyping T. cruzi. Conventional PCR using primers specific for the minicircle variable region of the kinetoplastid DNA (kDNA) and the highly repetitive genomic satellite DNA (satDNA) confirmed the presence of T. cruzi in 12/15 patients. Genotyping was based on the amplification of the intergenic region of the miniexon gene of T. cruzi and sequencing. Sequences were analyzed by BLAST and phylogenetic analysis by Maximum Likelihood method allowed the identification of non-TcI DTUs infection in six patients, which corresponded to DTUs TcII, TcV or TcVI, but not to TcIII or TcIV. Two of these six patients were also infected with a TcI DTU, indicating mixed infections in those individuals. Electrocardiographic abnormalities were seen among patients with single non-TcI and mixed infections of non-TcI and TcI DTUs. Our results indicate a greater diversity of T. cruzi DTUs circulating among autochthonous human Chagas disease cases in the southern US, including for the first time DTUs from the TcII-TcV-TcVI group. Furthermore, the DTUs infecting human patients in the US are capable of causing Chagasic cardiac disease, highlighting the importance of parasite detection in the population.

Detection of a Potential New Bartonella Species "Candidatus Bartonella rondoniensis" in Human Biting Kissing Bugs (Reduviidae; Triatominae)

BACKGROUND

Among the Reduviidae family, triatomines are giant blood-sucking bugs. They are well known in Central and South America where they transmit Trypanosoma cruzi to mammals, including humans, through their feces. This parasitic protozoan is the causative agent of Chagas disease, a major public health issue in endemic areas. Because of the medical and economic impact of Chagas disease, the presence of other arthropod-borne pathogens in triatomines was rarely investigated.

METHODOLOGY/PRINCIPAL FINDINGS

In this study, seven triatomines species involved in the transmission of T. cruzi were molecularly screened for the presence of known pathogens generally associated with arthropods, such as Rickettsia, Bartonella, Anaplasmataceae, Borrelia species and Coxiella burnetii. Of all included triatomine species, only Eratyrus mucronatus specimens tested positive for Bartonella species for 56% of tested samples. A new genotype of Bartonella spp. was detected in 13/23 Eratyrus mucronatus specimens, an important vector of T. cruzi to humans. This bacterium was further characterized by sequencing fragments of the ftsZ, gltA and rpoB genes. Depending on the targeted gene, this agent shares 84% to 91% of identity with B. bacilliformis, the agent of Carrion's disease, a deadly sandfly-borne infectious disease endemic in South America. It is also closely related to animal pathogens such as B. bovis and B. chomelii.

CONCLUSIONS

As E. mucronatus is an invasive species that occasionally feeds on humans, the presence of potentially pathogenic Bartonella-infected bugs could present another risk for human health, along with the T. cruzi issue.

Meningoencephalitis Caused by Reactivation of Chagas Disease in Patient Without Known Immunosuppression

Central nervous system (CNS) involvement in Chagas disease (CD) is an uncommon complication that can result from direct involvement of the parasite or from thromboembolic phenomena. Direct involvement of CNS can occur in both acute and chronic forms of CD, and can also be secondary to reactivation. Reactivation of CD generally occurs in immunosuppressed patients such as those with human immunodeficiency infection or malignancies being rarely described in patients without apparent immunosuppression. We report a case of a patient living for many years in a nonendemic area for CD that presented to the emergency department with sudden onset of neurological symptoms as a result of reactivation of the disease. The microorganism was isolated from cerebrospinal fluid, and despite appropriate use of benznidazole, the patient died of sepsis after 22 days of treatment. Further investigation did not show any apparent cause of immunosuppression. This case report shows the importance of considering the diagnostic possibility of neurological complications from CD reactivation in patients that have ever lived in CD-endemic areas even without apparent underlying immunosuppression.

Hematologic Changes Associated with Specific Infections in the Tropics

Anemia frequently accompanies and plays a minor role in the presentation and course of infection, whether parasitic, bacterial, or viral. However, a variety of infections, many of which are common in Africa and Asia, cause specific hematologic syndromes. The pathophysiology of these syndromes is complex, and to some extent, reduced red cell production may form part of an innate protective host response to infection. Across the world and in endemic areas, malaria is the most important among this group of infections and forms a major part of everyday practice.

Constituents from stem barks of Luehea ochrophylla Mart and evaluation of their antiparasitic, antimicrobial, and antioxidant activities

Luehea species are found in almost all Central and South American countries. The present work describes the phytochemical study, isolation, and structural characterisation of friedelin, β-friedelinol, lupeol, pseudotaraxasterol, β-sitosterol, betulinic acid, taraxasterol, (-)-epicatechin, β-sitosterol-3-O-β-d-glucopyranoside, and (+)-epicatechin-(4β→8)-epicatechin from stem barks of Luehea ochrophylla Mart. The structural identification of the isolated compounds was mainly performed by NMR analyses and comparison with the data from literature. These compounds were isolated for the first time in the genus Luehea, except β-sitosterol glucopyranoside, (-)-epicatechin, and lupeol. Hexane extract (HE) and dichloromethane (DF) and ethyl acetate (AF) fractions exhibited antiparasitic activity against amastigote (intracellular) and trypomastigote culture forms of Trypanosoma cruzi. The ethanol extract (EE), DF, and ethanol fraction (EF) exhibited considerable antifungal activity against Candida albicans. Moreover, extracts and fractions exhibited significant percentage of capture free radicals of 2,2-diphenyl-picrylhydrazyl (DPPH) when compared to the standard of ascorbic acid.

Chagas disease research and development: Is there light at the end of the tunnel?

Chagas disease, or American trypanosomiasis, is the result of infection by the parasite Trypanosoma cruzi. It is endemic in Latin America, and spreading around the globe due to human migration. Although it was first identified more than a century ago, only two old drugs are available for treatment and a lot of questions related to the disease progression, its pathologies, and not to mention the assessment of treatment efficacy, are subject to debate and remain to be answered. Indeed, the current status of evidence and data available does not allow any absolute statement related to treatment needs and outcome for Chagas patients to be made. Although there has been some new impetus in Research and Development for Chagas disease following recent new clinical trials, there is a scientific requirement to review and challenge the current status of evidence and define basic and clinical research priorities and next steps in the field. This should ensure that the best drugs for Chagas disease are developed, but will require a focused and collaborative effort of the entire Chagas disease research community.

Use of venoarterial extracorporeal membrane oxygenation in fulminant chagasic myocarditis as a bridge to heart transplant

A 17-year-old Brazilian male presented with progressive dyspnea for 15 days, worsening in the last 24 hours, and was admitted in respiratory failure and cardiogenic shock, with multiple organ dysfunctions. Echocardiography showed a left ventricle ejection fraction of 11%, severe diffuse hypokinesia, and a systolic pulmonary artery pressure of 50mmHg, resulting in the need for hemodynamic support with dobutamine (20mcg/kg/min) and noradrenaline (1.7mcg/kg/min). After 48 hours with no clinical or hemodynamic improvement, an extracorporeal membrane oxygenation was implanted. The patient presented with hemodynamic, systemic perfusion and renal and liver function improvements; however, his cardiac function did not recover after 72 hours, and he was transfer to another hospital. Air transport was conducted from Salvador to Recife in Brazil. A heart transplant was performed with rapid recovery of both liver and kidney functions, as well as good graft function. Histopathology of the explanted heart showed chronic active myocarditis and amastigotes of Trypanosoma cruzi. The estimated global prevalence of T. cruzi infections declined from 18 million in 1991, when the first regional control initiative began, to 5.7 million in 2010. Myocarditis is an inflammatory disease due to infectious or non-infectious conditions. Clinical manifestation is variable, ranging from subclinical presentation to refractory heart failure and cardiogenic shock. Several reports suggest that the use of extracorporeal membrane oxygenation in patients presenting with severe refractory myocarditis is a potential bridging therapy to heart transplant when there is no spontaneous recovery of ventricular function. In a 6-month follow-up outpatient consult, the patient presented well and was asymptomatic.

Trypanosoma cruzi induces cellular proliferation in the trophoblastic cell line BeWo

Congenital transmission of Trypanosoma cruzi (T. cruzi) is partially responsible for the progressive globalization of Chagas disease. During congenital transmission the parasite must cross the placental barrier where the trophoblast, a continuous renewing epithelium, is the first tissue in contact with the parasite. The trophoblast turnover implies cellular proliferation, differentiation and apoptotic cell death. The epithelial turnover is considered part of innate immunity. We previously demonstrated that T. cruzi induces cellular differentiation and apoptosis in this tissue. Here we demonstrate that T. cruzi induces cellular proliferation in a trophoblastic cell line. We analyzed the cellular proliferation in BeWo cells by determining DNA synthesis by BrdU incorporation assays, mitotic index, cell cycle analysis by flow cytometry, as well as quantification of nucleolus organizer regions by histochemistry and expression of the proliferation markers PCNA and Ki67 by Western blotting and/or immunofluorescence. Additionally, we determined the ERK1/2 MAPK pathway activation by the parasite by Western blotting.

Sylvatic Transmission of Trypanosoma cruzi Among Domestic and Wildlife Reservoirs in Texas, USA: A Review of the Historical Literature

Chagas disease (Trypanosoma cruzi infection) is one of the most important neglected tropical diseases affecting the Americas. The transmission dynamic of this parasite is a complicated process that involves three genera of Triatominae subfamily and over 100 known mammalian reservoirs composed of domestic, peridomestic and wildlife species. Understanding the complex relationship between vector species and mammalian hosts is important for preventing transmission to humans. We performed a historical literature review to assess the disease burden in the Texas wildlife and domestic animal population. Reports of sylvatic transmission in Texas date back to the 1940s. We found that up to 23 species can serve as reservoirs for T. cruzi in the state with wood rats, raccoons, and wild and domestic canine species most frequently reported as positive for the parasite. We finish with a discussion of the current research gaps, implications for high-risk populations and future directions for research.

Changes in the immune response after treatment with benznidazole versus no treatment in patients with chronic indeterminate Chagas disease

Symptomatic chronic Chagas disease affects up to 40% of patients infected with Trypanosoma cruzi. The lack of reliable early markers of cure after therapy hinders disease management and clinical trials with new drugs. We performed a study with 18 months of follow-up to compare changes in immune parameters and T. cruzi-specific immune responses as surrogate markers of response to therapy between patients treated with benznidazole and untreated patients. This was a pilot, open-label, randomised clinical trial of treatment with benznidazole versus no treatment in patients with indeterminate chronic T. cruzi infection. In both groups we investigated changes in T-cell activation, T-cell subpopulations, regulatory T-cell counts, IL6, and sCD14 levels, and T. cruzi-specific immune responses (Th1, Th2, and Th17 responses). Fourteen patients were included in the study (seven in each group). Median age was 35 years (P_25-75 31-43), 57% were female, and 93% were Bolivian. Benznidazole was administered at 5mg/kg/day for 60days. Three patients discontinued benznidazole owing to adverse reactions and were not evaluated. At the end of the follow-up period, treated patients showed significantly less immune activation and lower regulatory T-cell counts, with an increased Th17 and Th1 response. This randomised pilot clinical trial administering benznidazole to patients with indeterminate chronic Chagas disease brings about changes in the adaptive immunity, leading to a general decrease in inflammatory status. This apparently beneficial response could act as the basis for monitoring new antiparasitic drugs.

Triatoma infestans Calreticulin: Gene Cloning and Expression of a Main Domain That Interacts with the Host Complement System

Triatoma infestans is an important hematophagous vector of Chagas disease, a neglected chronic illness affecting approximately 6 million people in Latin America. Hematophagous insects possess several molecules in their saliva that counteract host defensive responses. Calreticulin (CRT), a multifunctional protein secreted in saliva, contributes to the feeding process in some insects. Human CRT (HuCRT) and Trypanosoma cruzi CRT (TcCRT) inhibit the classical pathway of complement activation, mainly by interacting through their central S domain with complement component C1. In previous studies, we have detected CRT in salivary gland extracts from T. infestans We have called this molecule TiCRT. Given that the S domain is responsible for C1 binding, we have tested its role in the classical pathway of complement activation in vertebrate blood. We have cloned and characterized the complete nucleotide sequence of CRT from T. infestans, and expressed its S domain. As expected, this S domain binds to human C1 and, as a consequence, it inhibits the classical pathway of complement, at its earliest stage of activation, namely the generation of C4b. Possibly, the presence of TiCRT in the salivary gland represents an evolutionary adaptation in hematophagous insects to control a potential activation of complement proteins, present in the massive blood meal that they ingest, with deleterious consequences at least on the anterior digestive tract of these insects.

Prediction and Prevention of Parasitic Diseases Using a Landscape Genomics Framework

Substantial heterogeneity exists in the dispersal, distribution and transmission of parasitic species. Understanding and predicting how such features are governed by the ecological variation of landscape they inhabit is the central goal of spatial epidemiology. Genetic data can further inform functional connectivity among parasite, host and vector populations in a landscape. Gene flow correlates with the spread of epidemiologically relevant phenotypes among parasite and vector populations (e.g., virulence, drug and pesticide resistance), as well as invasion and re-invasion risk where parasite transmission is absent due to current or past intervention measures. However, the formal integration of spatial and genetic data ('landscape genetics') is scarcely ever applied to parasites. Here, we discuss the specific challenges and practical prospects for the use of landscape genetics and genomics to understand the biology and control of parasitic disease and present a practical framework for doing so.

A Case of Possible Chagas Transmission by Blood Transfusion in Switzerland

BACKGROUND

Transfusion-transmitted Chagas disease has been reported from endemic countries in Latin America. Switzerland is a non-endemic country but high prevalence of antibodies against Trypanosoma cruzi was found among immigrants. Immigrants may participate in blood donation; therefore, risk-adapted anti-T. cruzi screening for blood donors was implemented in Switzerland in 2013.

METHODS

Between January 2013 and July 2015, 1 out of 1,183 at-risk donors, tested at Blood Transfusion Service Zurich, was found anti-T. cruzi IgG-positive.

RESULTS AND CONCLUSION

Out of 54 donations given by the index donor (ID), we identified 77 blood products which were delivered to hospitals. Archived serum samples from the donations given during the prior 5 years were available for retrospective testing. All samples from ID revealed positive findings for anti-T. cruzi IgG. Donor-triggered look-back procedure identified a 70-year-old male recipient of a platelet concentrate (PC) donated by ID. The recipient succumbed of acute T. cruzi infection 2 years after transfusion of the PC.

Overcoming research barriers in Chagas disease-designing effective implementation science

Chagas disease is a complex tropical parasitic infection. It affects a significant portion of the population in Latin America, especially in areas of poverty and poor access to health care. It also affects immigrants in high-income countries who lack access to health care due to their legal status. Millions of people are at risk of contracting the disease, and approximately 30 % of chronically infected patients will develop cardiomyopathy. The cost of caring for patients that have been infected is substantial. Basic science research has introduced new concepts and knowledge for the parasite and vector biology as well as better understanding of the pathophysiology of the disease. These research findings nevertheless require effective and timely translation into clinical practice. Likewise, the design of new research projects should account for the multiple system-based barriers. Implementation science facilitates the applicability of research findings and identifies barriers to its execution. Creation of implementation science measures to reach and sustain research programs with greater potential to impact Chagas disease are lacking. This point of view proposes opportunities for implementation science in Chagas disease and strategies for researching effective interventions for preventing and treating the disease.

The detection of Trypanosoma cruzi by nested-PCR in elderly patients: relationship to the clinical and epidemiological profile

Chagas disease, which is caused by Trypanosoma cruzi, is transmitted primarily by triatomine bugs, although the incidence of new cases has decreased as a result of vector control. In Brazil, most of those affected have the chronic form of the disease and are generally elderly individuals who require appropriate clinical follow-up. In this work, we undertook a descriptive study in which 85 patients were interviewed and blood samples were collected for molecular analyses based on the amplification of parasite satellite DNA. The cardiac form of the disease was the most prevalent among the patients and hypertension was the most frequent comorbidity; polypharmacy was detected in 34% of the cases. Serological tests were positive in 95% of cases while 36% were positive in nested-polymerase chain reaction. These findings indicate an increased use of medications and a larger number of age-related diseases in elderly patients with Chagas disease, even in patients with low parasitemia. We conclude that elderly patients with Chagas disease require special attention and that further studies should be done with elderly individuals who carry this disease.

Proteasome inhibition for treatment of leishmaniasis, Chagas disease and sleeping sickness

Chagas disease, leishmaniasis and sleeping sickness affect 20 million people worldwide and lead to more than 50,000 deaths annually. The diseases are caused by infection with the kinetoplastid parasites Trypanosoma cruzi, Leishmania spp. and Trypanosoma brucei spp., respectively. These parasites have similar biology and genomic sequence, suggesting that all three diseases could be cured with drugs that modulate the activity of a conserved parasite target. However, no such molecular targets or broad spectrum drugs have been identified to date. Here we describe a selective inhibitor of the kinetoplastid proteasome (GNF6702) with unprecedented in vivo efficacy, which cleared parasites from mice in all three models of infection. GNF6702 inhibits the kinetoplastid proteasome through a non-competitive mechanism, does not inhibit the mammalian proteasome or growth of mammalian cells, and is well-tolerated in mice. Our data provide genetic and chemical validation of the parasite proteasome as a promising therapeutic target for treatment of kinetoplastid infections, and underscore the possibility of developing a single class of drugs for these neglected diseases.

A Case of Cardboard Boxes Likely Facilitating the Biting of a Patient by Trypanosoma cruzi-Infected Triatomine Bugs

Chagas disease is a vector-borne and potentially fatal parasitic disease that is transmitted by the triatomine bug, a nocturnal feeding, flying arthropod, often referred to by its colloquial name, the “kissing bug.” Vector-borne transmission is considered the most important means of spreading Chagas disease in endemic and nonendemic areas. Corrugated cardboard boxes may accelerate the spread of these insect vectors to nonendemic areas through their ability to harbor and transport small terrestrial arthropods such as silverfish, termites, and cockroaches. We report the case of a patient living in northern California who presented to a community clinic 6 weeks after being bitten by a positively identified triatomine bug. A local pest control company identified a total of eight adult Triatoma protracta, nine nymphs, and two eggs; all within the patient's bedding. No bugs were found outside of the patient's bedroom. The Centers for Disease Control and Prevention confirmed one adult female was positive for Trypanosoma cruzi via polymerase chain reaction. The patient's bedroom doubled as an office and regularly received and stored corrugated cardboard shipping boxes. Corrugated cardboard boxes have been used to trap and study the triatomine bug. This is the first documented case that provides circumstantial evidence that corrugated cardboard boxes may be an inadvertent and unrecognized factor in the spread of Chagas disease.

Effect of physical exercise training in patients with Chagas heart disease: study protocol for a randomized controlled trial (PEACH study)

Background

The effects of exercise training on Chagas heart disease are still unclear. This study aimed to evaluate the effect of exercise training over functional capacity, cardiac function, quality of life, and biomarkers in Chagas heart disease.

Methods

The PEACH study is a superiority randomized clinical trial which will include subjects who meet the following criteria: Chagas heart disease with a left ventricular ejection fraction below 45 % with or without heart failure symptoms; clinical stability in the last 3 months; adherence to clinical treatment; and age above 18 years. The exclusion criteria are: pregnancy; neuromuscular limitations; smoking; evidence of non-chagasic heart disease; systemic conditions that limit exercise practice or cardiopulmonary exercise test; unavailability to attend the center three times a week during the intervention period; and practitioners of regular exercise. The intervention group will perform an exercise training intervention three times per week during 6 months and will be compared to the control group without exercise. Both groups will undergo the same monthly pharmaceutical and nutritional counseling as well as standard medical treatment according to the Brazilian consensus on Chagas disease. The primary outcome is functional capacity based on peak exercise oxygen consumption during cardiopulmonary exercise testing. Secondary outcomes are: cardiac function; body composition; muscle respiratory strength; microvascular reactivity; cardiac rhythm abnormalities; autonomic function; biochemical; oxidative stress and inflammatory biomarkers; and quality of life. Subjects will be evaluated at baseline, and at 3 and 6 months after randomization. Thirty patients will be randomly assigned into exercise or control groups at a ratio of 1:1.

Discussion

Findings of the present study will be useful to determine if physical exercise programs should be included as an important additional therapy in the treatment of patients with Chagas heart disease.

Trial registration

ClinicalTrials.gov ID: NCT02517632 (registered on 6 August 2015).

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1553-4) contains supplementary material, which is available to authorized users.

The bowel and beyond: the enteric nervous system in neurological disorders

The enteric nervous system (ENS) is large, complex and uniquely able to orchestrate gastrointestinal behaviour independently of the central nervous system (CNS). An intact ENS is essential for life and ENS dysfunction is often linked to digestive disorders. The part the ENS plays in neurological disorders, as a portal or participant, has also become increasingly evident. ENS structure and neurochemistry resemble that of the CNS, therefore pathogenic mechanisms that give rise to CNS disorders might also lead to ENS dysfunction, and nerves that interconnect the ENS and CNS can be conduits for disease spread. We review evidence for ENS dysfunction in the aetiopathogenesis of autism spectrum disorder, amyotrophic lateral sclerosis, transmissible spongiform encephalopathies, Parkinson disease and Alzheimer disease. Animal models suggest that common pathophysiological mechanisms account for the frequency of gastrointestinal comorbidity in these conditions. Moreover, the neurotropic pathogen, varicella zoster virus (VZV), unexpectedly establishes latency in enteric and other autonomic neurons that do not innervate skin. VZV reactivation in these neurons produces no rash and is therefore a clandestine cause of gastrointestinal disease, meningitis and strokes. The gut-brain alliance has raised consciousness as a contributor to health, but a gut-brain axis that contributes to disease merits equal attention.

Molecular Diagnosis of Chagas Disease in Colombia: Parasitic Loads and Discrete Typing Units in Patients from Acute and Chronic Phases

BACKGROUND

The diagnosis of Chagas disease is complex due to the dynamics of parasitemia in the clinical phases of the disease. The molecular tests have been considered promissory because they detect the parasite in all clinical phases. Trypanosoma cruzi presents significant genetic variability and is classified into six Discrete Typing Units TcI-TcVI (DTUs) with the emergence of foreseen genotypes within TcI as TcIDom and TcI Sylvatic. The objective of this study was to determine the operating characteristics of molecular tests (conventional and Real Time PCR) for the detection of T. cruzi DNA, parasitic loads and DTUs in a large cohort of Colombian patients from acute and chronic phases.

METHODOLOGY/PRINCIPAL FINDINGS

Samples were obtained from 708 patients in all clinical phases. Standard diagnosis (direct and serological tests) and molecular tests (conventional PCR and quantitative PCR) targeting the nuclear satellite DNA region. The genotyping was performed by PCR using the intergenic region of the mini-exon gene, the 24Sa, 18S and A10 regions. The operating capabilities showed that performance of qPCR was higher compared to cPCR. Likewise, the performance of qPCR was significantly higher in acute phase compared with chronic phase. The median parasitic loads detected were 4.69 and 1.33 parasite equivalents/mL for acute and chronic phases. The main DTU identified was TcI (74.2%). TcIDom genotype was significantly more frequent in chronic phase compared to acute phase (82.1% vs 16.6%). The median parasitic load for TcIDom was significantly higher compared with TcI Sylvatic in chronic phase (2.58 vs.0.75 parasite equivalents/ml).

CONCLUSIONS/SIGNIFICANCE

The molecular tests are a precise tool to complement the standard diagnosis of Chagas disease, specifically in acute phase showing high discriminative power. However, it is necessary to improve the sensitivity of molecular tests in chronic phase. The frequency and parasitemia of TcIDom genotype in chronic patients highlight its possible relationship to the chronicity of the disease.

Host-directed therapies for infectious diseases: current status, recent progress, and future prospects

Despite extensive global efforts in the fight against killer infectious diseases, they still cause one in four deaths worldwide and are important causes of long-term functional disability arising from tissue damage. The continuing epidemics of tuberculosis, HIV, malaria, and influenza, and the emergence of novel zoonotic pathogens represent major clinical management challenges worldwide. Newer approaches to improving treatment outcomes are needed to reduce the high morbidity and mortality caused by infectious diseases. Recent insights into pathogen–host interactions, pathogenesis, inflammatory pathways, and the host's innate and acquired immune responses are leading to identification and development of a wide range of host-directed therapies with different mechanisms of action. Host-directed therapeutic strategies are now becoming viable adjuncts to standard antimicrobial treatment. Host-directed therapies include commonly used drugs for non-communicable diseases with good safety profiles, immunomodulatory agents, biologics (eg monoclonal antibodies), nutritional products, and cellular therapy using the patient's own immune or bone marrow mesenchymal stromal cells. We discuss clinically relevant examples of progress in identifying host-directed therapies as adjunct treatment options for bacterial, viral, and parasitic infectious diseases.

A local innate immune response against Trypanosoma cruzi in the human placenta: The epithelial turnover of the trophoblast

Congenital Chagas disease, caused by Trypanosoma cruzi, is partially responsible for the progressive globalization of Chagas disease despite of its low transmission rate. The probability of congenital transmission depends on complex interactions between the parasite, the maternal and fetus/newborn immune responses and placental factors, being the latter the least studied one. During transplacental transmission, the parasite must cross the placental barrier where the trophoblast, a continuous renewing epithelium, is the first tissue to have contact with the parasite. Importantly, the epithelial turnover is considered part of the innate immune system since pathogens, prior to cell invasion, must attach to the surface of cells. The trophoblast turnover involves cellular processes such as proliferation, differentiation and apoptotic cell death, all of them are induced by the parasite. In the present review, we analyze the current evidence about the trophoblast epithelial turnover as a local placental innate immune response.

Evaluation of VDR gene polymorphisms in Trypanosoma cruzi infection and chronic Chagasic cardiomyopathy

Vitamin D is an important modulator of the immune response. It acts over several immune cell types where the Vitamin D receptor (VDR) is expressed. Due to the high relevance of this signaling pathway, several studies have investigated the possible influence of genes involved in the metabolism of Vitamin D and its receptor in different human diseases. Here, we analyzed whether four single-nucleotide polymorphisms of the VDR gene (rs731236, rs7975232, rs1544410 and rs2228570) are involved in the susceptibility to infection by Trypanosoma cruzi and/or to chronic Chagas cardiomyopathy (CCC) in a Colombian endemic population for this parasite. Our results showed that the rs2228570*A allele is associated with CCC development (P = 4.46E-03, OR = 1.51). In summary, the data presented in this report suggest that variation within the VDR gene may affect the immune response against T. cruzi, increasing the probability of cardiac complications in infected individuals.

Pathology of Chronic Chagas Cardiomyopathy in the United States: A Detailed Review of 13 Cardiectomy Cases

OBJECTIVES

The pathologic features of chronic Chagas cardiomyopathy may not be widely appreciated in the United States. We sought to describe the gross, microscopic, immunohistochemical, and molecular pathology features useful to diagnose chronic Chagas cardiomyopathy.

METHODS

The features from a case series of cardiectomy specimens of patients undergoing heart transplantation (12 patients) or mechanical circulatory support device implantation (one patient) for chronic Chagas cardiomyopathy at three institutions in the United States are reported and analyzed.

RESULTS

Gross findings included enlarged and dilated ventricles (100% of cases), mural thrombi (54%), epicardial plaques (42%), and left ventricular aneurysm (36%). Microscopic evaluation revealed myocarditis (100% of cases) characterized by mononuclear cell infiltration, fibrosis (100%), nonnecrotizing granulomas (62%), and giant cells (38%). Two specimens (15%) showed rare intracellular amastigotes. Immunohistochemical assays for Trypanosoma cruzi organisms were negative in all cardiectomy specimens, whereas tissue polymerase chain reaction was positive in six (54%) of 11 cases.

CONCLUSIONS

The gross and microscopic features of chronic Chagas cardiomyopathy in the United States appear similar to those reported in endemic countries. Importantly, tissue polymerase chain reaction may be useful to confirm the diagnosis.

1,3,4-Thiadiazole derivatives of R-(+)-limonene benzaldehyde-thiosemicarbazones cause death in Trypanosoma cruzi through oxidative stress

This work evaluated the in vitro and in vivo activity of TDZ 2 on Trypanosoma cruzi amastigotes and determined the possible mechanism of action of this compound on T. cruzi death. TDZ 2 inhibited T. cruzi proliferation in vitro and had low haemolytic potential. It also induced morphological and ultrastructural alterations. We observed a reduction of cell volume, the depolarization of the mitochondrial membrane, an increase in ROS production, lipoperoxidation of the cell membrane, lipid bodies formation and production of nitric oxide, a decrease in reduced thiols levels and, presence of autophagic vacuoles. The in vivo study found a reduction of parasitemia in animals treated with TDZ 2 alone or combined with benznidazole. Altogether, the alterations induced by TDZ 2 point to an oxidative stress condition that lead to T. cruzi cell death.

Chagas Disease Screening in Maternal Donors of Publicly Banked Umbilical Cord Blood, United States

To assess patterns of Chagas disease, we reviewed results of screening umbilical cord blood from a US public cord blood bank during 2007–2014. Nineteen maternal donors tested positive for Trypanosoma cruzi parasites (0.04%). Because perinatal transmission of Chagas disease is associated with substantial illness, targeted prenatal programs should screen for this disease.