The paradox of survival results after heart transplantation for cardiomyopathy caused by Trypanosoma cruzi. First Guidelines Group for Heart Transplantation of the Brazilian Society of Cardiology

Chagas disease: an overview of clinical and epidemiological aspects

Chagas disease, caused by the parasite Trypanosoma cruzi, is a serious health problem in Latin America and is an emerging disease in non-endemic countries. In recent decades, the epidemiological profile of the disease has changed due to new patterns of immigration and successful control in its transmission, leading to the urbanization and globalization of the disease. Dilated cardiomyopathy is the most important and severe manifestation of human chronic Chagas disease and is characterized by heart failure, ventricular arrhythmias, heart blocks, thromboembolic phenomena, and sudden death. This article will present an overview of the clinical and epidemiological aspects of Chagas disease. It will focus on several clinical aspects of the disease, such as chronic Chagas disease without detectable cardiac pathology, as well as dysautonomia, some specific features, and the principles of treatment of chronic cardiomyopathy.

Parasitic infections in solid organ transplant recipients

Parasitic diseases are rare infections after a solid organ transplant (SOT). Toxoplasmosis, Trypanosoma cruzi, and visceral leishmanias are the 3 main opportunistic protozoal infections that have the potential to be lethal if not diagnosed early and treated appropriately after SOT. Strongyloides stercoralis is the one helminthic disease that is life-threatening after transplant. This review addresses modes of transmission, methods of diagnosis, and treatment of the most serious parasitic infections in SOT. The role of targeted pretransplant screening of the donor and recipient for parasitic diseases is also discussed.

Chagas disease in Latin American immigrants with dilated cardiomyopathy in New York City

Chagas disease-associated cardiomyopathy is clinically similar to other causes of cardiomyopathy and, therefore, the diagnosis can be easily overlooked. We found a 13% point prevalence of Chagas disease in a sample of New York City immigrants with dilated cardiomyopathy.

Chagas' cardiomyopathy: the economic burden of an expensive and neglected disease

BACKGROUND

Chagas' cardiomyopathy (CC) is a rising etiology for heart failure (HF) that previously was restricted to some countries of Latin America. The chronic CC cases cause now a profound socio-economic impact. However this issue has not been well studied if compared to other causes of HF. The objective of this study was to assess the cost burden of CC during acute decompensated HF admissions (ADHF), and compare this cost to the other etiologies of HF.

METHODS AND RESULTS

By the end of 2006 we started a five year follow-up of 577 consecutive adult patients admitted at a high complexity cardiology university hospital in the city of Sao Paulo, Brazil. This study shows the data of the first admission of each patient of this follow-up. Patients were divided in two groups: CC (58 patients) and non-chagasic (NC) (519 patients). Mortality was different among groups, 19/58 (32.8%) in CC vs 113/519 (21.8%) in NC (p=0.046). The prevalence of signs of inadequate perfusion was higher in the CC group at admission, but in a multivariated analysis chagasic etiology and presence of diabetes were independent predictors of higher costs per day of hospitalization adjusted by mortality. Median costs per day were US$ 308 (277-542) vs US$ 467 (323-815) for NC and CC respectively (p<0.001).

CONCLUSION

Treating ADHF patients with CC etiology was more expensive and mortality was higher in this population at the first admission of this follow-up. This could be explained by the severity of Chagas' cardiomyopathy disease.

Chagas disease in non-endemic countries: epidemiology, clinical presentation and treatment

Imported Chagas disease (Trypanosoma cruzi infection) is increasingly recognized as an emerging problem in the USA and Europe due to immigration from Latin America. Most migrants from endemic countries will have been infected during childhood. Based on the natural history of the disease, up to 35 % of those infected may develop cardiac and/or gastrointestinal manifestations during the third or fourth decade of life. This disease was described more than 100 years ago, yet many challenges still remain such as the identification of risk factors for visceral involvement, effective treatment for chronic cases, and reliable markers of cure following treatment. Transmission of the infection may occur even in non-endemic areas through non-vectorial routes and many countries are therefore currently facing the challenge of this emerging public health problem.

American trypanosomiasis (Chagas disease)

Chagas disease, also known as American trypanosomiasis, is a chronic infection caused by Trypanosoma cruzi, a protozoan parasite. It is transmitted to human beings mainly through the feces of infected triatomine bugs. The disease affects an estimated 8 to 10 million people in the Americas, putting them at risk of developing life-threatening cardiac and gastrointestinal complications. This article provides a brief update on the epidemiology, clinical manifestations, diagnosis, and treatment of Chagas disease.

Diagnosis and management of Chagas disease and cardiomyopathy

Chagas cardiomyopathy is the most severe and life-threatening manifestation of human Chagas disease--a 'neglected' tropical disease caused by the protozoan parasite Trypanosoma cruzi. The disease is endemic in all continental Latin American countries, but has become a worldwide problem because of migration of infected individuals to developed countries, mainly in Europe and North America. Chagas cardiomyopathy results from the combined effects of persistent parasitism, parasite-driven tissue inflammation, microvascular and neurogenic dysfunction, and autoimmune responses triggered by the infection. Clinical presentation varies widely according to the extent of myocardial damage, and manifests mainly as three basic syndromes that can coexist in an individual patient: heart failure, cardiac arrhythmia, and thromboembolism. NYHA functional class, left ventricular systolic function, and nonsustained ventricular tachycardia are important prognostic markers of the risk of death. Management of Chagas cardiomyopathy focuses on the treatment of the three main syndromes. The use of β-blockers in patients with Chagas disease and heart failure is safe, well tolerated, and should be encouraged. Most specialists and international institutions now recommend specific antitrypanosomal treatment of patients with chronic Chagas disease, even in the absence of evidence obtained from randomized clinical trials. Further research on the management of patients with Chagas cardiomyopathy is necessary.

Sensitive and specific detection of Trypanosoma cruzi DNA in clinical specimens using a multi-target real-time PCR approach

Background

The laboratory diagnosis of Chagas disease is challenging because the usefulness of different diagnostic tests will depend on the stage of the disease. Serology is the preferred method for patients in the chronic phase, whereas PCR can be successfully used to diagnose acute and congenital cases. Here we present data using a combination of three TaqMan PCR assays to detect T. cruzi DNA in clinical specimens.

Methods/Principal Findings

Included in the analysis were DNA extracted from 320 EDTA blood specimens, 18 heart tissue specimens, 6 umbilical cord blood specimens, 2 skin tissue specimens and 3 CSF specimens. For the blood specimens both whole blood and buffy coat fraction were analyzed. The specimens were from patients living in the USA, with suspected exposure to T. cruzi through organ transplantation, contact with triatomine bugs or laboratory accidents, and from immunosuppressed patients with suspected Chagas disease reactivation. Real-time PCR was successfully used to diagnose acute and Chagas disease reactivation in 20 patients, including one case of organ-transmitted infection and one congenital case. Analysis of buffy coat fractions of EDTA blood led to faster diagnosis in six of these patients compared to whole blood analysis. The three real-time PCR assays produced identical results for 94% of the specimens. The major reason for discrepant results was variable sensitivity among the assays, but two of the real-time PCR assays also produced four false positive results.

Conclusions/Significance

These data strongly indicate that at least two PCR assays with different performances should be combined to increase the accuracy. This evaluation also highlights the benefit of extracting DNA from the blood specimen's buffy coat to increase the sensitivity of PCR analysis.

Chagas disease is endemic in several Latin American countries and affects approximately 8 to 11 million people. The protozoan parasite, Trypanosoma cruzi, is the agent of Chagas disease, a zoonotic disease that can be transmitted to humans by blood-sucking triatomine bugs. Other routes of infection include congenital transmission, blood transfusion, organ transplantation, accidental inoculation of the parasite during laboratory research and by consuming food and juice contaminated with the parasite. This study focused on the evaluation of three quantitative PCR (QPCR) assays for the diagnosis of Chagas disease. The evaluation was based on the analysis of 349 specimens submitted for confirmatory diagnosis of Chagas disease to the Centers for Disease Control and Prevention from 2008 to 2010. By using such assays we were able to diagnose acute and Chagas disease reactivation in 20 patients, including one case of organ-transmitted infection and one congenital case. The paper also highlights the benefit of extracting DNA from the blood specimen's buffy coat to increase the sensitivity of diagnostic PCR analysis. The results obtained in this study strongly indicate that at least two QPCR assays with different performance characteristics should be combined to increase diagnostic accuracy.

Transplant-associated and blood transfusion-associated tropical and parasitic infections

Blood transfusion and transplantation may represent efficient mechanisms of spreading infectious agents to naive populations. In the developed countries, as a consequence of globalization, several factors such as international commerce, tourism, and immigration have acted as important features for the emergence or reemergence of infectious diseases previously referred to as tropical. This article reviews the relevant bacterial, protozoan and viral infections that are more frequently associated with blood transfusion and/or solid organ or marrow transplantation and may affect susceptible populations worldwide.

Chagas heart disease: report on recent developments

Chagas disease, caused by the parasite Trypanosoma cruzi, is an important cause of cardiac disease in endemic areas of Latin America. It is now being diagnosed in nonendemic areas because of immigration. Typical cardiac manifestations of Chagas disease include dilated cardiomyopathy, congestive heart failure, arrhythmias, cardioembolism, and stroke. Clinical and laboratory-based research to define the pathology resulting from T. cruzi infection has shed light on many of the cellular and molecular mechanisms leading to these manifestations. Antiparasitic treatment may not be appropriate for patients with advanced cardiac disease. Clinical management of Chagas heart disease is similar to that used for cardiomyopathies caused by other processes. Cardiac transplantation has been successfully performed in a small number of patients with Chagas heart disease.

Safety of liver transplantation with Chagas disease-seropositive donors for seronegative recipients

The shortage of organs for transplantation has prompted the investigation of extended criteria donors, such as donors with transmissible infectious diseases. Here we report our recent experience with liver transplantation using organs from donors who were serologically positive for Chagas disease. We also provide a review of the literature and emphasize donor screening and preventive measures.

Trypanosoma cruzi and Chagas' Disease in the United States

Chagas' disease is caused by the protozoan parasite Trypanosoma cruzi and causes potentially life-threatening disease of the heart and gastrointestinal tract. The southern half of the United States contains enzootic cycles of T. cruzi, involving 11 recognized triatomine vector species. The greatest vector diversity and density occur in the western United States, where woodrats are the most common reservoir; other rodents, raccoons, skunks, and coyotes are also infected with T. cruzi. In the eastern United States, the prevalence of T. cruzi is highest in raccoons, opossums, armadillos, and skunks. A total of 7 autochthonous vector-borne human infections have been reported in Texas, California, Tennessee, and Louisiana; many others are thought to go unrecognized. Nevertheless, most T. cruzi-infected individuals in the United States are immigrants from areas of endemicity in Latin America. Seven transfusion-associated and 6 organ donor-derived T. cruzi infections have been documented in the United States and Canada. As improved control of vector- and blood-borne T. cruzi transmission decreases the burden in countries where the disease is historically endemic and imported Chagas' disease is increasingly recognized outside Latin America, the United States can play an important role in addressing the altered epidemiology of Chagas' disease in the 21st century.

Selective decrease of components of the creatine kinase system and ATP synthase complex in chronic Chagas disease cardiomyopathy

Background

Chronic Chagas disease cardiomyopathy (CCC) is an inflammatory dilated cardiomyopathy with a worse prognosis than other cardiomyopathies. CCC occurs in 30 % of individuals infected with Trypanosoma cruzi, endemic in Latin America. Heart failure is associated with impaired energy metabolism, which may be correlated to contractile dysfunction. We thus analyzed the myocardial gene and protein expression, as well as activity, of key mitochondrial enzymes related to ATP production, in myocardial samples of end-stage CCC, idiopathic dilated (IDC) and ischemic (IC) cardiomyopathies.

Methodology/Principal Findings

Myocardium homogenates from CCC (N = 5), IC (N = 5) and IDC (N = 5) patients, as well as from heart donors (N = 5) were analyzed for protein and mRNA expression of mitochondrial creatine kinase (CKMit) and muscular creatine kinase (CKM) and ATP synthase subunits aplha and beta by immunoblotting and by real-time RT-PCR. Total myocardial CK activity was also assessed. Protein levels of CKM and CK activity were reduced in all three cardiomyopathy groups. However, total CK activity, as well as ATP synthase alpha chain protein levels, were significantly lower in CCC samples than IC and IDC samples. CCC myocardium displayed selective reduction of protein levels and activity of enzymes crucial for maintaining cytoplasmic ATP levels.

Conclusions/Significance

The selective impairment of the CK system may be associated to the loss of inotropic reserve observed in CCC. Reduction of ATP synthase alpha levels is consistent with a decrease in myocardial ATP generation through oxidative phosphorylation. Together, these results suggest that the energetic deficit is more intense in the myocardium of CCC patients than in the other tested dilated cardiomyopathies.

Chronic Chagas disease cardiomyopathy (CCC) affects millions in endemic areas and is presenting in growing numbers in the USA and European countries due to migration currents. Clinical progression, length of survival and overall prognosis are significantly worse in CCC patients when compared to patients with dilated cardiomyopathy of non-inflammatory etiology. Impairment of energy metabolism seems to play a role in heart failure due to cardiomyopathies. Herein, we have analyzed energy metabolism enzymes in myocardium samples of CCC patients comparing to other non-inflammatory cardiomyopathies. We found that myocardial tissue from CCC patients displays a significant reduction of both myocardial protein levels of ATP synthase alpha and creatine kinase enzyme activity, in comparison to control heart samples, as well as idiopathic dilated cardiomyopathy and ischemic cardiomyopathy. Our results suggest that CCC myocardium displays a selective energetic deficit, which may play a role in the reduced heart function observed in such patients.

Heart transplantation in 107 cases of Chagas' disease

INTRODUCTION

Chagas' disease is endemic in South America.

OBJECTIVE

This research reviewed the experience with cardiac transplantation in Chagas' disease, emphasizing reactivation, immunosuppression, and mortality.

METHODS

Over 25 years from March 1985 to March 2010, 107/409 (26.2%) patients with Chagas' disease underwent heart transplantation, patients including 74 (71.1%) men and 72 (67.2%), in functional class IV with 33 (30.8%) on vasopressors and 17 (10.7%) on mechanical circulatory support.

RESULTS

The diagnosis of disease reactivation was performed by identifying the parasite in the myocardium (n = 23; 71.8%) in the subcutaneous tissue (n = 8; 25.0%), in blood (n = 11; 34.3%), or in central nervous tissue (n = 1; 3.1%). Hospital mortality was 17.7% (n = 19) due to infection (n = 6; 31.5%), graft dysfunction (n = 6; 31.5%), rejection (n = 4; 21.1%), or sudden death (n = 2; 10.5%). Late mortality was 27 (25.2%) cases, which were distributed as: rejection (n = 6; 22.2%), infection (n = 6; 22.2%), (n = lymphoma 4; 14.8%), sarcoma (n = 2; 7.4%), for constrictive pericarditis (n = 2; 7.4%) reactivation of Chagas' disease in the central nervous system (n = 1; 7.1%).

CONCLUSIONS

Transplantation in Chagas' disease has peculiar problems that differ from other etiologies due to the possibility of disease reactivation and the increased possibility of emergence of cancers. However, transplantation is the only treatment able to modify the natural progression of the disease in its terminal phase. Early diagnosis and rapid introduction of benzonidazole reverses the histological patterns. Immunosuppression, especially steroids, predisposes to the development of cancer and disease reactivation.

Cell-based therapy in Chagas disease

Chagas disease was first described one century ago, yet the mechanisms underlying chagasic cardiomyopathy remain elusive. Disease progression often leads to heart failure and patients with this infectious cardiomyopathy have a poor prognosis. Treatment options for heart failure due to Chagas disease are not different from standard therapy. Over the past decade, cell-based therapies have emerged as a new alternative in the treatment of this disease, not only because of the possibility of replacing lost vessels and cardiomyocytes but also because these cells could potentially influence the microenvironmental changes that perpetuate the disease. In this chapter, we will review current knowledge on cell-based therapies for the treatment of Chagas disease.

Autoimmunity

The scarcity of Trypanosoma cruzi in inflammatory lesions of chronic Chagas disease led early investigators to suggest that tissue damage had an autoimmune nature. In spite of parasite persistence in chronic Chagas disease, several reports indicate that inflammatory tissue damage may not be correlated to the local presence of T. cruzi. A significant number of reports have described autoantibodies and self-reactive T cells, often cross-reactive with T. cruzi antigens, both in patients and in animal models. Evidence for a direct pathogenetic role of autoimmunity was suggested by the development of lesions after immunization with T. cruzi antigens or passive transfer of lymphocytes from infected animals, and the amelioration of chronic myocarditis in animals made tolerant to myocardial antigens. Autoimmune and T. cruzi-specific innate or adaptative responses are not incompatible or mutually exclusive, and it is likely that a combination of both is involved in the pathogenesis of chronic Chagas disease cardiomyopathy. The association between persistent infection and autoimmune diseases-such as multiple sclerosis or diabetes mellitus-suggests that post-infectious autoimmunity may be a frequent finding. Here, we critically review evidence for autoimmune phenomena and their possible pathogenetic role in human Chagas disease and animal models, with a focus on chronic Chagas disease cardiomyopathy.

Current and emerging therapeutic options for the treatment of chronic chagasic cardiomyopathy

Chagas’ disease is an endemic disease in Latin America caused by a unicellular parasite (Trypanosoma cruzi) that affects almost 18 million people. This condition involves the heart, causing heart failure, arrhythmias, heart block, thromboembolism, stroke, and sudden death. In this article, we review the current and emerging treatment of Chagas’ cardiomyopathy focusing mostly on management of heart failure and arrhythmias. Heart failure therapeutical options including drugs, stem cells and heart transplantation are revised. Antiarrhythmic drugs, catheter ablation, and intracardiac devices are discussed as well. Finally, the evidence for a potential role of specific antiparasitic treatment for the prevention of cardiovascular disease is reviewed.

Cardiac involvement with parasitic infections

Parasitic infections previously seen only in developing tropical settings can be currently diagnosed worldwide due to travel and population migration. Some parasites may directly or indirectly affect various anatomical structures of the heart, with infections manifested as myocarditis, pericarditis, pancarditis, or pulmonary hypertension. Thus, it has become quite relevant for clinicians in developed settings to consider parasitic infections in the differential diagnosis of myocardial and pericardial disease anywhere around the globe. Chagas' disease is by far the most important parasitic infection of the heart and one that it is currently considered a global parasitic infection due to the growing migration of populations from areas where these infections are highly endemic to settings where they are not endemic. Current advances in the treatment of African trypanosomiasis offer hope to prevent not only the neurological complications but also the frequently identified cardiac manifestations of this life-threatening parasitic infection. The lack of effective vaccines, optimal chemoprophylaxis, or evidence-based pharmacological therapies to control many of the parasitic diseases of the heart, in particular Chagas' disease, makes this disease one of the most important public health challenges of our time.

Image-based high-throughput drug screening targeting the intracellular stage of Trypanosoma cruzi, the agent of Chagas' disease

Chagas' disease, caused by infection with the parasite Trypanosoma cruzi, is the major cause of heart failure in Latin America. Classic clinical manifestations result from the infection of heart muscle cells leading to progressive cardiomyopathy. To ameliorate disease, chemotherapy must eradicate the parasite. Current drugs are ineffective and toxic, and new therapy is a critical need. To expedite drug screening for this neglected disease, we have developed and validated a cell-based, high-throughput assay that can be used with a variety of untransfected T. cruzi isolates and host cells and that simultaneously measures efficacy against the intracellular amastigote stage and toxicity to host cells. T. cruzi-infected muscle cells were incubated in 96-well plates with test compounds. Assay plates were automatically imaged and analyzed based on size differences between the DAPI (4',6-diamidino-2-phenylindole)-stained host cell nuclei and parasite kinetoplasts. A reduction in the ratio of T. cruzi per host cell provided a quantitative measure of parasite growth inhibition, while a decrease in count of the host nuclei indicated compound toxicity. The assay was used to screen a library of clinically approved drugs and identified 55 compounds with activity against T. cruzi. The flexible assay design allows the use of various parasite strains, including clinical isolates with different biological characteristics (e.g., tissue tropism and drug sensitivity), and a broad range of host cells and may even be adapted to screen for inhibitors against other intracellular pathogens. This high-throughput assay will have an important impact in antiparasitic drug discovery.

Chagas disease

Chagas disease is a chronic, systemic, parasitic infection caused by the protozoan Trypanosoma cruzi, and was discovered in 1909. The disease affects about 8 million people in Latin America, of whom 30-40% either have or will develop cardiomyopathy, digestive megasyndromes, or both. In the past three decades, the control and management of Chagas disease has undergone several improvements. Large-scale vector control programmes and screening of blood donors have reduced disease incidence and prevalence. Although more effective trypanocidal drugs are needed, treatment with benznidazole (or nifurtimox) is reasonably safe and effective, and is now recommended for a widened range of patients. Improved models for risk stratification are available, and certain guided treatments could halt or reverse disease progression. By contrast, some challenges remain: Chagas disease is becoming an emerging health problem in non-endemic areas because of growing population movements; early detection and treatment of asymptomatic individuals are underused; and the potential benefits of novel therapies (eg, implantable cardioverter defibrillators) need assessment in prospective randomised trials.

Chagas cardiomyopathy--where do we stand after a hundred years?

A hundred years from its description, Chagas cardiomyopathy remains a challenging disease. Although successful vector-control strategies have decreased the incidence of Chagas disease in several Latin American countries, both migration to urban areas and immigration have spread the disease worldwide; and now, blood transfusion, organ transplantation, and vertical transmission are a concern. The pathogenesis of Chagas cardiomyopathy involves complex host-parasite interactions, where low-grade but incessant systemic infection and triggered autoimmune reaction are the main mechanisms for its development, with the contribution of autonomic damage and microvascular disturbances. Chagas cardiomyopathy is the most important clinical presentation of Chagas disease and comprises a wide range of manifestations, including heart failure, arrhythmias, heart blocks, sudden death, thromboembolism, and stroke. Recently, simple clinical prognostic scores have been developed to identify high-risk patients and help with management. The treatment of Chagas cardiomyopathy focuses mostly on managing heart failure, arrhythmias, and thromboembolism. The role of specific antiparasitic therapy in the chronic form is not yet defined, and a randomized trial is now under way to address this crucial point. In this article, we review the main clinical aspects of Chagas cardiomyopathy and underscore some upcoming challenges for the appropriate control, diagnosis, and management of this complex disease.

Epidemiology of neglected tropical diseases in transplant recipients: review of the literature and experience of a Brazilian HSCT center

The rising success rate of solid organ (SOT) and haematopoietic stem cell transplantation (HSCT) and modern immunosuppression make transplants the first therapeutic option for many diseases affecting a considerable number of people worldwide. Consequently, developing countries have also grown their transplant programs and have started to face the impact of neglected tropical diseases (NTDs) in transplant recipients. We reviewed the literature data on the epidemiology of NTDs with greatest disease burden, which have affected transplant recipients in developing countries or may represent a threat to transplant recipients living in other regions. Tuberculosis, Leprosy, Chagas disease, Malaria, Leishmaniasis, Dengue, Yellow fever and Measles are the topics included in this review. In addition, we retrospectively revised the experience concerning the management of NTDs at the HSCT program of Amaral Carvalho Foundation, a public transplant program of the state of São Paulo, Brazil.

[Heart transplantation: the experience of patients with Chagas disease]

Successful heart transplantation in patients with Chagas disease depends on special care to be provided during all phases of the transplantation process, and requires specific and rigorous follow-up by the health care team. Recipients must be aware of the permanence of the trypanosome in their organisms as well as of the possibility of infection reactivation after transplantation. Therefore, the patient's knowledge regarding this condition and his active participation in his own treatment are of utmost importance. This study aimed at investigating heart transplantation as experienced by patients with Chagas disease, seeking to understand the meanings that they attribute to such an experience. The methodological procedures included: patient selection; interviews; data analysis, indication of the meaning units and individual analysis; search for discourse convergence; and hermeneutic analysis of convergences. From the data analysis, the following themes emerged: the time lived by recipients with Chagas Disease; the conception of heart transplantation presented by patients with Chagas Disease; and care in the course of heart transplantation.

Transplantation and tropical infectious diseases

The number of transplant recipients with tropical infectious diseases is growing due to increasing international travel and the rising number of transplants taking place in the tropics and subtropics. With increases in population migration, the prevalence of individuals infected with geographically restricted organisms also rises. There are three potential categories of tropical infections in transplant patients: (1) donor-related infections transmitted by the graft or through transfusion of blood products; (2) reactivation or recrudescence of latent infections in the donor recipient; and (3) de novo acquisition of infection in the post-transplant period through the traditional route of infection. We present an overall discussion of the association of parasitic (protozoa and helminths) and non-parasitic (viral, bacterial, and fungal) tropical infectious diseases and solid-organ and hematopoietic transplantation. We also suggest potential screening guidelines for some of these tropical infections.

Induction of cardiac autoimmunity in Chagas heart disease: A case for molecular mimicry

Up to 18 million of individuals are infected by the protozoan parasite Trypanosoma cruzi in Latin America, one third of whom will develop chronic Chagas disease cardiomyopathy (CCC) up to 30 years after infection. Cardiomyocyte destruction is associated with a T cell-rich inflammatory infiltrate and fibrosis. The presence of such lesions in the relative scarcity of parasites in the heart, suggested that CCC might be due, in part, to a postinfectious autoimmune process. Over the last two decades, a significant amount of reports of autoimmune and molecular mimicry phenomena have been described in CCC. The authors will review the evidence in support of an autoimmune basis for CCC pathogenesis in humans and experimental animals, with a special emphasis on molecular mimicry as a fundamental mechanism of autoimmunity.

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Chagas disease which is caused by the parasite Trypanosoma cruzi is an important cause of cardiomyopathy in Latin America. In later stages chagasic cardiomyopathy is associated with congestive heart failure which is often refractory to medical therapy. In these individuals heart transplantation has been attempted. However, this procedure is fraught with many problems attributable to the surgery and the postsurgical administration of immunosuppressive drugs. Studies in mice suggest that the transplantation of bone-marrow-derived cells ameliorates the inflammation and fibrosis in the heart associated with this infection. Cardiac magnetic resonance imaging reveals that bone marrow transplantation ameliorates the infection induced right ventricular enlargement. On the basis of these animal studies the safety of autologous bone marrow transplantation has been assessed in patients with chagasic end-stage heart disease. The initial results are encouraging and more studies need to be performed.

Treatment of chronic systolic heart failure secondary to Chagas heart disease in the current era of heart failure therapy

The treatment of chronic heart failure secondary to Chagas disease has been based on extrapolation of data achieved in the treatment of non-Chagas disease heart failure. Because beta-blockers decrease the incidence of sudden cardiac death in non-Chagas disease heart failure and sudden cardiac death occurs preferentially in patients with mild Chagas disease heart failure, beta-blockers may be administered first to class I/II patients with Chagas disease heart failure. In advanced Chagas disease heart failure, angiotensin-converting enzyme inhibitor and diuretics may be given at first to compensate for congestive symptoms. After clinical status improvement, beta-blockers should be given at targeted doses, if necessary reducing angiotensin-converting enzyme inhibitor doses. Primary and secondary prevention of sudden cardiac death may be accomplished with implantable cardioverter defibrillators because of the high recurrence of life-threatening arrhythmias despite amiodarone administration. In refractory heart failure, heart transplantation is the treatment of choice.

Transmission of tropical and geographically restricted infections during solid-organ transplantation

In recent years, the increasing number of donors from different regions of the world is providing a new challenge for the management and selection of suitable donors. This is a worldwide problem in most countries with transplantation programs, especially due to the increase in immigration and international travel. This paper elaborates recommendations regarding the selection criteria for donors from foreign countries who could potentially transmit tropical or geographically restricted infections to solid-organ transplant recipients. For this purpose, an extensive review of the medical literature focusing on viral, fungal, and parasitic infections that could be transmitted during transplantation from donors who have lived or traveled in countries where these infections are endemic has been performed, with special emphasis on tropical and imported infections. The review also includes cases described in the literature as well as risks of transmission during transplantation, microbiological tests available, and recommendations for each infection. A table listing different infectious agents with their geographic distributions and specific recommendations is included.

An update on the management of Chagas cardiomyopathy

Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, infects nearly 18 million people in Latin America and mainly affects the heart, causing heart failure, arrhythmias, heart block, thromboembolism, stroke and death. In this review, the clinical diagnosis and management of Chagas cardiomyopathy are discussed. Particular emphasis is placed on the clinical staging of patients and the use of various diagnostic tests that may be useful in individualizing treatment of the two most relevant clinical syndromes, that is, heart failure and arrhythmias. The relevance of specific treatments are discussed, stressing the important role of parasite persistence in disease pathogenesis. We also discuss new therapy modalities that may have a role in the treatment of Chagas cardiomyopathy.