Stroke: a neglected complication of American trypanosomiasis (Chagas’ disease)

Predictors of ischemic stroke in Chagas disease: Insights into mechanisms beyond cardiomyopathy severity

BACKGROUND

Chagas disease is a risk factor for ischemic stroke, which causes high mortality rates and significant disability. This study aims to determine the incidence and risk factors for ischemic strokes in a large cohort of Chagas cardiomyopathy patients, with a particular focus on the mechanisms involved in the pathophysiology of stroke in this condition.

METHODS

The study enrolled 517 patients with Chagas cardiomyopathy who were referred to our institution from March 2000 to December 2021. All patients underwent systematic cardiological and neurological assessments. The primary outcome was the occurrence of ischemic stroke during the follow-up period, classified based on the SSS-TOAST and CCS criteria. Natural cubic splines functions were applied to examine the potential nonlinear association between continuous variables and stroke risk.

RESULTS

The mean age of the cohort was 52 ± 13 years, and 299 (58 %) were men. During a mean follow-up period of 4.8 years (interquartile range-IQR 1.1 to 7.1 years), a total of 72 patients (14.8 %) had an ischemic stroke, being fatal in 10. The overall incidence rate of ischemic stroke was 3.0/100 patient-years (95 % confidence interval 2.4 to 3.8). The stroke subtypes were cardioembolic (n = 41), undetermined (n = 11), and other subtypes (n = 20). The predictors of stroke were age, left atrial volume, left ventricular ejection fraction (LVEF), LV thrombus and prior stroke with thrombus. There was a nonlinear relationship between stroke risk, LVEF, and left atrial volume. A bimodal distribution of stroke occurrences was observed according to the severity of LV dysfunction, with a threshold for LVEF of 45 %. The final model for stroke risk prediction showed good discrimination, with a C statistic of 0.775.

CONCLUSIONS

In a contemporary cohort of Chagas disease patients with a broad spectrum of disease severity, stroke incidence remains high despite anticoagulation. Stroke risk shows a nonlinear association with ventricular dysfunction and left atrial size, highlighting a distinct bimodal pattern of stroke occurrence in Chagas disease.

Cardioembolic stroke in Chagas disease: unraveling the underexplored connection through a systematic review

BACKGROUND

Chagas disease (CD), triggered by the Trypanosoma cruzi parasite, is originally endemic across Latin America, affecting millions. While cardiac complications are widely recognized, the association between CD and stroke remains underexplored. This systematic review aims to elucidate the relationship between CD and stroke, highlighting the cardioembolic origins of stroke in CD patients and assessing the elevated stroke risk compared to non-infected individuals.

METHODOLOGY

Adhering to the PRISMA guidelines, we conducted a comprehensive search in PubMed and Scopus databases without date restrictions, including articles in both Spanish and English. This approach enabled the identification and analysis of relevant studies to understand the interplay between CD and stroke risk.

RESULTS

Our analysis of 25 selected studies indicates that strokes in CD patients predominantly arise from cardioembolic sources. The data underscore a significant increase in stroke risk among individuals infected with T. cruzi compared to uninfected counterparts. Additionally, CD patients face a higher stroke and mortality risk than those with other heart failure etiologies, irrespective of disease severity.

CONCLUSION

The review establishes CD as a critical contributor to stroke incidence, emphasizing the need for heightened awareness and diagnosis of CD in stroke patients, particularly in regions with high CD prevalence. Recognizing the increased stroke risk associated with T. cruzi infection is crucial for developing targeted educational and preventive strategies in endemic areas.

Prognosis of chronic Chagas heart disease and other pending clinical challenges

In this chapter, the main prognostic markers of Chagas heart disease are addressed, with an emphasis on the most recent findings and questions, establishing the basis for a broad discussion of recommendations and new approaches to managing Chagas cardiopathy. The main biological and genetic markers and the contribution of the electrocardiogram, echocardiogram and cardiac magnetic resonance are presented. We also discuss the most recent therapeutic proposals for heart failure, thromboembolism and arrhythmias, as well as current experience in heart transplantation in patients suffering from severe Chagas cardiomyopathy. The clinical and epidemiological challenges introduced by acute Chagas disease due to oral contamination are discussed. In addition, we highlight the importance of ageing and comorbidities in influencing the outcome of chronic Chagas heart disease. Finally, we discuss the importance of public policies, the vital role of funding agencies, universities, the scientific community and health professionals, and the application of new technologies in finding solutions for better management of Chagas heart disease.

Infectious Causes of Stroke

Stroke is one of the primary causes of mortality and morbidity worldwide. It can be ischemic or hemorrhagic, and the former can be due to an in-situ thrombus or a distant embolus. Despite being a rare cause, stroke can also be caused in the setting of infection. Bacterial agents are the most common cause of stroke, among other infectious agents. Until the antibiotic era, rheumatic heart disease was a predisposing risk factor of infective endocarditis. VZV is the most common cause of strokes in pediatric and adult populations. Cryptococcus and Candida spp are the most common yeasts involved in CNS infections, especially in immunocompromised patients. In COVID-19 patients, ischemic strokes are more common than hemorrhagic strokes. In this review, we will discuss the most common infectious agents, with particular emphasis on COVID-19.

Stroke in Chagas disease: from pathophysiology to clinical practice

Despite substantial progress toward its control, Chagas disease continues to be a major public health problem in Latin America and has become a global health concern. The disease affects approximately 6 million people, of whom 20-40% will develop cardiomyopathy over the years after the initial Trypanosoma cruzi infection. Chagas cardiomyopathy is the most serious and frequent manifestation of Chagas disease. Clinical manifestations vary widely according to the severity of myocardial dysfunction, ranging from asymptomatic to severe forms, including dilated cardiomyopathy with heart failure, arrhythmias, thromboembolism events, and sudden death. Chagas disease is a risk factor for stroke regardless of the severity of cardiomyopathy, which is a leading cause of chronic disability. Classically, stroke etiology in patients with Chagas disease is thought to be cardioembolic and related to apical aneurysm, mural thrombus, and atrial arrhythmias. Although most strokes are thromboembolic, other etiologies have been observed. Small vessel disease, atherosclerosis, and cryptogenic diseases have been reported in patients with Chagas disease and stroke. The potential mechanisms involved in non-embolic strokes include the presence of associated risk factors, pro-inflammatory and prothrombotic disease states, and endothelial dysfunction. However, the contribution of each mechanism to stroke in Chagas disease remains unclear. The review aims to provide an overview of stroke in Chagas disease, highlighting the main pathophysiological mechanisms, clinical presentation, approaches for prevention, and unanswered questions regarding treatment strategies.

Vector-borne protozoal infections of the CNS: cerebral malaria, sleeping sickness and Chagas disease

PURPOSE OF REVIEW

Malaria, Chagas Disease and Human African Trypanosomiasis are vector-borne protozoan illnesses, frequently associated with neurological manifestations. Intriguing but ignored, limited mainly to resource-limited, tropical settings, these disorders are now coming to light because of globalisation and improved diagnosis and treatment. Enhanced understanding of these illnesses has prompted this review.

RECENT FINDINGS

Methods of diagnosis have currently transitioned from blood smear examinations to immunological assays and molecular methods. Tools to assess neurological involvement, such as magnetic resonance imaging, are now increasingly available in regions and countries with high infection loads. Sleep and other electrophysiological technologies (electroencephalography, actigraphy) are also promising diagnostic tools but requiring field-validation. Access to treatments was formerly limited, even as limitations of agents used in the treatment are increasingly recognised. Newer agents are now being developed and trialled, encouraged by improved understanding of the disorders' molecular underpinnings.

SUMMARY

Prompt diagnosis and treatment are crucial in ensuring cure from the infections. Attention should also be due to the development of globally applicable treatment guidelines, the burden of neurological sequelae and elimination of the zoonoses from currently endemic regions.

Biomarkers assessment in patients with Chagas disease and systemic arterial hypertension

Chagas disease (ChD) and systemic arterial hypertension (SAH) are two severe comorbidities that lead to mortality and a reduction in people's quality of life, with an impact on public health. The aim of this study was to quantify the biomarkers of cardiac injury in patients with ChD and SAH. Eighty patients were divided into four groups: 20 hypertensive patients, 20 ChD-hypertensive patients, 20 ChD patients, and 20 normotensive volunteers; all of them came from outpatient's public health services. Among the evaluated markers for cardiac lesions (creatine kinase, creatine kinase-MB isoform, myoglobin, high-sensitive cardiac troponin T[hs-cTnT], B-type natriuretic peptide [BNP], and C-reactive protein), hs-cTnT and BNP were the most appropriate. Importantly, our results showed that the cut off point for hs-cTnT could be < 0.007 ng/mL, which could lead to the early detection of myocardial lesions. The BNP and hs-cTnT levels were high only in the ChD and ChD-hypertensive patient groups, suggesting that Chagas' disease may play an important role in the increase of these biomarkers. ChD patients, hypertensive or not, with cardiac or cardiodigestive involvement presented significantly higher values of hs-cTnT (p < 0.001) and BNP (p = 0.001) than ChD patients with indeterminate and digestive forms, which strengthens the validation of these markers for the follow-up of clinical cardiac form of ChD. This study suggests that the BNP and hs-cTnT can be used as possible indirect biomarkers of cardiac damage. In addition, the reference values of these biomarkers in Chagas and hypertensive cardiomyopathies should be better understood with further studies.

Chagas Cardiomyopathy: An Update of Current Clinical Knowledge and Management: A Scientific Statement From the American Heart Association

Background:

Chagas disease, resulting from the protozoan Trypanosoma cruzi , is an important cause of heart failure, stroke, arrhythmia, and sudden death. Traditionally regarded as a tropical disease found only in Central America and South America, Chagas disease now affects at least 300 000 residents of the United States and is growing in prevalence in other traditionally nonendemic areas. Healthcare providers and health systems outside of Latin America need to be equipped to recognize, diagnose, and treat Chagas disease and to prevent further disease transmission.

Methods and Results:

The American Heart Association and the Inter-American Society of Cardiology commissioned this statement to increase global awareness among providers who may encounter patients with Chagas disease outside of traditionally endemic environments. In this document, we summarize the most updated information on diagnosis, screening, and treatment of T cruzi infection, focusing primarily on its cardiovascular aspects. This document also provides quick reference tables, highlighting salient considerations for a patient with suspected or confirmed Chagas disease.

Conclusions:

This statement provides a broad summary of current knowledge and practice in the diagnosis and management of Chagas cardiomyopathy. It is our intent that this document will serve to increase the recognition of Chagas cardiomyopathy in low-prevalence areas and to improve care for patients with Chagas heart disease around the world.

Prevalence and risk factors of embolic cerebrovascular events associated with Chagas heart disease

BACKGROUND

Patients with Chagas disease are at increased risk for stroke that may result in major clinical disability and death. Identification of risk factors involved in the genesis of thromboembolic events related to this disease may lead to improved therapeutic decision making and outcomes.

OBJECTIVES

This study sought to assess the prevalence of ischemic cerebrovascular events (ICE) among patients with Chagas heart disease and to identify the risk factors associated with cardioembolism in this population.

METHODS

This study involved 330 patients, 193 were men (58%), with a mean age of 49 ± 12 years with Chagas disease classified in the chronic cardiac form of the disease. Comprehensive echocardiography was performed to search a substrate for cardioembolic events, especially apical aneurysm and intracavitary thrombus.

RESULTS

Most of the patients were classified as New York Heart Association classes I or II (75%) with mean left ventricular (LV) ejection fraction of 39 ± 14%. Sixty-seven patients had a previous ICE with the overall prevalence of 20%. Apical aneurysms were detected in 128 patients (39%), whereas LV mural thrombi were found in 48 patients (15%). In multivariate analysis including the potential predictors of ICE, apical aneurysm (adjusted odds ratio [OR]: 2.19, 95% confidence interval [CI]: 1.11 to 4.34; p = 0.024) and LV thrombus (adjusted OR: 2.43, 95% CI: 1.09 to 5.42; p = 0.030) emerged as important determinants of ICE, after adjusting for anticoagulation therapy.

CONCLUSIONS

In a selected population referred to a tertiary center for Chagas disease that included patients with different severities of cardiac involvement, the prevalence of ICE was 20%. The presence of apical aneurysm and intracavitary thrombus were independently associated with ICE, after adjustment for other risk factors for stroke.

Developments in the management of Chagas cardiomyopathy

Over 100 years have elapsed since the discovery of Chagas disease and there is still much to learn regarding pathogenesis and treatment. Although there are antiparasitic drugs available, such as benznidazole and nifurtimox, they are not totally reliable and often toxic. A recently released negative clinical trial with benznidazole in patients with chronic Chagas cardiomyopathy further reinforces the concerns regarding its effectiveness. New drugs and new delivery systems, including those based on nanotechnology, are being sought. Although vaccine development is still in its infancy, the reality of a therapeutic vaccine remains a challenge. New ECG methods may help to recognize patients prone to developing malignant ventricular arrhythmias. The management of heart failure, stroke and arrhythmias also remains a challenge. Although animal experiments have suggested that stem cell based therapy may be therapeutic in the management of heart failure in Chagas cardiomyopathy, clinical trials have not been promising.

COX-2 rs20417 Polymorphism Is Associated with Stroke and White Matter Disease

BACKGROUND

To investigate the effect of COX-2 polymorphism and its product, prostaglandin E2 (PGE2), on stroke risk in an endemic area for Chagas disease. In a separate cohort, to investigate the effect of COX-2 polymorphisms on the total burden of cerebral white matter disease.

METHODS

Cases were outpatients with ischemic stroke; controls were stroke-free subjects from 2 outpatient clinics (heart failure and caregivers of a movement disorders clinic). We extracted DNA from total blood to investigate the rs20417 COX-2 polymorphism. Serologic tests (Enzime-linked immunosorbent assay) were performed to confirm Trypanosoma cruzi infection and to quantify PGE2 levels. In the Boston cohort, white matter hyperintensity volume (WMHv) was quantified on the admission brain magnetic resonance images of subjects with ischemic stroke, who also donated DNA for the COX-2 gene region analysis.

RESULTS

We studied 44 patients with stroke and 96 controls (46 with heart failure and 50 caregivers) in the Brazilian cohort; and 788 stroke patients (302 cardioembolic and 486 noncardioembolic) in the Boston cohort. In the Brazilian cohort, rs20417 polymorphism was associated with both stroke (P = 5 × 10(-6)) and decreased PGE2 levels (P = 4 × 10(-5)); similarly, Chagas was associated with stroke (P = 4 × 10(-3)) and decreased PGE2 levels (P = 7 × 10(-3)). In the Boston cohort, rs20417 polymorphism was associated with increased WMHv among noncardioembolic (P = .037), but not among cardioembolic stroke patients.

CONCLUSIONS

Variation in COX-2 gene is associated with both symptomatic and silent brain cerebrovascular disease. This candidate gene region should be tested in population-based samples.

Acute Chagas disease induces cerebral microvasculopathy in mice

Cardiomyopathy is the main clinical form of Chagas disease (CD); however, cerebral manifestations, such as meningoencephalitis, ischemic stroke and cognitive impairment, can also occur. The aim of the present study was to investigate functional microvascular alterations and oxidative stress in the brain of mice in acute CD. Acute CD was induced in Swiss Webster mice (SWM) with the Y strain of Trypanosoma cruzi (T. cruzi). Cerebral functional capillary density (the number of spontaneously perfused capillaries), leukocyte rolling and adhesion and the microvascular endothelial-dependent response were analyzed over a period of fifteen days using intravital video-microscopy. We also evaluated cerebral oxidative stress with the thiobarbituric acid reactive species TBARS method. Compared with the non-infected group, acute CD significantly induced cerebral functional microvascular alterations, including (i) functional capillary rarefaction, (ii) increased leukocyte rolling and adhesion, (iii) the formation of microvascular platelet-leukocyte aggregates, and (iv) alteration of the endothelial response to acetylcholine. Moreover, cerebral oxidative stress increased in infected animals. We concluded that acute CD in mice induced cerebral microvasculopathy, characterized by a reduced incidence of perfused capillaries, a high number of microvascular platelet-leukocyte aggregates, a marked increase in leukocyte-endothelium interactions and brain arteriolar endothelial dysfunction associated with oxidative stress. These results suggest the involvement of cerebral microcirculation alterations in the neurological manifestations of CD.

Chagas disease (CD) is a neglected tropical illness caused by the parasite Trypanosoma cruzi (T. cruzi). It is endemic in Latin America and affects 10 million people worldwide. Meningoencephalitis occurs in children with acute CD and in immunosuppressed patients suffering acute CD reactivation. During the chronic phase, cerebral manifestations, including ischemic stroke and cognitive impairment, can also occur. Although microvascular alterations have been implicated in Chagas cardiomyopathy, the main clinical form of the disease, there is a lack of discussion in some studies regarding alterations of the cerebral microcirculation in CD. In the present study, we evaluated the functionality of the cerebral microcirculation in mice infected by T. cruzi. Utilizing an intravital video-microscope, we observed in the brain of infected mice a reduction in the number of perfused capillaries, an increased interaction between inflammatory cells and venules, the presence of microvascular platelet-leukocyte aggregates and alterations in the dilatation capacity of arterioles. Moreover, cerebral oxidative stress was increased in infected animals. We concluded that acute CD induced cerebral microvasculopathy.

The neglected

The dividing line between non-communicable and communicable disease is quite blurred. This has been explained through an analogy between neglected tropical diseases (NTDs) and spatial neglect. The electronic databases such as MEDLINE, Tropical Diseases Research Division at the WHO and Google Scholar were consulted and reference lists of articles were searched for relevant material. Spatial neglect is a common complication following stroke. Both NTDs and spatial neglect demonstrate a preference for space and pose challenges in control and management. Although they may appear to be different entities, at least three NTDs (Chagas disease, neurocysticercosis, and schistosomiasis) have been implicated as risk factors for stroke (and thence spatial neglect). This makes NTDs an issue of international concern, unrestricted to the tropics, and too important to be neglected.

Multiple causes of death related to Chagas' disease in Brazil, 1999 to 2007

INTRODUCTION

Chagas' disease is a major public health problem in Brazil and needs extensive and reliable information to support consistent prevention and control actions. This study describes the most common causes of death associated with deaths related to Chagas' disease (underlying or associated cause of death).

METHODS

Mortality data were obtained from the Mortality Information System of the Ministry of Health (approximately 9 million deaths). We analyzed all deaths that occurred in Brazil between 1999 and 2007, where Chagas' disease was mentioned on the death certificate as underlying or associated cause (multiple causes of death).

RESULTS

There was a total of 53,930 deaths related to Chagas' disease, 44,543 (82.6%) as underlying cause and 9,387 (17.4%) as associated cause. The main diseases and conditions associated with death by Chagas' disease as underlying cause included direct complications of cardiac involvement, such as conduction disorders/arrhythmias (41.4%) and heart failure (37.7%). Cerebrovascular disease (13.2%), ischemic heart disease (13.2%) and hypertensive diseases (9.3%) were the main underlying causes of deaths in which Chagas' disease was identified as an associated cause.

CONCLUSIONS

Cardiovascular diseases were often associated with deaths related to Chagas' disease. Information from multiple causes of death recorded on death certificates allows reconstruction of the natural history of Chagas' disease and suggests preventive and therapeutic potential measures more adequate and specifics.

Mode of death on Chagas heart disease: comparison with other etiologies. a subanalysis of the REMADHE prospective trial

Background

Sudden death has been considered the main cause of death in patients with Chagas heart disease. Nevertheless, this information comes from a period before the introduction of drugs that changed the natural history of heart failure. We sought to study the mode of death of patients with heart failure caused by Chagas heart disease, comparing with non-Chagas cardiomyopathy.

Methods and results

We examined the REMADHE trial and grouped patients according to etiology (Chagas vs non-Chagas) and mode of death. The primary end-point was all-cause, heart failure and sudden death mortality; 342 patients were analyzed and 185 (54.1%) died. Death occurred in 56.4% Chagas patients and 53.7% non-Chagas patients. The cumulative incidence of all-cause mortality and heart failure mortality was significantly higher in Chagas patients compared to non-Chagas. There was no difference in the cumulative incidence of sudden death mortality between the two groups. In the Cox regression model, Chagas etiology (HR 2.76; CI 1.34–5.69; p = 0.006), LVEDD (left ventricular end diastolic diameter) (HR 1.07; CI 1.04–1.10; p<0.001), creatinine clearance (HR 0.98; CI 0.97–0.99; p = 0.006) and use of amiodarone (HR 3.05; CI 1.47–6.34; p = 0.003) were independently associated with heart failure mortality. LVEDD (HR 1.04; CI 1.01–1.07; p = 0.005) and use of beta-blocker (HR 0.52; CI 0.34–0.94; p = 0.014) were independently associated with sudden death mortality.

Conclusions

In severe Chagas heart disease, progressive heart failure is the most important mode of death. These data challenge the current understanding of Chagas heart disease and may have implications in the selection of treatment choices, considering the mode of death.

Trial Registration

ClinicalTrails.gov NCT00505050 (REMADHE)

Chagas disease remains a burden for public health systems in Latin American countries. Several authors believe that sudden death is the main cause of death in this population. So many efforts have been made to prevent sudden death in Chagas disease. In order to verify if sudden death is the leading cause of death in Chagasic heart failure, we performed a subanalysis of the REMADHE prospective trial, which included a population of outpatients in a tertiary referral center for heart failure. We grouped patients according to etiology (Chagas vs non-Chagas) and modes of death that were classified as progressive heart failure death, sudden death, other cardiovascular death, noncardiovascular death or unknown death. Our study showed that in this end of the spectrum of presentation of Chagas disease, with systolic heart dysfunction, progressive heart failure is the main mode of death. These data have implications for the development of new strategies for prevention of chagasic heart failure.

American trypanosomiasis

American trypanosomiasis is a parasitic disease caused by the flagellate protozoan Trypanosoma cruzi. Chagas disease is endemic in Latin America, where an estimated 10-14 million people are infected, and an emerging disease in Europe and the USA. Trypanosoma cruzi is transmitted by blood-sucking bugs of the family Reduviidae. Rhodnius prolixus, Panstrongylus megistus, Triatoma infestans, and T. dimidiata are the main vectors in the sylvatic cycle. Non vector-borne transmission includes blood transfusion, congenital and oral transmission, transplantation, and accidental infections. Most cases of acute infection occur in childhood and are usually asymptomatic, although severe myocarditis and meningoencephalitis may occur. Approximately 30% of T. cruzi-infected people will develop the chronic stage of the disease. Chronic chagasic cardiomyopathy is characterized by progressive heart failure, arrhythmias, intraventricular conduction defects, sudden death, and peripheral thromboembolism. Acute exacerbation can occur in individuals with involvement of cellular immunity such as advanced AIDS (acquired immunodeficiency syndrome), and transplant-associated immunosuppression. Neurological involvement may present with encephalitis, meningoencephalitis, or a space-occupying cerebral lesion called chagoma. Chagas disease is a major cause of ischemic stroke in Latin America. Several epidemiological studies have found an association between T. cruzi infection and cardioembolic ischemic stroke. Benznidazole and nifurtimox are the two available trypanocide drugs against T. cruzi.

Hypercoagulability biomarkers in Trypanosoma cruzi -infected patients

There is a current controversy over the hypothesis that a number of thromboembolic events could be related to hypercoagulable state in patients with chronic Chagas disease. This study was designed to determine whether a prothrombotic state existed in chronic Trypanosoma cruzi-infected patients and, if so, to describe its evolution after treatment with Benznidazole. Twenty-five patients with chronic Chagas disease and 18 controls were evaluated. The markers used were prothrombin time, activated partial thromboplastin time, fibrinogen, antithrombin, plasminogen, protein C, total protein S, free protein S, factor VIII, D-dimer, activated factor VIIa, tissue-type plasminogen activator inhibitor-1, prothrombin fragment 1+2 (F₁+₂), plasmin-antiplasmin complexes, soluble P-selectin and endogenous thrombin potential (ETP). Despite statistically significant differences between cases and controls in several markers, only ETP (which quantifies the ability of plasma to generate thrombin when activated through tissue factor addition) (p<0.0001) and F₁+₂ (a marker of thrombin generation in vivo) (p<0.0001) showed values outside the normal levels in patients compared with controls. Similar results were obtained in these markers six months after treatment in the cohort of cases (p<0.0008 and p<0.004, respectively). These results may be relevant in clinical practice. Though current treatment for Chagas disease is still controversial, if it were considered as a thromboembolic risk factor the antiparasitic treatment strategy could be reinforced. The results also support further research on haemostasis parameters as candidates for early surrogate biomarkers of cure or progression of Chagas disease.

Importance of nonenteric protozoan infections in immunocompromised people

There are many neglected nonenteric protozoa able to cause serious morbidity and mortality in humans, particularly in the developing world. Diseases caused by certain protozoa are often more severe in the presence of HIV. While information regarding neglected tropical diseases caused by trypanosomatids and Plasmodium is abundant, these protozoa are often not a first consideration in Western countries where they are not endemic. As such, diagnostics may not be available in these regions. Due to global travel and immigration, this has become an increasing problem. Inversely, in certain parts of the world (particularly sub-Saharan Africa), the HIV problem is so severe that diseases like microsporidiosis and toxoplasmosis are common. In Western countries, due to the availability of highly active antiretroviral therapy (HAART), these diseases are infrequently encountered. While free-living amoebae are rarely encountered in a clinical setting, when infections do occur, they are often fatal. Rapid diagnosis and treatment are essential to the survival of patients infected with these organisms. This paper reviews information on the diagnosis and treatment of nonenteric protozoal diseases in immunocompromised people, with a focus on patients infected with HIV. The nonenteric microsporidia, some trypanosomatids, Toxoplasma spp., Neospora spp., some free-living amoebae, Plasmodium spp., and Babesia spp. are discussed.

Chagas disease: changes in knowledge and management

More than 100 years after the discovery of human American trypanosomiasis by Carlos Chagas, our knowledge and management of the disease are profoundly changing. Substantial progress made by disease control programmes in most endemic areas contrasts with persisting difficulties in the Gran Chaco region in South America and the recent emergence of the disease in non-endemic areas because of population movements. In terms of pathogenesis, major discoveries have been made about the life cycle and genomics of Trypanosoma cruzi, and the role of the parasite itself in the chronic phase of the disease. From a clinical perspective, a growing number of arguments have challenged the notion of an indeterminate phase, and suggest new approaches to manage patients. New methods such as standardised PCR will be necessary to ensure follow-up of this chronic infection. Although drugs for treatment of Chagas disease are limited, poorly tolerated, and not very effective, treatment indications are expanding. The results of the Benznidazole Evaluation For Interrupting Trypanosomiasis (BENEFIT) trial in 2012 will also help to inform treatment. Mobilisation of financial resources to fund research on diagnosis and randomised controlled trials of treatment are international health priorities.

Trypanosomiasis, cardiomyopathy and the risk of ischemic stroke

American (Chagas disease) and African (sleeping sickness) trypanosomiasis are neglected tropical diseases and are a heavy burden in Latin America and Africa, respectively. Chagas disease is an independent risk factor for stroke. Apical aneurysm, heart failure and cardiac arrhythmias are associated with ischemic stroke in chagasic cardiomyopathy. Not all chagasic patients who suffer an ischemic stroke have a severe cardiomyopathy, and stroke may be the first manifestation of Chagas disease. Cardioembolism affecting the middle cerebral artery is the most common stroke subtype. Risk of recurrence is high and careful evaluation of recurrence risk should be addressed. Repolarization changes, low voltage and prolonged QT interval are common electrocardiography alterations in human African trypanosomiasis, and can be found in more than 70% of patients. Epidemiological studies are needed to asses the risk of stroke in African trypanosomiasis perimyocarditis.

Chagas disease and stroke

Chagas disease is a neglected infectious disease in the tropics and an emerging health problem in Europe and the USA. In the past decade, a link has been recorded between ischaemic stroke and Trypanosoma cruzi infection in several epidemiological studies, and an increase in stroke prevalence is expected with the ageing of the population infected with T cruzi in Latin America. Heart failure, mural thrombus, left ventricular apical aneurysm, and several types of cardiac arrhythmias are associated with stroke in Chagas disease. Stroke could also be the first sign of Chagas disease in asymptomatic patients and those with mild systolic dysfunction, so patients with stroke who are from endemic regions should be screened for T cruzi infection. The most frequent stroke syndrome seen in patients with Chagas disease is partial anterior circulation infarction. Stroke recurrence has been estimated to occur in 20% of patients, and secondary prevention measures include chronic anticoagulation in cardioembolic chagasic stroke. So far, no studies have been done to assess the effect of chagasic stroke on vascular dementia.

Morbidity and prognostic factors in chronic chagasic cardiopathy

Chagas disease is a pleomorphic clinical entity that has several unique features. The aim of this study is to summarise some of the recent contributions from our research group to knowledge of the morbidity and prognostic factors in Chagas heart disease. A retrospective study suggested that ischaemic stroke associated with left ventricular (LV) apical thrombi is the first clinical manifestation of Chagas disease observed in a large proportion of patients. LV function and left atrial volume (LAV) are independent risk factors for ischaemic cerebrovascular events during follow-up of Chagas heart disease patients. Pulmonary congestion in Chagas-related dilated cardiomyopathy is common but usually mild. Although early right ventricular (RV) involvement has been described, we have shown by Doppler echocardiography that RV dysfunction is evident almost exclusively when it is associated with left ventricle dilatation and functional impairment. In addition, RV dysfunction is a powerful predictor of survival in patients with heart failure secondary to Chagas disease. We have also demonstrated that LAV provides incremental prognostic information independent of clinical data and conventional echocardiographic parameters that predict survival.

Chagas disease: independent risk factor for stroke

BACKGROUND AND PURPOSE

It has been suggested that Chagas disease (CD) and particularly CD cardiomyopathy are independent risk factors for cerebrovascular events. Strong evidence is scarce, cardioembolic and inflammatory mechanisms have been proposed, and most studies lack representative and well-matched controls. We sought to investigate CD, defined by positive serology, as an independent risk factor for stroke, by comparing patients admitted with ischemic stroke with representative control patients with a very similar cardiovascular risk factor profile.

METHODS

We performed a case-control study with 101 consecutive stroke patients and 100 consecutive acute coronary syndrome patients admitted to an emergency hospital. CD was investigated in all patients and was confirmed when both immunofluorescence and hemagglutination tests were positive. Clinical, laboratory, and ECG findings were analyzed.

RESULTS

We found that age (P=0.006), female sex (P=0.01), systolic blood pressure (P=0.001), diastolic blood pressure (P=0.03), previous stroke/transient ischemic attack history (P<0.001), atrial fibrillation (P=0.005), other arrhythmias (P=0.05), and CD-positive serology (P=0.002) were more frequent among stroke patients than among patients with acute coronary syndromes. After a multivariable analysis with a backward elimination procedure, previous stroke/transient ischemic attack history (odds ratio=6.98; 95% CI, 2.99 to 16.29), atrial fibrillation (odds ratio=4.52; 95% CI, 1.45 to 14.04), and CD-positive serology (odds ratio=7.17; 95% CI, 1.50 to 34.19) remained independently associated with stroke.

CONCLUSIONS

CD seems to be an independent risk factor for ischemic stroke. For patients in or coming from endemic regions, CD should be considered an etiologic or contributing factor for stroke.