Policy implications of the changing epidemiology of Chagas disease and stroke

The Importance of Screening for Chagas Disease Against the Backdrop of Changing Epidemiology in the USA

Purpose of Review

This review seeks to identify factors contributing to the changing epidemiology of Chagas disease in the United States of America (US). By showcasing screening programs for Chagas disease that currently exist in endemic and non-endemic settings, we make recommendations for expanding access to Chagas disease diagnosis and care in the US.

Recent Findings

Several factors including but not limited to increasing migration, climate change, rapid population growth, growing urbanization, changing transportation patterns, and rising poverty are thought to contribute to changes in the epidemiology of Chagas disease in the US. Outlined are some examples of successful screening programs for Chagas disease in other countries as well as in some areas of the US, notably those which focus on screening high-risk populations and are linked to affordable and effective treatment options.

Summary

Given concerns that Chagas disease prevalence and even risk of transmission may be increasing in the US, there is a need for improving detection and treatment of the disease. There are many successful screening programs in place that can be replicated and/or expanded upon in the US. Specifically, we propose integrating Chagas disease into relevant clinical guidelines, particularly in cardiology and obstetrics/gynecology, and using advocacy as a tool to raise awareness of Chagas disease.

Artificial Inteligence-Based Decision for the Prediction of Cardioembolism in Patients with Chagas Disease and Ischemic Stroke

BACKGROUND

Chagas disease (CD) and ischemic stroke (IS) have a close, but poorly understood, association. There is paucity of evidence on the ideal secondary prophylaxis and etiological determination, with few cardioembolic patients being identified.

AIMS

This study aimed to describe a multicenter cohort of patients with concomitant CD and IS admitted in tertiary centers and to create a predictive model for cardioembolic embolism in CD and IS.

MATERIALS AND METHODS

We retrospectively studied data obtained from electronic medical and regular medical records of patients with CD and IS in several academic, hospital-based, and university hospitals across Brazil. Descriptive analyses of cardioembolic and non-cardioembolic patients were performed. A prediction model for cardioembolism was proposed with 70% of the sample as the derivation sample, and the model was validated in 30% of the sample.

RESULTS

A total of 499 patients were analyzed. The median age was similar in both groups; however, patients with cardioembolic embolism were younger and tended to have higher alcoholism, smoking, and death rates. The predictive model for the etiological classification showed close relation with the number of abnormalities detected on echocardiography and electrocardiography as well as with vascular risk factors.

CONCLUSIONS

Our results replicate in part those previously published, with a higher prevalence of vascular risk factors and lower median age in patients with cardioembolic etiology. Our new model for predicting cardioembolic etiology can help identify patients with higher recurrence rate and therefore allow an optimized strategy for secondary prophylaxis.

Optimization of 1,4-Naphthoquinone Hit Compound: A Computational, Phenotypic, and In Vivo Screening against Trypanosoma cruzi

Chagas disease (CD) still represents a serious public health problem in Latin America, even after more than 100 years of its discovery. Clinical treatments (nifurtimox and benznidazole) are considered inadequate, especially because of undesirable side effects and low efficacy in the chronic stages of the disease, highlighting the urgency for discovering new effective and safe drugs. A small library of compounds (1a–i and 2a–j) was designed based on the structural optimization of a Hit compound derived from 1,4-naphthoquinones (C2) previously identified. The biological activity, structure-activity relationship (SAR), and the in silico physicochemical profiles of the naphthoquinone derivatives were analyzed. Most modifications resulted in increased trypanocidal activity but some substitutions also increased toxicity. The data reinforce the importance of the chlorine atom in the thiophenol benzene ring for trypanocidal activity, highlighting 1g, which exhibit a drug-likeness profile, as a promising compound against Trypanosoma cruzi. SAR analysis also revealed 1g as cliff generator in the structure-activity similarity map (SAS maps). However, compounds C2 and 1g were unable to reduce parasite load, and did not prevent mouse mortality in T. cruzi acute infection. Phenotypic screening and computational analysis have provided relevant information to advance the optimization and design of new 1,4-naphthoquinone derivatives with a better pharmacological profile.

Cerebral infarct topography of atrial fibrillation and Chagas disease

BACKGROUND

Chagas disease (CD) and ischemic stroke (IS) have a significant but poorly understood correlation. There is paucity of evidence regarding secondary prophylaxis of IS and etiological causes.

OBJECTIVES

To compare arterial stroke topography and the respective morbidities and mortality in patients with CD of undetermined and cardioembolic etiologies and with cardioembolic IS (atrial fibrillation [AF]).

METHODS

We compared vascular topography and outcomes using data obtained from the electronic medical records of all patients with IS with either CD (with cardioembolic or undetermined etiology) or AF, admitted to SARAH Hospital Brasilia between 2009 and 2013.

RESULTS

A total of 115 patients were investigated: 49 involving AF, 23 involving CD of unclear etiology, and 43 involving CD of cardioembolic etiology. Middle cerebral artery stroke was predominant in all groups, although more frequent in patients with CD of undetermined etiology. No significant difference was found in the arterial territories. Hemodynamic stroke was predominant among CD patients who experienced cardioembolic events. AF patients had worse modified Rankin scale scores upon admission and a higher mortality rate than CD patients in both categories.

CONCLUSIONS

Stroke topography is not useful in determining the etiological diagnosis. Patients with AF and IS are more likely to have worse outcomes than are those with CD and IS. The autonomic nervous system could be affected in patients with CD.

Mortality and Stroke Recurrence in a Rehabilitation Cohort of Patients with Cerebral Infarcts and Chagas Disease

Background: Chagas disease is related to ischemic stroke (IS), although few epidemiological studies have evaluated the associated mortality and recurrence. Our objective is to determine factors associated with mortality and recurrence of IS in patients with IS and Chagas disease. Methods: We retrospectively studied data obtained from electronic medical records of patients admitted at SARAH Hospitals across Brazil between 2009 and 2013. Using Cox regression analysis for mortality and logistic regression for recurrence, we assessed primary population characteristics and statistical associations between risk factors and outcomes. Results: We analyzed 279 patients who were followed up until 2016. The mean age at stroke onset was 61 with a 10% frequency of death. Multivariate analysis assessing mortality demonstrated that the associated factors were age at stroke (hazard ratio [HR] 1.04), initial modified Rankin Scale (mRS; HR 20.91), bladder dysfunction (HR 2.51), diabetes mellitus (DM; HR 3.64), and alcoholism (HR 3.37). Multivariate analysis assessing recurrence demonstrated that the associated factors were age at ictus (OR 0.96), cognitive deficit (OR 0.44), initial mRS (OR 1.84), cardioembolic etiology (OR 2.47), and female sex (OR 2.73). Conclusions: Cardiac conditions did not correlate with mortality or recurrence. Age was a protective factor against recurrence, probably due to cumulative risk of IS over time, while initial mRS was associated with both outcomes. Treating diseases such as DM and bladder dysfunction, and early treatment to reduce the initial mRS could potentially prevent both outcomes; also, establishing a correct etiological diagnosis is important.

Chagas disease

Chagas disease is an anthropozoonosis from the American continent that has spread from its original boundaries through migration. It is caused by the protozoan Trypanosoma cruzi, which was identified in the first decade of the 20th century. Once acute infection resolves, patients can develop chronic disease, which in up to 30-40% of cases is characterised by cardiomyopathy, arrhythmias, megaviscera, and, more rarely, polyneuropathy and stroke. Even after more than a century, many challenges remain unresolved, since epidemiological control and diagnostic, therapeutic, and prognostic methods must be improved. In particular, the efficacy and tolerability profile of therapeutic agents is far from ideal. Furthermore, the population affected is older and more complex (eg, immunosuppressed patients and patients with cancer). Nevertheless, in recent years, our knowledge of Chagas disease has expanded, and the international networking needed to change the course of this deadly disease during the 21st century has begun.

Infectious diseases causing autonomic dysfunction

OBJECTIVES

To review infectious diseases that may cause autonomic dysfunction.

METHODS

Review of published papers indexed in medline/embase.

RESULTS

Autonomic dysfunction has been reported in retrovirus (human immunodeficiency virus (HIV), human T-lymphotropic virus), herpes viruses, flavivirus, enterovirus 71 and lyssavirus infections. Autonomic dysfunction is relatively common in HIV-infected patients and heart rate variability is reduced even in early stages of infection. Orthostatic hypotension, urinary dysfunction and hypohidrosis have been described in tropical spastic paraparesis patients. Varicella zoster reactivation from autonomic ganglia may be involved in visceral disease and chronic intestinal pseudo-obstruction. Autonomic and peripheral nervous system dysfunction may happen in acute tick-borne encephalitis virus infections. Hydrophobia, hypersalivation, dyspnea, photophobia, and piloerection are frequently observed in human rabies. Autonomic dysfunction and vagal denervation is common in Chagas disease. Neuronal depopulation occurs mainly in chagasic heart disease and myenteric plexus, and megacolon, megaesophagus and cardiomyopathy are common complications in the chronic stage of Chagas disease. Parasympathetic autonomic dysfunction precedes left ventricle systolic dysfunction in Chagas disease. A high prevalence of subclinical autonomic neuropathy in leprosy patients has been reported, and autonomic nerve dysfunction may be an early manifestation of the disease. Autonomic dysfunction features in leprosy include anhidrosis, impaired sweating function, localised alopecia ,and reduced heart rate variability. Urinary retention and intestinal pseudo-obstruction have been described in Lyme disease. Diphtheritic polyneuropathy, tetanus and botulism are examples of bacterial infections releasing toxins that affect the autonomic nervous system.

CONCLUSIONS

Autonomic dysfunction may be responsible for additional morbidity in some infectious diseases.

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.

Cardioembolic sources in stroke patients in South of Brazil

Background. Stroke is a leading cause of mortality and disability in Brazil and around the world. Cardioembolism is responsible for nearly 30% of the origins of ischemic stroke. Methods. We analyzed data of 256 patients with cardioembolic ischemic stroke (according to TOAST classification) who were admitted into the Hospital São Lucas-PUCRS from October 2011 to January 2014. The cardioembolic subtype was divided into six subgroups: arrhythmias, valvular heart disease, coronary artery disease, cardiomyopathy, septal abnormalities, and intracardiac injuries. The prevalence of the most important cardiovascular risk factors and medications in use for prevention of systemic embolism by the time of hospital admission was analyzed in each patient. Results. Among 256 patients aged 60.2 +/− 6.9 years, 132 males, arrhythmias were the most common cause of cardioembolism corresponding to 50.7%, followed by valvular heart disease (17.5%) and coronary artery disease (16%). Hypertension (61.7%) and dyslipidemia (43.7%) were the most common risk factors. Less than 50% of patients with arrhythmias were using oral anticoagulants. Conclusions. Identifying the prevalence of cardioembolic stroke sources subgroups has become an increasingly important role since the introduction of new oral anticoagulants. In this study, arrhythmias (especially atrial fibrillation) were the main cause of cardioembolism.

Differential ability to resist to complement lysis and invade host cells mediated by MBL in R4 and 860 strains of Trypanosoma cruzi

To produce an infection Trypanosoma cruzi must evade lysis by the complement system. During early stages of infection, the lectin pathway plays an important role in host defense and can be activated by binding of mannan-binding lectin (MBL) to carbohydrates on the surface of pathogens. We hypothesized that MBL has a dual role during parasite-host cell interaction as lectin complement pathway activator and as binding molecule to invade the host cell. We used two polarized strains of T. cruzi, R4 (susceptible) and 860 (resistant) strains, to investigate the role of MBL in complement-mediated lysis. Interestingly R4, but not 860 metacyclic strain, markedly increases the invasion of host cells, suggesting that MBL drives the invasion process while the parasite deactivates the Lectin complement pathway.