Heart Failure Secondary to Chagas Disease: an Emerging Problem in Non-endemic Areas

Experiences with Diagnosis and Treatment of Chagas Disease at a United States Teaching Hospital-Clinical Features of Patients with Positive Screening Serologic Testing

Chagas disease (CD) is the third most common parasitic infection globally and can cause cardiac and gastrointestinal complications. Around 300,000 carriers of CD live in the U.S., with about 3000 of those in Colorado. We described our experience in diagnosing CD at a Colorado teaching hospital to revise screening eligibility criteria. From 2006 to 2020, we reviewed Trypanosoma cruzi (TC) IgG serology results for 1156 patients in our institution. We identified 23 patients (1.99%) who had a positive test. A total of 14/23 (60%) of positive serologies never had confirmatory testing, and 7 of them were lost to follow up. Confirmatory testing, performed in 9 patients, resulted in being positive in 3. One additional case of CD was identified by positive tissue pathology. All four confirmed cases were among patients born in Latin America. While most of the testing for CD at our institution is part of the pretransplant screening, no confirmed cases of CD derived from this strategy. Exposure risk in this population is not always documented, and initial positive results from screening are not always confirmed. The lack of standardized screening protocols for CD in our institution contributes to underdiagnosis locally and in health systems nationwide. Given a large number of individuals in the U.S. with chronic CD, improved screening is warranted.

Muscle mass, muscle strength, and functional capacity in patients with heart failure of Chagas disease and other aetiologies

Aims

Patients with Chagas disease and heart failure (HF) have a poor prognosis similar to that of patients with ischaemic or dilated cardiomyopathy. However, the impact of body composition and muscle strength changes in these aetiologies is still unknown. We aimed to evaluate these parameters across aetiologies in two distinct cohort studies [TESTOsterone‐Heart Failure trial (TESTO‐HF; Brazil) and Studies Investigating Co‐morbidities Aggravating Heart Failure (SICA‐HF; Germany)].

Methods and results

A total of 64 male patients with left ventricular ejection fraction ≤40% were matched for body mass index and New York Heart Association class, including 22 patients with Chagas disease (TESTO‐HF; Brazil), and 20 patients with dilated cardiomyopathy and 22 patients with ischaemic heart disease (SICA‐HF; Germany). Lean body mass (LBM), appendicular lean mass (ALM), and fat mass were assessed by dual energy X‐ray absorptiometry. Sarcopenia was defined as ALM divided by height in metres squared <7.0 kg/m² (ALM/height²) and handgrip strength cut‐off for men according to the European Working Group on Sarcopenia in Older People. All patients performed maximal cardiopulmonary exercise testing. Forearm blood flow (FBF) was measured by venous occlusion plethysmography. Chagasic and ischaemic patients had lower total fat mass (16.3 ± 8.1 vs. 19.3 ± 8.0 vs. 27.6 ± 9.4 kg; P < 0.05) and reduced peak oxygen consumption (VO₂) (1.17 ± 0.36 vs. 1.15 ± 0.36 vs. 1.50 ± 0.45 L/min; P < 0.05) than patients with dilated cardiomyopathy, respectively. Chagasic patients showed a trend towards decreased LBM when compared with ischaemic patients (48.3 ± 7.6 vs. 54.2 ± 6.3 kg; P = 0.09). Chagasic patients showed lower handgrip strength (27 ± 8 vs. 37 ± 11 vs. 36 ± 14 kg; P < 0.05) and FBF (1.84 ± 0.54 vs. 2.75 ± 0.76 vs. 3.42 ± 1.21 mL/min/100 mL; P < 0.01) than ischaemic and dilated cardiomyopathy patients, respectively. There was no statistical difference in the distribution of sarcopenia between groups (P = 0.87). In addition, FBF correlated positively with LBM (r = 0.31; P = 0.012), ALM (r = 0.25; P = 0.046), and handgrip strength (r = 0.36; P = 0.004). In a logistic regression model using peak VO₂ as the dependent variable, haemoglobin (odds ratio, 1.506; 95% confidence interval, 1.043–2.177; P = 0.029) and ALM (odds ratio, 1.179; 95% confidence interval, 1.011–1.374; P = 0.035) were independent predictors for peak VO₂ adjusted by age, left ventricular ejection fraction, New York Heart Association, creatinine, and FBF.

Conclusions

Patients with Chagas disease and HF have decreased fat mass and exhibit reduced peripheral blood flow and impaired muscle strength compared with ischaemic HF patients. In addition, patients with Chagas disease and HF show a tendency to have greater reduction in total LBM, with ALM remaining an independent predictor of reduced functional capacity in these patients. The percentage of patients affected by sarcopenia was equal between groups.

Chagas Disease in the United States: a Public Health Approach

Trypanosoma cruzi is the etiological agent of Chagas disease, usually transmitted by triatomine vectors. An estimated 20 to 30% of infected individuals develop potentially lethal cardiac or gastrointestinal disease. Sylvatic transmission cycles exist in the southern United States, involving 11 triatomine vector species and infected mammals such as rodents, opossums, and dogs. Nevertheless, imported chronic T. cruzi infections in migrants from Latin America vastly outnumber locally acquired human cases. Benznidazole is now FDA approved, and clinical and public health efforts are under way by researchers and health departments in a number of states. Making progress will require efforts to improve awareness among providers and patients, data on diagnostic test performance and expanded availability of confirmatory testing, and evidence-based strategies to improve access to appropriate management of Chagas disease in the United States.

Insights from quantitative and mathematical modelling on the proposed WHO 2030 goals for Chagas disease

Chagas disease (CD) persists as one of the neglected tropical diseases (NTDs) with a particularly large impact in the Americas. The World Health Organization (WHO) recently proposed goals for CD elimination as a public health problem to be reached by 2030 by means of achieving intradomiciliary transmission interruption (IDTI), blood transfusion and transplant transmission interruption, diagnostic and treatment scaling-up and prevention and control of congenital transmission. The NTD Modelling Consortium has developed mathematical models to study Trypanosoma cruzi transmission dynamics and the potential impact of control measures. Modelling insights have shown that IDTI is feasible in areas with sustained vector control programmes and no presence of native triatomine vector populations. However, IDTI in areas with native vectors it is not feasible in a sustainable manner. Combining vector control with trypanocidal treatment can reduce the timeframes necessary to reach operational thresholds for IDTI (<2% seroprevalence in children aged <5 years), but the most informative age groups for serological monitoring are yet to be identified. Measuring progress towards the 2030 goals will require availability of vector surveillance and seroprevalence data at a fine scale, and a more active surveillance system, as well as a better understanding of the risks of vector re-colonization and disease resurgence after vector control cessation. Also, achieving scaling-up in terms of access to treatment to the expected levels (75%) will require a substantial increase in screening asymptomatic populations, which is anticipated to become very costly as CD prevalence decreases. Further modelling work includes refining and extending mathematical models (including transmission dynamics and statistical frameworks) to predict transmission at a sub-national scale, and developing quantitative tools to inform IDTI certification, post-certification and re-certification protocols. Potential perverse incentives associated with operational thresholds are discussed. These modelling insights aim to inform discussions on the goals and treatment guidelines for CD.

Treatment of Chagas Disease in the United States

PURPOSE OF REVIEW

Chagas disease (CD) is endemic to much of Latin America, but also present in the United States (U.S.). Following a lengthy asymptomatic period, CD produces serious cardiac or gastrointestinal complications in 30-40% of people. Less than 1% of the estimated six million cases in the Americas, including 326,000-347,000 in the U.S., are diagnosed. Infected persons are typically unaware and the bulk of clinicians are unfamiliar with current treatment guidelines. This review provides U.S. and other clinicians with the latest knowledge of CD treatment.

RECENT FINDINGS

Chagas cardiomyopathy (CCM) causes severe fibrosis and autonomic damage in the myocardium. Eliminating the parasite through antitrypanosomal therapy with benznidazole, a nitroimidazole derivative or nifurtimox, a nitrofuran compound, potentially prevents heart failure and other sequelae of advanced CCM. Benznidazole, recently approved by the U.S. Food and Drug Administration (FDA) for children 2-12 years old, is the first-line therapy; optimal dosages are currently being studied. Antitrypanosomal therapy prevents congenital transmission; produces high cure rates for acute, congenital, and early chronic cases; and improves clinical outcomes in adult chronic indeterminate cases. However, this benefit was not observed in a large clinical trial that included patients with advanced CCM.

SUMMARY

Treatment with antitrypanosomal drugs can cure CD in acute, congenital, and early chronic cases and provides improved clinical outcomes for chronic indeterminate cases. This treatment should be offered as early as possible, before advanced CCM develops.

Electrocardiographic abnormalities in Chagas disease in the general population: A systematic review and meta-analysis

BACKGROUND

Chagas disease (CD) is a major public health concern in Latin America and a potentially serious emerging threat in non-endemic countries. Although the association between CD and cardiac abnormalities is widely reported, study design diversity, sample size and quality challenge the information, calling for its update and synthesis, which would be very useful and relevant for physicians in non-endemic countries where health care implications of CD are real and neglected. We performed to systematically review and meta-analyze population-based studies that compared prevalence of overall and specific ECG abnormalities between CD and non-CD participants in the general population.

METHODS

Six databases (EMBASE, Ovid Medline, Web of Science, Cochrane Central, Google Scholar and Lilacs) were searched systematically. Observational studies were included. Odds ratios (OR) were computed using random-effects model.

RESULTS

Forty-nine studies were selected, including 34,023(12,276 CD and 21,747 non-CD). Prevalence of overall ECG abnormalities was higher in participants with CD (40.1%; 95%CIs=39.2-41.0) compared to non-CD (24.1%; 95%CIs=23.5-24.7) (OR=2.78; 95%CIs=2.37-3.26). Among specific ECG abnormalities, prevalence of complete right bundle branch block (RBBB) (OR=4.60; 95%CIs=2.97-7.11), left anterior fascicular block (LAFB) (OR=1.60; 95%CIs=1.21-2.13), combination of complete RBBB/LAFB (OR=3.34; 95%CIs=1.76-6.35), first-degree atrioventricular block (A-V B) (OR=1.71; 95%CIs=1.25-2.33), atrial fibrillation (AF) or flutter (OR=2.11; 95%CIs=1.40-3.19) and ventricular extrasystoles (VE) (OR=1.62; 95%CIs=1.14-2.30) was higher in CD compared to non-CD participants.

CONCLUSIONS

This systematic review and meta-analysis provides an update and synthesis in this field. This research of observational studies indicates a significant excess in prevalence of ECG abnormalities (40.1%) related to T. cruzi infection in the general population from Chagas endemic regions, being the most common ventricular (RBBB and LAFB), and A-V B (first-degree) node conduction abnormalities as well as arrhythmias (AF or flutter and VE). Also, prevalence of ECG alterations in children was similar to that in adults and suggests earlier onset of cardiac disease.

A novel nanoluciferase-based system to monitor Trypanosoma cruzi infection in mice by bioluminescence imaging

Chagas disease, caused by the intracellular protozoan Trypanosoma cruzi, affects 8–10 million people worldwide and represents a major public health challenge. There is no effective treatment or vaccine to control the disease that is characterized by a mild acute phase followed by a chronic life-long infection. Approximately 30% of chronically infected individuals develop cardiac and/or digestive pathologies. T. cruzi can invade a wide variety of nucleated cells, but only persists at specific tissues in the host. However, the mechanisms that determine tissue tropism and the progression of the infection have not been fully described. Identification of infection niches in animal models has been difficult due to the limited quantity of parasite-infected cells and their focal distribution in tissues during the chronic phase. To better understand the course of chronic infections and parasite dissemination, we developed a bioluminescence imaging system based on the use of transgenic T. cruzi Colombiana strain parasites expressing nanoluciferase. Swiss Webster mice were infected with luminescent trypomastigotes and monitored for 126 days. Whole animal in vivo imaging showed parasites predominantly distributed in the abdominal cavity and surrounding areas throughout the infection. Bioluminescence signal reached a peak between 14 to 21 days post infection (dpi) and decreased progressively over time. Total animal luminescence could still be measured 126 dpi while parasites remained undetectable in blood by microscopy in most animals. Ex vivo imaging of specific tissues and organs dissected post-mortem at 126 dpi revealed a widespread parasite distribution in the skeletal muscle, heart, intestines and mesenteric fat. Parasites were also detected in lungs and liver. This noninvasive imaging model represents a novel tool to study host-parasite interactions and to identify parasite reservoirs of chronic Chagas Disease.

A New Development in Trypanosoma cruzi Detection

Chagas disease is caused by the parasite Trypanosoma cruzi and is an important cause of morbidity and mortality in areas of Latin America where Chagas disease is endemic and among infected individuals who have migrated to nonendemic areas of North America and Europe. There are many diagnostic tests that are employed in the serological diagnosis of this infection. In this issue of the Journal of Clinical Microbiology, Bautista-López et al. provide characterization of excretory vesicles (EVs) from Vero cells infected with T. cruzi and provide data on the EVs produced by trypomastigotes and amastigotes (N. L. Bautista-López et al., J Clin Microbiol 55:744-758, 2017, https://doi.org/10.1128/JCM.01649-16). Their proteomic study defines potential targets to evaluate for improved diagnostic tests, effects on host cell biology that contribute to the pathogenesis of infection, and vaccine candidates. If any of the EV-associated proteins identified were to be correlated to cure of infection, this would be a major advance.