Overcoming research barriers in Chagas disease-designing effective implementation science

Pharmaceutical agents for the treatment of Chagas disease: patenting trends in 2016-2021 period

American trypanosomiasis is a neglected tropical disease and an endemic problem in 21 Latin American countries, whose treatment relies on only two US FDA-approved drugs: benznidazole and nifurtimox. Patent literature reveals vital information on new trends in therapies for various diseases, including Chagas disease. The authors used the patent databases of the world's major patent offices to generate an overview of patent trends related to the treatment of Chagas disease. A total of 50 patent families were collected and grouped as 'small molecules', 'pharmaceutical compositions of known compounds' and vaccines. From the results and interpretation, it can be concluded that the treatment of Chagas disease receives little attention in the field of patents and that the upward trend is minimal.

In Search of Congenital Chagas Disease in the Sierra Nevada de Santa Marta, Colombia

Chagas disease remains a major impediment to sustainable socioeconomic development in Latin America. Transplacental transmission explains the persistence of transmission in urban areas, in non-endemic regions, and in areas with an established interrupted vectorial transmission. One of every five cases of congenital Chagas disease in the world occurs in Colombia and Venezuela. The massive migration of impoverished populations from neighboring Venezuela has worsened the situation creating a humanitarian crisis in Northeastern Colombia, including the Sierra Nevada de Santa Marta. The prevalence of Chagas infection among pregnant women in these areas is higher than the national average, and the public health resources are insufficient. This perspective discusses the associated increased morbidity and mortality of congenital Chagas in this region, where stigmatization contributes to the impression among health authorities and the general population that it affects indigenous communities only. The monitoring and control of congenital Chagas disease in the Sierra Nevada of Santa Marta is a public health necessity that demands urgent and effective interventions.

Duration and determinants of Chagas latency: an etiology and risk systematic review protocol

OBJECTIVE

The objective of this systematic review is to explore and discuss the latency duration among asymptomatic people with chronic Chagas disease.

INTRODUCTION

Studies estimate the latency period of Chagas disease to be approximately 10-30 years. However, new findings may indicate that this latency period is shorter and depends on the presence of clinical factors. This systematic review protocol will explore the duration and factors affecting this latency period to inform treatment, with the potential of improving outcomes.

INCLUSION CRITERIA

Eligible studies will include asymptomatic people with indeterminate Chagas disease confirmed through positive serologic testing and the absence of structural cardiomyopathy with no heart failure symptoms and normal electrocardiography results. Studies that involve a longitudinal observation period of participants will be considered. This period must start from the acute acquisition of the infection or an already established indeterminate form of the disease until the development of a primary or secondary cardiac outcome.

METHODS

The following electronic databases will be searched: MEDLINE, Embase, Cochrane Library, Web of Science Core Collection and LILACS. The search will include the following concepts: Chagas disease, latency duration and determinants of the Chagas latency period. The languages will be restricted to English, Spanish and Portuguese. Two reviewers will review the selected studies for methodological quality using critical appraisal tools and conduct data extraction. Studies will, where possible, be pooled in a statistical meta-analysis. All data will be presented and synthesized through tables, summaries, figures and charts.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42019118019.

Implementation science: Epidemiology and feeding profiles of the Chagas vector Triatoma dimidiata prior to Ecohealth intervention for three locations in Central America

The Ecohealth strategy is a multidisciplinary data-driven approach used to improve the quality of people's lives in Chagas disease endemic areas, such as regions of Central America. Chagas is a vector-borne disease caused by the parasite Trypanosoma cruzi. In Central America, the main vector is Triatoma dimidiata. Because successful implementation of the Ecohealth approach reduced home infestation in Jutiapa department, Guatemala, it was scaled-up to three localities, one in each of three Central American countries (Texistepeque, El Salvador; San Marcos de la Sierra, Honduras and Olopa, Guatemala). As a basis for the house improvement phase of the Ecohealth program, we determined if the localities differ in the role of sylvatic, synanthropic and domestic animals in the Chagas transmission cycle by measuring entomological indices, blood meal sources and parasite infection from vectors collected in and around houses. The Polymerase Chain Reaction (PCR) with taxa specific primers to detect both, blood sources and parasite infection, was used to assess 71 T. dimidiata from Texistepeque, 84 from San Marcos de la Sierra and 568 from Olopa. Our results show that infestation (12.98%) and colonization (8.95%) indices were highest in Olopa; whereas T. cruzi prevalence was higher in Texistepeque and San Marcos de la Sierra (>40%) than Olopa (8%). The blood meal source profiles showed that in Olopa, opossum might be important in linking the sylvatic and domestic Chagas transmission cycle, whereas in San Marcos de la Sierra dogs play a major role in maintaining domestic transmission. For Texistepeque, bird was the major blood meal source followed by human. When examining the different life stages, we found that in Olopa, the proportion bugs infected with T. cruzi is higher in adults than nymphs. These findings highlight the importance of location-based recommendations for decreasing human-vector contact in the control of Chagas disease.

Protein mass spectrometry extends temporal blood meal detection over polymerase chain reaction in mouse-fed Chagas disease vectors

BACKGROUND

Chagas disease is highly prevalent in Latin America, and vector control is the most effective control strategy to date. We have previously shown that liquid chromatography tandem mass spectrometry (LC-MS/MS) is a valuable tool for identifying triatomine vector blood meals.

OBJECTIVES

The purpose of this study was to determine blood meal detection ability as a function of method [polymerase chain reaction (PCR) vs. LC-MS/MS], time since feeding, and the effect of molting in mouse-fed triatomine insect vectors targeting hemoglobin and albumin proteins with LC-MS/MS and short interspersed nuclear elements (SINE)-based PCR.

METHODS

We experimentally fed Triatoma protracta on mice and used LC-MS/MS to detect hemoglobin and albumin peptides over time post-feeding and post-molting (≤ 12 weeks). We compared LC-MS/MS results with those of a standard PCR method based on SINEs.

FINDINGS

Hemoglobin-based LC-MS/MS detected blood meals most robustly at all time points post-feeding. Post-molting, no blood meals were detected with PCR, whereas LC-MS/MS detected mouse hemoglobin and albumin up to 12 weeks.

MAIN CONCLUSIONS

In our study, the hemoglobin signature in the insect abdomen lasted longer than that of albumin and DNA. LC-MS/MS using hemoglobin shows promise for identifying triatomine blood meals over long temporal scales and even post-molting. Clarifying the frequency of blood-feeding on different hosts can foster our understanding of vector behavior and may help devise sounder disease-control strategies, including Ecohealth (community based ecosystem management) approaches.

Amiodarone for arrhythmia in patients with Chagas disease: A systematic review and individual patient data meta-analysis

Background

Chagas disease is a neglected chronic condition caused by Trypanosoma cruzi, with high prevalence and burden in Latin America. Ventricular arrhythmias are common in patients with Chagas cardiomyopathy, and amiodarone has been widely used for this purpose. The aim of our study was to assess the effect of amiodarone in patients with Chagas cardiomyopathy.

Methodology

We searched MEDLINE, Embase and LILACS up to January 2018. Data from randomized and observational studies evaluating amiodarone use in Chagas cardiomyopathy were included. Two reviewers selected the studies, extracted data and assessed risk of bias. Overall quality of evidence was accessed using Grading of Recommendations Assessment, Development and Evaluation (GRADE).

Principal findings

We included 9 studies (3 before-after studies, 5 case series and 1 randomized controlled trial). Two studies with a total of 38 patients had the full dataset, allowing individual patient data (IPD) analysis. In 24-hour Holter, amiodarone reduced the number of ventricular tachycardia episodes in 99.9% (95%CI 99.8%-100%), ventricular premature beats in 93.1% (95%CI 82%-97.4%) and the incidence of ventricular couplets in 79% (RR 0.21, 95%CI 0.11–0.39). Studies not included in the IPD analysis showed a reduction of ventricular premature beats (5 studies), ventricular tachycardia (6 studies) and ventricular couplets (1 study). We pooled the incidence of adverse side effects with random effects meta-analysis; amiodarone was associated with corneal microdeposits (61.1%, 95%CI 19.0–91.3, 5 studies), gastrointestinal events (16.1%, 95%CI 6.61–34.2, 3 studies), sinus bradycardia (12.7%, 95%CI 3.71–35.5, 6 studies), dermatological events (10.6%, 95%CI 4.77–21.9, 3 studies) and drug discontinuation (7.68%, 95%CI 4.17–13.7, 5 studies). Quality of evidence ranged from moderate to very low.

Conclusions

Amiodarone is effective in reducing ventricular arrhythmias, but there is no evidence for hard endpoints (sudden death, hospitalization). Although our findings support the use of amiodarone, it is important to balance the potential benefits and harms at the individual level for decision-making.

Chagas disease is a chronic neglected tropical disease, with high prevalence and burden in Latin America. About 30% of chronically infected patients develop Chagas cardiomyopathy. Ventricular arrhythmias are common in patients with Chagas cardiomyopathy and treatment approaches include medications, resynchronization therapy, and implantable cardioverter defibrillator. Studies published from 1980 to 1990 have evaluated the effect of amiodarone. According to our systematic review and individual patient meta-analysis, amiodarone reduced ventricular tachycardia, ventricular premature beats and incidence of ventricular couplets. Although the strong evidence of clinical benefit with arrhythmia reduction, this information should be interpreted with caution, since arrhythmia is a surrogate outcome and since its clinical impact on death and hospitalization reduction over time is not clear. Little information was identified related to hard endpoints. Regarding side effects, our systematic review observed that amiodarone was associated with corneal microdeposits, gastrointestinal events, sinus bradycardia, dermatological events, pneumonitis, hypothyroidism and drug discontinuation. The currently available evidence shows that amiodarone seems to be an effective antiarrhythmic drug for patients with Chagas disease, especially in settings where an implantable cardioverter defibrillator is not available or affordable, but that a balance between potential benefits and harms at the individual level is needed.