Ten years of Chagas disease research: Looking back to achievements, looking ahead to challenges

Synthesis and activity of benzimidazole N-Acylhydrazones against Trypanosoma cruzi, Leishmania amazonensis and Leishmania infantum

In this study, we present the design, synthesis, and cytotoxic evaluation of a series of benzimidazole N-acylhydrazones against strains of T. cruzi (Y and Tulahuen) and Leishmania species (L. amazonensis and L. infantum). Compound (E)-N'-((5-Nitrofuran-2-yl)methylene)-1H-benzo[d]imidazole-2-carbohydrazide demonstrated significant activity against both trypomastigote and amastigote forms (Tulahuen strain), with an IC50/120 h of 0.033 μM and a selectivity index (SI) of 7680. This represents a potency 46 times greater than that of benznidazole (IC50/120 h = 1.520 μM, SI = 1390). Another compound (E)-N'-(2-Hydroxybenzylidene)-1H-benzo[d]imidazole-2-carbohydrazide showed promising activity against both trypomastigote and amastigote forms (Tulahuen strain), with an IC50/120 h of 3.600 μM and an SI of 14.70. However, its efficacy against L. infantum and L. amazonensis was comparatively lower. These findings provide valuable insights for the development of more effective treatments against Trypanosoma cruzi.

Geometric morphometry of the Rhodniusprolixus complex (Hemiptera, Triatominae): patterns of intraspecific and interspecific allometry and their taxonomic implications

In the subfamily Triatominae, the genus Rhodnius is one of the most studied, not only because of its epidemiological importance, but also because of the difficulty in differentiating its species. Currently, one of the strategies to control Chagas disease, besides other initiatives such as the analysis of donated blood, is focused on fighting the vector. Correctly identifying triatomines is essential for the entomoepidemiological surveillance of Chagas disease. The objective of the present work was to compare the species of the R.prolixus complex using geometric morphometry of hemelytra and heads to evaluate the patterns of intraspecific and interspecific allometry and their taxonomic implications. This method can help in the diagnosis of close species, whose morphological characteristics are insufficient for correct identification. Specimens from five different collections were used, covering the species included in the R.prolixus complex (R.barretti, R.dalessandroi, R.domesticus, R.marabaensis, R.milesi, R.montenegrensis, R.nasutus, R.neglectus, R.neivai, R.prolixus and R.robustus). Morphometric analyses indicated that the hemelytra are not structures with good resolution for separating species and, for this reason, the use of the heads proved to be more adequate for this group (thus allowing differentiation of all species of the R.prolixus complex). The results suggest that R.milesi is a variant of R.neglectus and confirms that R.prolixus and R.robustus are distinct species. Furthermore, we propose the creation of the R.neivai complex comprising R.domesticus and R.neivai.

Safety and preservation of cardiac function following therapeutic vaccination against Trypanosoma cruzi in rhesus macaques

BACKGROUND

Chronic Chagasic cardiomyopathy is responsible for a large disease burden in the Americas, and a therapeutic vaccine would be highly desirable. We tested the safety and efficacy of a therapeutic DNA vaccine encoding antigens TSA-1 and Tc24 for preventing cardiac alterations in experimentally infected macaques. A secondary objective was to evaluate the feasibility of detecting changes in cardiac alterations in these animals.

METHODS

Naïve rhesus macaques were infected with Trypanosoma cruzi and treated with three doses of DNA vaccines.

RESULTS

Blood cell counts and chemistry indicated that therapeutic vaccination was safe, as hepatic and renal function appeared unaffected by the vaccination and/or infection with T. cruzi. Electrocardiographic (ECG) recordings indicated that no marked arrhythmias developed up to 7 months post-infection. Univariate analysis of ECG parameters found no significant differences in any of these parameters between vaccinated and control macaques. However, linear discriminant analysis revealed that control macaques presented clear alterations in their ECG patterns at 7 months post-infection, indicative of the onset of conduction defects and cardiac alterations, and these changes were prevented in vaccine treated macaques.

CONCLUSIONS

This is the first evidence that therapeutic vaccination against T. cruzi can prevent cardiac alterations in non-human primates, strengthening the rationale for developing a human vaccine against Chagas disease.

Estimation of the morbidity and mortality of congenital Chagas disease: A systematic review and meta-analysis

Chagas disease is caused by the parasite Trypanosoma cruzi which can be transmitted from mother to baby during pregnancy. There is no consensus on the proportion of infected infants with clinical signs of congenital Chagas disease (cCD). The objective of this systematic review is to determine the burden of cCD. Articles from journal inception to 2020 reporting morbidity and mortality associated with cCD were retrieved from academic search databases. Observational studies, randomized-control trials, and studies of babies diagnosed with cCD were included. Studies were excluded if they were case reports or series, without original data, case-control without cCD incidence estimates, and/or did not report number of participants. Two reviewers screened articles for inclusion. To determine pooled proportion of infants with cCD with clinical signs, individual clinical signs, and case-fatality, random effects meta-analysis was performed. We identified 4,531 records and reviewed 4,301, including 47 articles in the narrative summary and analysis. Twenty-eight percent of cCD infants showed clinical signs (95% confidence interval (CI) = 19.0%, 38.5%) and 2.2% of infants died (95% CI = 1.3%, 3.5%). The proportion of infected infants with hepatosplenomegaly was 12.5%, preterm birth 6.0%, low birth weight 5.8%, anemia 4.9%, and jaundice 4.7%. Although most studies did not include a comparison group of non-infected infants, the proportion of infants with cCD with clinical signs at birth are comparable to those with congenital toxoplasmosis (10.0%-30.0%) and congenital cytomegalovirus (10.0%-15.0%). We conclude that cCD burden appears significant, but more studies comparing infected mother-infant dyads to non-infected ones are needed to determine an association of this burden to cCD.

Gold Nanoshells-Based Lateral Flow Assay for the Detection of Chagas Disease at the Point-of-Care

Chagas disease is a neglected parasitic infection and a major public health problem in the Americas. It remains underdiagnosed in the United States and internationally due to the lack of affordable testing and disparities in healthcare, particularly for those most at risk. We describe a proof-of-concept lateral flow immunoassay employing a recombinant Chagas multiantigen conjugated to gold nanoshells (AuNS) to detect circulating human anti-Chagas IgG antibodies. This is one of the first lateral flow immunoassays to capitalize on the larger surface area of AuNS compared with nanoparticles that can help amplify low-magnitude signals. Results were compared with 42 positive and negative Chagas serum samples, of which a subset of 27 samples was validated against an ELISA (Hemagen®). The sensitivity and specificity of our assay were 83% and 95%, respectively. These results suggest that an AuNS-based rapid testing for Chagas disease could facilitate in-field screening/diagnosis with a performance comparable to commercial methods.

Management of Esophageal Dysphagia in Chagas Disease

Chagas disease, caused by the infection of the protozoan parasite Trypanosoma cruzi, has clinical consequences in the heart and digestive tract. The most important changes in the digestive tract occur in the esophagus (megaesophagus) and colon (megacolon). Esophageal dysfunction in Chagas disease results from damage of the esophageal myenteric plexus, with loss of esophageal peristalsis, partial or absent lower esophageal sphincter relaxation, and megaesophagus, which characterizes secondary esophageal achalasia. The treatment options for the disease are similar to those for idiopathic achalasia, consisting of diet and behavior changes, drugs, botulinum toxin, peroral endoscopic myotomy (POEM), pneumatic dilation of the lower esophageal sphincter, laparoscopic Heller myotomy, and esophagectomy. Chagas disease causes a life-threatening cardiopathy, and this should be considered when choosing the most appropriate treatment for the disease. While some options are palliative, for temporary relief of dysphagia (such as drugs, botulinum toxin, and pneumatic dilation), other therapies provide a long-term benefit. In this case, POEM stands out as a modern and successful strategy, with good results in more than 90% of the patients. Esophagectomy is the option in Chagas disease patients with advanced megaesophagus, despite the increased risk of complications. In these cases, peroral endoscopic myotomy may be an option, which needs further evaluation.

Shelter cats host infections with multiple Trypanosoma cruzi discrete typing units in southern Louisiana

Trypanosoma cruzi is a zoonotic parasite endemic in the southern US and the Americas, which may frequently infect dogs, but limited information is available about infections in cats. We surveyed a convenience sample of 284 shelter cats from Southern Louisiana to evaluate T. cruzi infection using serological and PCR tests. Parasites from PCR positive cats were also genotyped by PCR and deep sequencing to assess their genetic diversity. We detected a seropositivity rate for T. cruzi of at least 7.3% (17/234), and 24.6% of cats (70/284) were PCR positive for the parasite. Seropositivity increased with cat age (R² = 0.91, P = 0.011), corresponding to an incidence of 7.2% ± 1.3 per year, while PCR positivity decreased with age (R² = 0.93, P = 0.007). Cats were predominantly infected with parasites from TcI and TcVI DTUs, and to a lesser extent from TcIV and TcV DTUs, in agreement with the circulation of these parasite DTUs in local transmission cycles. These results indicate that veterinarians should have a greater awareness of T. cruzi infection in pets and that it would be important to better evaluate the risk for spillover infections in humans.

Genetic diversity of Trypanosoma cruzi parasites infecting dogs in southern Louisiana sheds light on parasite transmission cycles and serological diagnostic performance

Background

Chagas disease is a neglected zoonosis of growing concern in the southern US, caused by the parasite Trypanosoma cruzi. We genotyped parasites in a large cohort of PCR positive dogs to shed light on parasite transmission cycles and assess potential relationships between parasite diversity and serological test performance.

Methodology/principal findings

We used a metabarcoding approach based on deep sequencing of T. cruzi mini-exon marker to assess parasite diversity. Phylogenetic analysis of 178 sequences from 40 dogs confirmed the presence of T. cruzi discrete typing unit (DTU) TcI and TcIV, as well as TcII, TcV and TcVI for the first time in US dogs. Infections with multiple DTUs occurred in 38% of the dogs. These data indicate a greater genetic diversity of T. cruzi than previously detected in the US. Comparison of T. cruzi sequence diversity indicated that highly similar T. cruzi strains from these DTUs circulate in hosts and vectors in Louisiana, indicating that they are involved in a shared T. cruzi parasite transmission cycle. However, TcIV and TcV were sampled more frequently in vectors, while TcII and TcVI were sampled more frequently in dogs.

Conclusions/significance

These observations point to ecological host-fitting being a dominant mechanism involved in the diversification of T. cruzi-host associations. Dogs with negative, discordant or confirmed positive T. cruzi serology harbored TcI parasites with different mini-exon sequences, which strongly supports the hypothesis that parasite genetic diversity is a key factor affecting serological test performance. Thus, the identification of conserved parasite antigens should be a high priority for the improvement of current serological tests.

Chagas disease is a neglected zoonosis of growing concern in the southern US, caused by the parasite Trypanosoma cruzi. Here we analyzed the parasite genetic diversity in a large cohort of infected dogs to better understand parasite transmission cycles and assess potential relationships between parasite diversity and serological test performance. We used DNA sequencing of a well characterized T. cruzi genetic marker to assess parasite diversity. We confirmed the presence of T. cruzi lineages TcI and TcIV, and report TcII, TcV and TcVI for the first time in US dogs. Parasite lineages TcIV TcII and TcVI appeared more frequent in dogs compared to insect vectors. Dogs with negative, discordant or confirmed positive T. cruzi serology harbored genetically different TcI parasites, which shows that parasite genetic diversity is a key factor affecting serological test performance. Thus, the identification of parasite antigens conserved across strains and lineages should be a high priority for the improvement of current serological tests.

Safety and immunogenicity of a recombinant vaccine against Trypanosoma cruzi in Rhesus macaques

Chagas disease, caused by the protozoan parasite Trypanosoma cruzi is one of the most important neglected parasitic diseases in the Americas. Vaccines represent an attractive complementary strategy for the control of T. cruzi infection and pre-clinical studies in mice demonstrated that trypomastigote surface antigen (TSA-1) and the flagellar calcium-binding (Tc24) parasite antigens are promising candidates for vaccine development. We performed here the first evaluation of the safety and immunogenicity of two recombinant vaccine antigens (named TSA1-C4 and Tc24-C4) in naïve non-human primates. Three rhesus macaques received 3 doses of each recombinant protein, formulated with E6020 (Eisai Co., Ltd.), a novel Toll-like receptor-4 agonist, in a stable emulsion. All parameters from blood chemistry and blood cell counts were stable over the course of the study and unaffected by the vaccine. A specific IgG response against both antigens was detectable after the first vaccine dose, and increased with the second dose. After three vaccine doses, stimulation of PBMCs with a peptide pool derived from TSA1-C4 resulted in the induction of TSA1-C4-specific TNFα-, IL-2- and IFNγ-producing CD4⁺ in one or two animals while stimulation with a peptide pool derived from Tc24-C4 only activated IFNγ-producing CD4⁺T cells in one animal. In two animals there was also activation of TSA1-C4-specific IL2-producing CD8⁺ T cells. This is the first report of the immunogenicity of T. cruzi-derived recombinant antigens formulated as an emulsion with a TLR4 agonist in a non-human primate model. Our results strongly support the need for further evaluation of the preventive efficacy of this type of vaccine in non-human primates and explore the effect of the vaccine in a therapeutic model of naturally-infected Chagasic non-human primates, which would strengthen the rationale for the clinical development as a human vaccine against Chagas disease.

Molecular Characterization of Tc964, A Novel Antigenic Protein from Trypanosoma cruzi

The Tc964 protein was initially identified by its presence in the interactome associated with the LYT1 mRNAs, which code for a virulence factor of Trypanosoma cruzi. Tc964 is annotated in the T. cruzi genome as a hypothetical protein. According to phylogenetic analysis, the protein is conserved in the different genera of the Trypanosomatidae family; however, recognizable orthologues were not identified in other groups of organisms. Therefore, as a first step, an in-depth molecular characterization of the Tc946 protein was carried out. Based on structural predictions and molecular dynamics studies, the Tc964 protein would belong to a particular class of GTPases. Subcellular fractionation analysis indicated that Tc964 is a nucleocytoplasmic protein. Additionally, the protein was expressed as a recombinant protein in order to analyze its antigenicity with sera from Chagas disease (CD) patients. Tc964 was found to be antigenic, and B-cell epitopes were mapped by the use of synthetic peptides. In parallel, the Leishmania major homologue (Lm964) was also expressed as recombinant protein and used for a preliminary evaluation of antigen cross-reactivity in CD patients. Interestingly, Tc964 was recognized by sera from Chronic CD (CCD) patients at different stages of disease severity, but no reactivity against this protein was observed when sera from Colombian patients with cutaneous leishmaniasis were analyzed. Therefore, Tc964 would be adequate for CD diagnosis in areas where both infections (CD and leishmaniasis) coexist, even though additional assays using larger collections of sera are needed in order to confirm its usefulness for differential serodiagnosis.

Synthesis, Antitrypanosomal and Antimycobacterial Activities of Coumarin N-acylhydrazonic Derivatives

BACKGROUND

Near to 5-7 million people are infected with T. cruzi in the world, and about 10,000 people per year die of problems associated with this disease.

METHODS

Herein, the synthesis, antitrypanosomal and antimycobacterial activities of seventeen coumarinic N-acylhydrazonic derivatives have been reported.

RESULTS

These compounds were synthesized using methodology with reactions global yields ranging from 46%-70%. T. cruzi in vitro effects were evaluated against trypomastigote and amastigote, forming M. tuberculosis activity towards H37Rv sensitive strain and resistant strains.

DISCUSSION

Against T. cruzi, the more active compounds revealed only moderate activity IC₅₀/96h~20 μM for both trypomastigotes and amastigotes intracellular forms. (E)-2-oxo-N'- (3,4,5-trimethoxybenzylidene)-2H-chromene-3-carbohydrazide showed meaningful activity in INH resistant/RIP resistant strain.

CONCLUSION

These compound acting as multitarget could be good leads for the development of new trypanocidal and bactericidal agents.

Determinants of intentions to prevent triatomine infestation based on the health belief model: An application in rural southern Ecuador

INTRODUCTION

Control of triatomine infestation is a key strategy for the prevention of Chagas disease (CD). To promote this strategy, it is important to know which antecedents to behavioral change are the best to emphasize when promoting prevention.

OBJECTIVE

The aim of this study was to determine predictors for intention to prevent home infestation based on the Health Belief Model (HBM), a commonly used health intervention planning theory.

MATERIALS & METHODS

A cross-sectional study was conducted with 112 heads of household in six communities with endemic and high rates of triatomine infestation in Loja province, Ecuador. The data was collected by a questionnaire including perceived severity, susceptibility, benefits to action, barriers to action, and self-efficacy. These data were also used to predict actual infestation of homes.

RESULTS

Community members reported strong intentions to prevent home infestation. HBM constructs predicted about 14% of the observed variance in intentions. Perceived susceptibility and severity did not predict behavioral intention well; perceived barriers to small-scale action that reduce likelihood of infestation and self-efficacy in participating in surveillance systems did. Self-efficacy and perception of barriers were equally powerful predictors. The HBM constructs, however, did not predict well actual infestation.

CONCLUSION

The findings supported the HBM as a way to predict intentions to prevent infestation of the home by triatomine bugs. The findings highlight that messages emphasizing self-efficacy in participating in surveillance systems and overcoming barriers to small-scale action that reduce likelihood of infestation, rather than a focus on risk, should be central messages when designing and implementing educational interventions for CD. The gap between behavioral intention and actual infestation reveals the need to assess home practices and their actual efficacy to fully enact and apply the HBM.

Why Funding for Neglected Tropical Diseases Should Be a Global Priority

Neglected tropical diseases affect >1 billion of the world's poorest persons. Control programs range from near-elimination (dracunculiasis) to increasing prevalence (dengue and cutaneous leishmaniasis). These are some of the most cost-effective public health interventions and should be a global priority.

High prevalence of Trypanosoma cruzi infection in shelter dogs from southern Louisiana, USA

Background

Chagas disease is a zoonotic disease caused by the protozoan parasite Trypanosoma cruzi. The role of dogs as sentinels has been proposed in multiple regions, as they are a domestic reservoir for T. cruzi. Our objective was to determine the prevalence of T. cruzi infection in shelter dogs from southern Louisiana, and assess its magnitude and distribution.

Results

A total of 540 dogs were enrolled, from 20 animal shelters, and tested for T. cruzi infection by serological tests (rapid test, ELISA and western blot) and PCR. We documented a high prevalence of T. cruzi infection with at least 6.9% (95% CI: 5.0–9.3%) seropositive and 15.7% (95% CI: 12.9–19.1%) PCR-positive dogs. Serological tests showed limited agreement, and concordance between serology and PCR was higher when considering reactivity to single serological tests. Trypanosoma cruzi infection was distributed evenly among shelters. Infection was significantly correlated with age (R² = 0.99), indicating an incidence of new cases of 2.27 ± 0.25% per year.

Conclusion

Trypanosoma cruzi infection is a significant and widespread veterinary problem in shelter dogs in the region, although it is mostly unnoticed by health professionals. This highlights the need for greater awareness of T. cruzi infection among the veterinary community and dog owners.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3572-y) contains supplementary material, which is available to authorized users.

Estimating the current burden of Chagas disease in Mexico: A systematic review and meta-analysis of epidemiological surveys from 2006 to 2017

BACKGROUND

In Mexico, estimates of Chagas disease prevalence and burden vary widely. Updating surveillance data is therefore an important priority to ensure that Chagas disease does not remain a barrier to the development of Mexico's most vulnerable populations.

METHODOLOGY/PRINCIPAL FINDINGS

The aim of this systematic review and meta-analysis was to analyze the literature on epidemiological surveys to estimate Chagas disease prevalence and burden in Mexico, during the period 2006 to 2017. A total of 2,764 articles were screened and 36 were retained for the final analysis. Epidemiological surveys have been performed in most of Mexico, but with variable study scale and geographic coverage. Based on studies reporting confirmed cases (i.e. using at least 2 serological tests), and taking into account the differences in sample sizes, the national estimated seroprevalence of Trypanosoma cruzi infection was 3.38% [95%CI 2.59-4.16], suggesting that there are 4.06 million cases in Mexico. Studies focused on pregnant women, which may transmit the parasite to their newborn during pregnancy, reported an estimated seroprevalence of 2.21% [95%CI 1.46-2.96], suggesting that there are 50,675 births from T. cruzi infected pregnant women per year, and 3,193 cases of congenitally infected newborns per year. Children under 18 years had an estimated seropositivity rate of 1.51% [95%CI 0.77-2.25], which indicate ongoing transmission. Cases of T. cruzi infection in blood donors have also been reported in most states, with a national estimated seroprevalence of 0.55% [95%CI 0.43-0.66].

CONCLUSIONS/SIGNIFICANCE

Our analysis suggests a disease burden for T. cruzi infection higher than previously recognized, highlighting the urgency of establishing Chagas disease surveillance and control as a key national public health priority in Mexico, to ensure that it does not remain a major barrier to the economic and social development of the country's most vulnerable populations.

Isosorbide and nifedipine for Chagas' megaesophagus: A systematic review and meta-analysis

BACKGROUND

Chagas disease is a neglected tropical disease. About 6 to 8 million people are chronically infected and 10% to 15% develop irreversible gastrointestinal disorders, including megaesophagus. Treatment focuses on improving symptoms, and isosorbide and nifedipine may be used for this purpose.

METHODOLOGY

We conducted a systematic review to evaluate the effectiveness of pharmacological treatment for Chagas' megaesophagus. We searched MEDLINE, Embase and LILACS databases up to January 2018. We included both observational studies and RCTs evaluating the effects of isosorbide or nifedipine in adult patients with Chagas' megaesophagus. Two reviewers screened titles and abstracts, selected eligible studies and extracted data. We assessed the risk of bias using NIH 'Quality Assessment Tool for Before-After (Pre-Post) Studies with No Control Group' and RoB 2.0 tool. Overall quality of evidence was assessed using GRADE.

PRINCIPAL FINDINGS

We included eight studies (four crossover RCTs, four before-after studies). Three studies evaluated the effect of isosorbide on lower esophageal sphincter pressure (LESP), showing a significant reduction (mean difference -10.52mmHg, 95%CI -13.57 to-7.47, very low quality of evidence). Three studies reported the effect of isosorbide on esophageal emptying, showing a decrease in esophageal retention rates (mean difference -22.16%, 95%CI -29.94 to -14.38, low quality of evidence). In one study, patients on isosorbide reported improvement in the frequency and severity of dysphagia (moderate quality of evidence). Studies evaluating nifedipine observed a decrease in LESP but no effect on esophageal emptying (very low and low quality of evidence, respectively). Isosorbide had a higher incidence of headache as a side effect than nifedipine.

CONCLUSIONS

Although limited, available evidence shows that both isosorbide and nifedipine are effective in reducing esophageal symptoms. Isosorbide appears to be more effective, and its use is supported by a larger number of studies; nifedipine, however, appears to have a better tolerability profile.

TRIAL REGISTRATION

PROSPERO CRD42017055143. ClinicalTrials.gov CRD42017055143.

Physician Knowledge, Attitudes, and Practices Related to Chagas Disease in Tabasco, Mexico

We designed and implemented a survey of physician knowledge, attitudes, and practices with respect to Chagas disease in the state of Tabasco, Mexico. Seventy-eight public sector physicians from across the state responded via Research Electronic Data Capture, an online survey capture tool. Improved performance on knowledge-based questions (P < 0.01) and an increase in decisions to screen (P = 0.04) were associated with previous training specific to this disease. Our results provide important descriptive information regarding knowledge, attitudes, and practices among a group of public sector Mexican doctors and highlight the importance of Chagas disease-specific physician training for identification and, ultimately, treatment of patients affected by this disease.

Clair RM, Vincent JJ, Monroy MC, Stevens L. Chagas disease vector blood meal sources identified by protein mass spectrometry

Chagas disease is a complex vector borne parasitic disease involving blood feeding Triatominae (Hemiptera: Reduviidae) insects, also known as kissing bugs, and the vertebrates they feed on. This disease has tremendous impacts on millions of people and is a global health problem. The etiological agent of Chagas disease, Trypanosoma cruzi (Kinetoplastea: Trypanosomatida: Trypanosomatidae), is deposited on the mammalian host in the insect’s feces during a blood meal, and enters the host’s blood stream through mucous membranes or a break in the skin. Identifying the blood meal sources of triatomine vectors is critical in understanding Chagas disease transmission dynamics, can lead to identification of other vertebrates important in the transmission cycle, and aids management decisions. The latter is particularly important as there is little in the way of effective therapeutics for Chagas disease. Several techniques, mostly DNA-based, are available for blood meal identification. However, further methods are needed, particularly when sample conditions lead to low-quality DNA or to assess the risk of human cross-contamination. We demonstrate a proteomics-based approach, using liquid chromatography tandem mass spectrometry (LC-MS/MS) to identify host-specific hemoglobin peptides for blood meal identification in mouse blood control samples and apply LC-MS/MS for the first time to Triatoma dimidiata insect vectors, tracing blood sources to species. In contrast to most proteins, hemoglobin, stabilized by iron, is incredibly stable even being preserved through geologic time. We compared blood stored with and without an anticoagulant and examined field-collected insect specimens stored in suboptimal conditions such as at room temperature for long periods of time. To our knowledge, this is the first study using LC-MS/MS on field-collected arthropod disease vectors to identify blood meal composition, and where blood meal identification was confirmed with more traditional DNA-based methods. We also demonstrate the potential of synthetic peptide standards to estimate relative amounts of hemoglobin acquired when insects feed on multiple blood sources. These LC-MS/MS methods can contribute to developing Ecohealth control strategies for Chagas disease transmission and can be applied to other arthropod disease vectors.

Cardiomyopathies: An Overview

The nonischemic cardiomyopathies are a diverse group of cardiac disorders that frequently cause heart failure and death and are now recognized with increasing frequency. There has been substantial progress in the clinical recognition and understanding of the natural history of these conditions. Well-established and new techniques of cardiac imaging are also helpful in this regard. Basic scientists are elucidating the pathogenesis and pathobiology of individual cardiomyopathies. In this compendium, some of the most important advances in this field are reviewed. Scientific opportunities to enhance further collaborative research to accelerate progress are identified.