Congenital Chagas disease: current diagnostics, limitations and future perspectives

Copaifera spp. oleoresins control Trypanosoma cruzi infection in human trophoblast cells (BeWo) and placental explants

Congenital Chagas disease (CCD) is a worldwide neglected problem with significant treatment limitations. This study aimed to evaluate the potential of Copaifera spp. oleoresins (ORs) against Trypanosoma cruzi infection in trophoblast cells (BeWo lineage) and human chorionic villous explants (HCVE). The cytotoxicity of ORs was investigated using LDH and MTT assays. T. cruzi (Y strain) proliferation, invasion and reversibility were assessed in OR-treated BeWo cells, and proliferation was evaluated in OR-treated HCVE. The ultrastructure of T. cruzi trypomastigotes and amastigotes treated with ORs were analyzed by scanning and transmission electronic microscopy. ROS production in infected and treated BeWo cells and cytokines in BeWo and HCVE were measured. The ORs irreversibly decreased T. cruzi invasion, proliferation and release in BeWo cells by up to 70 %, 82 % and 80 %, respectively, and reduced parasite load in HCVE by up to 80 %. Significant structural changes in treated parasites were observed. ORs showed antioxidant capacity in BeWo cells, reducing ROS production induced by T. cruzi infection. Also, T. cruzi infection modulated the cytokine profile in both BeWo cells and HCVE; however, treatment with ORs upregulated cytokines decreased by T. cruzi infection in BeWo cells, while downregulated cytokines increased by the T. cruzi infection in HCVE. In conclusion, non-cytotoxic concentrations of Copaifera ORs demonstrated promising potential for controlling T. cruzi infection in models of the human maternal-fetal interface.

Novel 3D human trophoblast culture to explore T. cruzi infection in the placenta

Introduction

Human trophoblastic cell lines, such as BeWo, are commonly used in 2D models to study placental Trypanosoma cruzi infections. However, these models do not accurately represent natural infections. Three-dimensional (3D) microtissue cultures offer a more physiologically relevant in vitro model, mimicking tissue microarchitecture and providing an environment closer to natural infections. These 3D cultures exhibit functions such as cell proliferation, differentiation, morphogenesis, and gene expression that resemble in vivo conditions.

Methods

We developed a 3D culture model using the human trophoblastic cell line BeWo and nonadherent agarose molds from the MicroTissues® 3D Petri Dish® system. Both small (12-256) and large (12-81) models were tested with varying initial cell numbers. We measured the diameter of the 3D cultures and evaluated cell viability using Trypan Blue dye. Trophoblast functionality was assessed by measuring β-hCG production via ELISA. Cell fusion was evaluated using confocal microscopy, with Phalloidin or ZO-1 marking cell edges and DAPI staining nuclei. T. cruzi infection was assessed by microscopy and quantitative PCR, targeting the EF1-α gene for T. cruzi and GAPDH for BeWo cells, using three parasite strains: VD (isolated from a congenital Chagas disease infant and classified as Tc VI), and K98 and Pan4 (unrelated to congenital infection and classified as Tc I).

Results

Seeding 1000 BeWo cells per microwell in the large model resulted in comparable cellular viability to 2D cultures, with a theoretical diameter of 408.68 ± 12.65 μm observed at 5 days. Functionality, assessed through β-hCG production, exceeded levels in 2D cultures at both 3 and 5 days. T. cruzi infection was confirmed by qPCR and microscopy, showing parasite presence inside the cells for all three tested strains. The distribution and progression of the infection varied with each strain.

Discussion

This innovative 3D model offers a simple yet effective approach for generating viable and functional cultures susceptible to T. cruzi infection, presenting significant potential for studying the placental microenvironment.

Chagas disease in immunocompromised patients

SUMMARYAs Chagas disease remains prevalent in the Americas, it is important that healthcare professionals and researchers are aware of the screening, diagnosis, monitoring, and treatment recommendations for the populations of patients they care for and study. Management of Trypanosoma cruzi infection in immunocompromised hosts is challenging, particularly because, regardless of antitrypanosomal treatment status, immunocompromised patients with Chagas disease are at risk for T. cruzi reactivation, which can be lethal. Evidence-based practices to prevent and manage T. cruzi reactivation vary depending on the type of immunocompromise. Here, we review available data describing Chagas disease epidemiology, testing, and management practices for various populations of immunocompromised individuals, including people with HIV and patients undergoing solid organ and hematopoietic stem cell transplantation.

Chagas disease

Chagas disease persists as a global public health problem due to the high morbidity and mortality burden. Despite the possibility of a cure and advances in transmission control, epidemiological transformations, such as urbanisation and globalisation, and the emerging importance of oral and vertical transmission mean that Chagas disease should be considered an emerging disease, with new cases occurring worldwide. Important barriers to diagnosis, treatment, and care remain, resulting in repressed numbers of reported cases, which in turn leads to inadequate public policies. The validation of new diagnostic tools and treatment options is needed, as existing tools pose serious limitations to access to health care. Integrated models of surveillance, with community and intersectional participation, embedded in the concept of One Health, are essential for control. In addition, mitigation strategies for the main social determinants of health, including difficulties imposed by migration, are important to improve access to comprehensive health care in a globalised scenario.

Chagas Disease in Europe

Chagas disease is currently present in many non-endemic countries and remains a neglected tropical disease globally. A review of the literature identified significant gaps and scarcity of updated information from European countries, with most studies reporting data from Spain and Italy. The index of underdiagnosis may be as high as 70%, affecting mainly females of child-bearing age. Standardized screening of fertile, non-pregnant, women from endemic countries and subsequent treatment is considered an essential strategy to control transmission and prevent new cases, yet no uniform legislation for screening risk groups exists. There is heterogeneity in Europe in terms of preventive strategies to avoid transfusion-related transmission of Chagas disease, not necessarily in line with the European directives, with some countries conducting systematic screening for T. cruzi infection in blood donors, whilst others rely on pre-transfusion questionnaires. The growing burden of the infection in resource-rich areas may provide an opportunity for progress in certain aspects of control and prevention. Options for improving screening strategies, management and linkage to care are reviewed.

Vector-borne disease, climate change and perinatal health

Vector-borne diseases (VBDs) are caused by infectious pathogens that spread from an infected human or animal reservoir to an uninfected human via a vector (mosquito, tick, rodent, others) and remain an important cause of morbidity and mortality worldwide. Pregnant individuals and their fetuses are especially at risk, as certain pathogens, such as Zika virus, have specific implications in pregnancy and for neonatal health. Global climate change is affecting the incidence and geographic spread of many VBDs. Thus, it is important for clinicians in the fields of obstetrics/gynecology and newborn medicine, regardless of geographic location, to familiarize themselves with a basic understanding of these conditions and how climate change is altering their distributions. In this chapter, we review the incidence, clinical presentation, implications during pregnancy and intersection with climate change for four of the most important VBDs in pregnancy: malaria, Zika, dengue and Chagas disease. Although not exhaustive of all VBDs, a more extensive table is included for reference, and our discussion provides a helpful framework for understanding other vector-borne pathogens and perinatal health.

Exclusion of Horizontal and Vertical Transmission as Major Sources of Trypanosoma Cruzi Infections in a Breeding Colony of Rhesus Macaques (Macaca Mulatta)

The vector-borne protozoal parasite Trypanosoma cruzi causes Chagas disease in humans and animals. This parasite is endemic to the southern United States where outdoor-housed NHP at biomedical facilities are at risk of infection. In addi- tion to the direct morbidity caused by T. cruzi, infected animals are of limited biomedical research use because infections can produce confounding pathophysiologic changes even in animals with no clinical disease. In part due to concerns for direct T. cruzi transmission between animals, infected NHP at some institutions have been culled, removed, or otherwise isolated from uninfected animal populations. However, data that document horizontal or vertical transmission in captive NHP in the United States are not available. To evaluate the potential for inter-animal transmission and to identify environmental factors that affect the distribution of new infections in NHPs, we conducted a retrospective epidemiologic study of a rhesus macaque ( Macaca mulatta ) breeding colony in south Texas. We used archived biologic samples and husbandry records to identify the time and location of macaque seroconversion. These data were used to perform a spatial analysis of how geographic location and animal associations affected the spread of disease and to infer the importance of horizontal or vertical routes of transmission. The majority of T. cruzi infections were spatially clustered, suggesting that environmental factors promoted vector exposure in various areas of the facility. Although we cannot not rule out horizontal transmission, our data suggest that horizontal transmission was not a critical route for spread for the disease. Vertical transmission was not a contributing factor in this colony. In conclusion, our findings suggest that local triatome vectors were the major source of T. cruzi infections in captive macaques in our colony. Therefore, limiting contact with vectors, rather than segregation of infected macaques, is a key strategy for disease prevention at institutions that house macaques outdoors in the southern United States.

Effects of Acute and Chronic Trypanosoma cruzi Infection on Pregnancy Outcomes in Mice: Parasite Transmission, Mortality, Delayed Growth, and Organ Damage in Pups

Chagas disease is caused by Trypanosoma cruzi. This study aimed to determine the effects of T. cruzi infection on fertility rate and health of the newborn pups in pregnant mice. Female mice were challenged with T. cruzi and mated at 21 days (acute parasitemic phase) or 90 days (chronic parasite persistence phase) after infection. Pups were examined for growth up to 20 days after birth; and parasite burden in brain, heart, skeletal muscle, and intestine was measured by real-time quantitative PCR. The inflammatory infiltrate, necrosis, and fibrosis in pups' heart and brain tissues were evaluated by histology. T. cruzi infection in dams delayed the onset of pregnancy, decreased the fertility rate, and led to vertical transmission of parasite to the pups. Furthermore, infected dams delivered pups that exhibited decreased survival rate, decreased birth weight, and decreased growth rate. Significantly increased inflammation, necrosis, and fibrosis of cardiac and brain tissues were noted in pups born to infected dams. Initial challenge with higher parasite dose had more detrimental effects on fertility rate and pups' health in both acutely and chronically infected dams. In conclusion, mice offer a promising model to evaluate the efficacy of new vaccines and therapeutic drugs in controlling the acute and chronic maternal T. cruzi infection and congenital transmission to newborns, and in improving the fertility rate and pups' health outcomes.

Chagas Disease

Chagas disease, which is caused by infection with the parasite Trypanosoma cruzi, is a leading neglected tropical disease in the United States. An estimated 240 000 to 350 000 persons in the United States are infected, primarily immigrants from Mexico, Central America, and South America, where the disease is endemic. The parasite is transmitted by the triatomine bug but can also be passed through blood transfusion, via organ transplant, or congenitally. Approximately 30% of infected persons later develop cardiac and/or gastrointestinal complications. Health care providers should consider screening at-risk patients with serologic testing. Early diagnosis and treatment with benznidazole or nifurtimox can help prevent complications.

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.

Effect of clinician information sessions on diagnostic testing for Chagas disease

Background

Chagas disease is a potentially life-threatening neglected disease of poverty that is endemic in continental Latin America. Caused by Trypanosoma cruzi (T. cruzi), it is one of six parasitic diseases in the United States targeted by the Centers for Disease Control as a public health problem in need of action. An estimated 300,000 people are infected with T. cruzi in the United States (US). Although its morbidity, mortality and economic burden are high, awareness of Chagas disease is lacking among many healthcare providers in the US. The purpose of this analysis is to determine if the number of diagnostic tests performed at a community health center serving an at-risk population for Chagas disease increased after information sessions. A secondary aim was to determine if there was a difference by provider type, i.e., nurse practitioner vs. physician, or by specialty in the number of patients screened.

Methodology/Principal findings

We conducted a retrospective data analysis of the number of Chagas serology tests performed at a community health center before and after information sessions for clinicians. A time series analysis was conducted focusing on the Adult and Family Medicine Departments at East Boston Neighborhood Health Center (EBNHC). Across all departments there were 1,957 T. cruzi tests performed before the sessions vs. 2,623 after the sessions. Interrupted time series analysis across departments indicated that testing volume was stable over time prior to the sessions (pre-period slope = +4.1 per month; p = 0.12), followed by an immediate shift after the session (+51.6; p = 0.03), while testing volume remained stable over time after the session (post-period slope = -6.0 per month; p = 0.11).

Conclusion/Significance

In this study, Chagas testing increased after information sessions. Clinicians who began testing their patients for Chagas disease after learning of the importance of this intervention added an extra, potentially time-consuming task to their already busy workdays without external incentives or recognition.

Chagas disease is a potentially fatal neglected disease of poverty. It is endemic in continental Latin America with an estimated 300,000 cases in the United States, primarily among low-income people who have immigrated to the US from Latin America. Few Chagas screening programs have been established in the US. Existing recommendations for Chagas disease testing and treatment are rarely followed for many reasons including a paucity of knowledge among providers. We aimed to determine if the number of Chagas tests performed increased after information sessions at a community health center. A secondary aim was to determine if there was a difference in number of tests performed by provider type. We found that the number of T. cruzi serologies performed in the ten months after information sessions increased significantly over that in the ten preceding months. Chagas testing increased across departments, though Chagas diagnostics were an extra and unmitigated time burden on clinicians. Increasing provider knowledge is a major step to increase diagnosis and treatment of this neglected disease, when clinicians are motivated by their inherent prosocial preferences including altruism i.e., by the positive impact of their work on patients’ lives.

Worldwide Control and Management of Chagas Disease in a New Era of Globalization: a Close Look at Congenital Trypanosoma cruzi Infection

Population movements have turned Chagas disease (CD) into a global public health problem. Despite the successful implementation of subregional initiatives to control vectorial and transfusional Trypanosoma cruzi transmission in Latin American settings where the disease is endemic, congenital CD (cCD) remains a significant challenge. In countries where the disease is not endemic, vertical transmission plays a key role in CD expansion and is the main focus of its control. Although several health organizations provide general protocols for cCD control, its management in each geopolitical region depends on local authorities, which has resulted in a multitude of approaches. The aims of this review are to (i) describe the current global situation in CD management, with emphasis on congenital infection, and (ii) summarize the spectrum of available strategies, both official and unofficial, for cCD prevention and control in countries of endemicity and nonendemicity. From an economic point of view, the early detection and treatment of cCD are cost-effective. However, in countries where the disease is not endemic, national health policies for cCD control are nonexistent, and official regional protocols are scarce and restricted to Europe. Countries of endemicity have more protocols in place, but the implementation of diagnostic methods is hampered by economic constraints. Moreover, most protocols in both countries where the disease is endemic and those where it is not endemic have yet to incorporate recently developed technologies. The wide methodological diversity in cCD diagnostic algorithms reflects the lack of a consensus. This review may represent a first step toward the development of a common strategy, which will require the collaboration of health organizations, governments, and experts in the field.

Congenital transmission of Mexican strains of Trypanosoma cruzi TcIa: interaction between parasite and human placental explants

Congenital transmission of Chagas disease plays an important role in endemic countries because it is not a diagnosis that is encountered frequently in prenatal care. Due to limited information regarding congenital transmission of Trypanosoma cruzi in Mexico, the present study aimed to investigate protozoan infectivity and modulation of immune responses in human placental explants infected with T. cruzi Ia Mexican strains. The Inc-5 strain showed increased infectivity and modulated IL-1β, IL-10 and TLR-4, decreasing their expression after 24 h of infection. Both strains (Inc-5 and Ninoa) stimulated the production of TNF-α and decreased IL-6 levels 96 h after infection. An important detachment of the syncytiotrophoblast caused by infection with T. cruzi was observed after 24 h of infection. In this study, ex vivo infection of human placental villi was performed to better understand interactions involving parasitic T. cruzi and human placental tissue. It was concluded that the strains of TcIa present parasitism in placental tissue, modulation of the innate immune system of the placenta, and cause intense detachment of the syncytiotrophoblast, a fact that may be more associated with abortion and premature birth events than the congenital transmission itself, justifying the low rate of this transmission mechanism by this genotype.

Chagas Disease in Pregnant Women from Endemic Regions Attending the Hospital General de Mexico, Mexico City

Trypanosoma cruzi infection leads to Chagas disease (CD), a neglected tropical infection of significant public health importance in South and Central America and other, non-endemic, countries. Pregnant women and their children are of particular importance to screen as T. cruzi can be transmitted vertically. The objective of this study was to screen for T. cruzi infection among pregnant women from endemic areas seen at the Hospital General de Mexico for prenatal care, so that they and their children may be quickly connected to CD treatment. Pregnant women were recruited through the hospital prenatal clinic and screened for T. cruzi infection using a series of serological and molecular tests. Of 150 screened patients, mean age 26.8 (SD 6.4), 30 (20.0%) were positive by at least one diagnostic test. Of these, only nine (6%) were positive as determined by PCR. Diagnosis of chronic CD is difficult in endemic places like Mexico due to the limitations of current commercially available diagnostic tests. Further evaluation of diagnostic performance of various assays could improve current CD diagnostic algorithms and proper care management in these regions. Genetic variability in the parasite may also play a role in the differing assay performances seen in this study, and this may be a valuable avenue of further research.

Trypanocidal treatment of Chagas disease

Chagas disease is a neglected parasitosis caused by the protozoan parasite Trypanosoma cruzi. This infection is present in most Latin American countries, although, due to migratory movements, it is a growing cause for concern in non-endemic countries. The only two drugs currently available for its treatment-benznidazole and nifurtimox-were marketed 50 years ago. While they are very effective for acute and recent infection, and for the prevention of maternofoetal transmission, their efficacy declines in people who have chronic infection, especially those older than 18 years of age. In the presence of visceral involvement, parasiticidal treatment is of little or no value. The safety profile of both drugs is far from ideal, with frequent adverse events and high rates of drug discontinuation, mainly in adults. So far, new drugs and new strategies have not been shown to improve the results of the current nitroimidazoles, although the results are promising. In this review, we focus on the aspects that allow clinicians to make the best use of currently available drugs. In addition, we discuss new therapeutic options and ongoing research in the field.

Congenital Chagas disease: progress toward implementation of pregnancy-based screening

PURPOSE OF REVIEW

Lack of recognition of congenital Chagas disease in infants of mothers from endemic regions who are living in countries nonendemic for Trypanosoma cruzi infection suggests a high rate of underdiagnosis. Pregnancy is the optimal access point for identifying Chagas disease in at-risk mothers and their infants. In this review, we update progress toward implementation of pregnancy-based screening for congenital Chagas disease in nonendemic settings.

RECENT FINDINGS

International organizations have updated recommendations for diagnosis, treatment and prevention of congenital Chagas disease. Reports of successful implementation of pregnancy-based screening at some centers provide a model for optimizing diagnosis of congenital Chagas disease. Screening family members of index patients may identify additional T. cruzi-infected persons. Promising tests to augment current diagnostic modalities for maternal and congenital Chagas disease are in development. Universal or risk-based screening would be cost-effective. More healthcare providers are now aware that treatment of congenital Chagas disease is curative and are promoting efforts to make pregnancy-based screening for congenital Chagas disease a standard of care.

SUMMARY

Ongoing efforts to implement routine pregnancy-based screening for congenital Chagas disease in nonendemic regions will mutually benefit infants, their mothers and family members and can prevent potentially fatal Chagas cardiomyopathy.

Assessing the entomo-epidemiological situation of Chagas disease in rural communities in the state of Piauí, Brazilian semi-arid region

BACKGROUND

In northeastern Brazil, the wild nature of Trypanosoma cruzi vectors has challenged control actions. This study aims to describe the entomological and epidemiological scenario of Chagas disease in rural communities in the state of Piauí.

METHODS

A cross-sectional study (n=683 individuals/244 dwellings) was carried out to obtain serum samples, sociodemographic data and intra- and peridomestic triatomines.

RESULTS

The overall seroprevalence rate was 8.1%, with no positive tests among subjects <30 y of age. Prevalence rates reached 34.3% and 39.1% among subjects 61-75 and >75 y of age, respectively; 1474 triatomines were collected, of which 90.3% were found in peridomiciliary structures and 9.7% inside houses; 87.2% were classified as Triatoma brasiliensis. T. cruzi infection rates in insects were 0.5% by light microscopy and 0.9% by culture in NNN/LIT medium. Five cultivated isolates were submitted to molecular genotyping, three of which were identified as T. cruzi I and two as T. cruzi II.

CONCLUSIONS

Although no vector transmission currently occurs, prevalence rates are high in adults and the elderly. This disease should be targeted by primary healthcare providers. Insect surveillance and control activities should not be discontinued in an environment favourable to the perpetuation of house colonization by triatomines.

Congenital Chagas disease in Santa Cruz Department, Bolivia, is dominated by Trypanosoma cruzi lineage V

BACKGROUND

This study identified Trypanosoma cruzi discrete typing units (DTUs) in maternal and infant specimens collected from two hospitals in Bolivia, using conventional genotyping and DTU-specific serotyping.

METHODS

Specimens from 142 mothers were used, including 24 seronegative and 118 seropositive individuals; 29 women transmitted T. cruzi to their infants. Maternal and infant parasite loads were determined by quantitative real-time PCR. Maternal sera were tested with an in-house parasite lysate ELISA and serotyped by a lineage-specific peptide ELISA, targeting the trypomastigote small surface antigen (TSSA). Trypanosoma cruzi genotypes in infected infants were determined by a triple PCR-RFLP assay.

RESULTS

All infant specimens were genotyped as TcV. Maternal parasite loads and absorbance values by the lysate ELISA were significantly higher for transmitters compared with non-transmitters. Among seropositive mothers, 65.3% had positive results by the TSSA II/V/VI peptide ELISA. No significant difference in reactivity to TSSA II/V/VI was observed for transmitters compared with non-transmitters (79.3% vs 60.7%, respectively).

CONCLUSIONS

Our findings reinforce the difficulty in obtaining sufficient sample numbers and parasite DNA to investigate the interaction between parasite genetics and the risk of congenital transmission and argue for the inclusion of DTU-specific serotyping in prospective studies.

Ruthenium(II)- and Palladium(II)-catalyzed position-divergent CH oxygenations of arylated quinones: Identification of hydroxylated quinonoid compounds with potent trypanocidal activity

A diversity-oriented synthesis of hydroxylated aryl-quinones via CH oxygenation reactions and their evaluation against Trypanosoma cruzi, the etiological agent of Chagas disease, was accomplished. With the use of ruthenium(II)- or palladium(II)-based catalysts, complementary regioselectivities were observed in the hydroxylation reactions and we have identified 9 compounds more potent than benznidazole (Bz) among these novel arylated and hydroxylated quinones. For instance, 5-hydroxy-2-[4-(trifluoromethyl)phenyl]-1,4-naphthoquinone (4h) with an IC₅₀/24 h value of 22.8 µM is 4.5-fold more active than the state-of-the-art drug Bz. This article provides the first example of the application of CH activation for the position-selective hydroxylation of arylated quinones and the identification of these compounds as trypanocidal drug candidates.

Prediction of parasitological cure in children infected with Trypanosoma cruzi using a novel multiplex serological approach: an observational, retrospective cohort study

BACKGROUND

Assessment of therapeutic response with standard serological diagnostic assays in patients with chronic Chagas disease is a major challenge due to the long persistence of parasite-specific antibodies. The current consensus for parasitological cure is to monitor conversion from positive to negative Trypanosoma cruzi serology (seroreversion). However, because of robust humoral immune response, seroreversion by standard serological tests can take years to decades. Developing novel tests of parasitological cure or surrogates is thus a priority in the Chagas disease field. We aimed to evaluate the MultiCruzi assay as a predictive tool for parasitological cure in a cohort of treated infants and children with acute and chronic Chagas disease enrolled in a long-term retrospective longitudinal study with clinical, serological, and parasitological follow-up, and to explore whether MultiCruzi could predict parasitological cure more quickly than the current reference method.

METHODS

Patients from two retrospective paediatric Chagas disease cohort studies with clinical, serological, and parasitological follow-up, diagnosed and treated at the parasitology service, Hospital de Niños Ricardo Gutierrez (Buenos Aires, Argentina) were included in this retrospective cohort study. Serum samples were collected every 6 months to 12 months between Oct 22, 1990, and June 3, 2019, for cohort 1 and 1 month after birth for cohort 2 and then every 3 months for a year between July 23, 2012, and April 19, 2016. We evaluated serological follow-up with the Chagatest ELISA (Wiener Lab, Rosario, Argentina) and used this as a clinical reference method for the evaluation of seroreversion. We compared Chagatest ELISA results with results of MultiCruzi (InfYnity Biomarkers, Lyon, France), a novel antibody profiling multiplex assay, investigating seroreversion events with both of the assays and prediction of seroreversion with MultiCruzi using an interpretation formula.

FINDINGS

Combining experimental data from discrete analysis of 15 T cruzi antigens efficiently predicted seroreversion at an early stage, which was later confirmed by conventional T cruzi serology. In cohort 1 (n=69), which included children of three different age groups, we observed differences 2 years after therapy. In the 27 individuals from cohort 1 who were treated within the first 12 months of age, MultiCruzi predicted early seroreversion in 21 (78%) patients whereas nine (33%) patients showed seroreversion with Chagatest ELISA (seroreversion difference 0·44, 95% CI 0·26-0·63; p=0·0005). In the 12 patients from cohort 1 treated between 1 year and 2 years of age, MultiCruzi predicted early seroreversion in six (50%) patients, whereas only one (8%) patient was confirmed to be seronegative with Chagatest ELISA (seroreversion difference 0·42, 95% CI 0·14-0·70; p=0·0253). In the 30 patients from cohort 1 who were treated between 2 years and 19 years of age, MultiCruzi predicted early seroreversion in five (6%) patients, whereas no patients were found to be seronegative with Chagatest ELISA (seroreversion difference 0·17, 0·03-0·30; p=0·0253). In cohort 2 (n=27), which included only children younger than 1 year of age and had a shorter follow up (between 5 months and 32 months), the proportion of reported events was significantly different 180 days after treatment for the T cruzi-positive group (early seroreversion predicted in nine [90%] of ten patients with MultiCruzi and confirmed seroreversion in four [40%] of ten patients with Chagatest ELISA; seroreversion difference 0·50, 95% CI 0·19-0·81; p=0·0253) and for the T cruzi-negative group 90 days (early seroreversion predicted in five [29%] of 17 patients with MultiCruzi and confirmed seroreversion in one [6%] of 17 patients with Chagatest ELISA; seroreversion difference 0·24, 0·03-0·44; p=0·0455) and 180 days (early seroreversion predicted in 17 [100%] of 17 patients with MultiCruzi and confirmed seroreversion only in seven [41%] of 17 patients with Chagatest ELISA; seroreversion difference 0·59, 0·35-0·82; p=0·0016) after treatment.

INTERPRETATION

The MultiCruzi assay can be used as a predictive monitoring tool to assess parasitological cure in children. This approach might be a solution to forecast forthcoming seroreversion in treated adults infected with T cruzi, but this requires further investigation.

FUNDING

Drugs for Neglected Diseases initiative.

TRANSLATIONS

For the Spanish, Portuguese and French translations of the abstract see Supplementary Materials section.

Human Placental Trophoblasts Are Resistant to Trypanosoma cruzi Infection in a 3D-Culture Model of the Maternal-Fetal Interface

Trypanosoma cruzi (T. cruzi), the etiological agent of Chagas Disease (CD), is transmitted to humans by infected kissing bugs, blood transfusion, organ transplantation, and from mother-to-child. Congenital transmission is now considered an important route of CD spread in non-endemic countries where no routine testing of pregnant women for the disease is implemented. The main cellular mechanisms that lead to fetal infection by T. cruzi, despite the presence of a placental barrier, remain unclear. Mother-to-child transmission most likely occurs when bloodstream trypomastigotes reach the placental intervillous space and interact with the large cellular surface provided by the syncytioptrophoblasts. These highly specialized cells not only function as a physical obstacle between mother and fetus, but also modulate immune responses against pathogen infections. To overcome the limitations associated with the use of human fetal tissues, we employed a three-dimensional (3D) cell culture model to recreate the human placenta environment. In this system, the trophoblast-derived JEG-3 cell line is co-cultured with human brain microvascular endothelial cells attached to microcarrier beads in a rotating bioreactor. Here, we report that 3D culture of JEG-3/HBMEC spheroids promote JEG-3 cells differentiation revealed by the formation of syncytia and production of β human chorionic gonadotropin and human placental lactogen (hPL). Under these growth conditions, we demonstrate that 3D-grown JEG-3 cells have reduced susceptibility to T. cruzi infection compared to JEG-3 cells grown in conventional tissue culture flasks. We also show that 3D-cultured JEG-3 cells release paracrine factors in the supernatant that prevent T. cruzi infection of non-trophoblastic cell lines. Our in vitro model of T. cruzi vertical transmission may help better understand the molecular processes by which parasites bypass the human placental barrier and could be exploited to evaluate therapeutics to reduce congenital CD.

Current knowledge of Chagas-related heart disease among pediatric cardiologists in the United States

Background

Chagas disease is a pathogenic parasitic infection with approximately 8 million cases worldwide and greater than 300,000 cases in the United States (U.S.). Chagas disease can lead to chronic cardiomyopathy and cardiac complications, with variable cardiac presentations in pediatrics making it difficult to recognize. The purpose of our study is to better understand current knowledge and experience with Chagas related heart disease among pediatric cardiologists in the U.S.

Methods

We prospectively disseminated a 19-question survey to pediatric cardiologists via 3 pediatric cardiology listservs. The survey included questions about demographics, Chagas disease presentation and experience.

Results

Of 139 responses, 119 cardiologists treat pediatric patients in the U.S. and were included. Most providers (87%) had not seen a case of Chagas disease in their practice; however, 72% also had never tested for it. The majority of knowledge-based questions about Chagas disease cardiac presentations were answered incorrectly, and 85% of providers expressed discomfort with recognizing cardiac presentations in children. Most respondents selected that they would not include Chagas disease on their differential diagnosis for presentations such as conduction anomalies, myocarditis and/or apical aneurysms, but would be more likely to include it if found in a Latin American immigrant. Of respondents, 87% agreed that they would be likely to attend a Chagas disease-related lecture.

Conclusions

Pediatric cardiologists in the U.S. have seen very few cases of Chagas disease, albeit most have not sent testing or included it in their differential diagnosis. Most individuals agreed that education on Chagas disease would be worth-while.

Perceived barriers to Chagas disease screening among a diverse group of prenatal care providers

BACKGROUND

Chagas disease is a vector borne infection of poverty endemic to Latin America which affects an estimated 40,000 women of child-bearing age in the United States (US). In the US Chagas disease is concentrated among individuals who have lived in endemic areas. Prenatal diagnosis and treatment are needed to prevent congenital transmission. The objective of this study was to assess perceived barriers to Chagas disease screening among prenatal care providers in Obstetrics/Gynecology and Family Medicine Departments of a tertiary care safety-net hospital caring for a significant at-risk population.

METHODOLOGY/PRINCIPAL FINDINGS

An anonymous survey was distributed to 178 Obstetrics/Gynecology and Family Medicine practitioners. Of the 66 respondents, 39% thought Chagas screening was very important, and 48% somewhat important as a public health initiative. One third judged screening patients during clinic visits as very important. Most respondents (64%) reported being familiar with Chagas disease. However, only 32% knew how to order a test and only 22% reported knowing what to do if a test was positive.

CONCLUSIONS/SIGNIFICANCE

These findings will be incorporated into measures to facilitate full implementation of Chagas screening, and can inform initiatives at other centers who wish to address this deeply neglected infection among their patient families. Greater integration of information on Chagas disease screening and treatment in medical and nursing education curricula can contribute to addressing this disease with the focus that its potentially fatal sequelae merit.

Congenital chagas disease: Development and assessment of a specific IgM capture-based assay for diagnosis of transmission

Transplacental transmission by Trypanosoma cruzi (T. cruzi) infection can be effectively treated if parasiticide drugs are administered as early as possible during childhood. Furthermore, an ideal situation would be to diagnose the infection near birth in order to avoid the loss of patients during the subsequent follow-up. These situation are desirable due to the maximum benefit of drugs in early stages which, consequently, implies a relevant contribution to eliminate mother-to-child transmission. However, available techniques for that purpose have limitations as being operator-dependent (microhematocrit), require several months follow-up (IgG detection) or specialized laboratories (PCR). In this study we propose to detect specific IgM antibodies (Ab) by developing a capture-based ELISA employing an improved antigen (Ag) to diagnose the transplacental transmission of T. cruzi, and in consequence, to enhance access to effective treatment. Firstly, a new chimera Ag (CP4) was obtained from the fusion of CP1 and CP3 protein, carrying FRA, SAPA, MAP, TSSAII/V/VI and TcD Ag from T. cruzi. Then, we optimized the assay by capturing IgM Ab with a polyclonal anti-IgM Ab and evaluating three Ag formulations to detect specific IgM bound. The formulations were formed as follows: i) F1: CP1 and CP3; ii) F2: CP1, CP3, B13 and P2β; iii) F3: by CP4. Detection of Ab-binding Ag was carried out using an anti-His Ab since all Ag were expressed with a His-tag. The evaluation panel consisted of sera from vertically infected children under 1-year-old (6 younger than 15 days, 7 older) and samples from non-infected children of women with chronic Chagas Disease. The ELISA assay employing CP4 showed better performance with notable high sensitivity and specificity (92.3% and 93.9%, respectively). Positive and negative likelihood ratios of the test (15.2 and 0.082) suggest its potential clinical relevance in term of post-test probability of infection. In conclution, we developed a standardized and non-operator dependent test to detect specific anti-T. cruzi IgM Ab. Although increased sample size is needed for its validation, our results indicate that this capture-based technique employing CP4 Ag can certainly improve the diagnosis of connatal infection.

Novel N,N-di-alkylnaphthoimidazolium derivative of β-lapachone impaired Trypanosoma cruzi mitochondrial electron transport system

Trypanosoma cruzi is a protozoan parasite that causes Chagas disease, a neglected tropical disease that is endemic in Latin America and spreading worldwide due to globalization. The current treatments are based on benznidazole and nifurtimox; however, these drugs have important limitations and limited efficacy during the chronic phase, reinforcing the necessity of an alternative chemotherapy. For the last 30 years, our group has been evaluating the biological activity of naphthoquinones and derivatives on T. cruzi, and of the compounds tested, N1, N2 and N3 were found to be the most active in vitro. Here, we show the synthesis of a novel β-lapachone-derived naphthoimidazolium named N4 and assess its activity on T. cruzi stages and the mechanism of action. The new compound was very active on all parasite stages (IC₅₀/24 h in the range of 0.8-7.9 μM) and had a selectivity index of 5.4. Mechanistic analyses reveal that mitochondrial ROS production begins after short treatment starts and primarily affects the activity of complexes II-III. After 24 h treatment, a partial restoration of mitochondrial physiology (normal complexes II-III and IV activities and controlled H₂O₂ release) was observed; however, an extensive injury in its morphology was still detected. During treatment with N4, we also observed that trypanothione reductase activity increased in a time-dependent manner and concomitant with increased oxidative stress. Molecular docking calculations indicated the ubiquinone binding site of succinate dehydrogenase as an important interaction point with N4, as with the FMN binding site of dihydroorotate dehydrogenase. The results presented here may be a good starting point for the development of alternative treatments for Chagas disease and for understanding the mechanism of naphthoimidazoles in T. cruzi.

Development and Evaluation of a Three-Dimensional Printer-Based DNA Extraction Method Coupled to Loop Mediated Isothermal Amplification for Point-of-Care Diagnosis of Congenital Chagas Disease in Endemic Regions

Vertical transmission of Trypanosomacruzi is the cause of congenital Chagas disease, a re-emerging infectious disease that affects endemic and nonendemic regions alike. An early diagnosis is crucial because prompt treatment achieves a high cure rate, precluding evolution to symptomatic chronic Chagas disease. However, early diagnosis involves low-sensitive parasitologic assays, making necessary serologic confirmation after 9 months of life. With the aim of implementing early diagnostic strategies suitable for minimally equipped laboratories, a T. cruzi-loop-mediated isothermal amplification (LAMP) prototype was coupled with an automated DNA-extraction device repurposed from a three-dimensional printer (PrintrLab). The whole process takes <3 hours to yield a result, with an analytical sensitivity of 0.1 to 2 parasite equivalents per milliliter, depending on the T. cruzi strain. Twenty-five blood samples from neonates born to seropositive mothers were tested blindly. In comparison to quantitative real-time PCR, the PrintrLab-LAMP dual strategy showed high agreement, while both molecular-based methodologies yielded optimal sensitivity and specificity with respect to microscopy-based diagnosis of congenital Chagas disease. PrintrLab-LAMP detected all 10 congenitally transmitted T. cruzi infections, showing promise for point-of-care early diagnosis of congenital Chagas disease.

Benznidazole modulates release of inflammatory mediators by cardiac spheroids infected with Trypanosoma cruzi

Chagas disease (CD) caused by Trypanosoma cruzi remains a serious public health problem in Latin America. The available treatment is limited to two old drugs, benznidazole (Bz) and nifurtimox, which exhibit limited efficacy and trigger side effects, justifying the search for new therapies. Also, more accurate and sensitive experimental protocols for drug discovery programs are necessary to shrink the translational gaps found among pre-clinical and clinical trials. Presently, cardiac spheroids were used to evaluate host cell cytotoxicity and anti-T.cruzi activity of benznidazole, exploring its effect on the release of inflammatory mediators. Bz presented low toxic profile on 3D matrices (LC₅₀ > 200 μM) and high potency in vitro (EC₅₀ = 0.99 μM) evidenced by qPCR analysis of T.cruzi-infected cardiac spheroids. Flow cytometry appraisal of inflammatory mediators released at the cellular supernatant showed increases in IL - 6 and TNF contents (≈190 and ≈ 25-fold) in parasitized spheroids as compared to uninfected cultures. Bz at 10 μM suppressed parasite load (92%) concomitantly decreasing in IL-6 (36%) and TNF (68%). Our findings corroborate the successful use of 3D cardiac matrices for in vitro identification of novel anti-parasitic agents and potential impact in host cell physiology.

Risk Factors for Maternal Chagas Disease and Vertical Transmission in a Bolivian Hospital

BACKGROUND

Vertical transmission of Trypanosoma cruzi infection accounts for a growing proportion of new cases of Chagas disease. Better risk stratification is needed to predict which women are more likely to transmit the infection.

METHODS

This study enrolled women and their infants at the Percy Boland Women's Hospital in Santa Cruz, Bolivia. Pregnant women were screened for Chagas disease by rapid test and received confirmatory serology. Infants of seropositive mothers underwent diagnostic testing with quantitative polymerase chain reaction (qPCR).

RESULTS

Among 5,828 enrolled women, 1,271 (21.8%) screened positive for Chagas disease. Older maternal age, family history of Chagas disease, home conditions, lower education level, and history of living in a rural area were significantly associated with higher adjusted odds of maternal infection. Of the 1,325 infants of seropositive mothers, 65 infants (4.9%) were diagnosed with congenital Chagas disease. Protective factors against transmission included Cesarean delivery (adjusted OR [aOR]: 0.60, 95% CI: 0.36-0.99) and family history of Chagas disease (aOR: 0.58, 95% CI: 0.34-0.99). Twins were significantly more likely to be congenitally infected than singleton births (OR: 3.32, 95% CI: 1.60-6.90). Among congenitally infected infants, 32.3% had low birth weight, and 30.8% required hospitalization after birth.

CONCLUSIONS

Although improved access to screening and qPCR increased the number of infants diagnosed with congenital Chagas disease, many infants remain undiagnosed. A better understanding of risk factors and improved access to highly sensitive and specific diagnostic techniques for congenital Chagas disease may help improve regional initiatives to reduce disease burden.

Starvation and pH stress conditions induced mitochondrial dysfunction, ROS production and autophagy in Trypanosoma cruzi epimastigotes

Chagas disease is a neglected illness endemic in Latin America that mainly affects rural populations. The etiological agent of Chagas disease is the protozoan Trypanosoma cruzi, which has three different parasite stages and a dixenous life cycle that includes colonization of the vertebrate and invertebrate hosts. During its life cycle, T. cruzi is subjected to stress conditions, including variations in nutrient availability and pH, which impact parasite survival and differentiation. The plasticity of mitochondrial function in trypanosomatids has been defined as mitochondrial activity related to substrate availability. Thus, mitochondrial remodeling and autophagy, which is a constitutive cellular process of turnover and recycling of cellular components, may constitute a response to the nutritional and pH stress in the host. To assess these processes, epimastigotes were subjected to acidic, alkaline, and nutritional stress conditions, and mitochondrial function and its influence on the autophagic process were evaluated. Our data demonstrated that the three stress conditions affected the mitochondrial structure, inducing organelle swelling and impaired oxidative phosphorylation. Stressed epimastigotes produced increased ROS levels and overexpressed antioxidant enzymes. The stress conditions resulted in an increase in the number of autophagosomes and exacerbated the expression of different autophagy-related genes (Atgs). A correlation between mitochondrial dysfunction and autophagic phenotypes was also observed. After 24 h, acid stress and nutritional deprivation induced metacyclogenesis phenotypes (mitochondrial remodeling and autophagy). On the other hand, alkaline stress was transient due to insect blood feeding and culminated in an increase in autophagic flux as a survival mechanism.

Trypanosoma cruzi loop-mediated isothermal amplification (Trypanosoma cruzi Loopamp) kit for detection of congenital, acute and Chagas disease reactivation

A Trypanosoma cruzi Loopamp kit was recently developed as a ready-to-use diagnostic method requiring minimal laboratory facilities. We evaluated its diagnostic accuracy for detection of acute Chagas disease (CD) in different epidemiological and clinical scenarios. In this retrospective study, a convenience series of clinical samples (venous blood treated with EDTA or different stabilizer agents, heel-prick blood in filter paper or cerebrospinal fluid samples (CSF)) from 30 infants born to seropositive mothers (13 with congenital CD and 17 noninfected), four recipients of organs from CD donors, six orally-infected cases after consumption of contaminated guava juice and six CD patients coinfected with HIV at risk of CD reactivation (N = 46 patients, 46 blood samples and 1 CSF sample) were tested by T. cruzi Loopamp kit (Tc LAMP) and standardized quantitative real-time PCR (qPCR). T. cruzi Loopamp accuracy was estimated using the case definition in the different groups as a reference. Cohen's kappa coefficient (κ) was applied to measure the agreement between Tc LAMP (index test) and qPCR (reference test). Sensitivity and specificity of T. cruzi Loopamp kit in blood samples from the pooled clinical groups was 93% (95% CI: 77-99) and 100% (95% CI: 80-100) respectively. The agreement between Tc LAMP and qPCR was almost perfect (κ = 0.92, 95% CI: 0.62-1.00). The T. cruzi Loopamp kit was sensitive and specific for detection of T. cruzi infection. It was carried out from DNA extracted from peripheral blood samples (via frozen EDTA blood, guanidine hydrochloride-EDTA blood, DNAgard blood and dried blood spots), as well as in CSF specimens infected with TcI or TcII/V/VI parasite populations. The T. cruzi Loopamp kit appears potentially useful for rapid detection of T. cruzi infection in congenital, acute and CD reactivation due to HIV infection.

Trypanocidal treatment of Chagas disease

Chagas disease is a neglected parasitosis caused by the protozoan parasite Trypanosoma cruzi. This infection is present in most Latin American countries, although, due to migratory movements, it is a growing cause for concern in non-endemic countries. The only two drugs currently available for its treatment-benznidazole and nifurtimox-were marketed 50 years ago. While they are very effective for acute and recent infection, and for the prevention of maternofoetal transmission, their efficacy declines in people who have chronic infection, especially those older than 18 years of age. In the presence of visceral involvement, parasiticidal treatment is of little or no value. The safety profile of both drugs is far from ideal, with frequent adverse events and high rates of drug discontinuation, mainly in adults. So far, new drugs and new strategies have not been shown to improve the results of the current nitroimidazoles, although the results are promising. In this review, we focus on the aspects that allow clinicians to make the best use of currently available drugs. In addition, we discuss new therapeutic options and ongoing research in the field.

The Clinical and Parasitologic Follow-up of Trypanosoma cruzi-infected Children in a Nonendemic Country

BACKGROUND

Chagas disease has become a global health problem, with the pediatric population being especially vulnerable. Our aim was to describe the clinical-epidemiologic aspects of disease in this population, as well as tolerance and adherence to treatment and the subsequent evolution of the disease.

METHODS

A prospective study involving 949 children 0-14 years of age screened from 2007 to 2018. Diagnosis was performed by polymerase chain reaction and/or microhematocrit in <1-year-old children or serology in those ≥1 year of age. After diagnosis, children were examined for the clinical manifestation of Chagas disease and were treated with benznidazole. Treatment response was monitored by polymerase chain reaction and serology.

RESULTS

Forty children were infected (4.2% of the population screened). Twelve children were diagnosed during the acute phase (≤1-year-old), 3 of whom were symptomatic, and 28 (4- to 14-year-olds) were in the chronic phase: 18 in the indeterminate phase and 10 presented cardiac and/or digestive involvement. Regarding treatment, 10 (25.6%) children had side effects (6 mild, 2 moderate and 2 severe reactions), leading to treatment interruption in 3 of them. No side effects were detected in ≤1-year-old children (P < 0.05). Cure was confirmed in 29.4% of the children during follow-up, and the age of the children at treatment (≤1 year) was clearly associated with the effectiveness of treatment (P < 0.05).

CONCLUSIONS

Effectiveness and safety of treatment were optimum in ≤1-year-old children. Increased side effects, cardiac and/or digestive disorder incidence and lower treatment effectiveness were detected in older children, highlighting the need for early screening.

The potential economic value of a therapeutic Chagas disease vaccine for pregnant women to prevent congenital transmission

BACKGROUND

Currently, there are no solutions to prevent congenital transmission of Chagas disease during pregnancy, which affects 1-40% of pregnant women in Latin America and is associated with a 5% transmission risk. With therapeutic vaccines under development, now is the right time to determine the economic value of such a vaccine to prevent congenital transmission.

METHODS

We developed a computational decision model that represented the clinical outcomes and diagnostic testing strategies for an infant born to a Chagas-positive woman in Mexico and evaluated the impact of vaccination.

RESULTS

Compared to no vaccination, a 25% efficacious vaccine averted 125 [95% uncertainty interval (UI): 122-128] congenital cases, 1.9 (95% UI: 1.6-2.2) infant deaths, and 78 (95% UI: 66-91) DALYs per 10,000 infected pregnant women; a 50% efficacious vaccine averted 251 (95% UI: 248-254) cases, 3.8 (95% UI: 3.6-4.2) deaths, and 160 (95% UI: 148-171) DALYs; and a 75% efficacious vaccine averted 376 (95% UI: 374-378) cases, 5.8 (95% UI: 5.5-6.1) deaths, and 238 (95% UI: 227-249) DALYs. A 25% efficacious vaccine was cost-effective (incremental cost-effectiveness ratio <3× Mexico's gross domestic product per capita, <$29,698/DALY averted) when the vaccine cost ≤$240 and ≤$310 and cost-saving when ≤$10 and ≤$80 from the third-party payer and societal perspectives, respectively. A 50% efficacious vaccine was cost-effective when costing ≤$490 and ≤$615 and cost-saving when ≤$25 and ≤$160, from the third-party payer and societal perspectives, respectively. A 75% efficacious vaccine was cost-effective when ≤$720 and ≤$930 and cost-saving when ≤$40 and ≤$250 from the third-party payer and societal perspectives, respectively. Additionally, 13-42 fewer infants progressed to chronic disease, saving $0.41-$1.21 million to society.

CONCLUSION

We delineated the thresholds at which therapeutic vaccination of Chagas-positive pregnant women would be cost-effective and cost-saving, providing economic guidance for decision-makers to consider when developing and bringing such a vaccine to market.

Epidemiology and pathogenesis of maternal-fetal transmission of Trypanosoma cruzi and a case for vaccine development against congenital Chagas disease

Trypanos o ma cruzi (T. cruzi or Tc) is the causative agent of Chagas disease (CD). It is common for patients to suffer from non-specific symptoms or be clinically asymptomatic with acute and chronic conditions acquired through various routes of transmission. The expecting women and their fetuses are vulnerable to congenital transmission of Tc. Pregnant women face formidable health challenges because the frontline antiparasitic drugs, benznidazole and nifurtimox, are contraindicated during pregnancy. However, it is worthwhile to highlight that newborns can be cured if they are diagnosed and given treatment in a timely manner. In this review, we discuss the pathogenesis of maternal-fetal transmission of Tc and provide a justification for the investment in the development of vaccines against congenital CD.

Antiparasitic and anti-inflammatory activities of ß-lapachone-derived naphthoimidazoles in experimental acute Trypanosoma cruzi infection

BACKGROUND

Chagas disease, which is caused by the protozoan Trypanosoma cruzi, is endemic to Latin America and mainly affects low-income populations. Chemotherapy is based on two nitrocompounds, but their reduced efficacy encourages the continuous search for alternative drugs. Our group has characterised the trypanocidal effect of naphthoquinones and their derivatives, with naphthoimidazoles derived from β-lapachone (N1, N2 and N3) being the most active in vitro.

OBJECTIVES

In the present work, the effects of N1, N2 and N3 on acutely infected mice were investigated.

METHODS

in vivo activity of the compounds was assessed by parasitological, biochemical, histopathological, immunophenotypical, electrocardiographic (ECG) and behavioral analyses.

FINDINGS

Naphthoimidazoles led to a decrease in parasitaemia (8 dpi) by reducing the number of bloodstream trypomastigotes by 25-50% but not by reducing mortality. N1 protected mice from heart injury (15 dpi) by decreasing inflammation. Bradycardia was also partially reversed after treatment with N1 and N2. Furthermore, the three compounds did not reverse hepatic and renal lesions or promote the improvement of other evaluated parameters.

MAIN CONCLUSION

N1 showed moderate trypanocidal and promising immunomodulatory activities, and its use in combination with benznidazole and/or anti-arrhythmic drugs as well as the efficacy of its alternative formulations must be investigated in the near future.

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.

Immunity and vaccine development efforts against Trypanosoma cruzi

Trypanosoma cruzi (T. cruzi) is the causative agent for Chagas disease (CD). There is a critical lack of methods for prevention of infection or treatment of acute infection and chronic disease. Studies in experimental models have suggested that the protective immunity against T. cruzi infection requires the elicitation of Th1 cytokines, lytic antibodies and the concerted activities of macrophages, T helper cells, and cytotoxic T lymphocytes (CTLs). In this review, we summarize the research efforts in vaccine development to date and the challenges faced in achieving an efficient prophylactic or therapeutic vaccine against human CD.

An observational longitudinal study to evaluate tools and strategies available for the diagnosis of Congenital Chagas Disease in a non-endemic country

OBJECTIVES

Congenital Chagas Disease (CCD) has become a global health problem. Early diagnosis and treatment is essential for the cure of the disease. Our aim was to evaluate techniques and samples used for the diagnosis of CCD in order to improve diagnostic strategies.

METHODS

A total of 181 children born in Spain from Latin American Chagas-infected mothers were consecutively enrolled and studied by microhematocrit, PCR and serology tests at 0-2, 6 and 9-12 months of age and followed up when it was required. Samples of cord blood and peripheral blood were collected for T. cruzi detection by PCR. Parasite culture was performed in patients with a positive PCR.

RESULTS

Of 181 children, 7 children (3.9%) were lost to follow-up. A total of 174 children completed follow-up, 12 were diagnosed with CCD (6.9%) and 162 (93.1%) as uninfected children (negative serology tests at the end of the follow-up). Traditional parasitological diagnosis by microhematocrit had a poor performance (sensitivity was 10%), while PCR in peripheral blood showed high sensitivity (90.9%) and specificity (100%), allowing the early diagnosis of 9 infected children during the first 6-months-old. In the other 3 congenital cases, diagnosis was only possible at 12 months by serological and molecular techniques. However, PCR in cord blood showed low sensitivity (33.3%) and less specificity (96.4%) for the diagnosis.

CONCLUSION

PCR in peripheral blood has proven to be the most adequate strategy for the diagnosis of CCD, allowing an early and reliable diagnosis.

Congenital transmission of Chagas disease in a non-endemic area, is an early diagnosis possible?

BACKGROUND

Chagas disease (CD) is an emergent disease in Europe, due to immigration. The aims of this study are to describe the epidemiological characteristics of a cohort of Chagas infected pregnant women in Spain, to assess the vertical transmission (VT) rate and evaluate the usefulness of the PCR in the diagnosis of congenital infection in the first months of life.

METHODS

A descriptive, retrospective study including Chagas seropositive pregnant women who were attended at three tertiary hospitals in Madrid, from January 2012 to September 2016. Infants were examined by PCR at birth and 1 month later and serologically studied at 9 months or later. Children were considered infected when the parasite was detected by PCR at any age or when serology remained positive without decline over the age of 9 months.

RESULTS

We included 122 seropositive-infected pregnant women, 81% were from Bolivia and only 8.2% had been treated before. 125 newborns were studied and finally 109 were included (12.8% lost the follow-up before performing the last serology). The VT rate was 2.75% (95% CI: 0,57-8,8%). Infected infants had positive PCR at birth and 1 month later. All of them were treated successfully with benznidazole (PCR and serology became negative later on). All non-infected children presented negative PCR. The mean age at which uninfected patients had negative serology was 10.5 months.

CONCLUSIONS

The VT rate is in keeping with literature and confirms the need to carry out a screening in pregnant women coming from endemic areas. PCR seems to be a useful tool to provide early diagnosis of congenital CD.

Synthesis of quinones with highlighted biological applications: A critical update on the strategies towards bioactive compounds with emphasis on lapachones

Naphthoquinones are of key importance in organic synthesis and medicinal chemistry. In the last few years, various synthetic routes have been developed to prepare bioactive compounds derived or based on lapachones. In this sense, this review is mainly focused on the synthetic aspects and strategies used for the design of these compounds on the basis of their biological activities for the development of drugs against the neglected diseases leishmaniases and Chagas disease and also cancer. Three strategies used to develop bioactive quinones are discussed and categorized: (i) C-ring modification, (ii) redox centre modification and (iii) A-ring modification. Framed within these strategies for the development of naphthoquinoidal compounds against T. cruzi. Leishmania and cancer, reactions including copper-catalyzed azide-alkyne cycloaddition (click chemistry), palladium-catalysed cross couplings, C-H activation reactions, Ullmann couplings and heterocyclisations reported up to July 2019 will be discussed. The aim of derivatisation is the generation of novel molecules that can potentially inhibit cellular organelles/processes, generate reactive oxygen species and increase lipophilicity to enhance penetration through the plasma membrane. Modified lapachones have emerged as promising prototypes for the development of drugs against leishmaniases, Chagas disease and cancer.

Trypanosoma cruzi Infection at the Maternal-Fetal Interface: Implications of Parasite Load in the Congenital Transmission and Challenges in the Diagnosis of Infected Newborns

Trypanosoma cruzi is the protozoan unicellular parasite that causes Chagas disease. It can be transmitted from infected mothers to their babies via the connatal route, thus being able to perpetuate even in the absence of Triatomine insect vectors. Chagas disease was originally endemic in Central and South America, but migration of infected women of childbearing age has spread the T. cruzi congenital infection to non-endemic areas like North America, Europe, Japan, and Australia. Currently, 7 million people are affected by this infection worldwide. This review focuses on the relevance of the T. cruzi parasite levels in different aspects of the congenital T. cruzi infection such as the mother-to-child transmission rate, the maternal and fetal immune response, and its impact on the diagnosis of infected newborns. Improvements in detection of this parasite, with tools that can be easily adapted to be used in remote rural areas, will make the early diagnosis of infected children possible, allowing a prompt trypanocidal treatment and avoiding the current loss of opportunities for the diagnosis of 100% of T. cruzi congenitally infected infants.

Dynamics of T Cells Repertoire During Trypanosoma cruzi Infection and its Post-Treatment Modulation

Chagas disease courses with different clinical phases and has a variable clinical presentation and progression. The acute infection phase mostly exhibits a non-specific symptomatology. In the absence of treatment, the acute phase is followed by a chronic phase, which is initially asymptomatic. This chronic asymptomatic phase of the disease is characterized by a fragile balance between the host's immune response and the parasite replication. The loss of this balance is crucial for the progression of the sickness. The virulence and tropism of the T. cruzi infecting strain together to the inflammation processes in the cardiac tissue are the main factors for the establishment and severity of the cardiomyopathy. The efficacy of treatment in chronic Chagas disease patients is controversial. However, several studies carried out in chronic patients demonstrated that antiparasitic treatment reduces parasite load in the bloodstream and leads to an improvement in the immune response against the Trypanosoma cruzi parasite. The present review is mainly focused on the cellular patterns associated to the clinical status and the evolution of the disease in chronic patients, as well as the effectiveness of the treatment related to T. cruzi infection control. Therefore, an emphasis is placed on the dynamics of specific-antigens T cell subpopulations, their memory and activation phenotypes, their functionality and their contribution to pathogenesis or disease control, as well as their association with risk of congenital transmission of the parasite.