Risk factors for vertical transmission of Chagas disease: A systematic review and meta-analysis

Diagnosing Chagas in Pregnancy and Childhood: What's Old and New

Trypanosoma cruzi, the parasite that causes Chagas disease, affects as many as 300,000 individuals in the United States. Screening individuals of childbearing age can prevent congenital transmission, and diagnosing infants and children can prevent long-term sequelae of Chagas disease. Current methods to diagnose Chagas have limations, including relying on identification of at-risk individuals and requiring at least 2 separate tests to confirm infection.

Prevalence and diagnostic accuracy of different diagnostic tests for Chagas disease in an indigenous community of the Paraguayan Chaco

INTRODUCTION

Chagas disease (CD), caused by the protozoan Trypanosoma cruzi (T. cruzi), poses a major health challenge in Paraguay, especially in the resource-limited Chaco region. Rapid diagnostic tests (RDTs) are valuable tools to enhance diagnostic access. This study evaluates CD prevalence and risk factors in an indigenous community in the Paraguayan Chaco and validates the national RDT-based diagnostic algorithm for resource-limited settings against the recommended standard algorithm, which relies solely on conventional serological tests.

METHODOLOGY

A descriptive cross-sectional study was conducted in Casanillo, Presidente Hayes, Paraguay. In July 2023, a two-week field campaign was executed using a non-probability convenience sampling method targeting individuals aged over 9 months. Screening involved a single RDT, with positives confirmed via enzyme-linked immunosorbent assay (ELISA). Algorithm accuracy was validated externally at the National Reference Laboratory of Paraguay against the standard algorithm, which, in this study, included an ELISA and Hemagglutination test. Discordant cases were resolved with a second ELISA or Immunofluorescence.

RESULTS

The study involved 999 participants, with a median age of 26 years (IQR 12-45), and 51.1% were female. The RDT-based diagnostic algorithm showed 97.1% agreement (κ = 0.94, 95%CI: 0.90-0.98) with the standard algorithm. The RDT alone had 96.0% agreement (κ = 0.91, 95%CI: 0.87-0.96), while the confirmatory ELISA had 94.3% agreement (κ = 0.88, 95%CI: 0.83-0.93). The algorithm's sensitivity/specificity (95%CI) were 94.6% (89.2-97.8)/98.6% (96.1-99.7), with the RDT at 94.6% (89.2-97.8)/96.8% (93.6-98.7) and the ELISA at 96.9% (92.3-99.2)/92.7% (88.5-95.8). T.cruzi infection seroprevalence was 12.6% (95%CI: 9.56-16.52). Age, Sanapaná ethnicity, and awareness of CD vectors were significantly associated with infection odds. No significant associations were found with other typical CD risk factors, clinical history, or health habits.

CONCLUSION

The study underscores the high burden of T. cruzi infection in indigenous communities in the Paraguayan Chaco, urging immediate interventions for improved diagnosis and treatment. The combination of RDTs with conventional serology for diagnostic screening in resource-constrained settings proved useful, and its further use is encouraged.

Understanding Host-Pathogen Interactions in Congenital Chagas Disease Through Transcriptomic Approaches

Chagas disease, caused by Trypanosoma cruzi, is a parasitic zoonosis with significant health impacts, particularly in Latin America. While traditionally associated with vector-borne transmission, increased migration has expanded its reach into urban and non-endemic regions. Congenital transmission has become a critical route of infection, involving intricate maternal-fetal immune interactions that challenge diagnosis and treatment. This review synthesizes findings from three RNA-seq studies that explore the molecular underpinnings of congenital Chagas disease, emphasizing differentially expressed genes (DEGs) implicated in host-pathogen interactions. The DAVID tool analysis highlighted the overexpression of genes associated with the innate immune response, including pro-inflammatory cytokines that drive chemotaxis and neutrophil activation. Additionally, calcium-dependent pathways critical for parasite invasion were modulated. T. cruzi exploits the maternal-fetal immune axis to establish a tolerogenic environment conducive to congenital transmission. Alterations in placental angiogenesis, cellular regeneration, and metabolic processes further demonstrate the parasite's ability to manipulate host responses for its survival and persistence. These findings underscore the complex interplay between the host and pathogen that facilitates disease progression. Future research integrating transcriptomic, proteomic, and metabolomic approaches is essential to unravel the molecular mechanisms underlying congenital Chagas disease, with a particular focus on the contributions of genetic diversity and non-coding RNAs in immune evasion and disease pathogenesis.

Chagas disease in Switzerland: current situation, challenges and opportunities

Chagas disease is a parasitic infection found mainly in continental Latin America. However, it is now present globally due to increasing international mobility and its lifelong persistence in the absence of timely treatment. In Switzerland, this neglected tropical disease presents a significant challenge because of its high potential for transmission, severe clinical manifestations and complications, and a lack of medical and public health programs at both the cantonal and national levels. This paper reviews the medical and public health interventions addressing Chagas disease in countries outside Latin America. It provides a specific perspective on the challenges, opportunities, and strategies for the elimination of Chagas disease as a public health problem within the Swiss context. This article concludes with the introduction of the newly created Swiss Chagas Network, which aims to develop strategies for improving the management of Chagas disease in Switzerland.

Preventing Vertical Transmission of Chagas Disease: An Emerging Public Health Issue in Perinatal Care

Chagas [shah-guhs] disease, caused by the Trypanosoma cruzi parasite, presents a growing concern for health care providers overseeing perinatal care in the United States due to existing and expanding vector-borne transmission and population migration. This life-threatening disease can be transmitted vertically during pregnancy, although adequate testing and treatment can effectively reduce morbidity and mortality caused by Chagas disease. This article presents an overview of the disease burden in the United States and its implications for perinatal care providers including recommended testing and treatment practices and the information needed for patient education and shared decision-making regarding the management of care for individuals at risk of Chagas disease. Being informed about Chagas disease and its implications is needed for all individuals providing perinatal care and is especially critical for those overseeing the care of refugee and immigrant populations.

New insights into Trypanosoma cruzi genetic diversity, and its influence on parasite biology and clinical outcomes

Chagas disease, caused by Trypanosoma cruzi, remains a serious public health problem worldwide. The parasite was subdivided into six distinct genetic groups, called "discrete typing units" (DTUs), from TcI to TcVI. Several studies have indicated that the heterogeneity of T. cruzi species directly affects the diversity of clinical manifestations of Chagas disease, control, diagnosis performance, and susceptibility to treatment. Thus, this review aims to describe how T. cruzi genetic diversity influences the biology of the parasite and/or clinical parameters in humans. Regarding the geographic dispersion of T. cruzi, evident differences were observed in the distribution of DTUs in distinct areas. For example, TcII is the main DTU detected in Brazilian patients from the central and southeastern regions, where there are also registers of TcVI as a secondary T. cruzi DTU. An important aspect observed in previous studies is that the genetic variability of T. cruzi can impact parasite infectivity, reproduction, and differentiation in the vectors. It has been proposed that T. cruzi DTU influences the host immune response and affects disease progression. Genetic aspects of the parasite play an important role in determining which host tissues will be infected, thus heavily influencing Chagas disease's pathogenesis. Several teams have investigated the correlation between T. cruzi DTU and the reactivation of Chagas disease. In agreement with these data, it is reasonable to suppose that the immunological condition of the patient, whether or not associated with the reactivation of the T. cruzi infection and the parasite strain, may have an important role in the pathogenesis of Chagas disease. In this context, understanding the genetics of T. cruzi and its biological and clinical implications will provide new knowledge that may contribute to additional strategies in the diagnosis and clinical outcome follow-up of patients with Chagas disease, in addition to the reactivation of immunocompromised patients infected with T. cruzi.

Design and Synthesis of Novel 3-Nitro-1H-1,2,4-triazole-1,2,3-triazole-1,4-disubstituted Analogs as Promising Antitrypanosomatid Agents: Evaluation of In Vitro Activity against Chagas Disease and Leishmaniasis

A series of 28 compounds, 3-nitro-1H-1,2,4-triazole, were synthesized by click-chemistry with diverse substitution patterns using medicinal chemistry approaches, such as bioisosterism, Craig-plot, and the Topliss set with excellent yields. Overall, the analogs demonstrated relevant in vitro antitrypanosomatid activity. Analog 15g (R1 = 4-OCF3-Ph, IC50 = 0.09 μM, SI = >555.5) exhibited an outstanding antichagasic activity (Trypanosoma cruzi, Tulahuen LacZ strain) 68-fold more active than benznidazole (BZN, IC50 = 6.15 μM, SI = >8.13) with relevant selectivity index, and suitable LipE = 5.31. 15g was considered an appropriate substrate for the type I nitro reductases (TcNTR I), contributing to a likely potential mechanism of action for antichagasic activity. Finally, 15g showed nonmutagenic potential against Salmonella typhimurium strains (TA98, TA100, and TA102). Therefore, 3-nitro-1H-1,2,4-triazole 15g is a promising antitrypanosomatid candidate for in vivo studies.

Assessment of Plasma Exovesicles and Prothrombotic Biomarkers Suggest Prethrombotic Conditions in Chagas Cardiomyopathy in Colombia

Chagas cardiomyopathy (CCC) is associated with coagulation disorders that frequently culminate in thrombotic events, contributing to increased mortality rates in this clinical condition. Considering the demonstrated effect that extracellular vesicles (EVs) have on regulating inflammatory processes, coagulation, and angiogenesis, the present study aims to characterize plasma EVs and their relationship with coagulation disorders in patients with CCC. A total of 78 patients were assessed with 46.1% (36/78) representing the CCC group, 8.9% (7/78) with cardiomyopathy unrelated to Chagas disease (CM group), and 44.8% (35/78) comprising the control group, which included individuals without cardiomyopathy and negative for T. cruzi infection. Plasma EVs concentration (EVs/mL) for each individual was evaluated by flow cytometry, along with the proportion of EVs expressing PSGL-1 (PSGL-1+ EVs), Tissue Factor (TF + EVs), and CD41a (CD41a + EVs). The ability of EVs to induce platelet aggregation was evaluated by spectrophotometry. We also evaluated other prothrombotic biomarkers, including platelet count, activated partial thromboplastin time (PTT), prothrombin time (PT), and D-dimer levels. The results revealed elevated D-dimer levels in the CCC group, accompanied by a decrease in the count of EVs per mL of plasma and a significant increase in the proportion of PSGL-1+ EVs (P < .05) compared to the control group. Other parameters did not exhibit significant differences between groups. The elevated levels of PSGL-1+ EVs in the CCC group may be attributed to myocardial inflammatory processes, which, upon interaction with platelet-derived P-selectin, could promote thrombus formation, as indicated by the increased D-dimer levels in this group.

Subunit nanovaccine elicited T cell functional activation controls Trypanosoma cruzi mediated maternal and placental tissue damage and improves pregnancy outcomes in mice

This study investigated a candidate vaccine effect against maternal Trypanosoma cruzi (Tc) infection and improved pregnancy outcomes. For this, TcG2 and TcG4 were cloned in a nanoplasmid optimized for delivery, antigen expression, and regulatory compliance (nano2/4 vaccine). Female C57BL/6 mice were immunized with nano2/4, infected (Tc SylvioX10), and mated 7-days post-infection to enable fetal development during the maternal acute parasitemia phase. Females were euthanized at E12-E17 (gestation) days. Splenic and placental T-cell responses were monitored by flow cytometry. Maternal and placental/fetal tissues were examined for parasites by qPCR and inflammatory infiltrate by histology. Controls included age/immunization-matched non-pregnant females. Nano2/4 exhibited no toxicity and elicited protective IgG2a/IgG1 response in mice. Nano2/4 signaled a splenic expansion of functionally active CD4+ effector/effector memory (Tem) and central memory (Tcm) cells in pregnant mice. Upon challenge infection, nano2/4 increased the splenic CD4+ and CD8+T cells in all mice and increased the proliferation of CD4+Tem, CD4+Tcm, and CD8+Tcm subsets producing IFNγ and cytolytic molecules (PRF1, GZB) in pregnant mice. A balanced serum cytokines/chemokines response and placental immune characteristics indicated that pregnancy prevented the overwhelming damaging immune response in mice. Importantly, pregnancy itself resulted in a significant reduction of parasites in maternal and fetal tissues. Nano2/4 was effective in arresting the Tc-induced tissue inflammatory infiltrate, necrosis, and fibrosis in maternal and placental tissues and improving maternal fertility, placental efficiency, and fetal survival. In conclusion, we show that maternal nano2/4 vaccination is beneficial in controlling the adverse effects of Tc infection on maternal health, fetal survival, and pregnancy outcomes.

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.

The transcriptome landscape of 3D-cultured placental trophoblasts reveals activation of TLR2 and TLR3/7 in response to low Trypanosoma cruzi parasite exposure

Vertical transmission of Trypanosoma cruzi (T. cruzi) become a globalized health problem accounting for 22% of new cases of Chagas disease (CD). Congenital infection is now considered the main route of CD spread in non-endemic countries where no routine disease testing of pregnant women is implemented. The main mechanisms that lead to fetal infection by T. cruzi remain poorly understood. Mother-to-child transmission may occur when bloodstream trypomastigotes interact with the syncytiotrophoblasts (SYNs) that cover the placenta chorionic villi. These highly specialized cells function as a physical barrier and modulate immune responses against pathogen infections. To model the human placenta environment, we have previously used a three-dimensional (3D) cell culture system of SYNs that exhibits differentiation characteristics comparable to placental trophoblasts. Further, we have shown that 3D-grown SYNs are highly resistant to T. cruzi infection. In this work, we used RNA sequencing and whole transcriptome analysis to explore the immunological signatures that drive SYNs' infection control. We found that the largest category of differentially expressed genes (DEGs) are associated with inflammation and innate immunity functions. Quantitative RT-PCR evaluation of selected DEGs, together with detection of cytokines and chemokines in SYNs culture supernatants, confirmed the transcriptome data. Several genes implicated in the Toll-like receptors signaling pathways were upregulated in 3D-grown SYNs. In fact, TLR2 blockade and TLR3/7 knockdown stimulated T. cruzi growth, suggesting that these molecules play a significant role in the host cell response to infection. Ingenuity Pathway Analysis of DEGs predicted the activation of canonical pathways such as S100 protein family, pathogen induced cytokine storm, wound healing, HIF1α signaling and phagosome formation after T. cruzi exposure. Our findings indicate that SYNs resist infection by eliciting a constitutive pro-inflammatory response and modulating multiple defense mechanisms that interfere with the parasite's intracellular life cycle, contributing to parasite killing and infection control.

Chagas Disease Diagnostic Testing in Two Academic Hospitals in New Orleans, Louisiana: A Call to Action

Chagas disease, caused by the protozoa parasite Trypanosoma cruzi, is an anthropozoonosis that represents a major public health problem in the Americas, affecting 7 million people with at least 65 million at risk. We sought to assess the intensity of disease surveillance based on diagnostic test requests from hospitals in New Orleans, Louisiana. We extracted information from send-out labs at two major tertiary academic hospitals in New Orleans, Louisiana, USA, from 1 January 2018 to 1 December 2020. We found that in these three years there were 27 patients for whom Chagas disease testing was ordered. Most of these patients were male (70%), with a median age of 40 years old, and their most common ethnical background was Hispanic (74%). These findings demonstrate undertesting of this neglected disease in our region. Given the low Chagas disease surveillance, we need to increase awareness, health promotion, and education among healthcare workers.

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.

Chagas Disease: Seroprevalence and Associated Factors in Indigenous Communities of the Southern Limit of Argentine Chaco

Chagas disease is more prevalent in socially vulnerable communities in the Gran Chaco Eco-region. The study evaluated the seroprevalence of Chagas disease and associated factors between May 2014 and September 2015, in indigenous communities of Santa Fe, Argentina, in the southern Chaco. Lysate ELISA and indirect hemagglutination tests were used to detect antibodies against Trypanosoma cruzi, and recombinant ELISA was used in the case of disagreement. Household surveys were conducted with the head of household about risk factors for the disease. Serological tests were conducted on 298 people from three indigenous communities, 127 male and 171 female. Seroprevalence was 18.5%. A total of 64 surveys were conducted; 82.8% of the heads of household were male, with a median age of 39 years, and 61.0% had not completed primary school. In 35.9% of the households, there was at least one member of the cohabiting group infected with T. cruzi. The level of education of the head of household showed a statistically significant association with Chagas disease (OR = 3.43), among all the risk factors studied. The prevalence of infection is lower than that of other indigenous communities of the Gran Chaco, probably because environmental conditions are moderating and disfavoring the establishment of the insect vector in homes, but also because of socioeconomic differences with the rest of the eco-region. Beyond this, serological controls are needed to prevent vertical transmission.

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.

Synthesis and evaluation of the in vitro and in vivo antitrypanosomal activity of 2-styrylquinolines

In this study, we report the synthesis and evaluation of in vitro and in vivo antitrypanosomal activity of styrylquinoline-like compounds (SQ) 3a-h. Synthesis was carried out by using quinaldine and 8- hydroxyquinaldine with a variety of aromatic aldehydes. The structure of SQs was corroborated by one and two-dimension NMR spectroscopy. In vitro antitrypanosomal activity on T. cruzi Talahuen strain was evaluated using β-galactosidase enzymatic method; cytotoxicity on U-937 cells was assessed by using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] method. On the other hand, in vivo therapeutical response to 3a-f compounds was evaluated in BALB/c mice (Mus musculus) experimentally infected with T. cruzi blood trypomastigotes and then orally administered with 100 mg/kg weight day for 20 days. All of the compounds showed in vitro activity with EC₅₀ values ranging between 4.6 ± 0.1 μg/mL (14.4 μM) and 36.6 ± 6.1 μg/mL (91 μM). Furthermore, treatment with 3a-f compounds for 20 days resulted in improvement in all of the mice, with a 83–96% decrease in parasitic load at day 90 post-treatment. Treatment with benznidazol (BZ) managed to cure 100% of the mice at the end of treatment. None of the treatments affected the weight of the animals or alanine aminotransferase (ALT), blood urea nitrogen (BUN) and creatinine levels in serum. These results suggest a therapeutic potential of 3a-f compounds as treatment for the infection.

Elevated Pediatric Chagas Disease Burden Complicated by Concomitant Intestinal Parasites and Malnutrition in El Salvador

The eradication of the vector Rhodnius prolixus from Central America was heralded as a victory for controlling transmission of Trypanosoma cruzi, the parasite that causes Chagas disease. While public health officials believed this milestone achievement would effectively eliminate Chagas disease, case reports of acute vector transmission began amassing within a few years. This investigation employed a cross-sectional serosurvey of children either presenting with fever for clinical care or children living in homes with known triatomine presence in the state of Sonsonate, El Salvador. Over the 2018 calendar year, a 2.3% Chagas disease seroprevalence among children with hotspot clustering in Nahuizalco was identified. Positive serology was significantly associated with dogs in the home, older participant age, and a higher number of children in the home by multivariate regression. Concomitant intestinal parasitic infection was noted in a subset of studied children; 60% having at least one intestinal parasite and 15% having two or more concomitant infections. Concomitant parasitic infection was statistically associated with an overall higher parasitic load detected in stool by qPCR. Lastly, a four-fold higher burden of stunting was identified in the cohort compared to the national average, with four-fifths of mothers reporting severe food insecurity. This study highlights that polyparasitism is common, and a systems-based approach is warranted when treating Chagas disease seropositive children.