Hydrazinated geraniol derivatives as potential broad-spectrum antiprotozoal agents.

Geraniol, a primary component of several essential oils, has been associated with broad-spectrum antiprotozoal activities, although moderate to weak. This study primarily concentrated on the synthesis of hydrazinated geraniol derivatives as potential antiprotozoal agents. The synthesised compounds were tested in vitro against different parasitic protozoans of clinical relevance, including Trypanosoma brucei brucei, Trypanosoma brucei rhodesiense, Trypanosoma cruzi and Leishmania infantum. Compounds 6, 8, 13, 14 and 15 demonstrated low micromolar activity against the different parasites. Compounds 8, 13, 14 and 15 had the highest efficacy against Trypanosoma brucei rhodesiense, as indicated by their respective IC50 values of 0.74, 0.56, 1.26 and 1.00 µM. Compounds 6, 14 and 15 displayed the best activity against Trypanosoma brucei brucei, with IC50 values of 1.49, 1.48 and 1.85 µM, respectively. The activity of compounds 6, 14 and 15 also extended to intracellular Trypanosoma cruzi, with IC50 values of 5.14, 6.30 and 4.90 µM, respectively. Compound 6, with an IC50 value of 11.73 µM, and compound 14, with an IC50 value of 8.14 µM, demonstrated some modest antileishmanial activity.

The Trypanosoma cruzi pleiotropic protein P21 orchestrates the intracellular retention and in-vivo parasitism control of virulent Y strain parasites.

P21 is a protein secreted by all forms of Trypanosoma cruzi (T. cruzi) with recognized biological activities determined in studies using the recombinant form of the protein. In our recent study, we found that the ablation of P21 gene decreased Y strain axenic epimastigotes multiplication and increased intracellular replication of amastigotes in HeLa cells infected with metacyclic trypomastigotes. In the present study, we investigated the effect of P21 in vitro using C2C12 cell lines infected with tissue culture-derived trypomastigotes (TCT) of wild-type and P21 knockout (TcP21-/-) Y strain, and in vivo using an experimental model of T. cruzi infection in BALB/c mice. Our in-vitro results showed a significant decrease in the host cell invasion rate by TcP21-/- parasites as measured by Giemsa staining and cell count in bright light microscope. Quantitative polymerase chain reaction (qPCR) analysis showed that TcP21-/- parasites multiplied intracellularly to a higher extent than the scrambled parasites at 72h post-infection. In addition, we observed a higher egress of TcP21-/- trypomastigotes from C2C12 cells at 144h and 168h post-infection. Mice infected with Y strain TcP21-/- trypomastigotes displayed higher systemic parasitemia, heart tissue parasite burden, and several histopathological alterations in heart tissues compared to control animals infected with scrambled parasites. Therewith, we propose that P21 is important in the host-pathogen interaction during invasion, cell multiplication, and egress, and may be part of the mechanism that controls parasitism and promotes chronic infection without patent systemic parasitemia.

Domestic Dog Infection with Trypanosoma cruzi from Northern and Southern Regions of Mexico.

Background: Chagas disease or American trypanosomiasis, caused by Trypanosoma cruzi and vectored by triatomines, affects millions of people worldwide. In endemic countries including Mexico, infections in domestic animals, such as dogs, may affect the risk of human disease when they serve as a source of infection to vectors that subsequently infect humans. Materials and Methods: We conducted a cross-sectional study of 296 dogs from two cities near the northern and southern borders of Mexico: Reynosa, Tamaulipas, and Tuxtla Gutierrez, Chiapas. Infection was measured based on testing of blood using T. cruzi quantitative PCR (qPCR) and up to three antibody detection assays. The StatPak immunochromatographic assay was used to screen samples and the indirect fluorescent antibody (IFA) and multiplex microsphere immunoassay (MIA) tests were used as secondary tests on all samples that screened positive and a subset of negatives. Serologic positivity was defined based on reactivity on at least two independent tests. Results: Of the 280 samples tested for parasite DNA, two (0.7%) were positive, one of which (0.4%) was confirmed as T. cruzi discrete typing unit TcIV. Overall, 72 (24.3%) samples were reactive for T. cruzi antibodies via StatPak of which 8 were also positive using MIA and 2 were also positive using IFA (including one of the PCR-positive dogs). Overall, nine dogs (3.4%) met study criteria of positivity based on either/both serology or PCR tests. Positive dogs were found in both regions of Mexico; five (2.7%) from Reynosa and four (3.6%) from Tuxtla Gutierrez. We found no association between infection status and state of origin, sex, age group, breed group, neighborhood, and whether other pets lived in the home. Conclusion: Our results re-emphasize dogs' utility as sentinels for T. cruzi in Mexico and underscore the need for improved veterinary diagnostic tests and parasite surveillance at the household level in endemic countries.

Trypanosoma cruzi Vps34 colocalizes with Beclin1 and plays a role in parasite invasion of the host cell by modulating the expression of a sub-group of trans-sialidases.

Trypanosoma cruzi, the etiological agent of Chagas' disease, can infect both phagocytic and non-phagocytic cells. T. cruzi gp82 and gp90 are cell surface proteins belonging to Group II trans-sialidases known to be involved in host cell binding and invasion. Phosphatidylinositol kinases (PIK) are lipid kinases that phosphorylate phospholipids in their substrates or in themselves, regulating important cellular functions such as metabolism, cell cycle and survival. Vps34, a class III PIK, regulates autophagy, trimeric G-protein signaling, and the mTOR (mammalian Target of Rapamycin) nutrient-sensing pathway. The mammalian autophagy gene Beclin1 interacts to Vps34 forming Beclin 1-Vps34 complexes involved in autophagy and protein sorting. In T. cruzi epimastigotes, (a non-infective replicative form), TcVps34 has been related to morphological and functional changes associated to vesicular trafficking, osmoregulation and receptor-mediated endocytosis. We aimed to characterize the role of TcVps34 during invasion of HeLa cells by metacyclic (MT) forms. MTs overexpressing TcVps34 showed lower invasion rates compared to controls, whilst exhibiting a significant decrease in gp82 expression in the parasite surface. In addition, we showed that T. cruzi Beclin (TcBeclin1) colocalizes with TcVps34 in epimastigotes, thus suggesting the formation of complexes that may play conserved cellular roles already described for other eukaryotes.

Efficacy of a Zn-based metalorganic framework doped with benznidazole on acute experimental Trypanosoma cruzi infection.

Metal-Organic Frameworks (MOFs) have been shown to enhance the activity of encapsulated compounds by facilitating their passage across cell membranes, thereby enabling controlled and selective release. This study investigates the efficacy of BNZ@Zn-MOFs against the acute phase of Trypanosoma cruzi infection in a mouse model. The particles were synthesized by electroelution (EL), doped with BZN via mechanochemistry, and characterized using scanning electron microscopy (SEM), infrared spectroscopy (FTIR), and X-ray diffraction (XRD). BNZ@Zn-MOFs released 80% of the encapsulated BZN within 3 h, demonstrating no cytotoxicity in NIH-3T3 and HeLa cells. Furthermore, in a model of acute experimental T. cruzi-infection in BALB/c mice, the delivery system exhibited antiparasitic activity at a significantly lower BZN concentration compared to free BZN treatment. PCR analysis of treated mice revealed no parasite DNA in their tissues, and hematoxylin-eosin staining showed no apparent damage to tissue architecture. Additionally, serum levels of liver function enzymes remained unchanged, indicating no adverse effects on liver function. This delivery system, utilizing suboptimal BZN doses, enables the preservation of drug activity while potentially facilitating a substantial decrease in side effects associated with Chagas disease treatment.

Quantitative Proteomic Analysis of Macrophages Infected with Trypanosoma cruzi Reveals Different Responses Dependent on the SLAMF1 Receptor and the Parasite Strain.

Chagas disease is caused by the intracellular protozoan parasite Trypanosoma cruzi. This disease affects mainly rural areas in Central and South America, where the insect vector is endemic. However, this disease has become a world health problem since migration has spread it to other continents. It is a complex disease with many reservoirs and vectors and high genetic variability. One of the host proteins involved in the pathogenesis is SLAMF1. This immune receptor acts during the infection of macrophages controlling parasite replication and thus affecting survival in mice but in a parasite strain-dependent manner. Therefore, we studied the role of SLAMF1 by quantitative proteomics in a macrophage in vitro infection and the different responses between Y and VFRA strains of Trypanosoma cruzi. We detected different significant up- or downregulated proteins involved in immune regulation processes, which are SLAMF1 and/or strain-dependent. Furthermore, independently of SLAMF1, this parasite induces different responses in macrophages to counteract the infection and kill the parasite, such as type I and II IFN responses, NLRP3 inflammasome activation, IL-18 production, TLR7 and TLR9 activation specifically with the Y strain, and IL-11 signaling specifically with the VFRA strain. These results have opened new research fields to elucidate the concrete role of SLAMF1 and discover new potential therapeutic approaches for Chagas disease.

Imaging Assays to Detect DNA Damage in Trypanosome Parasites Using γH2A.

Diseases caused by trypanosomatid parasites remain a significant unmet medical need for millions of people globally. Trypanosomatid parasites such as Trypanosoma cruzi and subspecies of Trypanosoma brucei cause Chagas disease and human African trypanosomiasis (HAT), respectively. Although efforts to find novel treatments have been successful for HAT, Chagas disease is still treated with decades-old therapies that suffer from long treatment durations and severe safety concerns. We recently described the identification and characterization of the cyanotriazole compound class that kills trypanosomes, in vitro and in vivo, by selective inhibition of the trypanosome nuclear topoisomerase II enzyme. To evaluate whether inhibition of the topoisomerase II enzyme led to parasite death due to lethal double-strand DNA breaks, we developed assays for detecting DNA damage in both intracellular amastigotes of T. cruzi and bloodstream-form T. brucei by using the canonical DNA damage marker γH2A. Herein, this article describes the protocols for detecting DNA damage using an immunofluorescence assessment of γH2A by microscopy in trypanosome parasites. Key features • Immunofluorescence-based assay to detect the γH2A response in T. brucei and T. cruzi parasites. • Robust DNA damage pathway-based cellular assays to evaluate topoisomerase II poisons' ability to cause DNA damage. • A 384-well plate-based T. cruzi protocol allows high-resolution and high-throughput evaluation of compounds that cause DNA damage by measuring γH2A in intracellular parasites. • This assay could be modifiable for evaluation of DNA damage responses in various intracellular and extracellular eukaryotic pathogens.

Nonsteroidal Anti-Inflammatory Drugs and Experimental Chagas Disease: An Unsolved Question.

Chagas disease is a parasitic disease caused by the protozoan Trypanosoma cruzi with an acute, detectable blood parasites phase and a chronic phase, in which the parasitemia is not observable, but cardiac and gastrointestinal consequences are possible. Mice are the principal host used in experimental Chagas disease but reproduce the human infection depending on the animal and parasite strain, besides dose and route of administration. Lipidic mediators are tremendously involved in the pathogenesis of T. cruzi infection, meaning the prostaglandins and thromboxane, which participate in the immunosuppression characteristic of the acute phase. Thus, the eicosanoids inhibition caused by the nonsteroidal anti-inflammatory drugs (NSAIDs) alters the dynamic of the disease in the experimental models, both in vitro and in vivo, which can explain the participation of the different mediators in infection. However, marked differences are founded in the various NSAIDs existing because of the varied routes blocked by the drugs. So, knowing the results in the experimental models of Chagas disease with or without the NSAIDs helps comprehend the pathogenesis of this infection, which still needs a better understanding.

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

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

Echocardiographic Documentation of Dilated Cardiomyopathy Development in Dogs Naturally Infected with Trypanosoma cruzi.

We aimed to characterize the echocardiographic alterations in dogs from an endemic region that were naturally infected with T. cruzi. Dogs (n = 130) seropositive for antibodies against T. cruzi and/or with acute parasitemia were enrolled in the study. Indicators of changes in the structure and systolic and diastolic functions of the left ventricle (LV) and blood flow patterns were evaluated by echocardiography. The frequency and extent of alterations in these indicators were associated with the severity of the disease. Briefly, 15 (11.54%) dogs were diagnosed with dilated cardiomyopathy (DCM), and 115 (88.46%) dogs were diagnosed as being without DCM. Infected dogs with DCM exhibited structural features of LV dysfunction, e.g., a significant (p < 0.05) increase in the LV internal diameter at systole and diastole (LVID-s, LVID-d) and a decline in the LV posterior wall (LVPW-d) thickness at diastole. Despite an increase in stroke volume and cardiac output indicating contraction force, DCM resulted in a decreased ejection fraction, affecting systolic function. Dogs that were diagnosed as DCM-negative but were positive for T. cruzi by PCR exhibited a high frequency of an increase in the thickness of the interventricular septum in systole (IVS-s) and the LV posterior wall in diastole (LVPW-d), a decline in the LV inner diameter (LVID-d, LVID-s), and fractional shortening (FS). The thinning of the LVPW at systole was the most defining feature observed in chronically infected dogs. In summary, this is the first study reporting the echocardiographic changes occurring in dogs naturally infected with T. cruzi and developing DCM. Our data suggest that changes in LVID are a major indicator of risk of cardiac involvement, and the observation of changes in the IVS, LVPW, and FS have predictive value in determining the risk of DCM development in infected dogs.

Evaluation of chimeric recombinant antigens for the serodiagnosis of Trypanosoma cruzi in dogs: a promising tool for Chagas disease surveillance.

BACKGROUND: Chagas disease (CD), a neglected parasitic disease caused by Trypanosoma cruzi, poses a significant health threat in Latin America and has emerged globally because of human migration. Trypanosoma cruzi infects humans and over 100 other mammalian species, including dogs, which are important sentinels for assessing the risk of human infection. Nonetheless, the serodiagnosis of T. cruzi in dogs is still impaired by the absence of commercial tests. In this study, we investigated the diagnostic accuracy of four chimeric recombinant T. cruzi IBMP antigens (IBMP-8.1, IBMP-8.2, IBMP-8.3, and IBMP-8.4) for detecting anti-T. cruzi antibodies in dogs, using latent class analysis (LCA). METHODS: We examined 663 canine serum samples, employing indirect ELISA with the chimeric antigens. LCA was utilized to establish a latent variable as a gold standard for T. cruzi infection, revealing distinct response patterns for each antigen. RESULTS: The IBMP (Portuguese acronym for the Molecular Biology Institute of Paraná) antigens achieved area under the ROC curve (AUC) values ranging from 90.9% to 97.3%. The highest sensitivity was attributed to IBMP-8.2 (89.8%), while IBMP-8.1, IBMP-8.3, and IBMP-8.4 achieved 73.5%, 79.6%, and 85.7%, respectively. The highest specificity was observed for IBMP-8.4 (98.6%), followed by IBMP-8.2, IBMP-8.3, and IBMP-8.1 with specificities of 98.3%, 94.4%, and 92.7%, respectively. Predictive values varied according to prevalence, indicating higher effectiveness in endemic settings. CONCLUSIONS: Our findings underscore the remarkable diagnostic performance of IBMP-8.2 and IBMP-8.4 for the serodiagnosis of Trypanosoma cruzi in dogs, representing a promising tool for the diagnosis of CD in dogs. These chimeric recombinant antigens may not only enhance CD surveillance strategies but also hold broader implications for public health, contributing to the global fight against this neglected tropical disease.

Chagas Disease across the Ages: A Historical View and Commentary on Navigating Future Challenges.

Chagas disease, discovered over a century ago, continues to pose a global health challenge, affecting millions mainly in Latin America. This historical review with commentary outlines the disease's discovery, its evolution into a global concern due to migration, and highlights significant advances in diagnostics and treatment strategies. Despite these advancements, the paper discusses ongoing challenges in eradication, including vector control, congenital transmission, the disease's asymptomatic nature, and socioeconomic barriers to effective management. It calls for a multidisciplinary approach, enhanced diagnostics, improved treatment accessibility, and sustained vector control efforts. The review emphasizes the importance of global collaboration and increased funding to reduce Chagas disease's impact.

Parasitic Effects on the Congenital Transmission of Trypanosoma cruzi in Mother-Newborn Pairs.

Maternal parasitemia and placental parasite load were examined in mother-newborn pairs to determine their effect on the congenital transmission of Trypanosoma cruzi. Parasitemia was qualitatively assessed in mothers and newborns by the microhematocrit test; parasite load was determined in the placental tissues of transmitting and non-transmitting mothers by the detection of T. cruzi DNA and by histology. Compared to transmitter mothers, the frequency and prevalence of parasitemia were found to be increased in non-transmitter mothers; however, the frequency and prevalence of parasite load were higher among the transmitter mothers than among their non-transmitter counterparts. Additionally, serum levels of interferon (IFN)-γ were measured by an enzyme-linked immunosorbent assay (ELISA) in peripheral, placental, and cord blood samples. Median values of IFN-γ were significantly increased in the cord blood of uninfected newborns. The median IFN-γ values of transmitter and non-transmitter mothers were not significantly different; however, non-transmitter mothers had the highest total IFN-γ production among the group of mothers. Collectively, the results of this study suggest that the anti-T. cruzi immune response occurring in the placenta and cord is under the influence of the cytokines from the mother's blood and results in the control of parasitemia in uninfected newborns.

Assessment of the Activity of Nitroisoxazole Derivatives against Trypanosoma cruzi.

The development of new compounds to treat Chagas disease is imperative due to the adverse effects of current drugs and their low efficacy in the chronic phase. This study aims to investigate nitroisoxazole derivatives that produce oxidative stress while modifying the compounds' lipophilicity, affecting their ability to fight trypanosomes. The results indicate that these compounds are more effective against the epimastigote form of T. cruzi, with a 52 ± 4% trypanocidal effect for compound 9. However, they are less effective against the trypomastigote form, with a 15 ± 3% trypanocidal effect. Additionally, compound 11 interacts with a higher number of amino acid residues within the active site of the enzyme cruzipain. Furthermore, it was also found that the presence of a nitro group allows for the generation of free radicals; likewise, the large size of the compound enables increased interaction with aminoacidic residues in the active site of cruzipain, contributing to trypanocidal activity. This activity depends on the size and lipophilicity of the compounds. The study recommends exploring new compounds based on the nitroisoxazole skeleton, with larger substituents and lipophilicity to enhance their trypanocidal activity.

Mammalian placental explants: A tool for studying host-parasite interactions and placental biology.

The placenta plays a critical role in host-pathogen interactions. Thus, ex vivo infection of mammalian placental explants is an excellent and simple method to study the mechanisms of cellular and tissue invasion by different pathogens in different mammalian species. These explants can be maintained in culture for several days, preserving the tissue architecture and resembling in-utero conditions under more physiological conditions than their isolated counterparts in isolated cell culture models. In addition, placental explants not only allow us to study how the placenta responds and defends itself against various infections but also provide a versatile platform for advancing our understanding of placental biology and the immune response. Furthermore, they serve as powerful tools for drug discovery, facilitating the screening of potential therapeutics for placental infections and for the identification of diagnostic markers. This review highlights the utility of mammalian placental explants in studying the host-pathogen interaction of two relevant protozoan parasites, Trypanosoma cruzi, the causative agent of Chagas disease, and Toxoplasma gondii, the etiological agent of Toxoplasmosis. Here, we discuss the different methodologies and technical aspects of the model, as well as the effect of both parasites on placental responses in human, canine, and ovine explants.

Protective Efficacy of the Epitope-Conjugated Antigen N-Tc52/TSkb20 in Mitigating Trypanosoma cruzi Infection through CD8+ T-Cells and IFNγ Responses.

Chagas disease, caused by the protozoan Trypanosoma cruzi, remains a major public health challenge affecting millions in Latin America and worldwide. Although significant progress has been made in vector control, no vaccine exists to prevent infection or mitigate disease pathogenesis. We developed a rationally designed chimeric protein vaccine, N-Tc52/TSkb20, incorporating immunodominant epitopes from two T. cruzi antigens, the amino-terminal portion of Tc52 and the TSkb20 epitope derived from trans-sialidase. The objectives of this study were to construct and characterize the antigen and evaluate its protective potential in an immunoprophylactic murine model of T. cruzi infection. The N-Tc52/TSkb20 protein was recombinantly expressed in E. coli and its identity was confirmed using mass spectrometry and Western blotting. Immunization with the chimeric protein significantly controlled parasitemia and reduced the heart, colon, and skeletal muscle parasite burdens compared to non-vaccinated mice. Protection was superior to vaccination with the individual parental antigen components. Mechanistically, the vaccine induced potent CD8+ T-cell and IFNγ responses against the incorporated epitopes and a protective IgG antibody profile. A relatively low IL-10 response favored early parasite control. These results validate the promising multi-epitope approach and support the continued development of this type of rational vaccine design strategy against Chagas disease.

Viperidae snakes infected by mammalian-associated trypanosomatids and a free-living kinetoplastid.

Trypanosomatids have achieved significant evolutionary success in parasitizing various groups, yet reptiles remain relatively unexplored. The utilization of advanced molecular tools has revealed an increased richness of trypanosomatids in vertebrate hosts. The aim of this study was to identify the trypanosomatid species infecting Bothrops moojeni and Crotalus durissus kept in captivity from 2000 to 2022. Blood samples were obtained from 106 snakes: 73C. durissus and 33 B. moojeni. Whole blood was collected for hemoculture, blood smears and centrifugated to obtain the blood clot that had its DNA extracted and submitted to Nested PCR (18S rDNA gene) to detect Trypanosomatidae. Positive samples were quantified and submitted to both conventional (Sanger) and next generation sequencing (NGS). Cloning of the amplified PCR product was performed for only one individual of C. durissus. To exclude the possibility of local vector transmission, attempts to capture sandflies were conducted using six CDC-LT type light traps. Molecular diagnosis revealed that 34% of the snakes presented trypanosomatid DNA, 47.94% in C. durissus and 3.9% in B. moojeni. The cloning process generated four colonies identified as a new MOTU named Trypanosomatidae sp. CROT. The presence of DNA of five trypanosomatids (Trypanosoma cruzi TcII/VI, Trypanosoma sp. DID, Trypanosoma cascavelli, Trypanosomatidae sp. CROT, Leishmania infantum and Leishmania sp.) and one free-living kinetoplastid (Neobodo sp.) was revealed through NGS and confirmed by phylogenetic analysis. The haplotypic network divided the T. cascavelli sequences into two groups, 1) marsupials and snakes and 2) exclusive to marsupials. Therefore, the diversity of Kinetoplastea is still underestimated. Snakes have the ability to maintain infection with T. cruzi and L. infantum for up to 20 years and the DNA finding of Neobodo sp. in the blood of a C. durissus suggests that this genus can infect vertebrates.

An Uncommon Presentation of Unstable Ventricular Tachycardia: Raising Awareness for Early Recognition of Chagas Disease.

Chagas disease (CD), caused by Trypanosoma cruzi, is a leading cause of cardiomyopathy in Latin America that can lead to heart failure, arrhythmias, and sudden cardiac death (SCD). We present a case of a 71-year-old female from El Salvador with symptomatic ventricular tachycardia (VT) requiring emergent cardioversion and implantable cardioverter-defibrillator (ICD) due to CD. Diagnostic evaluation is limited and unclear in cases of chronic disease. Treatment involves antiparasitic therapy, heart failure management, and arrhythmia prevention. With growing numbers of cases in the US and limited treatment options, we highlight the need for timely recognition and intervention to reduce the burden of CD.

Trypanosoma cruzi in Wild and Synanthropic Mammals in Two Regions of Mexico: A Fieldwork and Genetic Discrete Typing Unit Review.

Background: Marsupials and rodents are the most important wild and synanthropic hosts of Trypanosoma cruzi due to the high frequency of infection, maintenance of diverse genetic populations of the parasite, and their close proximity to interact with both transmission cycles, sylvatic and peridomestic. Our aim was to identify the discrete typing units (DTU) of T. cruzi from different wild and synanthropic hosts in two regions of Mexico and to carry out a review of historical data focusing on current knowledge on the diversity and T. cruzi DTUs of host species. Materials and Methods: One hundred fifteen samples were obtained from two areas in Tabasco and Nayarit state. The presence of T. cruzi was evaluated by PCR. Results: The 12.6% (12/95) of samples from Tabasco and 65% (13/20) from Nayarit were found to be positive for parasite DNA. All the sequences analyzed were grouped in T. cruzi DTU I; low nucleotide diversity was observed in Tabasco (π = 0.00566, and Ï´ = 0.00632), while high genetic diversity was observed in Nayarit sequences, up to 8.63 (π) to 11.10 (Ï´) times greater than Tabasco sequences. Genetic flow and migration between Tabasco, and Nayarit were scarce (FST = 0.37329 and Nm = 0.42), and genetic exchange was observed only between nearby areas. The bibliographic review of hosts in Mexico, together with our data, shows a heterogeneous T. cruzi prevalence in Chiroptera and domestic animals. For Atelidae and Canids, prevalence is generally below 25%. However, a high prevalence, greater than 25% and up to 100%, was recorded in Didelphimorphia, and Rodentia. Few studies in regions of Mexico have been described as infected with the parasite; in these, the genetic group with the highest prevalence is the DTU I. Conclusion: Marsupials and rodents are important reservoirs of T. cruzi; DTU I was frequently reported; however, recent genetic and reservoir studies have demonstrated the presence of greater diversity of genetic groups.

Structure-Metabolism Relationships of benzimidazole derivatives with anti-Trypanosoma cruzi activity for Chagas disease.

This study introduces further insights from the hit-to-lead optimization process involving a series of benzimidazole derivatives acting as inhibitors of the cruzain enzyme, which targets Trypanosoma cruzi, the causative parasite of Chagas disease. Here, we present the design, synthesis and biological evaluation of 30 new compounds as a third generation of benzimidazole analogues with trypanocidal activity, aiming to enhance our understanding of their pharmacokinetic profiles and establish a structure-metabolism relationships within the series. The design of these new analogues was guided by the analysis of previous pharmacokinetic results, considering identified metabolic sites and biotransformation studies. This optimization resulted in the discovery of two compounds (42e and 49b) exhibiting enhanced metabolic stability, anti-Trypanosoma cruzi activity compared to benznidazole (the reference drug for Chagas disease), as well as being non-cruzain inhibitors, and demonstrating a satisfactory in vitro pharmacokinetic profile. These findings unveil a new subclass of aminobenzimidazole and rigid compounds, which offer potential for further exploration in the quest for discovering novel classes of antichagasic compounds.