Search Results (130)

The successful transmission of Trypanosoma cruzi, the causative agent of Chagas disease, depends on intricate interactions with its insect vector. In Mexico, Meccus pallidipennis is a relevant triatomine species involved in the parasite’s life cycle. In the gut of these insects, the parasite moves from the anterior midgut (AMG) to the posterior midgut (PMG), where it multiplies. Finally, T. cruzi differentiates into its infective form by metacyclogenesis in the proctodeum or rectum (RE). This study aimed to characterize and compare the protein and glycoprotein profiles of the anterior midgut (AMG) and rectum (RE) of M. pallidipennis, and to assess their potential association with T. cruzi metacyclogenesis, with special attention to sex-specific differences. Insects were infected with the T. cruzi isolate ITRI/MX/12/MOR (Morelos). Protein profiles were analyzed by polyacrylamide gel electrophoresis, while glycoproteins were detected using ConA, WGA, and PNA lectins. The metacyclogenesis index was calculated for male and female triatomines. A lower overlap of protein fractions was found in the RE compared to the AMG between sexes, suggesting functional sexual dimorphism. Infected females showed greater diversity in glycoprotein patterns in the RE, potentially related to higher blood intake and parasite burden. The metacyclogenesis index was significantly higher in females than in males. These findings highlight sex-dependent differences in gut protein and glycoprotein profiles in M. pallidipennis, which may influence the efficiency of T. cruzi development within the vector. Further proteomic studies are needed to identify the molecular components involved and clarify their roles in parasite differentiation and suggest new targets for disrupting parasite transmission within the vector. Full article

Triatoma pallidipennis, the main vector of Chagas disease in central Mexico, hosts a diverse and complex gut bacterial community shaped by environmental and physiological factors. To gain insight into these microbes’ dynamics, we characterised the gut bacterial communities of wild and insectary insects under different feeding and Trypanosoma cruzi infection conditions, using 16S rRNA gene sequencing. We identified 91 bacterial genera across 8 phyla, with Proteobacteria dominating most samples. Wild insects showed greater bacterial diversity, led by Acinetobacter and Pseudomonas, while insectary insects exhibited lower diversity and were dominated by Arsenophonus. The origin of the insects, whether they were reared in the insectary (laboratory) or collected from wild populations, was the principal factor structuring the gut microbiota, followed by feeding and T. cruzi infection. A stable core microbiota of 12 bacterial genera was present across all conditions, suggesting key functional roles in host physiology. Co-occurrence and functional enrichment analyses revealed that feeding and infection induced condition-specific microbial interactions and metabolic pathways. Our findings highlight the ecological plasticity of the triatomine gut microbiota and its potential role in modulating vector competence, providing a foundation for future microbiota-based control strategies. Full article

Triatoma dimidiata is a widely distributed vector of Trypanosoma cruzi in Mexico and Central America, found across a range of habitats from sylvatic to domestic. Vector control has relied heavily on indoor residual spraying with pyrethroids; however, reinfestation and emerging resistance have limited its long-term effectiveness. In this study, we analyzed the genetic diversity and population structure of T. dimidiata from Veracruz, Oaxaca, and Yucatan using mitochondrial markers (cyt b and ND4) and screened for knockdown resistance (kdr)-type mutations in the voltage-gated sodium channel (VGSC) gene. High haplotype diversity and regional differentiation were observed, with most genetic variation occurring between populations. The ND4 marker provided greater resolution than cyt b, revealing ten haplotypes and supporting evidence of recent population expansion. Haplotype networks showed clear geographic segregation, particularly between populations east and west of the Isthmus of Tehuantepec. The L925I mutation, highly associated with pyrethroid resistance, was detected for the first time in Mexican populations of T. dimidiata, albeit at low frequencies. These findings highlight the importance of integrating population genetic data and resistance surveillance into regionally adapted vector control strategies for Chagas disease. Full article

Trypanosoma cruzi, the causative agent of Chagas disease, undergoes epimastigogenesis—a critical differentiation step in which trypomastigotes transform into epimastigotes. While this process is essential for the parasite’s survival in its insect vector, the molecular mechanisms regulating it remain poorly understood. Here, we present the first evidence implicating extracellular vesicles (EVs) as enhancing mediators of epimastigogenesis. Using in vitro models with T. cruzi strains CL Brener and Dm28c, we demonstrate that EVs, membrane-bound vesicles, were shown to enhance differentiation in a strain-specific and temperature-dependent manner. We observed strain-specific EV release patterns: Dm28c produced more EVs at 24 h, whereas CL Brener peaked at 72 h. Additionally, we confirm that epimastigogenesis occurs exclusively at 28 °C after 72 h. These findings establish EVs as novel regulators of T. cruzi differentiation and suggest new insight into parasite development, highlighting potential targets for therapeutic intervention. The observed enhancement of differentiation in the presence of EVs indicates a potential role for these vesicles in this developmental process, although the underlying mechanisms remain undefined. Full article

Chagas disease, caused by Trypanosoma cruzi, is a significant health concern in Latin America, with triatomine insects serving as its primary vectors. Among them, Triatoma barberi is an important yet understudied species in Querétaro, Mexico. This study employs ecological niche modeling (ENM) to predict the potential distribution of T. barberi in the region, using occurrence records and environmental variables. The MaxEnt algorithm was used to generate the model, which was validated through AUC and TSS metrics. Results indicate that temperature seasonality and altitude are key drivers of T. barberi distribution, with high-suitability areas found in semi-urban and peri-urban zones. Additionally, six new occurrence records were documented, suggesting a growing urban presence of this species. These findings highlight the need for enhanced vector surveillance and targeted control measures to reduce the risk of Chagas disease transmission. Full article

Autochthonous Chagas disease remains a health risk for humans in Latin American countries but is rarely found among residents of the United States (US), despite the presence of competent insect vectors and small mammal reservoirs of Trypanosoma cruzi in the lower two-thirds of the US. This report discusses the differences in the rates of autochthonous Chagas disease in Latin America and the US. The key to the differences may lie in the mode (or means) of transmission of parasites to humans. In both Latin America and the US, the so-called vectorial transmission of Chagas disease to humans is the mode of acquisition accepted by most authorities. This mode involves the improbable combination of an infected kissing bug defecating near the mouth or eyes or the site of the bite, followed by the bite victim rubbing infected feces into the wound site or mucous membranes. Outbreaks of Chagas disease due to fecal–oral contamination, known as oral Chagas, have been recorded in Latin America for decades, and at present, oral Chagas is the predominant mode of infection recognized in Brazil. It is perhaps time to consider fecal–oral transmission in its many manifestations as a risk factor for Chagas disease in the US rather than reflexively invoking vectorial transmission. Fecal–oral transmission includes contamination of food and drink by triatomine feces and infection via contaminated fomites and surfaces at home and at worksites, as well as transmission from infected small mammals and other routes discussed in this report. Full article

Trypanosoma cruzi, the protozoan causative of Chagas disease, is primarily transmitted through blood-sucking insects and infects mammalian and some reptilian hosts. In Chile, insects of the Mepraia genus are key vectors of T. cruzi in its wild transmission cycle. High prevalence and mixed infection of T. cruzi lineages have been reported in a Mepraia population on Santa María Island in the Atacama Desert. However, no small mammals have been reported. The island’s vertebrate community is dominated by the lizard Microlophus atacamensis and marine and scavenger birds. This study aimed to research blood samples of M. atacamensis for the presence of T. cruzi DNA (kDNA and satDNA) using conventional PCR (cPCR) and quantitative real-time PCR (qPCR) and estimate parasitemia. Our findings reveal that 39.4% of 33 individuals were positive with both cPCR and qPCR, while when assessing infection with either technique, it rises up to 81.8%. These findings confirm that M. atacamensis is a host of T. cruzi, suggesting its potential role as a key reservoir in the island’s transmission cycle. This study provides new insights into the life cycle of T. cruzi in the coastal Atacama Desert, highlighting the importance of reptiles in the epidemiology of this parasite. Full article

This review summarizes the interactions between Trypanosoma cruzi, the etiologic agent of Chagas disease, and its vectors, the triatomines, and highlights open questions. Four important facts should be emphasized at the outset: (1) The development of T. cruzi strains and their interactions with the mammalian host and the insect vector vary greatly. (2) Only about 10 of over 150 triatomine species have been studied for their interactions with the protozoan parasite. (3) The use of laboratory strains of triatomines makes generalizations difficult, as maintenance conditions influence the interactions. (4) The intestinal microbiota is involved in the interactions, but the mutualistic symbionts, Actinomycetales, have so far only been identified in four species of triatomines. The effects of the vector on T. cruzi are reflected in a different colonization ability of T. cruzi in different triatomine species. In addition, the conditions in the intestine lead to strong multiplication in the posterior midgut and rectum, with infectious metacyclic trypomastigotes developing almost exclusively in the latter. Starvation and feeding of the vector induce the development of certain stages of T. cruzi. The negative effects of T. cruzi on the triatomines depend on the T. cruzi strain and are particularly evident when the triatomines are stressed. The intestinal immunity of the triatomines responds to ingested blood-stage trypomastigotes of some T. cruzi strains and affects many intestinal bacteria, but not all and not the mutualistic symbionts. The specific interaction between T. cruzi and the bacteria is evident after the knockdown of antimicrobial peptides: the number of non-symbiotic bacteria increases and the number of T. cruzi decreases. In long-term infections, the suppression of intestinal immunity is indicated by the growth of specific microbiota. Full article

Chagas disease is a neglected disease caused by the parasite Trypanosoma cruzi, a public health problem in both endemic and non-endemic countries. In Mexico, the southern region is considered endemic, and cases are frequently reported; however, in the northwestern region, only a few cases are confirmed annually. This study describes, for the first time, the Discrete Typing Unit (DTU) of Trypanosoma cruzi in a volunteer blood donor rejected for being reactive in the northwestern region of Mexico. Seroreactivity was confirmed using “in-house” ELISAs which employed three different antigens: total extract from Trypanosoma cruzi isolated from a vector (Triatoma rubida) from Sonora (strain T1), strain H1 and CL-Brener. The molecular characterization of Trypanosoma cruzi was conducted by amplifying satellite DNA by qPCR and posterior sequencing of the mini-exon gene, using Next Generation Sequencing (NGS) to enhance the accuracy of genetic characterization. The results show that the reactive status of this blood donor was confirmed using our in-house ELISAs, and the presence of Trypanosoma cruzi by detecting TcI DTU confirmed the infection status. Full article

Background/Objectives: Many tropical diseases such as malaria, Chagas, human African Trypanosomiasis, and Lymphatic filariasis coexist in endemic countries, affecting more than 1 billion people worldwide, and are recognised as major global vector-borne diseases. Tackling this disease requires an accurate diagnosis that is sensitive, specific, and rapid. This study aimed to describe and validate a new highly sensitive and specific multiple-analysis system that can effectively detect numerous etiological agents in a single test. Methods: A total of 230 human blood samples were assessed retrospectively for parasite characterisation, as well as 58 stool samples from non-human primates. Primers and probes were designed in the small subunit ribosomal RNA gene, except for Plasmodium spp., for which the novel target was Cytochrome Oxidase Subunit 1. Results: The analytical specificity of the presented method was 100%, with no unspecific amplifications or cross-reactions with other blood parasitic diseases. The detection limit obtained was between 0.6 and 3.01 parasites/µL for Plasmodium species, 1.8 parasites/mL for Trypanosomatidae, and 2 microfilariae/mL in the case of Filariae. The sensitivity, specificity, predictive values, and kappa coefficient reached almost 100%, except for Filariae, whose sensitivity dropped to 93.9% and whose negative predicted value dropped to 89.5%. The operational features described a turnaround and a hands-on time shorter than the compared methods with a lower cost per essay. Conclusions: This work presents a cost-effective and highly sensitive multiplexed tool (RT-PCR-bp) capable of performing simultaneous detection for blood parasitic diseases using specific fluorescence probes, enabling the diagnosis of low parasite loads and coinfections. Full article

Chagas disease, caused by Trypanosoma cruzi, remains a significant public health challenge, particularly in Latin America, where it is one of the most neglected diseases and is primarily transmitted by triatomine insects. The disease exhibits complexity due to its diverse transmission routes, including vectorial and non-vectorial mechanisms such as blood transfusions and congenital transmission. Effective monitoring and control strategies are critical to mitigating its impact. This review focuses on current monitoring and control efforts, emphasizing the importance of enhanced surveillance systems, improved risk assessments, and integrated vector control programs. Surveillance plays a pivotal role in early detection and timely intervention, particularly in endemic regions, while vector control remains central to reducing transmission. Moreover, the development of novel diagnostic tools, treatments, and vaccines is a crucial step in advancing control efforts. This review also highlights the involvement of local governments, international organizations, and civil society in executing these strategies, stressing the need for sustained political commitment to ensure the success of public health programs. By addressing key challenges in monitoring, control, and prevention, this review aims to provide insights and recommendations to further global efforts in reducing the burden of Chagas disease. Full article

Triatoma sordida is a native South American species and the most frequently captured triatomine in artificial environments in Brazil. Although considered a secondary vector of Trypanosoma cruzi, it is typically associated with low infection rates. To investigate its role in an endemic area for Chagas disease in northern Minas Gerais, Brazil, we employed a multidimensional approach that combined triatomine capture data with quantitative and qualitative analyses of T. cruzi. A total of 1861 T. sordida specimens were captured, of which 1455 were examined and 210 (14.4%) were found to be infected with T. cruzi. The most prevalent discrete typing unit (DTU) was TcI (80%), followed by TcII (8%), TcV (5%), and TcIII (3%). Molecular techniques provided new insights into the ecology of T. sordida, revealing a higher infection rate than previously reported and a parasitic load lower than that observed in other quantified species. Chickens were confirmed as the primary food source, playing an epidemiological role in maintaining infected insects with four T. cruzi DTUs. The observed diversity of T. cruzi DTUs suggests a lack of environmental segregation, likely due to the extensive movement of various host species between wild and domestic habitats, resulting in overlapping transmission cycles. Full article

Triatomines are vectors of Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae), the agent of Chagas disease. Stercorarian transmission occurs when infectious parasites are passed in insect feces to vertebrates through the biting wound or mucosa. Defecating on hosts during or shortly after blood feeding is, therefore, critical for transmission, and delayed triatomine defecation behavior has been posited to contribute to a low incidence of human Chagas disease in the U.S. We allowed nymphal T. cruzi-infected and uninfected Triatoma gerstaeckeri (Stål, 1859) and Triatoma sanguisuga (LeConte, 1855) to interact with restrained guinea pigs and measured insect feeding and defecation events; South American Rhodnius prolixus (Stål, 1859; Latin America) served as a comparison group. In 148 trials, 40.0% of insects fed, of which 71.2% defecated. Compared to R. prolixus, T. gerstaeckeri had >9 times higher odds of feeding, and T. sanguisuga fed longer. Observations of defecation while feeding occurred across all three species. The post-feeding defecation interval (PFDI) of R. prolixus was significantly shorter (4.54 ± 2.46 min) than that of T. gerstaeckeri (9.75 ± 2.52 min) and T. sanguisuga (20.69 ± 8.98 min). Furthermore, the PFDI was shorter for TcI-infected insects compared to uninfected insects. Triatoma gerstaeckeri and T. sanguisuga are capable of stercorarian transmission, although the calculated metrics suggest they are less efficient vectors than R. prolixus. Full article

Chagas disease (ChD) is a neglected tropical disease caused by Trypanosoma cruzi, endemic in 21 countries across the Americas, with increasing cases globally. In São Paulo, Brazil, vector control has focused on Triatoma infestans, but secondary triatomine species continue to pose transmission risks. This study aimed to investigate the prevalence of T. cruzi in triatomine feces and characterize its genetic diversity using molecular techniques. Fecal samples were collected from 570 triatomines across 25 municipalities in São Paulo, followed by DNA extraction and PCR amplification targeting the mitochondrial cytochrome b gene and the V7V8 region of the 18S rRNA gene. The results revealed a low overall infection rate (3.2%). However, excluding the triatomines collected in palm trees, all of which were negative, we found mainly Panstrongylus megistus in residences and peridomiciles, showing the highest infection rate (65%) for T. cruzi, followed by Triatoma sordida and Rhodnius neglectus. Phylogenetic analysis confirmed that DTU TcI was the most prevalent genotype, consistent with previous findings in the region. This study highlights the importance of continued vector surveillance, as these secondary species are capable of maintaining T. cruzi transmission in both urban and rural environments, underscoring the ongoing risk of ChD resurgence in São Paulo. Full article

Neglected Tropical Diseases are a group of 25 conditions caused by diverse agents. They mostly affect people with poorer health outcomes, particularly preventable diseases. The social determinants of health influence the development and progression of these poverty diseases, with inadequate sanitation presenting chronicity, high morbidity, and economic impacts. Chagas disease, a prominent Neglected Tropical Disease caused by the intracellular pathogen Trypanosoma cruzi, is endemic in Latin America but is increasing as a global concern due to population migration. It is transmitted through insect vectors, congenitally, orally via contaminated food and beverage, via transfusions and organ donation, and due to laboratory accidents, among other minor relevant routes. As a silent illness, with many infected individuals remaining asymptomatic, it contributes to underdiagnosis, and delayed treatment that involves nitro derivatives is often discontinued due to side effects. Chagas disease spreads in non-endemic areas like the United States of America and Europe. Blood screening practices vary, with endemic regions implementing universal testing, while non-endemic areas rely on selective methods. Recent innovations, such as riboflavin–ultraviolet light treatment and arylimidamide compounds, represent promising alternatives to reduce transfusion transmission. This review presents an analysis of Trypanosoma cruzi transmission through blood and derivatives, addressing the main routes, globally implemented control strategies, and recent advancements in blood bank safety. Full article