Search Results (99)

In Brazil, public health programs have relied predominantly on chemical insecticides to control Aedes aegypti, Anopheles spp., Culex quinquefasciatus, triatomines, and phlebotomines. Rising vector-borne disease incidence and insecticide resistance (IR) call for a critical appraisal of historical and current control practices. This literature review compiles secondary data produced from 1901 to 2024 obtained from Medline/PubMed, Google Scholar, and governmental notes and reports. Brazil’s vector control progressed from organochlorines (e.g., DDT) to organophosphates, carbamates, pyrethroids, insect growth regulators, microbial larvicides (Bti and Lsp), spinosad, and recently formulations with dual active-ingredient. Ae. aegypti showed widespread resistance to temephos and pyrethroids, decreased susceptibility to pyriproxyfen, and no documented Bti resistance. Anopheles spp. exhibited low to moderate resistance to pyrethroids. Cx. quinquefasciatus resistance is likely influenced by collateral exposure from Aedes control and domestic use. Regarding triatomines and phlebotomines, there was a predominant reliance on pyrethroids; most studies indicate their susceptibility to these compounds. In short, Brazil’s century-long, insecticide-centric strategy has delivered episodic gains but fostered Aedes aegypti resistance. For other species, for which there is no dedicated program for a long period, data on resistance are scarce or nonexistent. Sustainable progress requires strengthened, nationwide IR surveillance and entomological mapping to coordinate cross-program actions. Full article

Chagas disease (CD), caused by the parasite Trypanosoma cruzi, remains one of the most important neglected tropical diseases. Historically confined to rural areas of Latin America, the disease has now become a global health challenge due to increased migration, urbanization, and ecological changes. This review explores how patterns of transmission and endemicity have evolved, emphasizing the emergence of new geographic hotspots and non-traditional routes of transmission, such as congenital and oral infections. We integrate evidence from ecological studies showing how deforestation, urban sprawl, and climate change are reshaping vector habitats and influencing the spread of triatomine insects. Furthermore, we highlight advances made between 2020 and 2025 in key research areas, including vector genomics and climate-based predictive mapping, as well as digital surveillance strategies that leverage machine learning and citizen science. These innovations provide valuable insights for predicting future risks and improving disease control. By linking global epidemiological trends, ecological drivers, and cutting-edge scientific advances, this review underscores the urgent need for integrated, collaborative strategies to prevent further spread and to protect vulnerable populations worldwide. Full article

Annona muricata (soursop) produces secondary metabolites with antimicrobial and insecticidal properties. Arbuscular mycorrhizal fungi (AMF) are known to enhance the production of secondary metabolites in medicinal plants. In this study, we aimed to evaluate the insecticidal activity of ethanolic leaf extracts from AMF-colonized soursop trees against the fall armyworm (Spodoptera frugiperda) and the triatomine bug Triatoma pallidipennis, a vector of Chagas disease. Ethanolic leaf extracts were obtained from trees inoculated with two AMF consortia (Cerro del Metate and Agua Dulce), with the species Rhizophagus intraradices and Funneliformis mosseae, and from non-mycorrhizal plants (SM). Extracts were tested in bioassays specific to each insect, including chemical and negative controls, and survival was analyzed using Kaplan–Meier curves. Extracts from plants colonized by F. mosseae exhibited insecticidal activity against S. frugiperda, causing 72% larval mortality, comparable to that of the commercial insecticide. In contrast, extracts from plants inoculated with the Agua Dulce consortium caused 65% mortality in T. pallidipennis adults. These extracts showed significantly higher annonacin content (µg·g⁻¹ DW). Overall, the results demonstrate that AMF colonization can enhance the synthesis of metabolites such as annonacins and contribute to increased insecticidal activity in A. muricata. Our findings suggest AMF-assisted cultivation has the potential to enhance botanical insecticides. Full article

Trypanosoma cruzi, the etiological agent of Chagas disease, exhibits remarkable developmental plasticity that enables its survival across distinct environments within the insect vector and mammalian host. This review focuses on two critical differentiation processes—metacyclogenesis and epimastigogenesis—emphasising their environmental triggers, metabolic regulation, and roles in parasite transmission and life cycle progression. Metacyclogenesis, occurring in the hindgut of triatomine vectors, transforms replicative epimastigotes into infective metacyclic trypomastigotes and is tightly controlled by factors such as nutrient starvation, pH, and temperature. In contrast, epimastigogenesis allows trypomastigotes to revert to epimastigote forms, primarily in the vector midgut, as part of the parasite’s adaptation to vector colonisation. We compare these processes through the lens of stress-induced signalling and proteomic reprogramming, highlighting their metabolic divergence and ecological significance. Emerging evidence also suggests that extracellular vesicles (EVs) released by different parasite forms may actively modulate these transitions, supporting parasite communication and immune evasion strategies. A better understanding of these transitions provides novel insight into parasite adaptation and reveals potential molecular targets for disrupting the life cycle of T. cruzi. Full article

Trypanosoma cruzi is the etiological agent of Chagas disease, traditionally transmitted by triatomine vectors. However, experimental and clinical evidence suggest a possibility that the parasite could also be transmitted sexually. In animal models, T. cruzi amastigotes and trypomastigotes have been identified in reproductive tissues and semen, and infection has been experimentally transmitted between mating partners. In humans, the presence of the parasite in menstrual blood, semen, and other genital secretions has been reported, raising the possibility of sexual transmission in both endemic and non-endemic settings. This potential route could contribute to the persistence of infection and the development of congenital cases. Here, we review the current evidence supporting the biological plausibility and experimental demonstration of sexual transmission of T. cruzi, and highlight key research priorities to clarify its clinical and epidemiological significance. Full article

In Yucatán state, Mexico, Triatoma dimidiata (Latreille, 1811) is the primary vector of Trypanosoma cruzi, the parasite that causes Chagas disease. The vector population presents diverse forms and colorations. Therefore, this study was designed to determine the morphotypes of T. dimidiata based on the taxonomy of the body and external genitalia. Between March 2023 and April 2025, 902 triatomines from 15 municipalities were examined. Three main morphotypes were characterized (I to III). Morphotype II was the most abundant (62.86%) and most distributed in the study area (12 of 15 municipalities), with a notable presence in forests and caves. Morphotypes I and III were found primarily outside houses and in chicken coops. Within the characterized specimens of T. dimidiata sensu lato, morphotype II displays more prominent morphological and structural characteristics. They are smaller compared to morphotypes I and III. In morphotype II, the spiracles are covered by a black spot that extends from the connexival plate to the urosternites. Males had short and robust parameres. The median process of the pygophore is long and slender compared to morphotypes I and III. The female tergite VIII has six sides. The taxonomy should be complemented by a study of the life cycle of each morphotype and analysis of its genome. Full article

Trypanosoma cruzi is a hemoflagellate protozoan and the causative agent of Chagas disease, also known as American trypanosomiasis. Transmission occurs through the feces of triatomine insects, its biological vector. It is estimated that around 7 million people are infected across Mexico, Central America, and South America. This study aimed to identify and characterize T. cruzi isolates obtained from wild triatomine vectors collected in Aguascalientes, Mexico. Molecular identification was performed at different developmental stages—epimastigotes in culture media, metacyclic trypomastigotes in triatomine feces, and amastigotes in mouse cardiac tissue—using endpoint PCR targeting satDNA and mtCytB regions. In addition, next-generation sequencing was employed to analyze variable regions of kinetoplast DNA minicircles. The pathogenicity of the isolated and identified T. cruzi strain was assessed in a murine model, where trypomastigote stages were detected in peripheral blood and amastigote stages in muscle tissue. Molecular analyses confirmed the presence of T. cruzi across different developmental stages from wild vectors, demonstrating that the isolated wild strain possesses pathogenic potential when completing its life cycle in an experimental mammalian host, specifically BALB/c mice. Full article

The Triatoma rubrovaria subcomplex, comprising several triatomine species, plays a significant role in the transmission of Chagas disease in southern Brazil. Despite morphological distinctions among these species, their genetic differentiation remains poorly understood, particularly in sympatric regions. This study investigates the genetic diversity and phylogenetic relationships through DNA sequencing analysis of five sympatric species within the T. rubrovaria subcomplex (T. rubrovaria, T. carcavalloi, T. klugi, T. circummaculata, and T. pintodiasi), using a 542-bp fragment of the mitochondrial cytochrome b (mtCytb) gene. A total of 84 specimens were collected from six municipalities in Rio Grande do Sul, Brazil, and analyzed alongside laboratory-reared specimens and sequences from the GenBank. Bayesian phylogenetic reconstructions, haplotype networks, and population structure analyses revealed a lack of clear genetic differentiation among the five species, with overlapping intra- and interspecific divergences and shared haplotypes. These findings suggest either a single species exhibiting phenotypic plasticity or a group of incipient species with ongoing gene flow. This study highlights the need for a taxonomic revision and suggests that this group could serve as a valuable model for further genomic research to elucidate potential aspects of phenotypic plasticity and/or sympatric speciation in triatomines. Full article

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

Via a One Health approach, this study concomitantly assessed the susceptibility of humans and dogs to Trypanosoma cruzi infections on three islands and in two mainland seashore areas of southern Brazil. Human serum samples were tested using an enzyme-linked immunosorbent assay (ELISA) to detect anti-T. cruzi antibodies, while dog serum samples were tested using indirect fluorescent antibodies in an immunofluorescence assay (IFA). Seropositive human and dog individuals were also tested using quantitative polymerase chain reaction (qPCR) in corresponding blood samples. Overall, 2/304 (0.6%) human and 1/292 dog samples tested seropositive for T. cruzi by ELISA and IFA, respectively, and these cases were also molecularly positive for T. cruzi by qPCR. Although a relatively low positivity rate was observed herein, these cases were likely autochthonous, and the individuals may have been infected as a consequence of isolated events of disturbance in the natural peridomicile areas nearby. Such a disturbance could come in the form of a fire or deforestation event, which can cause stress and parasitemia in wild reservoirs and, consequently, lead to positive triatomines. In conclusion, T. cruzi monitoring should always be conducted in suspicious areas to ensure a Chagas disease-free status over time. Further studies should also consider entomological and wildlife surveillance to fully capture the transmission and spread of T. cruzi on islands and in seashore mainland areas of Brazil and other endemic countries. 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

Arthropod-borne viruses (arboviruses) significantly impact human, domestic animal, and wildlife health. While most arboviruses are transmitted to vertebrate hosts by blood-feeding mosquitoes and ticks, a growing body of evidence highlights the importance of other hematophagous arthropods in arboviral transmission. These lesser-known vectors, while often overlooked, can play crucial roles in the maintenance, amplification, and spread of arboviruses. This review summarizes our understanding of hematophagous arthropods, other than mosquitoes and ticks, in arboviral transmission, as well as their associations with non-arboviral viruses. Thirteen arthropod groups are discussed: bat flies, blackflies, cimicids (bat bugs, bed bugs, and bird bugs), Culicoides midges, fleas, hippoboscid flies, lice, mites, muscid flies (including horn flies and stable flies), phlebotomine sandflies, tabanids (including deer flies and horse flies), triatomines, and tsetse flies. Some of these arthropods are regarded as known or likely arboviral vectors, while others have no known role in arbovirus transmission. Particular attention is given to species associated with arboviruses of medical and veterinary significance. As the burden of arboviruses continues to grow, it is critical not to overlook the potential contribution of these lesser-known vectors. Full article

The detection of food sources of blood-sucking vectors is essential for a better understanding of the hosts, reservoirs, and other fauna that participate in the transmission web of hemoparasites. The molecular identification of triatomine blood meal sources (BMSs) has been shown to be highly sensitive and taxonomically specific when compared to the immunological method. The application of molecular cloning makes it possible to identify multiple BMS species and/or different individuals/haplotypes of the same vertebrate species in a single triatomine specimen. In Brazil, the molecular detection of BMSs is incipient, with insufficient genetic information on the species of animals involved in the transmission of Trypanosoma cruzi. In this work, we evaluated the sensitivity and specificity of a molecular approach using molecular cloning for the detection of multiple Brazilian mammalian species. The DNA was extracted from blood clots of 13 species of canids, bats, xenarthral, marsupials, and rodents. Serial proportions were used to formulate mixtures combining taxonomically close (belonging to the same family or order) and taxonomically distant (different families) species. The results showed that GenBank lacks reference sequences for some native species tested, such as the sylvatic rodent, Necromys lasiurus, and the wild canid, Lycalopex gymnocercus, for cytb and 12S rDNA, and the rodent Oecomys cleberi for 12S rDNA. The study also demonstrated that it is possible to detect multiple different species, even for those that are taxonomically close. This approach was proven to be efficient for the detection of species in equal and even in disparate unequal proportions, which could represent complementary information about the diversity of potential hosts of T. cruzi. The detection of multiple BMS species in mixed samples provides a more comprehensive and accurate landscape of T. cruzi transmission in nature. 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

Vector-borne diseases (VBDs) significantly impact global child health, with mosquito-transmitted infections like malaria and arboviruses accounting for a substantial portion of this burden. However, other arthropod-borne diseases—transmitted by vectors such as ticks, fleas, sand flies, lice, and triatomine bugs—also pose serious health risks to children worldwide. This review specifically excludes mosquito-borne diseases to concentrate on these less-discussed yet clinically important pediatric VBDs. We examine their clinical manifestations, diagnostic challenges, and treatment options, highlighting the unique vulnerabilities of children, including immature immune systems, behavioral factors, and communication barriers that can delay diagnosis. Additionally, we explore how environmental and anthropogenic factors, such as climate change and urbanization, are expanding the geographic range of these vectors, leading to the emergence of diseases like Lyme disease and leishmaniasis in new regions. By focusing on non-mosquito VBDs, this review aims to raise awareness and inform healthcare providers and public health practitioners about the comprehensive landscape of pediatric vector-borne diseases. Full article