Triatomines （Hemiptera： Reduviidae） are obligate hematophagous insects. They are of medical importance because they are vectors of Trypanosoma cruzi, the causative agent of Chagas disease in the Americas. In recent...Triatomines （Hemiptera： Reduviidae） are obligate hematophagous insects. They are of medical importance because they are vectors of Trypanosoma cruzi, the causative agent of Chagas disease in the Americas. In recent years, the RNA interference （RNAi） technology has emerged as a practical and useful alternative means of studying gene function in insects, including triatomine bugs. RNAi research in triatomines is still in its early stages, several issues still need to be elucidated, including the description of the molecules involved in the RNAi machinery and aspects related to phenotype evaluation and persistence of the knockdown in different tissues and organs. This review considers recent applications of RNAi to triatomine research, describing the major methods that have been applied during the knockdown process such as the double-stranded RNA delivery mechanism （injection, microinjection, or ingestion） and the phenotype characterization （mRNA and target protein levels） in studies conducted with the intent to provide greater insights into the biology of these insects. In addition to the characterization of insect biomolecules, some with biopharmacological potential, RNAi may provide a new view of the interaction between triatomine and trypanosomatids, enabling the development of new measures for vector control and transmission of the parasite.展开更多
Trypanosoma cruzi,the causative agent of Chagas disease, interacts with molecules in the midgut of its insect vector to multiply and reach the infective stage. Many studies suggest that the parasite binds to midgut-sp...Trypanosoma cruzi,the causative agent of Chagas disease, interacts with molecules in the midgut of its insect vector to multiply and reach the infective stage. Many studies suggest that the parasite binds to midgut-specific glycans. We identified several glycoproteins expressed in the intestine and perimicrovillar membrane (PMM) of Triatoma (Meccus) pallidipennis under different feeding conditions. In order to assess changes in protein-linked glycans, we performed lectin and immunoblot analyses on glycoprotein extracts from these intestinal tissues using well-characterized lectins, and an antibody, which collectively recognize a wide range of different glycans epitopes. We observed that the amount and composition of proteins and glycoproteins associated with different glycans structures changed over time in the intestines and PMM under different physiological conditions. PMM extracts contained a wide variety of glycoproteins with different sugar residues, including abundant high-mannose and complex sialylated glycans. We propose that these molecules could be involved in the process of parasite-vector interactions.展开更多
Background:Since the late twentieth century,Chagas disease gained global attention to suppress the vector burden as a main control strategy in endemic countries.In Central America,multi-national initiative successfull...Background:Since the late twentieth century,Chagas disease gained global attention to suppress the vector burden as a main control strategy in endemic countries.In Central America,multi-national initiative successfully achieved significant reduction in the estimated disease prevalence as well as elimination of the region's principal vector species at the time in 2012.While the last decade has witnessed significant changes in ecosystem-such as urbanization and replacement of the main vector species-that can possibly affect the vector's habitation and residual transmission,the up-to-date vector burden in the region has not been evaluated thoroughly due to the cessation of active vector surveillance.The aim of this study was to update the risk of vector-borne Trypanosoma cruzi infection in El Salvador,the top Chagas disease-endemic country in Central America.Methods:A nationwide vector survey was conducted in the domestic environment of El Salvador from September 2018 to November 2020.The selection of the houses for inspection was based on expert purposeful sampling.Infection for T.cruzi was examined by microscopic observation of the insects'feces,followed by a species confrmation using PCR.The data were analyzed using R software version 4.1.3.Proportion estimates with 95%confidence intervals were inferred using the Jeffrey's method provided under the epiR package.Results:A total of 1529 Triatoma dimidiata was captured from 107 houses(infestation rate,34.4%;107/311)in all the fourteen departments of the country visited within the period;prevalence of T.cruzi infection was as high as 10%(153/1529).In the country,domestic T.dimidiata infestation was distributed ubiquitously,while T.cruzi infection rates varied across the departments.Five out of fourteen departments showed higher infection rates than the average,suggesting sporadic high-risk areas in the country.Conclusions:Our comprehensive study revealed substantial T.cruzi infection of T.dimidiata across the country,indicating potential active transmission of the disease.Therefore,strengthened surveillance for both vector and human infection is required to truly eliminate the risk of T.cruzi transmission in Central America.展开更多
文摘Triatomines （Hemiptera： Reduviidae） are obligate hematophagous insects. They are of medical importance because they are vectors of Trypanosoma cruzi, the causative agent of Chagas disease in the Americas. In recent years, the RNA interference （RNAi） technology has emerged as a practical and useful alternative means of studying gene function in insects, including triatomine bugs. RNAi research in triatomines is still in its early stages, several issues still need to be elucidated, including the description of the molecules involved in the RNAi machinery and aspects related to phenotype evaluation and persistence of the knockdown in different tissues and organs. This review considers recent applications of RNAi to triatomine research, describing the major methods that have been applied during the knockdown process such as the double-stranded RNA delivery mechanism （injection, microinjection, or ingestion） and the phenotype characterization （mRNA and target protein levels） in studies conducted with the intent to provide greater insights into the biology of these insects. In addition to the characterization of insect biomolecules, some with biopharmacological potential, RNAi may provide a new view of the interaction between triatomine and trypanosomatids, enabling the development of new measures for vector control and transmission of the parasite.
文摘Trypanosoma cruzi,the causative agent of Chagas disease, interacts with molecules in the midgut of its insect vector to multiply and reach the infective stage. Many studies suggest that the parasite binds to midgut-specific glycans. We identified several glycoproteins expressed in the intestine and perimicrovillar membrane (PMM) of Triatoma (Meccus) pallidipennis under different feeding conditions. In order to assess changes in protein-linked glycans, we performed lectin and immunoblot analyses on glycoprotein extracts from these intestinal tissues using well-characterized lectins, and an antibody, which collectively recognize a wide range of different glycans epitopes. We observed that the amount and composition of proteins and glycoproteins associated with different glycans structures changed over time in the intestines and PMM under different physiological conditions. PMM extracts contained a wide variety of glycoproteins with different sugar residues, including abundant high-mannose and complex sialylated glycans. We propose that these molecules could be involved in the process of parasite-vector interactions.
文摘Background:Since the late twentieth century,Chagas disease gained global attention to suppress the vector burden as a main control strategy in endemic countries.In Central America,multi-national initiative successfully achieved significant reduction in the estimated disease prevalence as well as elimination of the region's principal vector species at the time in 2012.While the last decade has witnessed significant changes in ecosystem-such as urbanization and replacement of the main vector species-that can possibly affect the vector's habitation and residual transmission,the up-to-date vector burden in the region has not been evaluated thoroughly due to the cessation of active vector surveillance.The aim of this study was to update the risk of vector-borne Trypanosoma cruzi infection in El Salvador,the top Chagas disease-endemic country in Central America.Methods:A nationwide vector survey was conducted in the domestic environment of El Salvador from September 2018 to November 2020.The selection of the houses for inspection was based on expert purposeful sampling.Infection for T.cruzi was examined by microscopic observation of the insects'feces,followed by a species confrmation using PCR.The data were analyzed using R software version 4.1.3.Proportion estimates with 95%confidence intervals were inferred using the Jeffrey's method provided under the epiR package.Results:A total of 1529 Triatoma dimidiata was captured from 107 houses(infestation rate,34.4%;107/311)in all the fourteen departments of the country visited within the period;prevalence of T.cruzi infection was as high as 10%(153/1529).In the country,domestic T.dimidiata infestation was distributed ubiquitously,while T.cruzi infection rates varied across the departments.Five out of fourteen departments showed higher infection rates than the average,suggesting sporadic high-risk areas in the country.Conclusions:Our comprehensive study revealed substantial T.cruzi infection of T.dimidiata across the country,indicating potential active transmission of the disease.Therefore,strengthened surveillance for both vector and human infection is required to truly eliminate the risk of T.cruzi transmission in Central America.
