Hemolymph of triatomines presents fungistatic activity against Cryptococcus neoformans and improves macrophage function through MCP-I/TNF-α increase

Triatomines are blood-feeding arthropods belonging to the subfamily Triatominae (Hemiptera; Reduviidae), capable of producing immunomodulatory and water-soluble molecules in their hemolymph, such as antimicrobial peptides (AMPs). In this work, we evaluated the antifungal and immunomodulatory activity of the hemolymph of Meccus pallidipennis (MPH) and Rhodnius prolixus (RPH) against Cryptococcus neoformans. Methods: We assessed the activity of the hemolymph of both insects on fungal growth by a minimum inhibitory concentration (MIC) assay. Further, RAW 264.7 macrophages were cultivated with hemolymph and challenged with C. neoformans. Then, their phagocytic and killing activities were assessed. The cytokines MCP-1, IFN-γ, TNF-α, IL-10, IL-12, and IL-6 were measured in culture supernatants 4- and 48-hours post-infection. Results: Both hemolymph samples directly affected the growth rate of the fungus in a dose-dependent manner. Either MPH or RPH was capable of inhibiting fungal growth by at least 70%, using the lowest dilution (1:20). Treatment of RAW 264.7 macrophages with hemolymph of both insects was capable of increasing the production of MCP-I and TNF-α. In addition, when these cells were stimulated with hemolymph in the presence of C. neoformans, a 2- and a 4-fold increase in phagocytic rate was observed with MPH and RPH, respectively, when compared to untreated cells. For the macrophage killing activity, MPH decreased in approximately 30% the number of viable yeasts inside the cells compared to untreated control; however, treatment with RPH could not reduce the total number of viable yeasts. MPH was also capable of increasing MHC-II expression on macrophages. Regarding the cytokine production, MCP-I and TNF-α, were increased in the supernatant of macrophages treated with both hemolymphs, 4 and 48 hours after stimulation. Conclusion: These results suggested that hemolymph of triatomines may represent a source of molecules capable of presenting antifungal and immunomodulatory activity in macrophages during fungal infection.(AU)

Ultrastructural and enzymatic alterations in the ovary of Rhodnius prolixus infected with Trypanosoma rangeli

Objective: To investigate the morphological structure of ovarian follicular cells and biochemical parameters of both ovaries and fat bodies (sites of vitellogenesis) from Rhodnius (R.) prolixus infected with Trypanosoma (T.) rangeli. Methods: Adult virgin females of R. prolixus were fed upon a membrane apparatus containing heat-inactivated citrated rabbit blood and a suspension of T. rangeli epimastigotes (Macias strain). Females from the control group and all the males received parasitefree blood. Transmission electron microscopy was used to reveal the morphological aspects of ovarian follicle cells in both control and parasite-infected groups. Protein profile, proteolytic activities and Western blotting analyses were performed in either ovary or fat body samples of control and parasite-infected groups. Results: According to the ultrastructural data, T. rangeli infection elicited a degeneration process in the ovarian follicular cells of R. prolixus. Proteolytic assays indicated a reduction in the activity of aspartic peptidases in the ovary and fat body from parasite-infected group, while a significant increase in the cysteine peptidase activity was measured in both insect organs. Additionally, immunoblotting revealed that vitellogenin was overexpressed in the ovary of parasite-infected insects. Conclusions: T. rangeli infection seems to elicit an early programmed cell death in the ovarian follicle cells as well as induces the modulation on the activities of different peptidase classes in either ovaries or fat bodies and the overexpression of the vitellogenin in the ovary of R. prolixus.

Monitoring Rhodnius neglectus (Lent, 1954) populations' susceptibility to insecticide used in controlling actions in urban areas northwest of São Paulo state

ABSTRACT Background: Chagas disease (CD) is caused by the flagellate protozoan Trypanosoma cruzi and can be carried by different species of triatomines, including Rhodnius neglectus, which is wild, well distributed in Brazil, and has formed colonies in palm trees located in urban areas of municipalities in the state of São Paulo. Chemical control has been routinely used to reduce population density, but each year, there has been an increase in species dispersion and density. This study aimed to evaluate the susceptibility of insects to insecticides used in control. Methods: The reference population was collected from Araçatuba municipality, Nilce Maia. Dilutions of deltamethrin were prepared and applied to the back of the first-stage nymphs, which were biologically synchronized. The control group received pure acetone only. Mortality was assessed after 72 h. Results: The mortality rate with respect to diagnostic dose was 100%. The susceptibility profile observed for this population showed RR50 ranging from 1.76 to 3.632. Conclusions: The populations were susceptible to the insecticides tested. It is possible that the insecticide residual effect on this ecotope has decreased the lifespan, and controlling failures may be the cause of recolonization in this environment.

The rediscovery of Rhodnius domesticus Neiva & Pinto, 1923 (Hemiptera: Reduviidae: Triatominae) in the state of Espírito Santo, Brazil

Abstract INTRODUCTION: Rhodnius domesticus Neiva & Pinto, 1923 is a rare sylvatic triatomine endemic to the Atlantic Forest, with one known record for Espírito Santo (ES), Brazil from 1969. We present here its rediscovery in ES, 42 years after its first record. METHODS: In January 2011, a triatomine specimen was collected from a rural area of the municipality of Santa Teresa, ES. RESULTS: We confirmed this as a new record of R. domesticus in the Baixo Caldeirão locality. CONCLUSIONS: This finding supports the possibility of a wild population of R. domesticus in the mountainous region of the Atlantic forest of ES.

Los patrones electroforéticos de proteínas salivales permiten diferenciar los grupos transandino y cisandino de las especies de Rhodnius de Colombia / Salivary proteins electrophoretic patterns enabled differentiating Colombian Rhodnius Trans-Andean and Cis-Andean groups

Introducción. Las especies Rhodnius (Hemiptera: Reduviidae: Triatominae) están conformadas por insectos hematófagos vectores de Trypanosoma cruzi, agente etiológico de la enfermedad de Chagas, y T. rangeli, parásito infectivo pero no patógeno para el vertebrado. El estudio de la diversidad proteica de la saliva de estos insectos permite la obtención de perfiles electroforéticos unidimensionales característicos de algunas especies de triatominos. Sin embargo, el reporte de los patrones electroforéticos de proteínas salivales de las especies de Rhodnius ha sido escaso. Objetivo. Hacer un análisis comparativo de los perfiles electroforéticos unidimensionales de las proteínas salivales de R. colombiensis, R. pallescens, R. pictipes, R. prolixus y R. robustus. Materiales y métodos. Se obtuvieron los perfiles electroforéticos de la saliva de las especies en estudio mediante electroforesis en gel de poliacrilamida con dodecilsulfato sódico (Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis, SDS-PAGE) y se construyó un fenograma mediante el método UPGMA (Unweighted Pair Group Method Using Arithmetic Averages). Resultados. Los perfiles electroforéticos de las proteínas solubles de saliva presentaron bandas en un rango de masa aproximado de 15 a 45 kDa, los cuales permitieron diferenciar las cinco especies estudiadas. El fenograma reveló la existencia de dos grupos principales: uno conformado por los grupos cisandinos Pictipes y Prolixus y otro constituido por el grupo transandino Pallescens. Conclusiones. Existen diferencias en los perfiles electroforéticos de las proteínas salivales entre R. colombiensis, R. pallescens, R. pictipes, R. prolixus y R. robustus, cuya variabilidad permitió construir un fenograma congruente con los grupos del género Rhodnius.

Introduction: Rhodnius (Hemiptera: Reduviidae: Triatominae) species are made up of haematophagous insect vectors for Trypanosoma cruzi (Chagas' disease aetiological agent) and T. rangeli, an infective parasite that is not pathogenic for vertebrate hosts. The study of their salivary protein diversity enables the obtention of characteristic one-dimensional electrophoretic profiles of some triatomine species; however, few reports have dealt with Rhodnius species salivary proteins electrophoretic patterns. Objective: To compare R. colombiensis, R. pallescens, R. pictipes, R. prolixus, and R. robustus' salivary proteins one-dimensional electrophoretic profiles. Materials and methods: SDS-PAGE was used for obtaining electrophoretic profiles of saliva from the species under study. The unweighted pair group method with arithmetic mean (UPGMA) was used for constructing a phenogram. Results: Electrophoretic profiles of soluble saliva had protein bands ranging from 15 to 45 kDa, thereby enabling the five species studied to be differentiated. The phenogram revealed two main groups, one formed by the Pictipes and Prolixus cis-Andean groups and another consisting of the Pallescens trans-Andean group. Conclusion: Differences were revealed regarding R. colombiensis, R. pallescens, R. pictipes, R. prolixus, and R. robustus electrophoretic profiles of salivary proteins; their variability facilitated constructing a phenogram which was taxonomically congruent with the groups from the genus Rhodnius.

Detection of Trypanosoma cruzi strains circulating in Córdoba department (Colombia) isolated from triatomines (Hemiptera: Reduviidae) collected by the community / Detección y caracterización molecular de cepas de Trypanosoma cruzi aisladas de triatominos recolectados por la comunidad en el departamento de Córdoba, Colombia

Abstract Introduction: From 2011 to 2016, 24 cases of Chagas disease were reported in Córdoba according to the national public health surveillance system (Sistema Nacional de Vigilancia en Salud Pública, Sivigila), but the information regarding Trypanosoma cruzi circulating strains and infection rates are unknown. Objectives: To establish the triatomine species with which people come in contact and recognize as Chagas disease vectors, as well as to assess the infection with trypanosomes and make an exploratory approach to host feeding preferences with the participation of the local community. Materials and methods: Triatomines sampling was conducted in 12 municipalities between 2011 and 2016; T. cruzi infection was established by k-PCR, SAT-PCR, while strain genotyping was done by mini-exon and SL-IR (spliced-leader intergenic region) sequence characterization. We also screened for blood sources. Results: Local community members collected the majority of triatomines and we identified three species: Rhodnius pallescens, Panstrongylus geniculatus, and Eratyrus cuspidatus. The overall T. cruzi infection rate in collected triatomines was 66.6% and we detected the TcIDOM and TcI sylvatic strains. Community-based insect collection allowed reporting the presence of P. geniculatus in two new disperse rural settlements, T. cruzi infection of P. geniculatus in Córdoba, and the first report of triatomines infected with T. cruzi in Montería municipality. Conclusions: These results revealed the presence of triatomines infected with T. cruzi inside dwellings in five municipalities of Córdoba. The dominant circulating T. cruzi strain was TcIDOM, a genotype associated with human Chagas disease and cardiomyopathies in Colombia. Our results highlight the importance of local community participation in entomological surveillance tasks.

Resumen Introducción. Entre el 2011 y el 2016, se reportaron 24 casos de enfermedad de Chagas en Córdoba, según el Sistema Nacional de Vigilancia en Salud Pública (Sivigila), pero la información sobre las unidades discretas de tipificación de Trypanosoma cruzi circulantes y las tasas de infección se desconoce. Objetivos. Identificar las especies de triatominos con las cuales las personas entran en contacto y que reconocen como vectores de la enfermedad de Chagas, así como establecer la infección por tripanosomas y explorar posibles fuentes de alimentación de los triatominos con la participación de la comunidad. Materiales y métodos. El muestreo de triatominos se hizo en 12 municipios entre el 2011 y el 2016. T. cruzi se detectó mediante las técnicas de kinetic-polymerase chain reaction (k-PCR) y serial amplification of targets-polymerase chain reaction (SAT-PCR), en tanto que la genotipificación de las cepas se logró mediante la caracterización de secuencias de genes miniexon y de la región intergénica SL-IR (Spliced-Leader Intergenic Region). Se evaluaron, asimismo, las fuentes de alimento. Resultados. La mayoría de los triatominos fue recolectada por miembros de la comunidad y se identificaron tres especies: Rhodnius pallescens, Panstrongylus geniculatus y Eratyrus cuspidatus. La tasa de infección general por T. cruzi fue de 66,6 % y se detectaron las cepas TcIDOM y TcI sylvatic. La participación de la comunidad permitió reportar la presencia de P. geniculatus en dos nuevas localidades, la infección con T. cruzi de P. geniculatus en Córdoba y reportar por primera vez triatominos infectados con T. cruzi en Montería. Conclusiones. Se demostró la presencia de triatominos infectados con T. cruzi dentro de las viviendas en cinco municipalidades. La cepa circulante dominante fue T. cruzi TcIDOM, asociada con la enfermedad de Chagas y con cardiomiopatías en Colombia. Los resultados resaltan la importancia de vincular a miembros de la comunidad en la vigilancia entomológica.

First report of Rhodnius neglectus (Hemiptera, Reduviidae, Triatominae) from the State of Acre, Brazil, and the Brazilian Western Amazon Region

Abstract INTRODUCTION This communication reports the occurrence of Rhodnius neglectus in the State of Acre, Brazil. METHODS An adult male R. neglectus specimen was collected from the Catuaba Experimental Reserve, which is located in the municipality of Senador Guiomard. RESULTS This increases the number of triatomine species reported from the State of Acre to eight and is also the first report of R. neglectus from the Brazilian Western Amazon Region. CONCLUSIONS The occurrence of R. neglectus is alarming because even though the species is wild, it can invade and colonize human dwellings and peridomiciles, thereby increasing Chagas disease transmission.

Blood-feeding of Rhodnius prolixus

Triatomines (Hemiptera: Reduviidae) are blood-sucking insect vectors of the protozoan Trypanosoma cruzi which is the causative agent of Chagas' disease. Rhodnius prolixus is the most epidemiologically important vector of T. cruzi in Colombia. Triatomines are regarded to be vessel-feeders as they obtain their blood meals from vertebrate hosts by directly inserting their mouthparts into vessels. Microscopic techniques are useful for visualizing and describing the morphology of biological structures. Here, we show images of the blood-feeding of R. prolixus, including some histological features by light microscopy and scanning electron microscopy of the mouthparts of R. prolixus when feeding on a laboratory mouse.

Los triatominos (Hemiptera: Reduviidae) son insectos hematófagos vectores del protozooTrypanosoma cruzi, el cual causa la enfermedad de Chagas. Rhodnius prolixus es el vector de T. cruzi de mayor importancia epidemiológica en Colombia. Para alimentarse, los triatominos introducen su probóscide directamente en los vasos sanguíneos de los huéspedes vertebrados. La microscopía es una técnica útil para visualizar y describir la morfología de estructuras biológicas. Se presentan imágenes de la hematofagia de R. prolixus, incluidas algunas características histológicas visibles por microscopía de luz y microscopía electrónica de barrido de las partes bucales de R. prolixus al alimentarse de un ratón de laboratorio.

Sympatry influence in the interaction of Trypanosoma cruzi with triatomine

Abstract INTRODUCTION: Trypanosoma cruzi, the etiologic agent of Chagas disease, is widely distributed in nature, circulating between triatomine bugs and sylvatic mammals, and has large genetic diversity. Both the vector species and the genetic lineages of T. cruzi present a varied geographical distribution. This study aimed to verify the influence of sympatry in the interaction of T. cruzi with triatomines. Methods: The behavior of the strains PR2256 (T. cruzi II) and AM14 (T. cruzi IV) was studied in Triatoma sordida (TS) and Rhodnius robustus (RR). Eleven fifth-stage nymphs were fed by artificial xenodiagnosis with 5.6 × 103 blood trypomastigotes/0.1mL of each T. cruzi strain. Every 20 days, their excreta were examined for up to 100 days, and every 30 days, the intestinal content was examined for up to 120 days, by parasitological (fresh examination and differential count with Giemsa-stained smears) and molecular (PCR) methods. Rates of infectivity, metacyclogenesis and mortality, and mean number of parasites per insect and of excreted parasites were determined. RESULTS: Sympatric groups RR+AM14 and TS+PR2256 showed higher values of the four parameters, except for mortality rate, which was higher (27.3%) in the TS+AM14 group. General infectivity was 72.7%, which was mainly proven by PCR, showing the following decreasing order: RR+AM14 (100%), TS+PR2256 (81.8%), RR+PR2256 (72.7%) and TS+AM14 (36.4%). CONCLUSIONS: Our working hypothesis was confirmed once higher infectivity and vector capacity (flagellate production and elimination of infective metacyclic forms) were recorded in the groups that contained sympatric T. cruzi lineages and triatomine species.

Lethal and sublethal effects of essential oil of Lippia sidoides (Verbenaceae) and monoterpenes on Chagas´ disease vector Rhodnius prolixus

The aim of this study was to identify the composition of the essential oil from leaves of Lippia sidoides (EOLS), a typical shrub commonly found in the dry northeast of Brazil, popularly known as “alecrim-pimenta”. Additionally, we investigated the nymphicidal, ovicidal, phagoinhibitory and excretion effects of EOLS, its major constituent thymol and its isomer carvacrol, on fourth instar nymphs and eggs of Rhodnius prolixus, the Chagas’ disease vector. The nymphicidal and ovicidal activity of thymol, carvacrol, and EOLS was assessed by tests using impregnated Petri dishes. The lethal concentration values (LC50) for EOLS, carvacrol, and thymol were 54.48, 32.98, and 9.38 mg/cm2, respectively. The ovicidal test showed that both carvacrol and thymol (50 mg/cm2) inhibited hatching (50% and 23.3%, respectively), while treatments with 10 mg/cm2 or 50 mg/cm2 EOLS did not affect the hatching rate at all (80% and 90%, respectively). We observed an anti-feeding effect in insects fed with blood containing natural products at the higher concentrations (100 µg/mL). Finally, excretion rate was affected by EOLS and carvacrol, but not by thymol. These findings offer novel insights into basic physiological processes that make the tested natural compounds interesting candidates for new types of insecticides.

Behavioral fever response in Rhodnius prolixus (Reduviidae: Triatominae) to intracoelomic inoculation of Trypanosoma cruzi

Abstract: INTRODUCTION: Behavioral fever is a response to infections with microorganisms observed in some poikilothermic animals. Rhodnius prolixus is involved in the transmission of two parasites: Trypanosoma cruzi (pathogenic for humans and transmitted in feces) and Trypanosoma rangeli (non-pathogenic for humans, pathogenic for Rhodnius and transmitted by the bite of an infected individual). Only T. rangeli is found in the hemolymph of Rhodnius as it travels to the salivary glands. METHODS: To study vector-parasite interactions, we evaluated possible behavioral fever responses of R. prolixus to intracoelomic inoculation with T. cruzi or T. rangeli. Temperature preferences of fifth-instar nymphs of R. prolixus were evaluated after inoculation with T. rangeli KP1(+), KP1(-), T. cruzi I, or the Trypanosome culture medium. Four different fixed temperatures (25, 30, 35, and 40°C) in two simultaneous experiments (enclosed and free-moving insects) were evaluated. Free-moving insects were marked daily according to their temperature preferences on each of the 15 days after inoculation. Numbers of insects in each temperature shelter and daily mortality were compared with those enclosed shelters of different temperatures. RESULTS: Rhodnius prolixus inoculated with both strains of T. rangeli and with the trypanosome culture medium showed preferences for the lowest temperatures (25°C). However, R. prolixus inoculated with T. cruzi I showed significant preferences for temperatures around 35°C. CONCLUSIONS: This is the first known investigation to demonstrate a behavioral fever response in R. prolixus injected intracoelomically with T. cruzi I.

Estrategia para determinar la línea base en áreas de interrupción vectorial de la enfermedad de Chagas / Strategy for determining a baseline in areas of vector interruption for Chagas disease

RESUMEN Objetivos Presentar una estrategia para determinar la línea de base en áreas endémicas en el proceso de interrupción vectorial de la enfermedad de Chagas (ECh). Métodos Con un cuestionario socioambiental y una encuesta entomológica, se evaluaron las condiciones físicas de los domicilios, el conocimiento de los habitantes sobre la ECh, los indicadores entomológicos de triatominos y la relación estadística entre estas variables. Resultados Existe colonización e infección natural con Trypanosoma cruzi en Rhodnius prolixus, el principal vector de la ECh en Colombia. La colonización estuvo relacionada con casas de techos de hojas de palma y paredes de adobe o bahareque. Se encontró el vector Panstrongylus geniculatus con hábitos de colonización. Casi 50% de la población encuestada asociaba el término ECh con una enfermedad humana y 37%, con los triatominos. Conclusiones R. prolixus puede considerarse el principal vector de T. cruzi en ambientes domésticos y el proceso de interrupción vectorial es factible dentro del municipio priorizado. Se necesitan nuevos estudios que comprueben la existencia de poblaciones silvestres de R. prolixus que puedan afectar las etapas futuras del proceso y demostrar si hay una participación de P. geniculatus en la dinámica de transmisión de T. cruzi. Los anteriores escenarios pueden ser viabilizados con la inclusión de los habitantes en todo el proceso, ya que han sido altamente sensibles en la detección de vectores dentro de sus casas. El diseño del estudio aquí presentado puede ser adaptado en otras áreas endémicas de la Región de las Américas.

ABSTRACT Objectives Present a strategy to determine the baseline in endemic areas in the process of vector interruption for Chagas disease (CHD). Methods A social and environmental questionnaire and an entomological survey evaluated the physical conditions of dwellings, the inhabitants’ knowledge of CHD, the entomological triatomine indicators and the statistical relationship among these variables. Results Colonization and natural infection with Trypanosoma cruzi exist in Rhodnius prolixus, the principal vector of CHD in Colombia. Colonization was related to palm-thatched houses constructed with adobe or wattle and daub. The Panstrongylus geniculatus vector was found to be colonizing. Almost 50% of the surveyed population associated the term CHD with human disease and 37%, with triatomines. Conclusions R. prolixus can be considered to be the principal vector of T. cruzi in domestic environments and the process of interruption is feasible within the prioritized municipality. New studies are needed to verify the existence of wild populations of R. prolixus that could affect future stages of the process and demonstrate whether P. geniculatus is a factor in the transmission of T. cruzi. These scenarios can be made viable by including the inhabitants throughout the process, since they have been highly sensitive in vector detection inside their houses. The study design presented here can be adapted to other endemic areas of the Region of the Americas.

Risk factors associated with Trypanosoma cruziexposure in domestic dogs from a rural community in Panama

Chagas disease, caused by Trypanosoma cruziinfection, is a zoonosis of humans, wild and domestic mammals, including dogs. In Panama, the main T. cruzivector is Rhodnius pallescens, a triatomine bug whose main natural habitat is the royal palm, Attalea butyracea. In this paper, we present results from three T. cruziserological tests (immunochromatographic dipstick, indirect immunofluorescence and ELISA) performed in 51 dogs from 24 houses in Trinidad de Las Minas, western Panama. We found that nine dogs were seropositive (17.6% prevalence). Dogs were 1.6 times more likely to become T. cruziseropositive with each year of age and 11.6 times if royal palms where present in the peridomiciliary area of the dog’s household or its two nearest neighbours. Mouse-baited-adhesive traps were employed to evaluate 12 peridomestic royal palms. All palms were found infested with R. pallescenswith an average of 25.50 triatomines captured per palm. Of 35 adult bugs analysed, 88.6% showed protozoa flagellates in their intestinal contents. In addition, dogs were five times more likely to be infected by the presence of an additional domestic animal species in the dog’s peridomiciliary environment. Our results suggest that interventions focused on royal palms might reduce the exposure to T. cruzi infection.

First report of Rhodnius montenegrensis (Hemiptera, Reduviidae, Triatominae) in the State of Acre, Brazil

This paper reports, for the first time, the presence of Rhodnius montenegrensis in the State of Acre, Brazil.

New scenarios of Trypanosoma cruzi transmission in the Orinoco region of Colombia

Rhodnius prolixus, a blood-sucking triatomine with domiciliary anthropophilic habits, is the main vector of Chagas disease. The current paradigm of Trypanosoma cruzi transmission in Columbia includes a sylvatic and domiciliary cycle co-existing with domestic and sylvatic populations of reservoirs. The aim of this study is to evaluate the population densities and relative abundance of triatomines and mammals that may be involved in the sylvatic cycle of Chagas disease to clarify the epidemiological scenario in an endemic area in the province of Casanare. Insect vectors on Attalea butyracea palms were captured using both manual searches and bait traps. The capture of mammals was performed using Sherman and Tomahawk traps. We report an infestation index of 88.5% in 148 palms and an index of T. cruzi natural infection of 60.2% in 269 dissected insects and 11.9% in 160 captured mammals. High population densities of triatomines were observed in the sylvatic environment and there was a high relative abundance of reservoirs in the area, suggesting a stable enzootic cycle. We found no evidence of insect domiciliation. Taken together, these observations suggest that eco-epidemiological factors shape the transmission dynamics of T. cruzi, creating diverse scenarios of disease transmission.

Susceptibility of different Rhodnius species (Hemiptera, Reduviidae, Triatominae) to a Brazilian strain of Trypanosoma rangeli (SC58/KP1-) / Sensibilidad de diferentes especies de Rhodnius (Hemiptera, Reduviidae, Triatominae) a una cepa brasileña de Trypanosoma rangeli (SC58/KP1-)

Introduction: Specific host-parasite a ssociations have been detected experimentally and suggest that triatomines of the genus Rhodnius act as biological filters in the transmission of Trypanosoma rangeli . Objective: To analyze the susceptibility of four Rhodnius species ( Rhodnius robustus , Rhodnius neglectus , Rhodnius nasutus and Rhodnius pictipes ) to a Brazilian strain of T. rangeli (SC-58/KP1-). Materials and methods: We selected t hirty nymphs of each species, which were fed on blood infected with T. rangeli . Periodically, samples of feces and hemolymph were analyzed. Triatomines with T. rangeli in their hemolymph were fed on mice to check for transmission by bites. Later, the triatomines were dissected to confirm salivary gland infection. Results: Specimens of R. pictipes showed higher rates of intestinal infection compared to the other three species. Epimastigotes and trypomastigotes were detected in hemolymph of four species; however, parasitism was lower in the species of the R. robustus lineage. Rhodnius robustus and R. neglectus specimens did not transmit T. rangeli by bite; after dissection, their glands were not infected. Only one specimen of R. nasutus and two of R. pictipes transmitted the parasite by bite. The rate of salivary gland infection was 16% for R. pictipes and 4% for R. nasutus . Conclusions: Both infectivity (intestinal, hemolymphatic and glandular) and transmission of T. rangeli (SC58/KP1-) were greater and more efficient in R. pictipes. These results reinforce the hypothesis that these triatomines may act as biological filters in the transmission of T. rangeli .

Introducción. Se han detectado asociaciones biológicas huésped-parásito específicas que sugieren que los triatominos del género Rhodnius podrían actuar como filtros biológicos en la transmisión de Trypanosoma rangeli . Objetivo. Estudiar la sensibilidad de cuatro especies de Rhodnius ( Rhodnius robustus , Rhodnius neglectus , Rhodnius nasutus y Rhodnius p ictipes ) frente a la cepa de T. rangeli (SC-58/KP1-). Materiales y métodos. Se seleccionaron treinta ninfas de cada especie después de xenodiagnóstico artificial en sangre infectada con T. rangeli. Se examinaron periódicamente m uestras de heces y hemolinfa. Los insectos con hemolinfas infectadas fueron alimentados en ratones a fin de comprobar la transmisión por picadura y posteriormente disecados para confirmar la infección de las glándulas salivales . Resultados . En Rhodnius pictipes se encontró un mayor porcentaje de infección intestinal que en las otras especies . Se detectaron epimastigotes y tripomastigotes en la hemolinfa de las cuatro especies , y se encontró que el parasitismo fue menor en las especies del linaje R. robustus . Rhodnius robustus y R. neglectus no transmitían T. rangeli a ratones por picadura: después de la disección , sus glándulas no estaban infectadas. Solo un espécimen de R. nasutus y dos de R. pictipes transmitieron el parásito por la picadura . La tasa de infección glandular fue de 16 % para R. pictipes y de 4 % para R. nasutus . Conclusiones . La capacidad infecciosa ( hemolinfática, intestinal y glandular ) y la transmisión de T. rangeli (SC-58/KP1-) fueron mayores y más eficientes en R. pictipes . Estos resultados refuerzan la hipótesis de que estos triatominos actúan como filtros biológicos en la transmisión de T. rangeli .

Comparison of hemocytes of V-instar nymphs of Rhodniusprolixus (Stål) and Rhodnius robustus (Larousse 1927), before and after molting / Comparación de los hemocitos de las ninfas de V instar de Rhodnius prolixus (Stål) and Rhodnius robustus, antes y después de la muda (Larousse 1927)

Background. The immune response of insects involves humoral factors and cellular elements known as hemocytes. There are different reports that explore the response of hemocytes to infections, but the effect that molting has on this response has not been explored so far. We hypothesized that there would be a change in the percentage of hemocytes as a response to the molting process. Objective. The aim of this work was to compare the hemogram (CBC), the formula, and the differential count of hemocytes in IV instar before molting and in V instar nymphs 24 hours after molting in two species: Rhodnius prolixus and Rhodnius robustus. Materials and methods. We assayed different staining methodologies including Giemsa, Alcian Blue pH 2.0, Alcian Blue pH 2.6, Gomori substrate, PAS (Schiff), Sudan Black and Papanicolau with positive controls for each one. In the Gomori staining, we observed lysosomes in the granulocytes and plasmatocytes, but the differentiation was better detected using Giemsa staining. Results. There were no statistically significant differences between the two species studied in plasmatocytes (p=0,053) or even in granulocytes (p=0,5). However, differences were significant in the prohemocytes (p=0,001) during the molting process in both Rhodnius prolixus and Rhodnius robustus. Conclusions. Significant differences in prohemocytes between nymphs of IV and V instar were detected. No significant differences in the amount of cells were observed between the two species and the two stages. These findings may be explained due to their role as precursor cell of prohemocytes.

Antecedentes. La respuesta inmune de los insectos involucra factores humorales y elementos celulares llamados hemocitos. Existen varios trabajos explorando la respuesta de los hemocitos frente a infecciones, pero no como respuesta al proceso de muda. Objetivo. Comparar el hemograma: la fórmula y el recuento diferencial de hemocitos de Rhodnius prolixus y Rhodnius robustus en ninfas de IV estadio antes de la muda y ninfas de V estadio 24 horas después de la muda. Materiales y métodos. Se ensayaron las coloraciones Giemsa, Alcian Blue pH 2.0, Alcian Blue pH 2.6, sustrato Gomori, PAS (Schiff), Sudán Negro, Papanicolau, con controles positivos para cada una. Con la coloración de Gomori se observaron lisosomas en los granulocitos y en plasmatocitos, pero la diferenciación se logró mejor con la coloración de Giemsa. Resultados. Los plasmatocitos fueron más abundantes en las ninfas de IV estadio de Rhodnius robustus y en las de V estadio de las dos especies, pero en las ninfas de V estadio de R. prolixus, el recuento de prohemocitos fue mayor; para los oenocitoides, esferulocitos y adipohemocitos el recuento no alcanzó al 1 %. En las dos especies no se encontraron diferencias estadísticamente significativas en plasmatocitos (p=0,05319), ni en granulocitos (p=0,5), entre las ninfas de IV y V estadio, pero fue significativa en prohemocitos (p=0,001). Conclusiones. Se detectaron diferencias significativas en prohemocitos entre las ninfas de IV y V estadio. No hubo un aumento significativo en el conteo de células en los diferentes estadios.

COLONIZATION OF PALM TREES BY Rhodnius neglectus AND HOUSEHOLD AND INVASION IN AN URBAN AREA, ARAÇATUBA, SÃO PAULO STATE, BRAZIL / Colonização de palmeiras por Rhodnius neglectus e invasão domiciliar em área urbana, Araçatuba, São Paulo, Brasil

The objective of this study is to report on the colonization of palm trees by Rhodnius neglectus, its invasion in an urban area, in Araçatuba - São Paulo, and the control and surveillance measures that have been put in place. Domiciliary triatomine searches occurred in apartments upon the inhabitants' notification. The collected insects were identified and examined for natural infection and food sources with a precipitin test. To search the palm trees, tarps were used to cover the floor, and a “Munck” truck equipped with a tree-pruning device was utilized. Chemical control was performed with the utilization of a manual compression. In 2009, 81 specimens of Rhodnius neglectus were collected from the domiciles by the population. The precipitin test revealed a presence of human blood in 2.7% of the samples. Entomological studies were carried out in these domiciles and in those located within a radius of 200 meters. The search performed in the palm trees resulted in the capture of 882 specimens of triatomines, negative for tripanosomatids. Mechanical and chemical controls were carried out. New searches conducted in the palm trees in the same year resulted in the capture of six specimens. The mechanical and chemical controls of the palm trees, together with the population's work, proved to be effective, therefore preventing these insects' colonization of the city's domiciles.

O objetivo deste trabalho é relatar a colonização de palmeiras por Rhodnius neglectus, sua invasão em área urbana, na cidade de Araçatuba - São Paulo, o controle e as medidas de vigilância instituídas. As pesquisas de triatomíneos nos domicílios ocorreram nos apartamentos quando da notificação pelo morador. Os insetos coletados foram identificados, examinados quanto à infecção natural e teste de precipitina. Na pesquisa das palmeiras foram utilizados lonas para forração do chão e caminhão Munck equipado com moto poda. O controle químico foi realizado com a utilização de compressor manual. No ano de 2009, foram coletados pela população 81 exemplares de Rhodnius neglectus em domicílios. O teste de precipitina acusou presença de sangue humano em 2,7% das amostras. Pesquisas entomológicas foram realizadas nestas edificações e naquelas situadas em um raio de 200 metros onde ocorreram as invasões. A pesquisa realizada nas palmeiras resultou na captura de 882 exemplares de triatomíneos, negativos para tripanosomatídeos. Foi realizado controle mecânico e químico. Novas pesquisas realizadas nas palmeiras avaliadas no mesmo ano resultaram na coleta de seis exemplares. Os controles mecânicos e químicos das palmeiras aliado ao trabalho de participação popular mostraram-se factíveis impedindo a colonização destes insetos nos domicílios da cidade.

Conocimientos y factores de riesgo relacionados con la enfermedad de Chagas en dos comunidades panameñas donde Rhodnius pallescens es el vector principal / Knowledge and risk factors related to Chagas´ disease in two Panamanian communities where Rhodnius pallescens is the main vector

Introducción. La implementación de los programas de vigilancia, prevención y control de la enfermedad de Chagas requiere una aproximación integral. La sostenibilidad de los programas depende de la participación comunitaria amparada en un conocimiento básico del problema. Objetivo. Evaluar los conocimientos de los entrevistados que facilitan o limitan la vigilancia, prevención y control de la enfermedad de Chagas en dos comunidades endémicas de Panamá donde Rhodnius pallescens es el vector principal. Materiales y métodos. Mediante un cuestionario se evaluaron los conocimientos y los factores de riesgo relacionados con la enfermedad de Chagas en 201 personas mayores de 10 años de las comunidades endémicas de Las Pavas y Lagartera Grande, ubicadas en la ribera oeste del Canal de Panamá. Con ayuda de los moradores también se evaluó la presencia de chinches triatominos en 93 viviendas a lo largo de un año. Resultados. De las personas entrevistadas, 69,2 % (139/201) tenía pocos o muy pocos conocimientos sobre la enfermedad de Chagas y 93 % (187/201) estaba expuesto a factores de riesgo moderados o altos. Se capturaron chinches triatominos en 20,4 % (19/93) de las viviendas evaluadas, de los cuales, el 86,8 % (66/76) era R. pallescens. Se encontró asociación significativa entre la presencia de chinches dentro de las viviendas y las viviendas catalogadas como precarias (p<0,01). Conclusión. A pesar de que en estas dos comunidades se han desarrollado programas de educación sanitaria, es necesario reforzar los conocimientos básicos sobre la enfermedad de Chagas antes de establecer medidas de prevención y vigilancia que involucren la participación activa de sus habitantes.

Introduction: The implementation of surveillance, control and prevention measures for Chagas´ disease requires an integrated approach. The sustainability of programs depends on community participation supported on a basic understanding of the problem. Objective: To evaluate the knowledge of people interviewed which facilitates or limits the surveillance, prevention and control of Chagas´ disease in two endemic Panamanian communities where Rhodnius pallescens is the main vector. Materials and methods: A questionnaire assessed the knowledge and risk factors related to Chagas´ disease in 201 people over 10 years of age from the endemic communities of Las Pavas and Lagartera Grande located on the western shore of Panama Canal. Additionally, with the help of the residents, the presence of triatomine bugs in 93 dwellings was evaluated during a year. Results: Of those interviewed, 69.2% (139/201) had poor or very poor knowledge about Chagas´ disease. Nearly 93% (187/201) was exposed to moderate or high risk factors. Triatomine bugs were collected in 20.4% (19/93) of the evaluated homes; 80% (66/76) of them were R. pallescens . Significant association was found between the presence of triatomines inside the houses and precarious housing (p<0.01). Conclusion: Despite having been exposed to health education-related programs, it is necessary to strengthen the basic knowledge about Chagas´ disease in the two communities before establishing prevention and surveillance measures which involve active participation of its inhabitants.

Primeiro encontro de Rhodnius domesticus Neiva e Pinto, 1923 (Hemiptera: Reduvidae) no município de Açucena, Minas Gerais, Brasil / First meeting of Rhodnius domesticus Neiva e Pinto, 1923 (Hemiptera: Reduvidae) in the municipality of Açucena, Minas Gerais, Brazil

Os triatomíneos são insetos vetores do Trypanosoma cruzi, protozoário causador da doença de Chagas. Em agosto de 2013, profissionais da Superintendência Regional de Saúde de Coronel Fabriciano, Minas Gerais, registraram a entrada de uma fêmea de triatomíneo que foi identificada como Rhodnius prolixus. O inseto era proveniente do intradomicílio de uma residência do povoado de Caeté, município de Açucena. Para confirmação da identificação, o exemplar foi encaminhado ao Laboratório de Referência em Triatomíneos e Epidemiologia da Doença de Chagas do Centro de Pesquisas René Rachou (CPqRR/FIOCRUZ). Na identificação do exemplar, utilizaram-se chaves taxonômicas e a morfologia externa da genitália feminina, o que permitiu identificá-lo como Rhodnius domesticus. Os caracteres diferenciais em relação às outras espécies de Rhodnius foram: o tamanho de 15,5 mm, a cor parda-amarelada com partes em castanho escuro, a ausência de aspecto sarapintado, a cabeça curta e as patas não aneladas. Além disso, a genitália da fêmea, em vista dorsal, apresentava uma linha em forma de lua dividindo o nono e décimo segmentos e, em perspectiva ventral, o nono segmento terminava ligeiramente abaixo do décimo. O exemplar foi depositado na coleção de vetores da doença de Chagas (Fiocruz-COLVEC) do CPqRR/FIOCRUZ. Esta foi a primeira vez em que esta espécie foi identificada na região. É importante que o serviço de vigilância entomológica esteja atento à presença de triatomíneos raros e os identifique corretamente. As coleções entomológicas e os serviços de referência têm importante papel no sentido de assegurar um serviço de qualidade nas identificações.

Triatomines are insect vectors of Trypanosoma cruzi, the protozoan agent of Chagas Disease. In August 2013, a professional from the Regional Health Superintendence of Coronel Fabriciano, Minas Gerais, registered the arrival of a triatomine female identified as Rhodnius prolixus. The insect originated from a domestic residence in Caeté, Açucena municipality. In order to confirm its identity, the insect was sent to the René Rachou Research Center (CPqRR/FIOCRUZ). For identification of the triatomine, taxonomic keys and external morphology of the female genitalia were used, allowing the insect to be identified as Rhodnius domesticus. The differentiating features in relation to other species were: the size of 15.5 mm, the brownish-yellow colour with chestnut brown in parts, absence of the spotted or speckled aspect, short head and non-curled feet. As well as this, the female genitalia, in dorsal view, presented a moon shaped line dividing the ninth and tenth segment, and in ventral view presented the ninth segment finishing slightly below the tenth. The sample was stored in the collection of Chagas disease vectors (Fiocruz- COLVEC) do CPqRR/FIOCRUZ. It was the first time that this species was identified in the region. It is important that the entomology surveillance service is aware of the presence of rare triatomines and processes their identification correctly. In this way, entomologic collections and reference services have an important role, ensuring a quality service in identification.