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.

Survey of trypanosoma (kinetoplastida: trypanosomatidae) infection in Monte Negro Municipality, State of Rondônia, western amazon, with first record of T. evansi in the state

Abstract INTRODUCTION: Trypanosomes can infect humans and animals. This is the first record of the occurrence of Trypanosoma evansi in Rondônia. METHODS: Blood samples were collected from 7 dogs and 22 humans. Furthermore, triatomines and tabanids were collected. RESULTS: It was observed that 42.8% of the dogs tested positive for T. evansi and 14.3% presented mixed infection; 15% of the triatomines tested positive for flagellates identified as T. cruzi TCI (3 specimens), T. cruzi TCI, and T. rangeli (1 specimen), and one with T. cruzi TCV. Two tabanids were infected with T. theileri. CONCLUSIONS: These findings may benefit vector control strategies.

Occurrence of triatomines in an urban residential complex in the municipality of Rio Branco, Acre, South-Western Amazon

Abstract INTRODUCTION: This study describes the occurrence of triatomines, and their positivity for trypanosomatids, in a residential complex in Rio Branco, Acre, Brazil. METHODS: Triatomines were collected through direct capture in a home environment. Positivity analysis for trypanosomatids was performed by PCR assays. RESULTS Collected insects consisted of 31 Rhodnius robustus, 4 Rhodnius montenegrensis, and 1 Panstrongylus geniculatus specimens. All were adults, with no presence of domiciliation, and with an infection rate of 30.6%. CONCLUSIONS Future studies are recommended in other locations of Rio Branco in order to develop a georeference database of the occurrence of triatomines in urban areas.

Insect vectors of Chagas disease (Trypanosoma cruzi) in Northeastern Brazil

Abstract INTRODUCTION: Chagas disease remains a public health problem in the rural and urban areas of 19 countries in the Americas. METHODS: The aim of the present study was to investigate the Trypanosoma cruzi infection rate of triatomines collected from both intra- and peridomiciliary areas in eleven municipalities of Southeastern Ceará, Brazil, from 2009 to 2015. RESULTS: A total of 32,364 triatomine specimens, including nymphs and adults, were collected, and 31,736 (98.06%) of these were examined. More nymphs were collected than adults, and the greatest number of triatomines (n = 8,548) was collected in 2010, for which the infection rate was 1.3%, with the highest rate of infections observed for specimens from Quixere. The species collected during the study were identified as Triatoma pseudomaculata, Triatoma brasiliensis, Panstrongylus megistus, Panstrongylus lutzi, and Rhodnius nasutus, with T. pseudomaculata being the most abundant (n = 19,962). CONCLUSIONS: These results verify the presence of triatomines in both intra- and peridomiciliary areas, thereby ensuring persistence of the pathogen and consequently, the disease, as the presence of infected vectors in households is an important risk factor. According to these findings, the Chagas Disease Control Program should intensify its efforts in order to prevent the spread of the disease.

Rhodnius stali: new vector infected by Trypanosoma rangeli (Kinetoplastida, Trypanosomatidae)

Abstract INTRODUCTION Rhodnius stali infection by Trypanosoma rangeli is reported in this study for the first time. METHODS The triatomines were collected from the campus of the Federal University of Acre in Rio Branco, Acre, Brazil. The identification of T. rangeli was confirmed by multiplex polymerase chain reaction. RESULTS The examinations of two specimens revealed R. stali infection by the epimastigote forms of T. rangeli. CONCLUSIONS The encounter of R. stali infected by T. rangeli generates an alert for the state of Acre, since the simultaneous presence with Trypanosoma cruzi can make the differential diagnosis of Chagas disease difficult.

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.

Characteristics of Triatomine infestation and natural Trypanosoma cruzi infection in the State of Rio Grande do Norte, Brazil

Abstract: INTRODUCTION Natural and artificial ecotope infestation by the kissing bug triatomines and their colonization and infection by Trypanosoma cruzi , the Chagas disease agent, were evaluated in nine municipalities of the State of Rio Grande do Norte, Brazil. METHODS Following identification, triatomine intestinal contents were analyzed by direct microscopic examination, xenoculture, and polymerase chain reaction (PCR) for parasite detection. Trypanosoma cruzi isolates were genotyped using three different markers. RESULTS Of 842 triatomines captured, 65% were Triatoma brasiliensis , 17.8% Triatoma pseudomaculata , 12.5% Panstrongylus lutzi , and 4.7% Rhodnius nasutus . Triatoma brasiliensis and P. lutzi adults were found in the intradomicile. T. brasiliensis, T. pseudomaculata , and R. nasutus nymphs and adults were found in the peridomicile and wild environment. Intradomiciliary and peridomiciliary infestation indexes were 5.6% and 33.7%, respectively. In the peridomicile, chicken coops were the most infested ecotope. The T. cruzi triatomine infection rate was 30.2%, of which PCR detected 29%. P . lutzi (78.1%), T . brasiliensis (24.5%), and T . pseudomaculata (22.7%) were the most infected species. TcII and III genotypes were detected in T. brasiliensis and TcIII in P. lutzi . CONCLUSIONS T. brasiliensis was found in all environments and most ecotopes with high T. cruzi infection rates. High infection rates were also detected in T . pseudomaculata and P. lutzi , suggesting their role in the interchange between the wild and peridomestic transmission cycles. The combination of PCR, microscopic examination, and xenoculture contributed to improving T. cruzi infection evaluation in triatomine bugs. The TcII and TcIII genotypes were predominant in the study area.

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 .

Transmisión oral de Trypanosoma cruzi: una nueva situación epidemiológica de la enfermedad de Chagas en Colombia y otros países suramericanos / Oral transmission of Trypanosoma cruzi : a new epidemiological scenario for Chagas´ disease in Colombia and other South American countries

Durante la última década se han reportado numerosos casos de infección por Trypanosoma cruzi por vía oral, debidos a la contaminación de alimentos con heces de triatominos silvestres o con secreciones de reservorios en áreas donde los vectores domiciliados han sido controlados o no hay antecedentes de domiciliación. Con base en criterios epidemiológicos, clínicos y socioeconómicos, la Organización de las Naciones Unidas para la Agricultura y la Alimentación (FAO) y la Organización Mundial de la Salud (OMS) establecieron una clasificación de los parásitos transmitidos por contaminación de alimentos en diferentes regiones del mundo, en la cual T. cruzi ocupó el décimo lugar de importancia en un grupo de 24 parásitos. Los cambios ambientales, como la deforestación y el calentamiento global, han afectado los ecotopos y el comportamiento de los vectores y de los reservorios de T. cruzi , de manera que estos se han desplazado a nuevas zonas, generando una nueva forma de transmisión por contaminación de alimentos que requiere su evaluación en el país. La presente revisión aborda la transmisión oral de la enfermedad de Chagas con énfasis en los estudios orientados a identificar los factores de riesgo, las especies de triatominos involucrados, la fisiopatología de la infección oral y los genotipos del parásito que están implicados en esta forma de transmisión en Colombia y en otras regiones de América Latina, así como la necesidad de adoptar políticas para su control y vigilancia epidemiológica.

Many cases of infection caused by the oral transmission of Trypanosoma cruzi have been reported during the last decade. These have been due to the contamination of food by faeces from sylvatic triatomines or by leakage from reservoirs in areas where domiciliated vectors have been controlled or where there has been no prior background of domiciliation. The United Nations Food and Agriculture Organization (FAO) and the World Health Organization (WHO) have used epidemiological, clinical and socioeconomic criteria for ranking parasites transmitted by the contamination of food in different areas of the world; T. cruzi was placed tenth in importance amongst a group of 24 parasites in such ranking. Environmental changes such as deforestation and global warming have affected ecotopes and the behaviour of T. cruzi vectors and reservoirs so that these have become displaced to new areas, thereby leading to such new transmission scenario caused by the contamination of food, which requires evaluation in Colombia. The current review deals with the oral transmission of Chagas´ disease, emphasising studies aimed at identifying the pertinent risk factors, the triatomine species involved, the physiopathology of oral infection, the parasite´s genotypes implicated in this type of transmission in Colombia and other Latin American regions, as well as the need for ongoing epidemiological surveillance and control policies.

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.

Interação de Rhodnius prolixus com Trypanosoma rangeli: avaliação do sistema de defesa celular e humoral e microbiota intestinal / Rhodnius prolixus interaction with Trypanosoma rangeli: evaluation of the cellular defense system and humoral and intestinal microbiota

A susceptibilidade de Rhodnius prolixus ao T. rangeli depende da cepa do parasita e das interações moleculares no intestino e na hemocele do vetor. T. rangeli pode modular a resposta imune do vetor, preparando o hospedeiro à invasão e a sobrevivência dos parasitas na hemocele, superando assim as adversidades encontradas nos diferentes órgãos do inseto. Neste trabalho, são discutidos os mecanismos destas interações, destacando também o papel da microbiota intestinal e outros mecanismos importantes para o desenvolvimento do parasita. Inicialmente nossas investigações foram realizadas para comparar aspectos da imunidade celular e humoral de ninfas de 4º e 5º estádio de R. prolixus em resposta a uma infecção oral com a cepa Macias de T. rangeli. Na infecção oral em 4º estádio (acompanhamento em longo prazo), não foi observada diferença na mortalidade e muda ao comparar com os insetos controle não infectados. Constatou-se um número aumentado de flagelados no intestino das ninfas de 5º estádio durante o curso da infecção. Também, não houve alteração significativa na contagem de microagregados hemocitários (nódulos) em infecções de 4º estádio, enquanto em ninfas infectadas em 5º estádio houve um aumento no número de nódulos. Por outro lado, não houve diferença no número de hemócitos em ambas as infecções.

Demonstramos nos dois tipos de infecção oral com T. rangeli em R. prolixus, em comparação com os insetos controle não infectados, que o intestino médio atenuou a atividade de fenoloxidase, aumentou as atividades antibacterianas testadas in vitro contra Serratia marcescens, e alterou a expressão relativa de genes que codificam para defensinas (DefA, DefB, DefC), prolixicina e lisozimas (LisAe LisB). Isto sugere a influência destas atividades sobre a contagem de unidades formadoras de colônias, encontradas diminuídas no trato digestivo do inseto. Em uma segunda etapa do estudo, foram comparadas as respostas de defesa em ninfas de 5º estádio de R. prolixus inoculadas com T. rangeli, cepas Macias e H14. A cepa Macias de T. rangeli não aumentou a mortalidade desses insetos, apresentou capacidade de sobreviver e se multiplicar na hemolinfa, aumentou o número de hemócitos, e induziu alta atividade de fenoloxidase. Em contraste, estes mesmos parâmetros medidos em insetos inoculados com a cepa H14 de T. rangeli foram diferentes daqueles encontrados com inoculação de insetos usando a cepa Macias. Conclui-se que R. prolixus responde de forma distinta frente a vias de infecção oral ou por inoculação com T. rangeli, sugerindo que a capacidade infectiva deste protozoário, pode ser alterada por modulação do sistema imune do vetor.

New focus of active transmission of Chagas disease in indigenous populations in the Peruvian Amazon basin

Introduction Several cases of acute Chagas disease (ACD) have been reported in the Peruvian Amazon basin. Methods The objective was to describe and investigate 6 ACD cases in children from indigenous Amazon communities in the province of Datem del Marañón in Loreto department (2006-2010). Results The mean age was 3.6 years. All patients had fever, 4/6 hepatomegaly, 2/6 splenomegaly, and 5/6 had trypomastigotes of Trypanosoma cruzi on thick smears. The fatality rate was 33.3%. Rhodnius pictipes and Rhodnius robustus adults were found inside the homes and in the peri-domiciles. Conclusions All cases reported were isolated cases. We report a new focus of ACD in indigenous populations. .

Behavioural biology of Chagas disease vectors

Many arthropod species have adopted vertebrate blood as their main food source. Blood is rich in nutrients and, except for the presence of parasites, sterile. However, this food source is not freely available, nor is obtaining it devoid of risk. It circulates inside vessels hidden underneath the skin of mobile hosts that are able to defend themselves and even predate the insects that try to feed on them. Thus, the haematophagous lifestyle is associated with major morphological, physiological and behavioural adaptations that have accumulated throughout the evolutionary history of the various lineages of blood-sucking arthropods. These adaptations have significant consequences for the evolution of parasites as well as for the epidemiology of vector-transmitted diseases. In this review article, we analyse various aspects of the behaviour of triatomine bugs to illustrate how each behavioural trait represents a particular adaptation to their close association with their hosts, which may easily turn into predators. Our aim is to offer to the reader an up-to-date integrative perspective on the behaviour of Chagas disease vectors and to propose new research avenues to encourage both young and experienced colleagues to explore this aspect of triatomine biology.

Sensibilidad al benzonidazol de cepas de Trypanosoma cruzi sugiere la circulación de cepas naturalmente resistentes en Colombia / Trypanosoma cruzi strains resistant to benznidazole occurring in Colombia

Introducción. La enfermedad de Chagas, causada por Trypanosoma cruzi, es uno de los problemas más graves de salud pública en el continente americano. El benzonidazol es uno de los dos medicamentos utilizados para tratar la enfermedad de Chagas. Sin embargo, la variación de la sensibilidad del parásito a este medicamento es una de las principales causas del fracaso del tratamiento. Objetivo. Evaluar la sensibilidad in vitro al benzonidazol de cepas colombianas de T. cruzi de diferentes orígenes y procedencia geográfica. Materiales y métodos. Treinta y tres cepas colombianas de T. cruzi aisladas de humanos, vectores y mamíferos, se analizaron in vitro mediante el micrométodo enzimático de MTT para determinar la concentración inhibitoria 50 (CI50) al benzonidazol. Se estudió la correlación entre la sensibilidad in vitro al medicamento y diferentes parámetros biológicos y eco-epidemiológicos. Resultados. El análisis de sensibilidad al medicamento indicó que el 36 % de las cepas eran sensibles, el 48 %, parcialmente resistentes y, el 16 %, resistentes al benzonidazol. Los análisis de correlación entre las CI50 con algunos parámetros biológicos y eco-epidemiológicos, mostraron diferencias en cuanto a la sensibilidad según el origen biológico y el área geográfica de procedencia de la cepa. Conclusiones. Existe una gran variabilidad en cuanto a la sensibilidad al benzonidazol de las cepas circulantes de T. cruzi en Colombia, lo cual sugiere la presencia de cepas naturalmente resistentes en el país.

Introduction. Chagas disease caused by Trypanosoma cruzi is one of the most serious public health problems in the Americas. Benznidazole is one of two drugs used to treat Chagas´ disease. However, the variation in susceptibility of the parasite to this drug is one of the main causes of treatment failure. Objective. The in vitro susceptibility to benznidazole was assessed in Colombian strains of T. cruzi from several sources and geographical regions. Materials and methods. Thirty-three Colombian T. cruzi strains were isolated from humans, vectors and mammals. These were analyzed in vitro by the MTT enzymatic micromethod to determine the IC50 to benznidazole. Additionally, the in vitro susceptibility was correlated with several biological and ecoepidemiological parameters. Results. Thirty-six percent of the strains were considered to be sensitive, 48% partially resistant, and 16% were resistant. Correlations between the IC50 and several biological and eco-epidemiological parameters indicated that differences in susceptibility depended on the biological source and geographical origin of the strain. Conclusions. A high degree of variability exists in the susceptibility to benznidazole of T. cruzi strains in Colombia. The distribution data indicate the presence and circulation of naturally resistant strains.

Natural infection of triatomines (Hemiptera: Reduviidae) by trypanosomatids in two different environments in the municipality of Ouro Preto do Oeste, State of Rondônia, Brazil / Infecção natural de triatomíneos (Hemiptera: Reduviidae) por tripanosomatídeos em dois ambientes distintos no município de Ouro Preto do Oeste, Estado de Rondônia, Brasil

INTRODUCTION: This study analyzed the occurrence and the contamination of triatomines by trypanosomatids in Orbignya speciosa (babassu) specimens in the State of Rondônia, Brazil, in two different environments (pasture and woods). METHODS: Capture of triatomines on babassus and microscopic search for trypanosomatids in their digestive tube were carried out. RESULTS: Four hundred ninety-four (494) specimens were captured (Rhodnius prolixus and R.robustus), of which 35.6% of the triatomines were positive for trypanosomatids. CONCLUSIONS: The high index of natural infection along with the abundance of triatomines points out to the necessity to create an epidemiological surveillance system to monitor vector-borne transmission and deepen the studies on the ecology of such vectors in the Amazon.

INTRODUÇÃO: O estudo analisou a ocorrência e o índice de contaminação por tripanosomatídeos de triatomíneos em Orbynia speciosa no Estado de Rondônia, Brasil, em 2 ambientes (pastagem e floresta). MÉTODOS: Captura em palmeiras e esfregaços do conteúdo do tubo digestivo dos triatomíneos analisados por microscopia óptica. RESULTADOS: Capturaram-se 494 espécimes (Rhodnius prolixus e R. robustus), sendo que 35,6% dos triatomíneos estavam positivos para tripanosomatídeos. CONCLUSÕES: O elevado índice de infecção natural, aliados à abundância de triatomíneos, mostram a necessidade de se criar um sistema de vigilância epidemiológica para monitorar a transmissão vetorial e aprofundar estudos sobre a ecologia destes vetores na Amazônia.

Rhodnius prolixus en Nicaragua: distribución geogrßfica, control y vigilancia entre 1998 y 2009 / Rhodnius prolixus in Nicaragua: geographical distribution, control, and surveillance, 1998-2009

OBJETIVO: Presentar la perspectiva general del control de Rhodnius prolixus, el principal vector en la transmisión de la enfermedad de Chagas en Centroamérica, durante el período 1998-2009 en Nicaragua. Describir el control vectorial realizado y presentar la distribución geogrßfica de las localidades infestadas. MÉTODOS: Se estudió y analizó la información disponible en el Ministerio de Salud de Nica ragua. Se visualizó la distribución geogrßfica de R. prolixus mediante el programa visualiza dor de mapas Quantum GIS 1.5.0. RESULTADOS: Se determinó que 59 localidades en 14 municipios de 8 departamentos presen taron antecedentes de infestación con R. prolixus entre 1998 y 2009. La altitud de las locali dades infestadas oscila entre 160 y 1 414 metros sobre el nivel del mar. Se han tratado con mßs de dos ciclos de control químico 56 localidades. En el segundo ciclo de rociamiento se detectó la presencia del vector, pero durante el tercer ciclo no se lo encontró en ninguna localidad. CONCLUSIONES: La mayor concentración geogrßfica de R. prolixus se observó en dos depar tamentos de la región norte: Madriz y Nueva Segovia. La cantidad de localidades infestadas es menor en Nicaragua que en otros países centroamericanos. El control químico ha sido exitoso en las localidades intervenidas, pero es necesario fortalecer el sistema de vigilancia institucio nal y comunitaria tanto para vigilar la reinfestación con R. prolixus como para ampliar la cobertura del control vectorial.

OBJECTIVE: Present an overview of the control of Rhodnius prolixus, the principal vector in the transmission of Chagas' disease in Central America, during the period 1998-2009 in Nicaragua. Describe the vector control carried out and the geographical distribution of the infested localities. METHODS: The available information in Nicaragua's Ministry of Health was studied and analyzed. The geographical distribution of R. prolixus was visualized using the Quantum GIS 1.5.0 map visualization program. RESULTS: It was determined that 59 localities in 14 municipalities of 8 departments had a history of R. prolixus infestation between 1998 and 2009. The altitude of the infested localities ranges between 160 and 1 414 meters above sea level. A total of 56 localities have been treated with more than two cycles of chemical control. The presence of the vector was detected in the second spraying cycle, but it was not found in any locality during the third cycle. CONCLUSIONS: The greatest geographical concentration of R. prolixus was found in two departments in the northern region: Madriz and Nueva Segovia. There were fewer infested localities in Nicaragua than in other Central American countries. Chemical control has been successful in the localities treated, but the institutional and community surveillance system needs to be strengthened to monitor R. prolixusreinfestation and expand vector control coverage.

Aspectos ecológicos da Tripanossomíase Americana em comunidades do médio Tapajós, Pará, Brasil, e riscos de transmissão do Trypanosoma cruzi às populações humanas da região

O número crecente de casos agudos da doença de Chagas no estado do Pará, notificados nas últimas duas décadas, tem sido associados, em parte, a ingestão de suco de frutos de palmeiras locais, principalmente açaí e bacaba. O objetivo do presente trabalho foi avaliar os aspectos ecológicos da Tripanossomíase Americana em comunidades do médio Tapajós, Pará, Brasil, e riscos de transmissão do Trypanosoma cruzi às populações humanas da região. Para isto, foram dissecadas 136 palmeiras, sendo 60 no final do período chuvoso e 76 no final do período de seca. Destas, 73 (53,7%) estavam infestadas por triatomíneos e foram encontradas três espécies, a saber: Rhodnius robustus, Rhodnius pictipes e Panstrongylus lignarius. Foram coletados 743 triatomíneos, sendo predominante a presença de R. robustus (n=739). A identificação da infecção natural dos insetos por tripanosomatídeos revelou que 125 triatomíneos estavam infectados pelo T. cruzi, 69 por T. rangeli e 14 apresentaram ambos os parasitas, indicando a presença de infecção mista no mesmo vetor. Foi realizada a tipagem molecular de T. cruzi de acordo com a nova nomenclatura e os resultados demonstraram predominância do grupo TCI (n=29). Além disso, foi constatada a ocorrência de TCII, a presença de TCI e TCII no mesmo triatomíneo e 12 isolados de TCI apresentaram uma variante, sugerindo a existência de um subgrupo dentro de TCI. A análise das fontes alimentares revelou que R. robustus, espécie predominante de triatomíneo coletada nas palmeiras investigadas, alimentou-se na sua grande maioria em mamíferos silvestres

Foram também identificados “sangue” de outras fontes alimentares, como aves e répteis no conteúdo digestivo dos espécies investigados. As análises cartográficas de Kernel e do Interpolador de Médias demonstraram que a comunidade São Tomé apresenta maiores aglomerados (hotspots) tanto em infestação das palmeiras, quanto na densidade triatomínica e número de insetos infectados. Desta forma, os resultados sugerem que São Tomé é a comunidade com maior risco de infecção à população e demonstram a existência de um ciclo silvestre intenso na região que demanda vigilância para prevenção da transmissão

Aspectos ecológicos da Tripanossomíase Americana em comunidades do médio Tapajós, Pará, Brasil, e riscos de transmissão do Trypanosoma cruzi às populações humanas da região / Ecological aspects of American trypanosomiasis in communities of the middle Tapajós, Pará, Brazil, and risks of transmission of Trypanosoma cruzi to human populations in the region

O número crecente de casos agudos da doença de Chagas no estado do Pará, notificados nas últimas duas décadas, tem sido associados, em parte, a ingestão de suco de frutos de palmeiras locais, principalmente açaí e bacaba. O objetivo do presente trabalho foi avaliar os aspectos ecológicos da Tripanossomíase Americana em comunidades do médio Tapajós, Pará, Brasil, e riscos de transmissão do Trypanosoma cruzi às populações humanas da região. Para isto, foram dissecadas 136 palmeiras, sendo 60 no final do período chuvoso e 76 no final do período de seca. Destas, 73 (53,7%) estavam infestadas por triatomíneos e foram encontradas três espécies, a saber: Rhodnius robustus, Rhodnius pictipes e Panstrongylus lignarius. Foram coletados 743 triatomíneos, sendo predominante a presença de R. robustus (n=739). A identificação da infecção natural dos insetos por tripanosomatídeos revelou que 125 triatomíneos estavam infectados pelo T. cruzi, 69 por T. rangeli e 14 apresentaram ambos os parasitas, indicando a presença de infecção mista no mesmo vetor. Foi realizada a tipagem molecular de T. cruzi de acordo com a nova nomenclatura e os resultados demonstraram predominância do grupo TCI (n=29). Além disso, foi constatada a ocorrência de TCII, a presença de TCI e TCII no mesmo triatomíneo e 12 isolados de TCI apresentaram uma variante, sugerindo a existência de um subgrupo dentro de TCI. A análise das fontes alimentares revelou que R. robustus, espécie predominante de triatomíneo coletada nas palmeiras investigadas, alimentou-se na sua grande maioria em mamíferos silvestres. Foram também identificados “sangue” de outras fontes alimentares, como aves e répteis no conteúdo digestivo dos espécies investigados. As análises cartográficas de Kernel e do Interpolador de Médias demonstraram que a comunidade São Tomé apresenta maiores aglomerados (hotspots) tanto em infestação das palmeiras, quanto na densidade triatomínica e número de insetos infectados. Desta forma, os resultados sugerem que São Tomé é a comunidade com maior risco de infecção à população e demonstram a existência de um ciclo silvestre intenso na região que demanda vigilância para prevenção da transmissão.

Ocorrência de triatomíneos em ambientes silvestres e domiciliares do município de Manaus, Estado do Amazonas / Occurrences of triatomines in wild and domestic environments in the municipality of Manaus, State of Amazonas

A análise da distribuição de triatomíneos é essencial para a formulação de estratégias de controle da doença de Chagas na Região Amazônica. Neste trabalho, apresentam-se os resultados de capturas realizadas em ambientes silvestres e artificiais, em localidades rurais e urbanas de Manaus, Amazonas. Dos 115 triatomíneos coletados, 85 (73,9 por cento) são da espécie Rhodnius pictipes, 25 (21,7 por cento) de Rhodnius robustus e cinco (4,4 por cento) de Panstrongylus geniculatus. A taxa de infecção natural por flagelados foi de 5,9 por cento para Rhodnius pictipes e 8 por cento para Rhodnius robustus. Nenhum exemplar de Panstrongylus geniculatus estava infectado. Todos os exemplares infectados eram oriundos de fragmentos de matas da zona urbana. Verificou-se que 106 (92,2 por cento) triatomíneos foram coletados no ambiente silvestre e nove (7,8 por cento) nas unidades domiciliares pela busca ativa. O gênero Rhodnius predominou nitidamente no ambiente silvestre. Os exemplares de Panstrongylus geniculatus, todos adultos, foram coletados no intradomicílio. Não foram encontrados indícios de colonização domiciliar por triatomíneos.

Analysis of the distribution of triatomines is essential for formulating control strategies for Chagas disease in the Amazon region. In this paper, the results from trapping in wild and artificial environments in rural and urban localities in Manaus, Amazonas, are presented. Out of the 115 triatomines collected, 85 (73.9 percent) were of the species Rhodnius pictipes, 25 (21.7 percent) of Rhodnius robustus and five (4.4 percent) of Panstrongylus geniculatus. The rate of natural infection by flagellates was 5.9 percent for Rhodnius pictipes and 8 percent for Rhodnius robustus. None of the specimens of Panstrongylus geniculatus were infected. All of the infected specimens were from forest fragments in the urban zone. It was found that 106 insects (92.2 percent) were collected from the forest environment and nine (7.8 percent) in households, by means of the active search. The genus Rhodnius clearly predominated in the wild environment. The specimens of Panstrongylus geniculatus (all adults) were collected inside homes. There were no signs of domestic colonization by triatomines.