Systematic review on the biology, ecology, genetic diversity and parasite transmission potential of Panstrongylus geniculatus (Latreille 1811) in Latin America

Panstrongylus geniculatus (Latreille, 1811) is the triatomine with the largest geographic distribution in Latin America. It has been reported in 18 countries from southern Mexico to northern Argentina, including the Caribbean islands. Although most reports indicate that P. geniculatus has wild habitats, this species has intrusive habits regarding human dwellings mainly located in intermediate deforested areas. It is attracted by artificial light from urban and rural buildings, raising the risk of transmission of Trypanosoma cruzi. Despite the wide body of published information on P. geniculatus, many knowledge gaps exist about its biology and epidemiological potential. For this reason, we analysed the literature for P. geniculatus in Scopus, PubMed, Scielo, Google Scholar and the BibTriv3.0 databases to update existing knowledge and provide better information on its geographic distribution, life cycle, genetic diversity, evidence of intrusion and domiciliation, vector-related circulating discrete taxonomic units, possible role in oral T. cruzi transmission, and the effect of climate change on its biology and epidemiology.

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.

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.

Trypanosoma cruzi isolated from a triatomine found in one of the biggest metropolitan areas of Latin America

Abstract: INTRODUCTION: To characterize Trypanosoma cruzi (TcI) isolated from a Panstrongylus megistus specimen found in one of the biggest metropolitan areas of Latin America, the relationship between the TcI group of T. cruzi and the transmission cycle in the urban environment was studied. METHODS: The T. cruzi strain, Pm, was isolated in a culture medium from the evolutionary forms present in the hindgut of a live male specimen of P. megistus found in the Jabaquara subway in São Paulo City. The sample from the triatomine showed trypomastigote forms of Trypanosomatidae, which were inoculated in the peritoneum of Balb/c mice. The sample was then inoculated in Liver Infusion Tryptose medium and J774 cells for the molecular identification and characterization of the parasite. The Pm strain of T. cruzi was identified by isolation in axenic culture medium, and based on the morphology, cell infection, growth kinetics, and molecular characterization. RESULTS: After isolation, the protozoan was identified as T. cruzi. No parasites were detected in the peripheral blood of the animal, which can be a characteristic inherent to the strain of T. cruzi that was isolated. Cell invasion assays were performed in triplicate in the J774 cell line to confirm the invasive ability of the Pm strain and revealed amastigote forms of the parasite within macrophages. CONCLUSIONS: Our biological and molecular characterizations helped understand parasite-host interactions and their evolutionary history in context of the associations between vectors, ecotopes, hosts, and groups of the parasite.

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.

Evaluation of the Chagas Disease Control Program in Açucena Municipality, Rio Doce Valley, State of Minas Gerais, Brazil

Introduction Açucena Municipality, Rio Doce Valley, State of Minas Gerais, Brazil temporarily (2001-2005) interrupted epidemiological surveillance for Chagas disease. The objective of this work was to evaluate the Chagas Disease Control Program (CDCP) in Açucena and to offer suggestions for improving local epidemiological surveillance. Methods This study was conducted in three phases: I) a serological investigation of schoolchildren aged 5 to 15 years using an enzyme-linked immunosorbent assay (ELISA) test performed on blood collected on filter paper followed by ELISA, indirect immunofluorescence (IIF) and indirect hemaglutination (IHA) on venous blood for borderline cases and those in the gray zone of reactivity; II) vector evaluation using the data obtained by local health agents during 2006-2010; and III) examination by ELISA, IIF and IHA of serum samples from the inhabitants of houses where infected Triatoma vitticeps was found and evaluation of their knowledge about Chagas disease. Results Five individuals had inconclusive results in the ELISA screening but were seronegative for Chagas disease. The triatomine evaluation revealed the presence of three species: Triatoma vitticeps, Panstrongylus megistus and Panstrongylus diasi. Triatoma vitticeps was the most prevalent and widespread, with a higher (67%) index of Trypanosoma cruzi flagellates and evidence of colonization. Most of the inhabitants of the infested houses recognized triatomines and had basic knowledge about Chagas disease. Conclusions Although T. vitticeps is not clearly associated with Chagas disease transmission, these results highlight the importance of maintaining CDCP in endemic areas and the need for greater emphasis on epidemiological surveillance, especially in areas with important vectorial changes or that have been modified by human intervention. .

Evaluation of natural foci of Panstrongylus megistus in a forest fragment in Porto Alegre, State of Rio Grande do Sul, Brazil

Introduction Panstrongylus megistus is commonly found in wild environments of the State of Rio Grande do Sul, Brazil. The aim of this study was to characterize the network of refuges used by triatomine in a forest fragment of Porto Alegre and to identify Trypanosoma cruzi infection, associated hosts and the epidemiological importance of both hosts and triatomines. Methods Techniques including the spool-and-line method and active searching (transects) were used to identify natural foci. Results The food source for each triatomine was determined using the precipitin test, and the infection of marsupials was determined by xenodiagnosis. A total of 33 adults (domestic environment) and 27 nymphs (wild environment) of P. megistus were found in addition to 43 Didelphis albiventris specimens. The infection rates of triatomine adults, triatomine nymphs and opossums with T. cruzi I were 64%, 73% and 69%, respectively. Birds, rodents and opossums were the main resources used by triatomine. Conclusions This work presents the first characterization of a natural focus of P. megistus in Rio Grande do Sul. The natural characteristics of this focus and its implication in the transmission of T. cruzi are discussed. .

Triatomines in dwellings and outbuildings in an endemic area of Chagas disease in northeastern Brazil / Triatomíneos no intra e peridomicílio de área endêmica de doença de Chagas no Nordeste do Brasil

INTRODUCTION: The present study identified the triatomines collected in intra and peri-domestic environments, observed the occurrence of Trypanosoma cruzi infection in triatomines and correlated this information with housing conditions and the fauna associated with the rural areas of the City of Itabaianinha, located in the State of Sergipe, Brazil. METHODS: Quarterly visits were conducted between March 2009 and March 2010, and the homes to be visited for the active search of insects were determined by random selection. In each housing unit, the insects were collected by a manual search with a metal clip and flashlight to inspect openings and cavities, with a collection time of one hour/home/individual. The Pirisa® dislodge chemical was used to force the insects to leave their ecotopes. Analysis of the intestinal contents of triatomines was performed in the laboratory to establish the presence of Trypanosomatidae. RESULTS: Of the 103 dwellings surveyed, 17.5% were infested with Panstrongylus megistus. The village of Mutuca exhibited the highest infestation rate (38.1%). All the villages with relevant infestation rates were situated in the northern area of the city. The highest percentage of vector infection was found in the village of Água Boa (56.5%). The rural dwellings were found to be primarily brick or wooden house with or without roughcast or plastered walls, and the outbuilding most frequently associated with triatomines was the chicken run. CONCLUSIONS: These results emphasise the need for broader vector control and surveillance and for educational campaigns in the context of the Chagas Disease Control Program.

INTRODUÇÃO: O presente trabalho teve como objetivo identificar os triatomíneos coletados no intra e peridomicílio, assim como verificar a ocorrência de infecção por Trypanosoma cruzi e correlacionar essas informações às condições habitacionais e à fauna associada na zona rural de Itabaianinha, Sergipe, Brasil. MÉTODOS: Visitas trimestrais foram realizadas entre março de 2009 e março de 2010, e as casas visitadas para a busca ativa de insetos foram determinadas por sorteio. Em cada unidade habitacional, os insetos foram capturados por coleta manual com pinça e lanterna para examinar aberturas e cavidades, com um tempo de coleta de uma hora/casa/indivíduo. O desalojador químico Pirisa® foi utilizado para forçar os insetos a abandonar seus ecótopos. A análise do conteúdo intestinal dos triatomíneos foi realizado no laboratório para estabelecer a presença de tripanosomatídeos. RESULTADOS: Em 103 unidades domiciliares examinadas, 17,5% estavam infestadas por triatomíneos da espécie Panstrongylus megistus. O Povoado Mutuca apresentou a mais elevada taxa de infestação das unidades domiciliares (38,1%). Todos os povoados que apresentaram índices de infestação relevantes estavam localizados na região norte do município. A maior percentagem de infecção desse vetor foi observada no Povoado Água Boa (56,5%). As habitações rurais observadas eram em sua maioria de tijolo ou madeira com as paredes rusticamente rebocadas ou sem reboco, e o anexo frequentemente associado ao triatomíneo foi o galinheiro. CONCLUSÕES: Os resultados obtidos ressaltam a necessidade de vigilância e controle vetorial mais abrangentes, bem como de campanhas educativas no contexto do PCDCh.

Panstrongylus rufotuberculatus (Hemiptera, Reduviidae, Triatominae) infectado con Trypanosoma cruzi en el estado Anzoátegui (Venezuela) / Panstrongylus rufotuberculatus (Hemiptera, Reduviidae, Triatominae) infected with Trypanosoma cruzi in the state of Anzoátegui (Venezuela) Antonio Morocoima

En el caserío rural Mundo Nuevo, municipio Pedro María Freites, estado Anzoátegui (Venezuela) se capturaron en la pared externa de una vivienda cuatro ejemplares adultos de Panstrongylus rufotuberculatus (Champion, 1899) (Hemiptera, Reduviidae, Triatominae), uno de los cuales mostró infección por Trypanosoma cruzi, evidenciada por examen directo del contenido intestinal. El comportamiento del aislado en ratones NMRI presentó parasitismo tisular en 47% de 12 tejidos estudiados. La especie T. cruzi fue confirmada por PCR-ADNk y PCR ADN satélite. Se demuestra por primera vez la presencia de esta especie silvestre en el estado Anzoátegui.

In the rural village Mundo Nuevo, municipality Pedro Maria Freites, Anzoátegui state (Venezuela), four adults of Panstrongylus rufotuberculatus (Champion, 1899) (Hemiptera, Reduviidae, Triatominae) were captured in the external wall of a human dwelling. One triatomine was infected by Trypanosoma cruzi. The isolate inoculated in NMRI mice showed parasites in 47% of 11 studied tissues. T.cruzi was confirmed by PCR-kDNA and PCR satellite DNA.The presence of this species represents, to our knowledge,the first report for this state.

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.

Prevalence and intensity of infection, metacyclogenesis and nuclear phenotypes in Panstrongylus megistus (Burmeister, 1835) after ingestion of Trypanosoma cruzi (Chagas, 1909) II and subjection to heat shock / Prevalência e intensidade de infecção, metaciclogênese e fenótipos nucleares em Panstrongylus megistus (Burmeister, 1835) após ingestão de Trypanosoma cruzi (Chagas, 1909) II e choque de temperatura

This study aimed to contribute to our knowledge of the parasite-vector interaction associated with Trypanosoma cruzi (Chagas, 1909) infection in Panstrongylus megistus (Burmeister, 1835), an important vector of Chagas' disease in Brazil. The prevalence and intensity of T. cruzi infection, the incidence of metacyclogenesis and the frequency of nuclear phenotypes in Malpighian tubules were investigated in nymphs of P. megistus, reared at 28 °C and subjected to heat shock (40 °C, 1 hour) two days after infection with T. cruzi II (Y strain). Following the 45-day post-infection period, the frequency of epimastigotes was much higher than that of trypomastigotes in both heat-shocked and non-shocked insects, and the prevalence of infection was not altered by heat shock. Fewer epimastigotes and trypomastigotes were found in the infected insects subjected to the heat shock, indicating that the multiplication and metacyclogenesis of the parasites were affected by the stress. In infected specimens heat shock promoted an increased frequency of cell nuclei with heterochromatin decondensation, a cell survival response to stress, and did not affect insect survival. The effects of infection and heat shock, especially on the multiplication and metacyclogenesis of T. cruzi, and the observed resistance to heat shock developed by P. megistus nymphs are suggestive that they should be considered when adequate conditions for rearing these infected insects in the laboratory are pursued.

O presente estudo teve como objetivo contribuir para o conhecimento sobre a interação parasita-vetor associada à infecção por Trypanosoma cruzi (Chagas, 1909) em Panstrongylus megistus (Burmeister, 1835), importante vetor da doença de Chagas no Brasil. A prevalência e a intensidade da infecção por T. cruzi, a incidência de metaciclogênese e a frequência de fenótipos nucleares presentes em túbulos de Malpighi foram investigadas em ninfas de P. megistus criadas à temperatura de 28 °C e submetidas a choque térmico por 1 hora a 40 °C, dois dias após alimentação em camundongos infectados com T. cruzi II (linhagem Y). A análise realizada 45 dias pós-infecção revelou que tanto nos insetos submetidos ao choque térmico como nos respectivos controles a frequência de epimastigotos se apresentava muito maior do que a dos tripomastigotos; a prevalência da infecção não foi alterada pelo choque térmico. Menos epimastigotos e tripomastigotos foram encontrados nos insetos submetidos ao choque térmico, indicando que a multiplicação e a metaciclogênese dos parasitas possam ser afetadas com o estresse. Nos espécimes infectados, o choque térmico induziu aumento na frequência de núcleos com descompactação da heterocromatina, uma resposta de sobrevivência celular ao estresse, e não afetou a sobrevivência propriamente dita do inseto. Os efeitos da infecção e do choque térmico, especialmente sobre a multiplicação e a metaciclogênese de T. cruzi, e a resistência ao choque térmico desenvolvidos pelas ninfas de P. megistus são indicativos de que devam ser considerados quando se buscam condições adequadas de criação em laboratório de insetos infectados.

Dinâmica do Panstrongylus megistus nos ciclos de transmissão de Trypanosoma cruzi em áreas de cerrado e mata atlântica no estado de Minas Gerais, Brasil / Dynamics of Panstrongylus megistus in Trypanosoma cruzi transmission cycles in areas of savannah and rainforest in the state of Minas Gerais, Brazil

O triatomíneo Panstrongylus megistus pode ser encontrado ao longo do Brasil em um diversificado número de hábitats, tanto silvestres como artificiais. Este trabalho teve como objetivo estudar a dinâmica populacional de P. megistus nos ciclos de transmissão do Trypanosoma cruzi em áreas de Cerrado e Mata Atlântica no Estado de Minas Gerais/ Brasil. Os municípios estudados foram Bambuí (Cerrado) e Piracema (Mata Atlântica). Foram realizadas coletas nos ambientes natural e artificial, com objetivo de identificar a dinâmica populacional, as fontes alimentares(FA) e os ecótopos naturais utilizados por P. megistus, bem como caracterizar a interrelação dos ciclos de transmissão do T. cruzi a partir dos reservatórios e vetores associados. As amostragens de campo foram realizadas em locais de maior presença do barbeiro e proximidade de áreas naturais. A partir dos dados avaliados foi observado o sucesso das atividades de controle vetorial, alcançadas em momentos diferentes em cada município. Através da análise por morfometria geométrica, foi possível identificar uma semelhança entre as populações doméstica e silvestre de P. megistus, sugerindo o ambiente natural como principal foco de infestação triatomínica nos municípios...

As análises de FA revelaram uma grande mobilidade da espécie no ambiente domiciliar, destacando as aves (49%) e os cães(22%) como principais recursos utilizados. A investigação do ambiente natural levou ao encontro do primeiro foco silvestre de P. megistus em Bambuí, após 69 anos de pesquisas, demonstrando a baixa densidade da espécie no meio silvestre. Foram identificados os gambás (Didelphis sp.) e os cães domésticos como principais reservatórios de T. cruzi nos ambientes natural e artificial, respectivamente. Os dados mostram que as infestações domiciliares por P. megistus, embora reduzidas,se mantêm permanentes na última década avaliada, mesmo com poucos focos silvestres, como detectado em Bambuí. Ficou evidenciado também a ocorrência de um progressivo declínio das densidades triatomínico-tripanossômicas nas áreas estudadas, o que se deve provavelmente à fatores relacionados com a permanente vigilância epidemiológica, à redução da população rural, a melhoria das habitações rurais e redução das áreas naturais associada à expansão agropecuária...

Dinâmica do Panstrongylus megistus nos ciclos de transmissão de Trypanosoma cruzi em áreas de cerrado e mata atlântica no estado de Minas Gerais, Brasil

O triatomíneo Panstrongylus megistus pode ser encontrado ao longo do Brasil em um diversificado número de hábitats, tanto silvestres como artificiais. Este trabalho teve como objetivo estudar a dinâmica populacional de P. megistus nos ciclos de transmissão do Trypanosoma cruzi em áreas de Cerrado e Mata Atlântica no Estado de Minas Gerais/ Brasil. Os municípios estudados foram Bambuí (Cerrado) e Piracema (Mata Atlântica). Foram realizadas coletas nos ambientes natural e artificial, com objetivo de identificar a dinâmica populacional, as fontes alimentares(FA) e os ecótopos naturais utilizados por P. megistus, bem como caracterizar a interrelação dos ciclos de transmissão do T. cruzi a partir dos reservatórios e vetores associados. As amostragens de campo foram realizadas em locais de maior presença do barbeiro e proximidade de áreas naturais. A partir dos dados avaliados foi observado o sucesso das atividades de controle vetorial, alcançadas em momentos diferentes em cada município. Através da análise por morfometria geométrica, foi possível identificar uma semelhança entre as populações doméstica e silvestre de P. megistus, sugerindo o ambiente natural como principal foco de infestação triatomínica nos municípios.

As análises de FA revelaram uma grande mobilidade da espécie no ambiente domiciliar, destacando as aves (49%) e os cães(22%) como principais recursos utilizados. A investigação do ambiente natural levou ao encontro do primeiro foco silvestre de P. megistus em Bambuí, após 69 anos de pesquisas, demonstrando a baixa densidade da espécie no meio silvestre. Foram identificados os gambás (Didelphis sp.) e os cães domésticos como principais reservatórios de T. cruzi nos ambientes natural e artificial, respectivamente. Os dados mostram que as infestações domiciliares por P. megistus, embora reduzidas,se mantêm permanentes na última década avaliada, mesmo com poucos focos silvestres, como detectado em Bambuí. Ficou evidenciado também a ocorrência de um progressivo declínio das densidades triatomínico-tripanossômicas nas áreas estudadas, o que se deve provavelmente à fatores relacionados com a permanente vigilância epidemiológica, à redução da população rural, a melhoria das habitações rurais e redução das áreas naturais associada à expansão agropecuária.

Análise da fonte alimentar de Panstrongylus megistus (Hemiptera, Reduviidae, Triatominae) e sua atual importância como vetor do Trypanosoma cruzi, no Estado de Minas Gerais / Analysis on the food source of Panstrongylus megistus (Hemiptera, Reduviidae, Triatominae) and its present importance as a vector for Trypanosoma cruzi, in the State of Minas Gerais

INTRODUÇÃO: A pesquisa da fonte alimentar dos triatomíneos auxilia no conhecimento sobre a biologia destes insetos, inclusive para inferir-se a importância dos mesmos como transmissores do Trypanosoma cruzi ao homem. MÉTODOS: O presente estudo objetivou registrar, através da reação de precipitina, a fonte alimentar de triatomíneos provenientes de 54 municípios da região centro-oeste de Minas Gerais, assim como a infecção natural destes para flagelados semelhantes ao Trypanosoma cruzi. RESULTADOS: De julho de 2003 até março de 2007, foram avaliados 416 insetos, todos da espécie Panstrongylus megistus. Somando-se as ocorrências, as aves (70 por cento) e os humanos (22,5 por cento) constituíram as principais fontes sanguíneas. Encontrou-se 16 (3,8 por cento) insetos positivos para flagelados semelhantes ao Trypanosoma cruzi sendo que oito realizaram hematofagia no homem. CONCLUSÕES: Os resultados demonstram necessidade de acentuar a vigilância entomológica na região, visto que foi detectada a possibilidade de ocorrência de novos casos da doença de Chagas através da transmissão vetorial.

INTRODUCTION: Investigation of the food source of triatomines helps in understanding the biology of these insects, and also helps to infer their importance in transmitting Trypanosoma cruzi to humans. METHODS: The present study aimed to use the precipitin reaction to record the food source of triatomines from 54 municipalities in the central-western region of the State of Minas Gerais, as well as their natural infection by flagellates similar to Trypanosoma cruzi. RESULTS: From July 2003 to March 2007, 416 insects were evaluated, all from the species Panstrongylus megistus. Among all these occurrences, birds (70 percent) and humans (22.5 percent) were the major blood sources. Sixteen (3.8 percent) of the insects were found to be positive for flagellates similar to Trypanosoma cruzi, and eight performed hematophagia on humans. CONCLUSIONS: The results show the need to increase the entomological surveillance in this region, given that the possibility of new cases of Chagas disease occurring through vector transmission was detected.

Entomological surveillance of Chagas disease in Berilo municipality, Jequitinhonha Valley, State of Minas Gerais, Brazil / Vigilância Entomológica da doença de Chagas no município de Berilo, Vale do Jequitinhonha, Estado de Minas Gerais, Brasil

This study aimed to evaluate the Chagas Disease Control Program which has operated since 1982 in the municipality of Berilo in the Jequitinhonha Valley, Minas Gerais, Brazil, based on evaluation of 5,242 domiciliary units (DUs) and 7,807 outbuildings over an eight-year period of epidemiological surveillance implanted in 1997. A total of 391 triatomines (280 Panstrongylus megistus and 111 Triatoma pseudomaculata) were captured, indicating the continued predominance of the former species. However, Triatoma pseudomaculata is clearly becoming more important in this region, with intradomiciliary colonies being detected in recent years. Entomological parameters, such as dispersion (17 percent) and intradomiciliary infestation (0.15 percent) indices, are compatible with the results of the epidemiological surveillance. The majority of DUs were of construction type A (plaster over bricks) or C (plaster over adobe). Twenty-five percent of the inhabitants of the DUs infested by triatomines were reactive in ELISA, IHA and IIF tests for Trypanosoma cruzi antigens.

O objetivo deste estudo foi avaliar o Programa de Controle de doença de Chagas instalado desde 1982 no município de Berilo, Vale do Jequitinhonha, MG, Brasil, baseado na avaliação de 5.242 unidades domiciliares e 7.807 anexos após oito anos de implantação da vigilância epidemiológica que ocorreu em 1997. Um total de 391 triatomíneos (280 Panstrongylus megistus e 111 Triatoma pseudomaculata) foram capturados, indicando o contínuo predomínio da primeira espécie. No entanto, Triatoma pseudomaculata está claramente se tornando mais importante nesta região, com colônias intradomiciliares sendo detectadas recentemente. Parâmetros entomológicos, como os índices de dispersão (17 por cento) e infestação intradomiciliar (0,15 por cento), são compatíveis com a fase de vigilância epidemiológica. A maioria das UDs apresenta padrão de construção tipo A (tijolo com reboco) e C (adobe com reboco). Dentre os habitantes das unidades domiciliares infestadas por triatomíneos, 25 por cento apresentavam testes reativos na ELISA, HAI e IFI para antígenos de Trypanosoma cruzi.

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.

Levantamento da fauna de Triatominae (Hemiptera: Reduviidae) em ambiente domiciliar e infecção natural por Trypanosomatidae no Estado de Mato Grosso do Sul / Survey of Triatominae (Hemiptera: Reduviidae) fauna in domestic environments and natural infection by Trypanosomatidae in the State of Mato Grosso do Sul

Entre 2000 a 2004, foi realizado levantamento da fauna de Triatominae (Hemiptera: Reduviidae) e exame de infecção natural por Trypanosomatidae, no Estado de Mato Grosso do Sul. Um total de 13.671 espécimes foram capturados. Na análise faunística das espécies capturadas, Triatoma sordida foi caracterizada como muito abundante, muito freqüente, constante e dominante. Os índices de infecção natural para Trypanosoma cruzi apresentaram os valores de 3,2 por cento para Panstrongylus geniculatus, 0,6 por cento para Rhodnius neglectus e 0,1 por cento para Triatoma sordida, apesar do Estado de Mato Grosso do Sul apresentar-se livre da transmissão vetorial endêmica.

Between 2000 and 2004, a survey of Triatominae fauna (Hemiptera: Reduviidae) and examination of natural infection caused by Trypanosomatidae in the State of Mato Grosso do Sul, Brazil, was conducted. A total of 13,671 specimens were collected. Through fauna analysis on the insects that were caught, Triatoma sordida was characterized as very abundant, very frequent, constant and dominant. The rates of natural infection with Trypanosoma cruzi were 3.2 percent for Panstrongylus geniculatus, 0.6 percent for Rhodnius neglectus and 0.1 percent for Triatoma sordida. Nevertheless, the State of Mato Grosso do Sul is free from endemic vector transmission.

Foco de doença de Chagas em São Fidélis, no estado do Rio de Janeiro / Focus of Chagas disease in São Fidélis, in the State of Rio de Janeiro

Foram capturados quatro exemplares de Triatoma vitticeps e um de Panstrongylus geniculatus, no intradomicílio, no município de São Fidélis, Rio de Janeiro. Ficou comprovado a infecção positiva para Trypanosoma cruzi num dos exemplares de Triatoma vitticeps. Dois moradores da residência, um adulto e uma adolescente apresentaram sorologia positiva.

Four specimens of Triatoma vitticeps and one of Panstrongylus geniculatus were caught inside a home in the municipality of São Fidélis, Rio de Janeiro. One of the specimens of Triatoma vitticeps proved positive for infection with Trypanosoma cruzi. Two people living in that home (one adult and one adolescent) presented positive serology.