Vigilância à saúde da doença de Chagas em municípios endêmicos de Minas Gerais: percepção e conhecimento de profissionais da vigilância entomológica / Health surveillance of Chagas disease in endemic municipalities of Minas Gerais state, Brazil: perception and knowledge of Entomological Surveillance professionals

Resumo Objetivo Traçar o perfil sociodemográfico dos agentes de combate a endemias (ACEs) dos municípios que compõem a microrregional de saúde de Itaúna, Minas Gerais; e apreender a percepção dos profissionais da vigilância entomológica sobre a doença de Chagas e serviços de saúde. Metodologia Aplicou-se um questionário semiestruturado aos ACEs e foi realizado um grupo focal com os coordenadores de endemias e digitadores. Resultados Dentre os ACEs, a maioria era do sexo feminino, entre 21 e 40 anos, com ensino médio, possuindo contrato de trabalho temporário há menos de 5 anos. Foi possível apreender: as más condições de trabalho dos ACEs, destacando-se a alta rotatividade e defasagem salarial; ausência de ações de promoção à saúde relacionadas à doença de Chagas; desarticulação entre a Atenção Primária à Saúde (APS) e Vigilância à Saúde (VS); e críticas às ações de controle da doença pós-processo de descentralização da saúde. Conclusões Há urgência na concretização da legislação inerente à natureza trabalhista e às condições de trabalho dos ACEs, bem como ao planejamento conjunto das ações de APS e VS, garantindo a atenção integral por meio de ações de promoção à saúde voltadas à população, focando especialmente a doença de Chagas, consolidando o SUS.

Abstract Objective To trace the sociodemographic profile of endemic disease combat agents (ACEs) in the municipalities that make up the health microregion of Itaúna, Minas Gerais; and apprehend the perception of entomological surveillance professionals about Chagas disease and health services. Methodology A semi-structured questionnaire was applied to the ACEs and a focus group was held with coordinators of endemic diseases and typists. Results Among the ACEs, the majority were female, between 21 and 40 years old, with high school education, with a temporary work contract for less than 5 years. It was possible to apprehend: the poor working conditions of the ACEs, highlighting the high turnover and wage gap; absence of health promotion actions related to Chagas disease; disarticulation between Primary Health Care (PHC) and Health Surveillance (HS); and criticism of disease control actions after the health decentralization process. Conclusions There is an urgent need to implement the legislation inherent to the labor nature and working conditions of the ACEs, as well as the joint planning of PHC and SV actions, guaranteeing comprehensive care through health promotion actions aimed at the population, focusing especially on Chagas disease, consolidating the SUS.

Moradores de áreas rurais de municípios mineiros endêmicos para a doença de Chagas: ideias e concepções sobre a doença, os vetores e os serviços de saúde / Residents of rural areas in municipalities of Minas Gerais endemic for Chagas disease: their ideas and conceptions about the disease, vector, and health services

Resumo Introdução A vigilância da doença de Chagas (DC), baseada na participação popular, ocorre por meio da detecção e notificação de insetos suspeitos de serem vetores da DC aos Postos de Informação de Triatomíneos (PITs). Objetivo Compreender as ideias e concepções dos moradores em áreas rurais dos municípios da Microrregião de Saúde de Itaúna (MSI) em relação a aspectos relacionados à DC, seus vetores e serviços de saúde. Método Em 2016, foram realizados quatro grupos focais nos municípios da MSI. Esses grupos focais foram gravados, transcritos e analisados utilizando a técnica de análise de conteúdo. Neste processo, identificamos e categorizamos unidades de análise tanto dentro de cada grupo focal quanto entre eles. Resultados Descobrimos que há compreensão por parte de alguns moradores sobre a natureza da transmissão da DC, as características morfológicas e hábitos dos vetores, o encaminhamento do vetor para os PITs e o diagnóstico da DC. Também encontramos relatos da ausência de intervenções educacionais e de saúde relacionadas à DC. Conclusão Compreender as concepções e ideias sobre a DC das populações em áreas endêmicas é fundamental para desenvolver futuras estratégias envolvendo a participação popular.

Abstract Background The surveillance of Chagas disease (CD) based on public participation is carried out through the detection and notification of insects suspected of being vectors of CD to Triatomine Information Posts (TIPs). Objective To understand the ideas and conceptions of residents in rural areas of the municipalities of the Micro-region of Health de Itaúna (MHI) regarding aspects related to CD, its vectors, and health services. Method In 2016, four focus groups were conducted in the municipalities of MHI. These focus groups were recorded, transcribed, and analyzed using the content analysis technique. In this process, units of analysis, both within each focus group and between them, were identified and categorized. Results It was found that some residents have a good understanding of the nature of CD transmission and of the morphological characteristics and habits of the vectors, in addition to an understanding of the forwarding of the vector to TIPs, and the diagnosis of CD. Reports of the absence of education and health interventions related to CD were also found. Conclusion Understanding the conceptions and ideas about CD of populations in endemic areas is fundamental to developing future strategies involving public participation.

Conhecimentos sobre a doença de Chagas entre escolares de dois municípios de Minas Gerais, Brasil / Knowledge about Chagas disease among schoolchildren from two municipalities of Minas Gerais, Brazil

Resumo Introdução: No Brasil, a vigilância entomológica da doença de Chagas (DCh) é respaldada na participação comunitária, que notifica a presença dos vetores nas habitações. Assim, a sustentabilidade desta medida de controle depende do conhecimento da população sobre os vetores. Objetivo: Avaliar o conhecimento de escolares sobre a doença de Chagas nos municípios mineiros de Itatiaiuçu (vigilância ativa) e Sabará (vigilância inativa). Método: Questionário semiestruturado foi aplicado para alunos matriculados no ensino médio em duas escolas de Sabará (rural e urbana) e uma em Itatiaiuçu (urbana). Resultados: Em geral, os alunos residentes em Sabará demonstraram conhecimento limitado acerca dos vetores, patógeno, transmissão e doença (sem diferenças relevantes quanto à localização entre área urbana e rural), quando comparados aos residentes em Itatiaiuçu, que apesar de ter uma vigilância mais atuante, também não apresentaram conhecimento totalmente satisfatório. Conclusões: Os resultados enfatizam a carência de informações sobre a DCh tanto em relação ao conhecimento acadêmico quanto às campanhas de educação firmadas pelo programa. Ações educativas para sensibilizar a comunidade e promover o conhecimento sobre esta doença mostram-se necessárias e fundamentais para a manutenção da vigilância ao longo do tempo e espaço.

Abstract Background: In Brazil, entomological surveillance of Chagas disease (ChD) is based on community participation, which notifies the presence of vectors inside their homes. Thus, the sustainability of this control measure depends on the knowledge of the population about the vectors. Objective: To evaluate the knowledge of schoolchildren about ChD in the municipalities of Itatiaiuçu (active surveillance) and Sabará (inactive surveillance). Method: A semi-structured questionnaire was given to students enrolled in two high schools in Sabará (rural and urban) and one in Itatiaiuçu (urban). Results: In general, students living in Sabará demonstrated only limited knowledge about vectors, pathogens, transmission, and disease (with no significant differences between the schools in urban and rural areas). Similarly, the schoolchildren in Itatiaiuçu, despite living in an area of active surveillance, also did not have a fully satisfactory knowledge of ChD. Conclusions: The results emphasize the lack of information about ChD, both in relation to academic knowledge and the education campaigns established by the program. Improvements in educational interventions to raise community awareness and promote knowledge about ChD are necessary and vital for maintaining vigilance against ChD over space and time.

Entomological surveillance of Chagas disease in the East of Minas Gerais region, Brazil

ABSTRACT Background: After decentralizing the actions of the Chagas Disease Control Program (CDCP) in Brazil, municipalities were now responsible for control measures against this endemic, supervised by the Regional Health Superintendencies (RHS). We aimed to evaluate the recent entomological surveillance of Chagas disease in the Regional Health Superintendence of Governador Valadares (RHS/GV) from 2014 to 2019. Methods: Triatomines captured by residents during entomological surveillance were sent to the reference laboratory, where the species and evolutionary stages were identified, place of capture, and presence of Trypanosoma cruzi. A database was created, and the following were calculated: the rate of infection by T. cruzi (overall rate and rate by species), monthly seasonality, spatial distribution of species, number of captures, and infected triatomines/health microregions. Results: We identified 1,708 insects; 1,506 (88.2%) were triatomines, most were adult instars (n=1,469), and few were nymphs (n=37). The identified species were Triatoma vitticeps, Panstrongylus megistus, Panstrongylus diasi, Rhodnius neglectus, and Panstrongylus geniculatus. The first three were most frequently captured and distributed throughout the study area. Most bugs were captured intradomicile (72.5%), mainly in the second semester, between September and November, with an average infection rate of 41.5% (predominantly T. vitticeps, 49.2%). All municipalities sent triatomines, especially in the microregions of Governador Valadares. Conclusions: These data reinforce the need and importance of improving Chagas disease control measures in the region to establish active and participatory entomological surveillance.

Chagas disease in the context of the 2030 agenda: global warming and vectors

The 2030 Agenda for Sustainable Development is a plan of action for people, planet and prosperity. Thousands of years and centuries of colonisation have passed the precarious housing conditions, food insecurity, lack of sanitation, the limitation of surveillance, health care programs and climate change. Chagas disease continues to be a public health problem. The control programs have been successful in many countries in reducing transmission by T. cruzi; but the results have been variable. WHO makes recommendations for prevention and control with the aim of eliminating Chagas disease as a public health problem. Climate change, deforestation, migration, urbanisation, sylvatic vectors and oral transmission require integrating the economic, social, and environmental dimensions of sustainable development, as well as the links within and between objectives and sectors. While the environment scenarios change around the world, native vector species pose a significant public health threat. The man-made atmosphere change is related to the increase of triatomines' dispersal range, or an increase of the mobility of the vectors from their sylvatic environment to man-made constructions, or humans getting into sylvatic scenarios, leading to an increase of Chagas disease infection. Innovations with the communities and collaborations among municipalities, International cooperation agencies, local governmental agencies, academic partners, developmental agencies, or environmental institutions may present promising solutions, but sustained partnerships, long-term commitment, and strong regional leadership are required. A new world has just opened up for the renewal of surveillance practices, but the lessons learned in the past should be the basis for solutions in the future.

Different profiles and epidemiological scenarios: past, present and future

The multiplicity of epidemiological scenarios shown by Chagas Disease, derived from multiple transmission routes of the aetiological agent, occurring on multiple geo-ecobiosocial settings determines the complexity of the disease and reveal the difficulties for its control. From the first description of the link between the parasite, the vector and its domestic habitat and the disease that Carlos Chagas made in 1909, the epidemiological scenarios of the American Trypanosomiasis has shown a dynamic increasing complexity. These scenarios changed with time and geography because of new understandings of the disease from multiple studies, because of policies change at the national and international levels and because human movements brought the parasite and vectors to new geographies. Paradigms that seemed solid at a time were broken down, and we learnt about the global dispersion of Trypanosoma cruzi infection, the multiplicity of transmission routes, that the infection can be cured, and that triatomines are not only a health threat in Latin America. We consider the multiple epidemiological scenarios through the different T. cruzi transmission routes, with or without the participation of a Triatominae vector. We then consider the scenario of regions with vectors without the parasite, to finish with the consideration of future prospects.

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.

Occurrence of Panstrongylus megistus (Burmeister, 1835) in an area under entomological surveillance in the Southeast Region of Brazil

Abstract INTRODUCTION: Panstrongylus megistus is the main triatomine involved in the human transmission of Trypanosoma cruzi in Minas Gerais, Brazil. We analyzed the occurrence of triatomines in the Itaúna micro-regions for healthcare. METHODS: Data were collected as part of routine entomological surveillance activities, including the species identity, capture site, developmental stage, and trypanosome infection. RESULTS: In total, 503 specimens from five species were captured (495 P. megistus). Adults were mainly captured by residents inside their homes, whereas nymphs were mostly captured by public health professionals outside. CONCLUSIONS: The epidemiologically important triatomine, P. megistus, continues to persist in our study region.

Evaluation of the insecticide susceptibility profile in Cimex lectularius (Hemiptera: Cimicidae) in Belo Horizonte (Brazil)

Abstract INTRODUCTION: Since 2013, major Cimex lectularius infestations have been detected in public shelters in Belo Horizonte (Brazil). Due to this, insecticide resistance has been investigated as one of the possible causes for the failure to control bedbugs. METHODS: Cimicids were subjected to bioassays according to the World Health Organization recommendations using deltamethrin and all commercial insecticides available for control of Cimex in Brazil. RESULTS: Cimicids were deltamethrin resistant and presented indicative of resistance to other insecticides, except for propoxur 1%. CONCLUSIONS: The commercial insecticides have a limited effect on bedbug populations, which may justify the unsatisfactory control observed in the shelters studied.

Agentes comunitários de saúde: percepção sobre os serviços de saúde relacionados à doença de Chagas / Community health agents: perception about health services related to Chagas' disease

Resumo Introdução A doença de Chagas ainda é um importante problema de saúde pública na América Latina, apresentando alta prevalência, ampla distribuição geográfica e grande impacto social. Vários serviços relacionados à doença de Chagas são solucionados na Atenção Primária à Saúde (APS). Na Estratégia Saúde da Família (ESF), destaca-se o agente comunitário de saúde (ACS), profissional responsável pela mediação entre a comunidade e as unidades básicas de saúde (UBS). Objetivo Apreender a percepção dos coordenadores da ESF e dos ACSs sobre o conhecimento a respeito da doença de Chagas e dos serviços de saúde relacionados nos municípios da microrregional de saúde de Itaúna, em Minas Gerais, Brasil. Método Foram aplicados questionários semiestruturados aos ACSs e realizados grupos focais com os coordenadores da ESF. Resultados Foi observado que, entre os profissionais, há ausência de informações básicas relacionadas à doença de Chagas; inexiste um protocolo/fluxograma de serviço; há uma ineficiência dos serviços de referência e contrarreferência; ocorre precariedade nas condições de trabalho; há ausência de capacitação dos profissionais e de ações de promoção à saúde nos municípios. Conclusão Este é o primeiro estudo abordando esta temática: percepção dos ACSs sobre a doença de Chagas e seus serviços. Sugere-se a extensão deste estudo a outras regiões do Brasil.

Abstract Background Chagas disease is still an important public health issue in Latin America, presenting high prevalence, broad geographical distribution and great social impact. Several services related to Chagas disease are solved in Primary Health Care (PHC). In the Family Health Strategy (FHS) it is highlighted the Community Health Agent (CHA), professional responsible for mediating between the community and units basics of health (UBH). Objective To raise the perception of the coordinators of the FHS and the CHAs about the knowledge on Chagas disease and related health services in the municipalities of the micro-regional health of Itaúna, Minas Gerais, Brazil. Method Semi-structured questionnaires were applied to the CHAs and focus groups were carried out with coordinators of the FHSs. Result It was observed that among professionals there is no basic information related to Chagas' disease; the lack of a service protocol/flowchart was noticed; inefficiency of reference and counter/reference services; precariousness in working conditions and training of professionals and absence of health promotion actions in municipalities. Conclusion This is the first study addressing this theme: perception of professionals about Chagas disease and its services. It is suggested that this study be extended to other regions of Brazil.

Synanthropic triatomines (hemiptera: reduviidae): infestation, colonization, and natural infection by trypanosomatids in the state of Rio Grande do Norte, Brazil

Abstract INTRODUCTION The ecoepidemiological situation in the State of Rio Grande do Norte, Brazil is characterized by frequent invasion and colonization of domiciliary units (DUs) by several triatomine species, with high rates of natural infection by Trypanosoma cruzi. METHODS: We evaluated the possibility of vector transmission of T. cruzi based on records of the occurrence of domiciled triatomines collected by the Secretariat of State for Public Health from 2005 to 2015. During this period, 67.7% (113/167) of municipalities conducted at least one active search and 110 recorded the presence of insects in DUs. These activities were more frequent in municipalities considered to have a high and medium-level risk of T. cruzi transmission. RESULTS Of 51,569 captured triatomines, the most common species were Triatoma brasiliensis (47.2%) and T. pseudomaculata (40.2%). Colonies of T. brasiliensis, T. pseudomaculata, T. petrocchiae, Panstrongylus lutzi, and Rhodnius nasutus were also recorded in the intradomicile and peridomicile. Natural infection by trypanosomatids was detected in 1,153 specimens; the highest rate was found in R. nasutus (3.5%), followed by T. brasiliensis (2.5%) and T. pseudomaculata (2.4%). There have been high levels of colonization over the years; however, not all infested DUs have been sprayed. CONCLUSIONS: This is the first report of intradomicile and peridomicile colonization by P. lutzi. These results demonstrate the risk of new cases of infection by T. cruzi and reinforce the need for continuous entomological surveillance in the State of Rio Grande do Norte.

Description of an amazing nest of Caatinga Cachalote Pseudoseisura cristata infested by Psammolestes tertius in Tauá, state of Ceará, Northeastern Brazil

Psammolestes tertius Lent & Jurberg 1965 is a triatomine species part of the tribe Rhodniini. It is only wild and found in bird nests, mostly of the Furnariidae family. This work describes the amazing infestation of a nest of Pseudoseisura cristata in the municipality of Taua, Ceará. The nest harbored a colony with about 40 specimens of P. tertius in all evolutionary stages, all negative for trypanosomatids. A rodent of the species Wiedomys pyrrhorhinos was seen running away from the nest. The materials used to build the nest included the typical natural wigs, and various anthropogenic materials such as razor blades, shaver, fork, sunglasses, metal fragments, fragments of plastic objects, wire, barbed wire, plastic sandal straps, paper, plastic lid, pieces of plastic bags, gas cylinder label, large feathers and the exuviae of a snake.

Chagas disease ecoepidemiology and environmental changes in northern Minas Gerais state, Brazil

BACKGROUND Triatoma sordida and Triatoma pseudomaculata are frequently captured triatomine species in the Brazilian savannah and caatinga biomes, respectively, and in Brazilian domiciles. OBJECTIVES This study identified eco-epidemiological changes in Chagas disease in northern Minas Gerais state, Brazil, and considered the influence of environmental shifts and both natural and anthropogenic effects. METHODS Domicile infestation and Trypanosoma cruzi infection rates were obtained from triatomines and sylvatic reservoirs during the following two time periods: the 1980s and 2007/2008. Entomological and climatic data with land cover classification derived from satellite imagery were integrated into a geographic information system (GIS), which was applied for atmospheric correction, segmentation, image classification, and mapping and to analyse data obtained in the field. Climatic data were analysed and compared to land cover classifications. RESULTS A comparison of current data with data obtained in the 1980's showed that T. sordida colonised domiciliary areas in both periods, and that T. pseudomaculata did not colonise these areas. There was a tendency toward a reduction in T. cruzi infection rates in sylvatic reservoirs, and of triatomines captured in both households and in the sylvatic environment. T. sordida populations have reduced in the sylvatic environment, while T. pseudomaculata showed an expanding trend in the region compared to counts observed in the 1980's in the sylvatic environment. This may be related to high deforestation rates as well as gradual increases in land surface temperature (LST) and temperatures along the years. MAIN CONCLUSIONS Our results suggest a geographical expansion of species into new biomes as a result of anthropogenic and climatic changes that directly interfere with the reproductive and infection processes of vectors.

Fortalecimento da vigilância em saúde no Brasil: Rede de Monitoramento da Resistência dos Triatomíneos aos Inseticidas / Strengthening of health surveillance in Brazil: Monitoring network of the insecticide resistance in Triatominae

Em 2010 foi criada no Brasil, pelo Ministério da Saúde e pelo Laboratório de Referência em Triatomíneos e Epidemiologia da Doença de Chagas da Fundação Oswaldo Cruz a "Rede de Monitoramento da Resistência de Triatomíneos aos Inseticidas" com vistas a: 1) caracterizar e monitorar a suscetibilidade/resistência das populações triatomínicas brasileiras aos inseticidas, 2) desenvolver métodos destinados ao diagnóstico da resistência dos triatomíneos aos inseticidas e 3) contribuir na avaliação e melhoria das atividades desenvolvidas junto ao controle químico dos triatomíneos. A implantação desta iniciativa, que possui hoje reconhecimento internacional junto a Organização Mundial de Saúde, está apresentada neste trabalho de forma detalhada.

Conhecimentos sobre triatomíneos e sobre a doença de Chagas em localidades com diferentes níveis de infestação vetorial / Knowledge of triatomine insects and of the Chagas disease among people from localities which have different levels of vector infestations

Resumo A participação comunitária é a principal estratégia para a manutenção da vigilância entomológica da doença de Chagas. O objetivo deste estudo foi avaliar conhecimentos sobre triatomíneos e a doença de Chagas entre moradores de oito localidades de Diamantina, Minas Gerais, atentando a uma eventual relação entre os conhecimentos e a infestação vetorial. Para avaliação dos conhecimentos foi aplicado questionário com questões fechadas e abertas a 583 moradores com idade igual ou superior a dez anos e, para avaliar a capacidade de reconhecimento de triatomíneos, foi apresentado mostruário com insetos. As respostas às questões fechadas foram analisadas quanto à frequência e associação com a infestação triatomínica. As respostas às questões abertas foram organizadas em eixos temáticos e analisadas descritivamente. Embora a capacidade de reconhecer os triatomíneos não tenha sido associada à infestação das localidades, os residentes em áreas com maior infestação demonstraram conhecer melhor os serviços de referência e a necessidade de encaminhar os insetos a estes. Não foi observada associação entre a infestação triatomínica e os conhecimentos sobre a doença de Chagas. Os resultados ora apresentados podem orientar ações de educação em saúde voltadas para a participação da comunidade na notificação de triatomíneos.

Abstract Community participation is the main strategy to sustainability of Chagas disease entomological surveillance. The purpose of this study was to evaluate the level of knowledge on triatomine insects and Chagas disease among the residents from eight localities of Diamantina, in Minas Gerais, with a view to observing any associations between their knowledge and infestations by triatomines. In order to evaluate this knowledge, questionnaires were used containing both closed and open questions. They were applied to 583 residents who were ten years old or over. To establish if they could recognize the triatomine insect, they were given samples to look at. The responses to the closed questions were analyzed with reference to any frequencies of and associations with infestations involving this insect. The responses to the questions were organized into different thematic areas and were descriptively analyzed. Although the resident’s ability to recognize the triatomine insect was not associated with the infestation of the localities, the residents in the areas that had higher infestations showed that they had a good knowledge of the available support services and the need to send the insects to them. We did not observe any associations between triatomine infestations and knowledge of Chagas disease. The results of this study can provide guidance on education that can be given by the health services to the community in order to encourage them to provide notifications of the triatomine insects.

Assessing the mitochondrial DNA diversity of the Chagas disease vector Triatoma sordida (Hemiptera: Reduviidae)

Triatoma sordida is a species that transmits Trypanosoma cruzi to humans. In Brazil, T. sordida currently deserves special attention because of its wide distribution, tendency to invade domestic environments and vectorial competence. For the planning and execution of control protocols to be effective against Triatominae, they must consider its population structure. In this context, this study aimed to characterise the genetic variability of T. sordida populations collected in areas with persistent infestations from Minas Gerais, Brazil. Levels of genetic variation and population structure were determined in peridomestic T. sordida by sequencing a polymorphic region of the mitochondrial cytochrome b gene. Low nucleotide and haplotype diversity were observed for all 14 sampled areas; π values ranged from 0.002-0.006. Most obtained haplotypes occurred at low frequencies, and some were exclusive to only one of the studied populations. Interpopulation genetic diversity analysis revealed strong genetic structuring. Furthermore, the genetic variability of Brazilian populations is small compared to that of Argentinean and Bolivian specimens. The possible factors related to the reduced genetic variability and strong genetic structuring obtained for studied populations are discussed in this paper.

Spatial distribution of triatomines in domiciles of an urban area of the Brazilian Southeast Region

Reports of triatomine infestation in urban areas have increased. We analysed the spatial distribution of infestation by triatomines in the urban area of Diamantina, in the state of Minas Gerais, Brazil. Triatomines were obtained by community-based entomological surveillance. Spatial patterns of infestation were analysed by Ripley’s K function and Kernel density estimator. Normalised difference vegetation index (NDVI) and land cover derived from satellite imagery were compared between infested and uninfested areas. A total of 140 adults of four species were captured (100 Triatoma vitticeps, 25Panstrongylus geniculatus, 8 Panstrongylus megistus, and 7 Triatoma arthurneivai specimens). In total, 87.9% were captured within domiciles. Infection by trypanosomes was observed in 19.6% of 107 examined insects. The spatial distributions ofT. vitticeps, P. geniculatus, T. arthurneivai, and trypanosome-positive triatomines were clustered, occurring mainly in peripheral areas. NDVI values were statistically higher in areas infested by T. vitticeps and P. geniculatus. Buildings infested by these species were located closer to open fields, whereas infestations of P. megistus andT. arthurneivai were closer to bare soil. Human occupation and modification of natural areas may be involved in triatomine invasion, exposing the population to these vectors.

Thermal preferences and limits of Triatoma brasiliensis in its natural environment - Field observations while host searching

The goal of this work was to explore the thermal relationship between foraging Triatoma brasiliensis and its natural habitat during the hottest season in the state of Ceará, Brazil. The thermal profiles were determined using infrared analysis. Although the daily temperature of rock surfaces varied in a wide range, T. brasiliensisselected to walk through areas with temperatures between 31.7-40.5ºC. The temperature of T. brasiliensisbody surface ranged from 32.8-34.4ºC, being higher in legs than the abdomen. A strong relationship was found between the temperature of the insect and the temperature of rock crevices where they were hidden (r: 0.96, p < 0.05). The species was active at full sunlight being a clear example of how the light-dark rhythm may be altered, even under predation risk. Our results strongly suggest a thermal borderline for T. brasiliensisforaging activity near 40ºC. The simultaneous determination of insect body and rock temperatures here presented are the only obtained in natural habitats for this or other triatomines.

Variability of susceptibility to deltamethrin in peridomestic Triatoma sordida from Triângulo Mineiro, State of Minas Gerais, Brazil

Despite chemical and physical vector control strategies, persistent infestations of Triatoma sordida have been reported in a large part of Minas Gerais, Brazil, and the cause for this is little investigated. We aimed to characterize the deltamethrin toxicological profile in peridomestic T. sordidapopulations from Triângulo Mineiro area of Minas Gerais.