Vulnerabilidade de municípios brasileiros para ocorrência de triatomíneos sinantrópicos baseada em indicadores sociais, demográficos, epidemiológicos, entomológicos e ambientais

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Medicina, Programa de Pós-Graduação em Medicina Tropical, 2013.Apesar da drástica redução da transmissão vetorial de Trypanosoma cruzi no Brasil, casos agudos da doença de Chagas (DC) ainda têm sido registrados. A identificação de áreas com maior vulnerabilidade para ocorrência de triatomíneos sinantrópicos é fundamental para orientar as ações de prevenção, controle e vigilância epidemiológica. Foi realizada uma classificação dos municípios brasileiros quanto a esta vulnerabilidade baseada em nove indicadores (socioeconômicos, demográficos, epidemiológicos, entomológicos e ambiental) usando análise multicritério de decisão (AMD) apoiada por modelagem de nicho ecológico (MNE). A MNE dos casos humanos estimou uma maior adequabilidade climática para transmissão vetorial na região Norte e Nordeste do país. Áreas climaticamente mais adequadas para presença dos triatomíneos foram detectadas na região extra-amazônica. Os modelos produzidos por meio da AMD foram muito diferentes; aqueles em que foi conferido maior peso aos indicadores demográficos e ambiental não mostraram um padrão de vulnerabilidade adequado comparando com municípios historicamente vulneráveis, diferente dos modelos baseados em dados entomológicos e socioeconômicos. Os municípios classificados com maior vulnerabilidade apresentaram maior pobreza extrema na zona rural e maior área antropizada. Os valores das variáveis demográficas foram similares entre os municípios de alta e baixa vulnerabilidade para ocorrência de triatomíneos. Os estados da região Nordeste, principalmente Ceará, e os estados de Goiás, Minas Gerais e Tocantins apresentaram maior porcentagem de municípios classificados com alta vulnerabilidade. A MNE e AMD podem auxiliar a identificar os estados e municípios mais vulneráveis para ocorrência de triatomíneos, o que é fundamental para direcionamento das ações de vigilância e controle em um cenário em que os dados entomológicos são cada vez mais escassos. Os dois novos indicadores entomológicos elaborados no presente trabalho (ocorrência real ponderada das espécies e ocorrência predita das espécies) poderão ser aplicados para aperfeiçoar a vigilância da doença de Chagas no Brasil e outros países.Despite the drastic reduction of the vectorial transmission of Trypanosoma cruzi in Brazil, acute cases of Chagas disease (CD) still have been recorded. The identification of areas with greater vulnerability for the occurrence of synanthropic triatomines is essential to orient prevention, control and surveillance activities. A classification of municipalities vulnerability for the occurrence of synanthropic triatomines was performed based on nine indicators (socioeconomic, demographic, epidemiological, entomological and environmental) using multi-criteria decision analysis (MCDA) supported by ecological niche modeling (ENM). The ENM of human cases estimated a higher climatic suitability for vector transmission in the North and Northeast regions of Brazil. The most climatically suitable areas for the presence of triatomines were detected in extra-Amazonian region. The models produced by MCAD were very different, and unlike the models based on entomological and socioeconomic data, those in which it was given a greater weight to demographic and environmental indicators did not show an appropriate pattern of vulnerability when compared to historically vulnerable municipalities. The municipalities classified with a high level of vulnerability for the occurrence of synanthropic triatomines were those with high levels of rural poverty and anthropized area. Municipalities with high and low levels of vulnerability for the occurrence of triatomines showed similar demographic variables values. The states of the Northeast region, especially Ceará, and the states of Goiás, Minas Gerais and Tocantins were prioritized to receive proper triatomine surveillance and control activities in Brazil for having the highest percentage of municipalities with high vulnerability. The ENM and MCDA can help to identify the states and municipalities most vulnerable for the occurrence of synanthropic triatomines, which is critical for directing adequate surveillance and control activities in a scenario where entomological data are increasingly scarce. The two new entomological indicators developed in this work (weighted actual occurrence of species and predicted occurrence of the species) may be applied to improve the surveillance of Chagas disease in Brazil and other countries

Evaluation of the impact of vector control programs through serological testing in Mambaí/Buritinópolis, Goiás State

Em 1999, realizamos a avaliação do impacto das medidas de controle vetorial sobre a transmissão da doença de Chagas nas áreas endêmicas Mambaí e Bruritinópolis (GO). Após o recenseamento populacional foram realizados os inquéritos entomológico das unidades domiciliares e sorológico da população. As amostras de sangue foram coletadas por punção digital, em papel de filtro. O teste sorológico utilizado inicialmente para detectar anticorpos contra Trypanosoma cruzi foi a reação de imunofluorescência indireta (IFI) quantitativa com ponto de corte a diluição 1/20 e, os reagentes realizaram a reação de hemaglutinação indireta (HAI). A prevalência da IFI reagente foi 12,3% (95% IC: 11,5-13,2%). Triatoma infestans não foi encontrado nas habitações. A ausência de infecção de indivíduos menores de 14 anos e a ausência de T. infestans no inquérito entomológico demonstra o sucesso do programa de controle da doença de Chagas nessas áreas, podendo ser considerada interrompida a transmissão vetorial.In 1999, we performed serological and entomological surveys to evaluate the impact of vectorial control measures against transmission of Chagas' disease in the endemic area of Mambaí and Buritinópolis (GO). A census was undertaken of the population, after which the entomological survey was performed regarding the dwelling units and serological evaluation of the human population. Blood samples were collected by digital puncture in filter paper. The first serologic test performed to detect antibodies against Trypanosoma cruzi was the indirect immunofluorescence test (IFI) with 1/20 positive dilution as cut-off point and, positive samples were further evaluated with indirect hemagglutination reaction (HAI). The prevalence of positive IFI reactions was 12.3% (95%CL: 11.5-13.2). Triatoma infestans was not found within the dwellings. The absence of infection among individuals younger than 14 years and, the absence of T. infestans during the last entomological survey demonstrates the success of the control program of Chagas' disease in the studied area where the vectorial transmission can be considered to have been interrupted

Avaliação do impacto das ações de controle químico e vigilância entomológica da doença de Chagas nos municípios de Mambaí e Buritinópolis, Estado de Goiás, Brasil

Em 1980, foram implantadas as atividades de vigilância epidemiológica em Mambaí/Buritinópolis (GO). Vinte anos após buscamos avaliar o impacto dessas ações sobre a transmissão da doença de Chagas, com base em indicadores entomológicos. A pesquisa entomológica foi feita, pela técnica hora-homem, alcançando todas as unidades domiciliares. Para o estudo de fontes alimentares foi analisado o conteúdo estomacal dos triatomíneos através da técnica de precipitinas modificada. Em 48 (71,6%) das 67 localidades comprovou-se a presença de triatomíneos. Os índices de infestação peridomiciliar em Mambaí correspondem a 8,7% e 12,1% em Buritinópolis e com taxas para o intradomicilio de 0,7% e 1,2% respectivamente. Triatoma sordida foi a espécie identificada em 97,3 % das capturas. Esta foi a única espécie que se comprovou naturalmente infectada pelo Trypanosoma cruzi. As aves constituíram-se na fonte alimentar mais freqüente (45%) do T. sordida. O resultado mais significativo foi a completa ausência de Triatoma infestans nos dois municípios.Epidemiological surveillance activities were implemented in 1980 in Mambaí and Buritinópolis counties, Goiás State. Twenty years later the authors evaluated the impact of these vector control measures on Chagas' disease transmission, based on entomological indicators. Entomological investigation was conducted using the man-hour technique and covering all domiciles. In order to study vector food sources the stomach contents of triatomines were analyzed using the modified precipitins technique. Triatomines were shown to be present in 48 (71.6%) of the 67 locations. Peridomiciliary infestation rates in Mambaí and Buritinópolis were 8.7% and 12.1%, respectively, while intradomiciliary rates were 0.7% and 1.2%. Triatoma sordida was the species identified in 97.3% of all captured specimens. It was also the only species found to be naturally infected with Trypanosoma cruzi. Birds were the most frequent food source (45%) for Triatoma sordida. The most significant result was the complete absence of Triatoma infestans in the two counties

Monitoring the Domiciliary and Peridomiciliary Invasion Process of Triatoma rubrovaria in the State of Rio Grande do Sul, Brazil

The presence of Triatoma rubrovaria in Brazil has only been confirmed in the States of Paran and Rio Grande do Sul (RS), where it is found naturally infected with Trypanosoma cruzi. In the wild environment it occurs in rocky habitats and has an eclectic diet, feeding from cockroaches, reptiles and mammals. Data from the Chagas Disease Control Program obtained by the Fundao Nacional de Sade, between 1975 and 1997, indicate a growing domiciliary and peridomiciliary invasion of T. rubrovaria in RS, where it has become the most frequently Triatominae species captured in this state since the control of Triatoma infestans. In order to monitor this process, we analyzed collection data derived from 22 years of control campaigns against T. infestans. Collection data for triatomines from domestic habitats show an inverse relationship, with high numbers of T. infestans and low numbers of T. rubrovaria during 1976-1987, compared to the following ten years, 1986-1997, when the number of T. infestans dropped drastically and that of T. rubrovaria increased. There are no consistent indications of intradomiciliary colonization by T. rubrovaria, since only low numbers of nymphs have been captured in the intradomiciliary ecotopes. Nevertheless, this species appears to have preadaptive characteristics for anthropic ecotopes, and should be kept under constant epidemiological surveillance

The epidemiologic importance of Triatoma brasiliensis as a Chagas disease vector in Brazil: a revision of domiciliary captures during 1993-1999

To clarify the epidemiologic importance of Triatoma brasiliensis , the most important Chagas disease vector in the Northeastern of Brazil, capture data related to this species, its distribution, capture index, and percentages of natural infection by Trypanosoma cruzi were examined in 12 different Brazilian states. The Brazilian National Health Foundation collected these data from 1993 to 1999, a period during which a total of 1,591,280 triatomines (21 species) were captured in domiciles within the geographic range of T. brasiliensis. Of this total, 422,965 (26.6%) were T. brasiliensis, 99.8% of which were collected in six states, and 54% in only one state (Ceará). The percentage of bugs infected with T. cruzi varied significantly among states, ranging from 0% (Goiás, Maranhão, Sergipe, and Tocantins) to more than 3% (Alagoas, Minas Gerais, and Rio Grande do Norte) with an average of 1.3%. This latter value represents a dramatic reduction in the natural infection percentages since 1983 (6.7%) suggesting that, despite the impossibility of eradicating this native species, the control measures have significantly reduced the risk of transmission. However, the wide geographic distribution of T. brasiliensis, its high incidence observed in some states, and its variable percentages of natural infection by T. cruzi indicate the need for sustained entomological surveillance and continuous control measures against this vector

The epidemiologic importance of Triatoma brasiliensis as a Chagas disease vector in Brazil: a revision of domiciliary captures during 1993-1999

To clarify the epidemiologic importance of Triatoma brasiliensis, the most important Chagas disease vector in the Northeastern of Brazil, capture data related to this species, its distribution, capture index, and percentages of natural infection by Trypanosoma cruzi were examined in 12 different Brazilian states. The Brazilian National Health Foundation collected these data from 1993 to 1999, a period during which a total of 1,591,280 triatomines (21 species) were captured in domiciles within the geographic range of T. brasiliensis. Of this total, 422,965 (26.6%) were T. brasiliensis, 99.8% of which were collected in six states, and 54% in only one state (Ceará). The percentage of bugs infected with T. cruzi varied significantly among states, ranging from 0% (Goiás, Maranhão, Sergipe, and Tocantins) to more than 3% (Alagoas, Minas Gerais, and Rio Grande do Norte) with an average of 1.3%. This latter value represents a dramatic reduction in the natural infection percentages since 1983 (6.7%) suggesting that, despite the impossibility of eradicating this native species, the control measures have significantly reduced the risk of transmission. However, the wide geographic distribution of T. brasiliensis, its high incidence observed in some states, and its variable percentages of natural infection by T. cruzi indicate the need for sustained entomological surveillance and continuous control measures against this vector

Avaliação do impacto das ações de controle vetorial da doença de Chagas através do inquérito sorológico em Mambaí/Buritinópolis, Goiás Evaluation of the impact of vector control programs through serological testing in Mambaí/Buritinópolis, Goiás State

Em 1999, realizamos a avaliação do impacto das medidas de controle vetorial sobre a transmissão da doença de Chagas nas áreas endêmicas Mambaí e Bruritinópolis (GO). Após o recenseamento populacional foram realizados os inquéritos entomológico das unidades domiciliares e sorológico da população. As amostras de sangue foram coletadas por punção digital, em papel de filtro. O teste sorológico utilizado inicialmente para detectar anticorpos contra Trypanosoma cruzi foi a reação de imunofluorescência indireta (IFI) quantitativa com ponto de corte a diluição 1/20 e, os reagentes realizaram a reação de hemaglutinação indireta (HAI). A prevalência da IFI reagente foi 12,3% (95% IC: 11,5-13,2%). Triatoma infestans não foi encontrado nas habitações. A ausência de infecção de indivíduos menores de 14 anos e a ausência de T. infestans no inquérito entomológico demonstra o sucesso do programa de controle da doença de Chagas nessas áreas, podendo ser considerada interrompida a transmissão vetorial.<br>In 1999, we performed serological and entomological surveys to evaluate the impact of vectorial control measures against transmission of Chagas' disease in the endemic area of Mambaí and Buritinópolis (GO). A census was undertaken of the population, after which the entomological survey was performed regarding the dwelling units and serological evaluation of the human population. Blood samples were collected by digital puncture in filter paper. The first serologic test performed to detect antibodies against Trypanosoma cruzi was the indirect immunofluorescence test (IFI) with 1/20 positive dilution as cut-off point and, positive samples were further evaluated with indirect hemagglutination reaction (HAI). The prevalence of positive IFI reactions was 12.3% (95%CL: 11.5-13.2). Triatoma infestans was not found within the dwellings. The absence of infection among individuals younger than 14 years and, the absence of T. infestans during the last entomological survey demonstrates the success of the control program of Chagas' disease in the studied area where the vectorial transmission can be considered to have been interrupted