Chagas disease in the Brazilian Amazon: IV. a new cross-sectional study

Coura, José Rodrigues; Junqueira, Ângela Cristina Veríssimo; Bóia, Márcio Neves; Fernandes, Octávio; Bonfante, C Rodríguez; Campos, José Eduardo; Santos, Lucilaide; Devera, Rodolfo

doi:10.1590/s0036-46652002000300009

Cited by 36 publications

(45 citation statements)

References 35 publications

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“…The numbers of blood samples collected on filter paper, along with the percentage of positivity for T. cruzi infection, varied according to the number of people living in the area and their degree of exposure to infection in rural areas, especially in relation to piassava harvesters and their families. This characteristic has already been presented in previous studies by our group ( Coura et al 1995a , b , 2002a , b , 1999 , Albajar et al 2003 a, b, Junqueira et al 2005 , Xavier et al 2006 , Brum-Soares et al 2010 , Coura & Junqueira 2012 , Junqueira et al 2013 ).…”

Section: Resultssupporting

confidence: 83%

“…Previously, between 1991-1997, we conducted three serological surveys of human Trypanosoma cruzi infection in the main settlement of the municipality of Barcelos, in the Rio Negro microregion, state of Amazonas (AM) ( Coura et al 1995a , b , 1999 , 2002a , b ). In the first serological survey (1991), in which 710 indirect immunofluorescence (IIF) tests were performed on blood collected on filter paper, 89 (12.5%) were positive.…”

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confidence: 99%

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A new survey of the serology of human Trypanosoma cruziinfection in the Rio Negro microregion, Brazilian Amazon: a critical analysis

Coura

Marquez

Guerra

et al. 2013

Mem. Inst. Oswaldo Cruz

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The serology of human Trypanosoma cruzi infection in the Rio Negro microregion is very complex because of the large numbers of false-positive cases that result from low antibody titres and cross-reactions with other infections. In the present study, we collected 4,880 blood samples on filter paper; of these, indirect immunofluorescence (IIF) was strongly reactive in 221 (4.5%), which were considered to be positive (IIF strongly reactive; high intensity of fluorescence) and weakly reactive in 302 (6.2%), which were considered to be doubtful (IIF weakly reactive; low intensity of fluorescence). The confirmatory test on the serum using at least two of three techniques (IIF, conventional ELISA and recombinant ELISA) on 137 samples that were positive in the screening test only confirmed 33 cases (24.1%). Of the 178 samples that were considered doubtful in the screening test, only 10 (5.6%) were considered to be positive in the confirmatory test. Finally, we recommend that the serological diagnosis of T. cruzi infection in the Amazon region be made using at least two different techniques, for example immunofluorescence and ELISA and confirmed by Western blot analysis when possible.

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Section: Resultssupporting

confidence: 83%

mentioning

confidence: 99%

A new survey of the serology of human Trypanosoma cruziinfection in the Rio Negro microregion, Brazilian Amazon: a critical analysis

Coura

Marquez

Guerra

et al. 2013

Mem. Inst. Oswaldo Cruz

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“…According to the work carried out by Martins et al 22 , R. robustus shows a considerable susceptibility to some T. cruzi strains, and, therefore, it is quite possible that part of the triatomines found positive in this study may be infected by T. cruzi.…”

Section: Discussionmentioning

confidence: 60%

Study on Chagas disease occurrence in the municipality of Monte Negro, State of Rondônia, Brazilian Amazon

Carvalho

Rosa

Carvalho

et al. 2011

Rev. Soc. Bras. Med. Trop.

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Introduction: Studies on Chagas disease deal with the perspective of its occurrence in the Amazon region, which is directly correlated to the population growth and the spread of the bug biotope. The state of Rondônia has an immense source of vectors (Triatomine) and reservoirs of Trypanosoma cruzi. Environmental changes brought forth by the deforestation in the region may cause vector behavior changes and bring these vectors to a closer contact with humans, increasing the probability of vector infection. Methods: This study was carried out to check the occurrence of Chagas disease in the municipality of Monte Negro, Rondônia, Brazil, based on a random sampling of the farms and people wherein blood collection from the population and capturing triatomines were done. The blood samples were submitted to serologic tests to detect antibodies of the IgG class against T. cruzi. The triatomines that were collected had their digestive tract checked for the presence of trypanosomatidae with morphology resembling that of the T. cruzi. Results: The population examined was mostly from other states. From the 322 bugs examined on the microscope, 50% showed parasites with morphology compatible with T. cruzi. From the serology of 344 random samples of human blood, 1.2% was found positive, 6% showed inconclusive results, and 92.8% were negative. Conclusions: Monte Negro shows low prevalence of human infection by T. cruzi and none active vector transmission; however, preventive and surveying measures, which are not performed until now, shall be taken due to the abundance of vectors infected by trypanosomatidae. Keywords: Chagas disease. Amazon. Trypanosoma cruzi. Triatomines. RESUMO Introdução:Estudos anteriores sobre doença de Chagas tratam da perspectiva da ocorrência endêmica da parasitose na região Amazônica, que se correlaciona diretamente com o aumento populacional e a invasão do ecótopo pelos triatomíneos. O Estado de Rondônia possui um imenso manancial de vetores e reservatórios de Trypanosoma cruzi. As modificações ambientais ocasionadas pelo desmatamento na região podem gerar mudanças nos hábitos dos vetores, trazendo-os para um contato mais próximo do homem, aumentando as possibilidades de infecção vetorial. Métodos: Este estudo foi realizado para verificar a ocorrência da doença de Chagas em Monte Negro, Rondônia, equivalente à amostragem aleatória das propriedades rurais e de pessoas residentes no município, onde foram realizadas coletas sanguíneas dos moradores e coleta de triatomíneos. As amostras sanguíneas foram submetidas a testes sorológicos para detecção de anticorpos da classe IgG contra T. cruzi e os triatomíneos coletados foram analisados para verificar a presença de tripanosomatídeos em seu trato digestivo. Resultados: A população estudada, randomicamente selecionada, é em sua maioria advinda de outros estados. Dos 322 barbeiros avaliados microscopicamente, 50% apresentavam flagelados com morfologia compatível com Trypanosoma cruzi. A sorologia das 344 amostras de sangue humano coletadas randomicame...

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“…However, there were records of 6.8% and 4.6% prevalence in Barcelos and Novo Airão, respectively 6,16 . Regardless of such numbers, the infection dynamics has not been well established yet, as there are no records of the domiciliation of vectors.…”

Section: Article/artigomentioning

confidence: 92%

“…In 1971, the occurrence of T. cruzi from naturally infected triatomines, which were implicated in the transmission of the disease, was reported in the City of Manaus 15 . Since then, there have been suspected or confirmed acute and chronic CD cases in this state, occasionally [5][6][16][17][18] .…”

Section: Article/artigomentioning

confidence: 99%

Serological survey for Chagas disease in the rural areas of Manaus, Coari, and Tefé in the Western Brazilian Amazon

Magalhães

Coelho

Maciel

et al. 2011

Rev. Soc. Bras. Med. Trop.

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Introduction: Deforestation, uncontrolled forest, human population migration from endemic areas, and the large number of reservoirs and wild vectors naturally infected by Trypanosoma cruzi promote the endemicity of Chagas disease in the Amazon region. Methods: We conducted an initial serological survey (ELISA) in a sample of 1,263 persons; 1,095 (86.7%) were natives of the State of Amazonas, 666 (52.7%) were male, and 948 (75.1%) were over 20 years old. Serum samples that were found to be reactive, indeterminate, or inconclusive by indirect immunofluorescence (IFI) or positive with low titer by IFA were tested by Western blot (WB). Serologically confirmed patients (WB) were evaluated in terms of epidemiological, clinical, ECG, and echocardiography characteristics. Results: Fifteen patients had serologically confirmed T. cruzi infection, and 12 of them were autochthonous to the state of Amazonas, for an overall seroprevalence of 1.2% and 0.9% for the state of Amazonas. Five of the 15 cases were males, and the average age was 47 years old; most were farmers with low education. One patient who was not autochthonous, having originated from Alagoas, showed right bundle branch block, bundle branch block, and anterosuperior left ventricular systolic dysfunction with an ejection fraction of 54%. Conclusions: The results of this study ratify the importance of monitoring CD cases in Amazonia, particularly in the state of Amazonas. Keywords: Chagas Disease. Serological Survey. Brazilian Amazon. RESUMOIntrodução: Na Amazônia, o desmatamento desordenado da floresta, as migrações populacionais humanas de áreas endêmicas e o grande número de reservatórios e vetores silvestres naturalmente infectados por Trypanosoma cruzi, favorece a endemicidade da doença de Chagas nessa região. Métodos: Foi realizado um inquérito sorológico inicial por ensaio imunoenzimático (ELISA), em uma amostra de 1.263 pessoas, 1.095 (86,7% ) as quais eram autóctones do Estado do Amazonas, 666 (52,7%) do sexo masculino, 948 (75,1%) com idade superior a 20 anos. As amostras de soro reativas, indeterminadas ou inconclusivas por imunofluorescência indireta (IFI) positivas ou com baixo título na IFI foram submetidas ao Western blot (WB). Os pacientes com sorologia confirmada (WB) foram avaliados do ponto de vista epidemiológico, clínico, eletro e ecocardiográfico. Resultados: Quinze pacientes tiveram sorologia confirmada para infecção por T. cruzi, 12 dos quais autóctones do Estado do Amazonas, com uma prevalência sorológica geral de 1,2% e de 0,9% para o Estado do Amazonas. Entre os 15 casos com sorologia positiva, cinco eram do sexo masculino, média de idade de 47 anos, baixa escolaridade e a maioria agricultores. Um paciente não autoctone, procedente de Alagoas, apresentou bloqueio de ramo direito, bloqueio divisional ântero-superior e disfunção sistólica ventricular esquerda com fração de ejeção de 54%. Conclusões:O resultado deste estudo reforça a importância do monitoramento de casos da doença de Chagas na Amazônia, em especial no Amazonas. Pa...

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Chagas disease in the Brazilian Amazon: IV. a new cross-sectional study

Cited by 36 publications

References 35 publications

A new survey of the serology of human Trypanosoma cruziinfection in the Rio Negro microregion, Brazilian Amazon: a critical analysis

A new survey of the serology of human Trypanosoma cruziinfection in the Rio Negro microregion, Brazilian Amazon: a critical analysis

Study on Chagas disease occurrence in the municipality of Monte Negro, State of Rondônia, Brazilian Amazon

Serological survey for Chagas disease in the rural areas of Manaus, Coari, and Tefé in the Western Brazilian Amazon

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