Morbidity of Chagas heart disease in the microregion of Rio Negro,Amazonian Brazil: a case-control study

A case-control study on the morbidity of Chagas heart disease was carried out in the municipality of Barcelos in the microregion of the Rio Negro, state of Amazonas. One hundred and six individuals, who were serologically positive for Trypanosoma cruzi infection, as confirmed by at least two techniques with different principles, were matched according to age and sex with an equal number of seronegative individuals. The cases and controls were evaluated using an epidemiological questionnaire and clinical, electrocardiograph and echocardiograph examinations. In the seroepidemiological evaluation, 62% of the interviewees recognised triatomines and most of them confirmed that they had seen these insects in the piassava plantations of the riverside communities of the Negro River tributaries. Of the seropositive patients, 25.8% affirmed that they had been stung by the triatomines and 11.7% denied having been stung. The principal clinical manifestations of the seropositive individuals were palpitations, chest pain and dyspnoea upon effort. Cardiac auscultation revealed extrasystoles, bradycardia and systolic murmurs. The electrocardiographic alterations were ventricular extrasystoles, left and right bundle branch block, atrioventricular block and primary T wave alterations. The echocardiogram was altered in 22.6% of the seropositive individuals and in 8.5% of the seronegative individuals.     

Chagas disease: control,elimination and eradication. Is it possible?

From an epidemiological point of view, Chagas disease and its reservoirs and vectors can present the following characteristics: (i) enzooty, maintained by wild animals and vectors, with broad occurrence from southern United States of America (USA) to southern Argentina and Chile (42ºN 49ºS), (ii) anthropozoonosis, when man invades the wild ecotope and becomes infected with Trypanosoma cruzi from wild animals or vectors or when the vectors and wild animals, especially marsupials, invade the human domicile and infect man, (iii) zoonosis-amphixenosis and exchanged infection between animals and humans by domestic vectors in endemic areas and (iv) zooanthroponosis, infection that is transmitted from man to animals, by means of domestic vectors, which is the rarest situation in areas endemic for Chagas disease. The characteristics of Chagas disease as an enzooty of wild animals and as an anthropozoonosis are seen most frequently in the Brazilian Amazon and in the Pan-Amazon region as a whole, where there are 33 species of six genera of wild animals: Marsupialia, Chiroptera, Rodentia, Edentata (Xenarthra), Carnivora and Primata and 27 species of triatomines, most of which infected with T. cruzi . These conditions place the resident populations of this area or its visitors - tourists, hunters, fishermen and especially the people whose livelihood involves plant extraction - at risk of being affected by Chagas disease. On the other hand, there has been an exponential increase in the acute cases of Chagas disease in that region through oral transmission of T. cruzi , causing outbreaks of the disease. In four seroepidemiological surveys that were carried out in areas of the microregion of the Negro River, state of Amazonas, in 1991, 1993, 1997 and 2010, we found large numbers of people who were serologically positive for T. cruzi infection. The majority of them and/or their relatives worked in piassava extraction and had come into contact with and were stung by wild triatomines in that area. Finally, a characteristic that is greatly in evidence currently is the migration of people with Chagas disease from endemic areas of Latin America to non-endemic countries. This has created a new dilemma for these countries: the risk of transmission through blood transfusion and the onus of controlling donors and treating migrants with the disease. As an enzooty of wild animals and vectors, and as an anthropozoonosis, Chagas disease cannot be eradicated, but it must be controlled by transmission elimination to man.     

Acute Chagas disease in El Salvador 2000-2012 - Need for surveillance and control

Several parasitological studies carried out in El Salvador between 2000-2012 showed ahigher frequency of acute cases of Chagas disease than that in other Central Americancountries. There is an urgent need for improved Chagas disease surveillance andvector control programs in the provinces where acute Chagas disease occurs andthroughout El Salvador as a whole.     

Integrated control of Chagas disease for its elimination as public health problem - A Review

Chagas disease or American trypanosomiasis is, together with geohelminths, the neglected disease that causes more loss of years of healthy life due to disability in Latin America. Chagas disease, as determined by the factors and determinants, shows that different contexts require different actions, preventing new cases or reducing the burden of disease. Control strategies must combine two general courses of action including prevention of transmission to prevent the occurrence of new cases (these measures are cost effective), as well as opportune diagnosis and treatment of infected individuals in order to prevent the clinical evolution of the disease and to allow them to recuperate their health. All actions should be implemented as fully as possible and with an integrated way, to maximise the impact. Chagas disease cannot be eradicated due because of the demonstrated existence of infected wild triatomines in permanent contact with domestic cycles and it contributes to the occurrence of at least few new cases. However, it is possible to interrupt the transmission of Trypanosoma cruzi in a large territory and to eliminate Chagas disease as a public health problem with a dramatic reduction of burden of the disease.     

Climatic factors influencing triatomine occurrence in Central-West Brazil

We estimated the geographic distributions of triatomine species in Central-West Region of Brazil (CW) and analysed the climatic factors influencing their occurrence. A total of 3,396 records of 27 triatomine species were analysed. Using the maximum entropy method, ecological niche models were produced for eight species occurring in at least 20 municipalities based on 13 climatic variables and elevation. Triatoma sordida and Rhodnius neglectus were the species with the broadest geographic distributions in CW Brazil. The Cerrado areas in the state of Goiás were found to be more suitable for the occurrence of synanthropic triatomines than the Amazon forest areas in the northern part of the state of Mato Grosso. The variable that best explains the evaluated models is temperature seasonality. The results indicate that almost the entire region presents climatic conditions that are appropriate for at least one triatomine species. Therefore, it is recommended that entomological surveillance be reinforced in CW Brazil.     

The Politics of Mediation: Local–Global Interactions in the Central Amazon of Brazil

The proliferation of a nongovernmental sector held the promise of linking local actors with national and international ones, thereby contributing to a highly participatory, Habermasian ideal in which the formerly marginalized would find greater participation and expression. Yet the role of international agents in community-based resource management projects has recently come under scrutiny. In addressing these issues in this article, I consider the roles of different interlocutors in two contrastive phases in an Amazonian community's movement to preserve its endangered fisheries. The comparative exercise demonstrates how institutional agents, by establishing a discourse that structures the criteria through which collective demands may be problematized, may inadvertently shift from mediation to domination, and from local partnering to local production.     

Allelic frequencies and statistical data obtained from 12 codis STR loci in an admixed population of the Brazilian Amazon

The allelic frequencies of 12 short tandem repeat loci were obtained from a sample of 307 unrelated individuals living in Macapá, a city in the northern Amazon region, Brazil. These loci are the most commonly used in forensics and paternity testing. Based on the allele frequency obtained for the population of Macapá, we estimated an interethnic admixture for the three parental groups (European, Native American and African) of, respectively, 46%, 35% and 19%. Comparing these allele frequencies with those of other Brazilian populations and of the Iberian Peninsula population, no significant distances were observed. The interpopulation genetic distances (F(ST) coefficients) to the present database ranged from F(ST) = 0.0016 between Macapá and Belém to F(ST) = 0.0036 between Macapá and the Iberian Peninsula.     

Television's Interpellation: Heeding, Missing, Ignoring, and Resisting the Call for Pan-National Identity in the Brazilian Amazon

ABSTRACT   In this article, I focus on the ways in which audiences in the Amazonian community of Gurupá respond to television's interpellation for pan-national identity. I examine how viewers heed, miss, ignore, and resist the call for identity as well as how their various responses to this "call" shape their worldview and behavior and impact the process of nation building. Utilizing audience ethnography over a 25-year period, I show in this study how televisual messages are contextualized and localized, mitigating the forces of nationalistic homogenization.     

Palms,Pastures, and Swidden Fields: The Grounded Political Ecology of “Agro-Extractive/Shifting-cultivator Peasants” in Maranhão,Brazil

This article examines transformations associated with changes in resource use and land cover dynamics in the community of São Manoel, Maranhão state, in the eastern Brazilian Amazon. The shifting cultivator peasants in São Manoel integrate swidden fields for annual cropping, the extraction of babassu palm products, and pastures for cattle ranching. Since the early twentieth century, predominant vegetative cover patterns have been altered from species-rich mature forests to secondary succession with babassu dominant to pasture or swidden fields containing palm stands of various densities. A grounded political ecology of resource use in the area suggests that management strategies and the resulting land cover dynamics integrate site-specific decisions of peasant producers. I discuss the trajectory of production strategies in São Manoel since the establishment of the community in the 1920s, and identify the multiple dimensions affecting resource use and environmental outcomes, with an emphasis on the period following land struggles and the recovery of peasant tenure rights in the mid-1980s. The analysis indicates that socionatural trajectories that optimize resource use and address the socioeconomic needs of the community include the maintenance of palm/pastures associations.     

Certifying the interruption of Chagas disease transmission by native vectors: cui bono?

Certifying the absence of Chagas disease transmission by native vectors lacks scientific grounds and weakens long-term control-surveillance systems to the detriment of people living under risk conditions. Instead, a regular \"certification of good practice\" (including vector control-surveillance, case detection/patient care and blood safety) could help achieve sustained disease control.     

Binding capacity of mannose-binding lectin (MBL) is associated with the severity of chronic Chagas cardiomyopathy

Chagas disease (CD) is a global problem. Currently, it affects approximately 15 million individuals in Latin America. It is well know that the human immune response is related to different clinical manifestations. Mannose binding lectin (MBL) plays an important role in innate immunity, and it mediates the phagocytosis and complement-mediated destruction of pathogens. The binding capacity is enhanced by the oligomerization of MBL. In this study, we evaluated the serum concentration and the binding capacity of MBL in patients with chronic chagasic cardiomyopathy. A total of 77 patients with chronic CD were included with indeterminate (n?=?19), mild cardiac (n?=?29) and severe cardiac (n?=?29) forms. The serum concentration and the binding capacity were measured using enzyme-linked immunosorbent assays (ELISA). There was no significant difference in the serum MBL levels between the groups of patients. However, we found a relationship between the binding capacity and the groups studied. Our results suggest that binding capacity of MBL could be an indicator of clinical manifestation in Chronic Chagas cardiomyopathy. Furthermore, combined with the Mannose Binding Index results in a useful clinical tool for management of Chronic Chagas Patients.     

Contributions of Fire Use Study to Land Use/Cover Change Frameworks: Understanding Landscape Change in Agricultural Frontiers

The impact of fire use and hazard in frontier settlement is a critical environmental concern that has been historically overshadowed by deforestation issues- and thus underexamined at local and regional scales by social scientists. Consequently, conceptual frameworks of LUCC change consider fire use as an outcome of land use decisions and neglect the capacity of burning choices to influence these decisions and subsequent land cover change. This paper examines the relationship of settlement, land use, and fire use. It considers recent LUCC frameworks, and then uses household surveys on fire use practices to discuss how the study of fire use can contribute to understanding frontier landscape change. Planting decisions, settlement history, location desires, and burning logistics work in combination to influence burning choices and thus LUCC.