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.     

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 a higher frequency of acute cases of Chagas disease than that in other Central American countries. There is an urgent need for improved Chagas disease surveillance and vector control programs in the provinces where acute Chagas disease occurs and throughout El Salvador as a whole.     

Asymptomatic infection in individuals from the municipality of Barcelos (Brazilian Amazon) is not associated with the anti-Plasmodium falciparum glycosylphosphatidylinositol antibody response

Anti-glycosylphosphatidylinositol (GPI) antibodies (Abs) may reflect and mediate, at least partially, anti-disease immunity in malaria by neutralising the toxic effect of parasitic GPI. Thus, we assessed the anti-GPI Ab response in asymptomatic individuals living in an area of the Brazilian Amazon that has a high level of malaria transmission. For comparative purposes, we also investigated the Ab response to a crude extract prepared from Plasmodium falciparum, the merozoite surface protein (MSP)3 antigen of P. falciparum and the MSP 1 antigen of Plasmodium vivax (PvMSP1-₁₉) in these individuals and in Angolan patients with acute malaria. Our data suggest that the Ab response against P. falciparum GPI is not associated with P. falciparum asymptomatic infection in individuals who have been chronically exposed to malaria in the Brazilian Amazon. However, this Ab response could be related to ongoing parasitaemia (as was previously shown) in the Angolan patients. In addition, our data show that PvMSP1-₁₉may be a good marker antigen to reflect previous exposure to Plasmodium in areas that have a high transmission rate of P. vivax.     

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.     

Ecoepidemiology,short history and control of Chagas disease in the endemic countries and the new challenge for non-endemic countries

Chagas disease is maintained in nature through the interchange of three cycles: the wild, peridomestic and domestic cycles. The wild cycle, which is enzootic, has existed for millions of years maintained between triatomines and wild mammals. Human infection was only detected in mummies from 4,000-9,000 years ago, before the discovery of the disease by Carlos Chagas in 1909. With the beginning of deforestation in the Americas, two-three centuries ago for the expansion of agriculture and livestock rearing, wild mammals, which had been the food source for triatomines, were removed and new food sources started to appear in peridomestic areas: chicken coops, corrals and pigsties. Some accidental human cases could also have occurred prior to the triatomines in peridomestic areas. Thus, triatomines progressively penetrated households and formed the domestic cycle of Chagas disease. A new epidemiological, economic and social problem has been created through the globalisation of Chagas disease, due to legal and illegal migration of individuals infected by Trypanosoma cruzi or presenting Chagas disease in its varied clinical forms, from endemic countries in Latin America to non-endemic countries in North America, Europe, Asia and Oceania, particularly to the United States of America and Spain. The main objective of the present paper was to present a general view of the interchanges between the wild, peridomestic and domestic cycles of the disease, the development of T. cruzi among triatomine, their domiciliation and control initiatives, the characteristics of the disease in countries in the Americas and the problem of migration to non-endemic countries.     

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

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.     

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.     

Update on oral Chagas disease outbreaks in Venezuela: epidemiological, clinical and diagnostic approaches

Orally transmitted Chagas disease has become a matter of concern due to outbreaks reported in four Latin American countries. Although several mechanisms for orally transmitted Chagas disease transmission have been proposed, food and beverages contaminated with whole infected triatomines or their faeces, which contain metacyclic trypomastigotes of Trypanosoma cruzi, seems to be the primary vehicle. In 2007, the first recognised outbreak of orally transmitted Chagas disease occurred in Venezuela and largest recorded outbreak at that time. Since then, 10 outbreaks (four in Caracas) with 249 cases (73.5% children) and 4% mortality have occurred. The absence of contact with the vector and of traditional cutaneous and Romana’s signs, together with a florid spectrum of clinical manifestations during the acute phase, confuse the diagnosis of orally transmitted Chagas disease with other infectious diseases. The simultaneous detection of IgG and IgM by ELISA and the search for parasites in all individuals at risk have been valuable diagnostic tools for detecting acute cases. Follow-up studies regarding the microepidemics primarily affecting children has resulted in 70% infection persistence six years after anti-parasitic treatment. Panstrongylus geniculatus has been the incriminating vector in most cases. As a food-borne disease, this entity requires epidemiological, clinical, diagnostic and therapeutic approaches that differ from those approaches used for traditional direct or cutaneous vector transmission.     

Pharmacokinetic and pharmacodynamic responses in adult patients with Chagas disease treated with a new formulation of benznidazole

Pharmacological treatment of Chagas disease with benznidazole (BNZ) is effective in children in all stages, but it is controversial in chronically infected adults. We report the pharmacokinetics and pharmacodynamics in six adult patients with Chagas disease treated with the new BNZ formulation (ABARAX^®) in doses between 2.5-5.5 mg/Kg/day. All but one patient had plasmatic BNZ concentrations within the expected range. All patients finalised treatment with nondetectable Trypanosoma cruziquantitative polymerase chain reaction, which remained nondetectable at the six month follow-up. Our data suggests parasitological responses with the new BNZ and supports the hypothesis that treatment protocols with lower BNZ doses may be effective.     

Intrusive versus domiciliated triatomines and the challenge of adapting vector control practices against Chagas disease

Chagas disease prevention remains mostly based on triatomine vector control to reduce or eliminate house infestation with these bugs. The level of adaptation of triatomines to human housing is a key part of vector competence and needs to be precisely evaluated to allow for the design of effective vector control strategies. In this review, we examine how the domiciliation/intrusion level of different triatomine species/populations has been defined and measured and discuss how these concepts may be improved for a better understanding of their ecology and evolution, as well as for the design of more effective control strategies against a large variety of triatomine species. We suggest that a major limitation of current criteria for classifying triatomines into sylvatic, intrusive, domiciliary and domestic species is that these are essentially qualitative and do not rely on quantitative variables measuring population sustainability and fitness in their different habitats. However, such assessments may be derived from further analysis and modelling of field data. Such approaches can shed new light on the domiciliation process of triatomines and may represent a key tool for decision-making and the design of vector control interventions.     

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.     

Impact of a community-based bug-hunting campaign on Chagas disease control: a case study in the department of Jalapa,Guatemala

Chagas disease control requires an innovative approach to strengthen community participation in vector surveillance. This paper presents a case study of a community-based bug-hunting campaign in Guatemala. The campaign was implemented in 2007 in the following three stages: (i) a four week preparation stage to promote bug-hunting, (ii) a one week bug-hunting stage to capture and collect bugs and (iii) a 10 week follow-up stage to analyse the bugs and spray insecticide. A total of 2,845 bugs were reported, of which 7% were Triatominae vectors, such as Rhodnius prolixus and Triatoma dimidiata. The bug-hunting campaign detected a five-six-fold higher amount of vectors in one week than traditional community-based surveillance detects in one year. The bug-hunting campaign effectively detected vectors during a short period, provided information to update the vector infestation map and increased community and political awareness regarding Chagas disease. This approach could be recommended as an effective and feasible strategy to strengthen vector surveillance on a larger scale.     

The ghosts of forests past and future: deforestation and botanical sampling in the Brazilian Amazon

The remarkable biodiversity of the Brazilian Amazon is poorly documented and threatened by deforestation. When undocumented areas become deforested, in addition to losing the fauna and flora, we lose the opportunity to know which unique species had occupied a habitat. Here we quantify such knowledge loss by calculating how much of the Brazilian Amazon has been deforested and will likely be deforested until 2050 without having its tree flora sufficiently documented. To this end, we analysed 399 147 digital specimens of nearly 6000 tree species in relation to official deforestation statistics and future deforestation scenarios. We find that by 2017, 30% of all the localities where tree specimens had been collected were mostly deforested. Some 300 000 km² (12%; 485 25 × 25 km grid cells) of the Brazilian Amazon had been deforested by 2017, without having a single tree specimen recorded. An additional 250 000–900 000 km² of severely under-collected rainforest will likely become deforested by 2050. If future tree sampling is to cover this area, sampling effort has to increase two- to six-fold. Nearly 255 000 km² or 7% of rainforest in the Brazilian Amazon is easily accessible but does yet but remain under-collected. Our study highlights how progressing deforestation increases the risk of losing undocumented species of a hyper-diverse tree flora.     

Current situation and perspectives regarding human Chagas disease in midwestern of the state of Minas Gerais,Brazil

Recognising the importance of Chagas disease in Brazil, Bambuí set up epidemiological surveillance for Chagas disease in 1974 and was the first municipality to do so. To ascertain the current epidemiology of Chagas disease in this municipality, 1.782 blood samples from the general population were analysed; 7.7% of samples were found to be seropositive for Chagas disease. A strong positive correlation between increasing age and Chagas disease was evident in both genders, with the highest prevalence in individuals aged over 60 years. Clinically, the cardiodigestive form of Chagas disease was the most common in these samples. These data confirm the interruption of Trypanosoma cruzi transmission, in parallel with a still important residual morbidity of Chagas disease in the county, thus supporting political decisions that will prioritise epidemiological surveillance and medical treatment of Chagas disease in the coming years.     

The main sceneries of Chagas disease transmission. The vectors,blood and oral transmissions - A comprehensive review

This review deals with transmission of Trypanosoma cruzi by the most important domestic vectors, blood transfusion and oral intake. Among the vectors, Triatoma infestans, Panstrongylus megistus, Rhodnius prolixus, Triatoma dimidiata, Triatoma brasiliensis, Triatoma pseudomaculata, Triatoma sordida, Triatoma maculata, Panstrongylus geniculatus, Rhodnius ecuadoriensis and Rhodnius pallescens can be highlighted. Transmission of Chagas infection, which has been brought under control in some countries in South and Central America, remains a great challenge, particularly considering that many endemic countries do not have control over blood donors. Even more concerning is the case of non-endemic countries that receive thousands of migrants from endemic areas that carry Chagas disease, such as the United States of America, in North America, Spain, in Europe, Japan, in Asia, and Australia, in Oceania. In the Brazilian Amazon Region, since Shaw et al. (1969) described the first acute cases of the disease caused by oral transmission, hundreds of acute cases of the disease due to oral transmission have been described in that region, which is today considered to be endemic for oral transmission. Several other outbreaks of acute Chagas disease by oral transmission have been described in different states of Brazil and in other South American countries.     

Triatominae species of Suriname (Heteroptera: Reduviidae) and their role as vectors of Chagas disease

Nine species of Triatominae, representing three tribes and five genera, are currently known in Suriname. An annotated list of the species based on the collections of the Bureau of Public Health (Suriname), the National Zoological Collection Suriname and the National History Museum Leiden (the Netherlands) is provided. Additionally, the results of several years of opportunistic collection in two domestic environments are presented. The most common species are Rhodnius pictipes Stål, 1972, Rhodnius robustus Larrouse, 1972 and Panstrongylus geniculatus (Latreille, 1811). The significance of the species as vectors of Chagas disease in Suriname is discussed.     

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.     

Urban Chagas disease in children and women in primary care centres in Buenos Aires,Argentina

The primary objective of this study was to estimate the prevalence of this disease in women of childbearing age and children treated at health centres in underserviced areas of the city of Buenos Aires. Demographic and Chagas disease status data were collected. Samples for Chagas disease serology were obtained on filter paper and the reactive results were confirmed with conventional samples. A total of 1,786 subjects were screened and 73 positive screening results were obtained: 17 were from children and 56 were from women. The Trypanosoma cruzi infection risk was greater in those individuals who had relatives with Chagas disease, who remember seeing kissing bugs, who were of Bolivian nationality or were born in the Argentine province of Santiago del Estero. The overall prevalence of Chagas disease was 4.08%. Due to migration, Chagas disease is currently predominantly urban. The observed prevalence requires health programme activities that are aimed at urban children and their mothers. Most children were infected congenitally, which reinforces the need for Chagas disease screening of all pregnant women and their babies in Argentina. The active search for new cases is important because the appropriate treatment in children has a high cure rate.     

Biomarkers of therapeutic responses in chronic Chagas disease: state of the art and future perspectives

The definition of a biomarker provided by the World Health Organization is any substance, structure, or process that can be measured in the body, or its products and influence, or predict the incidence or outcome of disease. Currently, the lack of prognosis and progression markers for chronic Chagas disease has posed limitations for testing new drugs to treat this neglected disease. Several molecules and techniques to detect biomarkers in Trypanosoma cruzi-infected patients have been proposed to assess whether specific treatment with benznidazole or nifurtimox is effective. Isolated proteins or protein groups from different T. cruzi stages and parasite-derived glycoproteins and synthetic neoglycoconjugates have been demonstrated to be useful for this purpose, as have nucleic acid amplification techniques. The amplification of T. cruzi DNA using the real-time polymerase chain reaction method is the leading test for assessing responses to treatment in a short period of time. Biochemical biomarkers have been tested early after specific treatment. Cytokines and surface markers represent promising molecules for the characterisation of host cellular responses, but need to be further assessed.     

Behavioural alterations are independent of sickness behaviour in chronic experimental Chagas disease

The existence of the nervous form of Chagas disease is a matter of discussion since Carlos Chagas described neurological disorders, learning and behavioural alterations in Trypanosoma cruzi-infected individuals. In most patients, the clinical manifestations of the acute phase, including neurological abnormalities, resolve spontaneously without apparent consequence in the chronic phase of infection. However, chronic Chagas disease patients have behavioural changes such as psychomotor alterations, attention and memory deficits, and depression. In the present study, we tested whether or not behavioural alterations are reproducible in experimental models. We show that C57BL/6 mice chronically infected with the Colombian strain of T. cruzi (150 days post-infection) exhibit behavioural changes as (i) depression in the tail suspension and forced swim tests, (ii) anxiety analysed by elevated plus maze and open field test sand and (iii) motor coordination in the rotarod test. These alterations are neither associated with neuromuscular disorders assessed by the grip strength test nor with sickness behaviour analysed by temperature variation sand weight loss. Therefore, chronically T. cruzi-infected mice replicate behavioural alterations (depression and anxiety) detected in Chagas disease patients opening an opportunity to study the interconnection and the physiopathology of these two biological processes in an infectious scenario.