[show abstract][hide abstract] ABSTRACT: The etiological treatment of Chagas disease is recommended for all patients with acute or recent chronic infection, but controversies remain regarding the benefit of chemotherapy and interpretations of the parasitological cure after etiological treatment. This study compares the laboratory and clinical evaluations of Chagas disease patients who were diagnosed 13 years earlier. Fifty-eight Chagas disease patients (29 treated with benznidazole and 29 untreated) were matched at the time of treatment based on several variables. Conventional serology revealed the absence of seroconversion in all patients. However, lower serological titres were verified in the treated group, primarily among patients who had the indeterminate form of the disease. Haemoculture performed 13 years after the intervention was positive for 6.9% and 27.6% of the treated and untreated patients, respectively. Polymerase chain reaction tests were positive for 44.8% and 13.8% of the treated and untreated patients, respectively. Patients who presented with the indeterminate form of the disease at the beginning of the study exhibited less clinical progression (17.4%) compared with the untreated group (56.5%). Therefore, this global analysis revealed that etiological treatment with benznidazole may benefit patients with respect to the clinical progression of Chagas disease and the prognosis, particularly when administered to patients with the indeterminate form of the disease.
Memórias do Instituto Oswaldo Cruz 09/2013; · 1.36 Impact Factor
[show abstract][hide abstract] ABSTRACT: We performed a critical study of conventional serology, followed by supplementary serological, parasitological, and molecular tests, to assess the response to etiologic treatment of Chagas' disease. A group of 94 Chagas' disease patients treated with benznidazole at least 10 years earlier were evaluated from the laboratory and clinical points of view. When conventional serology (enzyme-linked immunosorbent assay [ELISA], indirect immunofluorescence [IIF], and indirect hemagglutination [IHA]) and classic criteria (consistent results with any two of the three tests) or more rigorous criteria (consistent results from the three tests) were used, 10.6% and 8.5% of patients were considered treated and cured (TC) by classic and rigorous criteria, respectively. Patients were then evaluated using supplementary (recombinant ELISA and Trypanosoma cruzi excreted-secreted antigen blotting [TESA-blot]), parasitological (hemoculture), and molecular (PCR) tests. The results of recombinant ELISA were similar to those with the rigorous criterion (three consistent test results). The TESA-blot group showed a higher percentage (21.3%) of negative results than the groups defined by either cure criterion. Hemoculture and PCR gave negative results for all treated and cured (TC) patients, regardless of the criterion used. Recombinant ELISA and TESA-blot tests showed negative results for 70% and 87.5% of the patients categorized as TC by the classic and three-test criteria, respectively. For patients with discordant conventional serology, the supplementary serological and molecular tests were the decisive factor in determining therapeutic failure. Clinical evaluation showed that 62.5% of TC patients presented with the indeterminate form of the disease. Additionally, treated patients with negative TESA-blot results should be reevaluated later with all methodologies used here to verify whether TESA-blot is a reliable way to determine early parasitological cure of Chagas' disease.
[show abstract][hide abstract] ABSTRACT: One of the challenges on immunodiagnostic of Chagas disease in endemic areas has been the search for more practical and safe antigenic preparation that provides tests with higher sensitivity and specificity, with low cross-reactivity. A new approach using fixed Trypanosoma cruzi epimastigotes to detect IgG reactivity was investigated previously. In order to continue this investigation, this study aimed at optimizing the flow cytometry-based method to the diagnosis of Chagas disease patients after specific chemotherapy. To achieve our goal, serum samples from 93 subjects - 52 adults chronically infected by T. cruzi, and 41 uninfected controls were tested by flow cytometry. Secondly, serum samples from patients Treated Cured and Treated Uncured from Chagas disease were also tested to evaluate the potential of the method on assessing cure. After establishing the ideal serum dilution and cut off, 121 serum samples from patients with other endemic infections were tested to check cross-reactivity. The results showed that parasite staining with Evan's blue dye eliminated debris, allowing trustworthy analysis of anti-fixed epimastigote IgG reactivity. The applicability of the method to diagnose Chagas disease was confirmed by the high sensitivity (98.1%) and specificity (100%) found. This method also contributed for post-therapeutic assessment of cure, identifying 94.1% of Treated Uncured and 83.3% of Treated Cured patients. Cross-reactivity was observed in a very low number (6.7%). On the whole, these data highly recommend the use of anti-fixed T. cruzi epimastigote IgG reactivity by flow cytometry to the diagnosis and cure monitoring of Chagas disease in endemic areas.
Journal of immunological methods 06/2011; 369(1-2):22-32. · 2.35 Impact Factor
[show abstract][hide abstract] ABSTRACT: In 1943, the Center for the Study and Prophylaxis of Chagas Disease, Oswaldo Cruz Foundation, state of Minas Gerais (MG), was created in the municipality of Bambuí to carry out studies related to Chagas disease in the mid-western region of MG. Since that time, several investigations have been conducted to determine the natural habitat of triatomines, but Panstrongylus megistus colonies have never been found in this region. This paper records the first finding of a P. megistus sylvatic colony in 69 years of research. The characteristics of this ecotope and its implications for the epidemiology of Chagas disease are discussed.
Memórias do Instituto Oswaldo Cruz 06/2011; 106(4):510-3. · 1.36 Impact Factor
[show abstract][hide abstract] ABSTRACT: Following advances in the control of vector and blood transfusion transmission of Chagas disease, alternative mechanisms of transmission have become more relevant. This article discusses the importance of each one of these alternative mechanisms and the measures to prevent them.
A review was conducted of the scientific literature concerning alternative transmission mechanisms of Trypanosoma cruzi occurring in Brazil and the measures to prevent them. PubMed and BVS databases were consulted.
Twenty-five publications describing alternative mechanisms of transmission of Chagas disease were identified.
Oral transmission, through ingestion of contaminated food items has been the most frequent mode of transmission in Brazil in recent years. Other alternative mechanisms of transmission occur less frequently. It is important to understand these occurrences, especially now that vector transmission of the parasite is under control. Preventive measures have been presented, according to each of the situations considered, in line with current knowledge.
Revista da Sociedade Brasileira de Medicina Tropical 05/2011; 44(3):375-9. · 0.93 Impact Factor
[show abstract][hide abstract] ABSTRACT: Between 1950 and 1951, the first Prophylactic campaign against Chagas Diseases was carried on in Brazil by the so existing Serviço Nacional de Malária. The actions involving chemical vector control comprehended 74 municipalities along the Rio Grande Valley, between the States of São Paulo and Minas Gerais. Ever since, until 1975, the activities were performed according the availability of resources, being executed with more or less regularity and coverage. At that time, Chagas disease did no represent priority, in comparison with other endemic diseases prevalent in the Country. Even so, taking into account the accumulated data along those 25 years, the volume of work realized cannot be considered despicable. Nevertheless, it was few consistent, in terms of its impact on disease transmission. In 1975, with an additional injection of resources surpassed from the malaria program, plus the methodological systematization of the activities, and with the results of two extensive national inquiries (entomologic and serologic), the activities for vector control could be performed regularly, following two basic principles: interventions in always contiguous areas, progressively enlarged, and sustainability (continuity) of the activities, until being attained determined requirements and purpose previously established. Such actions and strategies lead into the exhaustion of the populations of the principal vector species, Triatoma infestans, no autochthonous and exclusively domiciliary, as well as the control of the domiciliary colonization of autochthonous species important to disease transmission. Vector transmission today is being considered residual, by means of some few native and peridomestic species, such as Triatoma brasiliensis and Triatoma pseudomaculata. There is, also, the risk of progressive domiciliation of some species before considered sylvatic, such as Panstrongylus lutzi and Triatoma rubrovaria. Finally, there is the possibility of the occurrence of cases of human infection directly related to the enzootic cycle of the parasite. By all these reasons, it is still indispensable the maintenance of a strict epidemiological surveillance against Chagas Disease in Brazil.
Revista da Sociedade Brasileira de Medicina Tropical 01/2011; 44 Suppl 2:52-63. · 0.93 Impact Factor
[show abstract][hide abstract] ABSTRACT: Originating from the ancient enzootic cycle of Trypanosoma cruzi, human Chagas disease (HCD) emerged focally in different points of America, in the Pre Christian period. Being slowly expanded as a consequence of internal migrations, HCD was settled in those locals where some vector species reached domiciliation and where different kinds of reservoirs entered in domestic environment , with major expression in the post Columbus era, particularly between the final of XIX Century and the middle of XX Century, when the maximum prevalence rates were attained. Originally, scarce evidences of acute cases, chronic cardiopathy and megacolon could be detected in different points of the Region, but the diagnosis of such clinical pictures was not easily ascertained. Nevertheless, the megaoesophagus picture proved to be the more specific marker of ancient HCD, with several descriptions of its occurrence in different Brazilian regions, mainly since the XVIII Century. The social burden of HCD depends basically of the presence of chronic cardiopathy, and only after its recognition, control actions of the disease were definitely lounged in endemic countries.
Revista da Sociedade Brasileira de Medicina Tropical 01/2011; 44 Suppl 2:6-11. · 0.93 Impact Factor
[show abstract][hide abstract] ABSTRACT: In order to investigate the prevalence of chagasic heart disease in Brazil, a national electrocardiographic survey was carried out from 1977 to 1981. A total of 5,347 electrocardiograms (ECG) were performed and paired by age and gender. The results obtained in relation with the autochthonous cases, were distributed by Brazilian states, as follows: Rio Grande do Sul (1,078), Minas Gerais (760), Bahia (612), Paraná (400), Paraiba (340), Piauí (218), Sergipe (216), Goiás (176), Pernambuco (170), Ceará (136) and Alagoas 134. The higher proportions of altered ECGs among seropositive individuals were found in the States of Goiás (63.6%), Minas Gerais (57.6%), Ceará (57.3%), Paraná (54.5%), Piauí (53.2%) and Paraiba (52.3%). Among the control individuals, these proportions were respectively 25%, 25.7%, 25%, 12.5%, 22.9% and 26.5%. A significant statistical difference of altered ECGs between positive and negative individuals was verified in all the States, with a single exception (Alagoas). The estimation of the gradient showed to be higher in Paraná State (42%), followed by Goiás (38.6%), Ceará (32.3%), Minas Gerais (31.9%), Piauí (30.3%), Paraíba (25.8%), Pernambuco (22.3%), Bahia (18.9%), Sergipe (16.7%), Rio Grande do Sul (9.9%) and Alagoas (7.5%). Concerning the distribution of the electrocardiographical alterations found in the eleven states, the main alterations find among the seropositive group were: ventricular extrasystoles, complete right bundle branch block, left anterior fascicular block, the association of complete right bundle branch block with left anterior fascicular block and primary alterations of the ST segment and of the T wave. Furthermore, these ECG alterations were more prevalent in the group of infected individuals.
Revista da Sociedade Brasileira de Medicina Tropical 01/2011; 44 Suppl 2:40-6. · 0.93 Impact Factor
[show abstract][hide abstract] ABSTRACT: Very soon Carlos Chagas took into account the need of trypanosomiasis control, considering its great social impact and geographical dispersion The vector was considered the more vulnerable target and housing improvement the basic strategy to face the disease. In parallel, it was required a more clinical visibility for the disease, as an argument for its control. The first concrete tentative occurred in 1918 when Souza Araújo dedicating his efforts in Paraná, trying housing improvement. He was followed by Ezequiel Dias et al, in 1921, employing chemical compounds against the vector, The chemical fight will be retaken by Emmanuel Dias in 1944, assaying several old compounds, fire thrower and cyanidric gas. In 1946, DDT showed to be ineffective, but one year later Dias & Pellegrino described the insecticide gammexane, highly effective against domestic triatomines. Working with Mario Pinotti, expanded trials occurred in Minas Gerais (Triangle Region), justifying the expansion of the campaign to other endemic regions, with the rationale of continuous work in contiguous areas. In 1957 Pedreira de Freitas proposed the selective spraying, which was the model for the future strategy of program evaluation, by SUVEN and SUCAN organizations. In 1975 the national program is reorganized, launching two national surveys (entomology and serology). In 1979 the new pyrethroid compounds are tried and im 1983 the national program is expanded. Transfusion transmitted Chagas Disease was studied since the 1950 by the Nussenzweig group in S. Paulo, showing to be vulnerable to chemoprophylaxis and blood donor pre transfusional serologic screening. Nevertheless, these preventive measures only were implemented in the 1980 decade, following the emergence of HIV/AIDS pandemic. Practically, since the pioneer essays, the control of Chagas Disease transmission showed to be efficient against vector and blood bank mechanisms, depending on continuity, educative support and political will.
Revista da Sociedade Brasileira de Medicina Tropical 01/2011; 44 Suppl 2:12-8. · 0.93 Impact Factor
[show abstract][hide abstract] ABSTRACT: Vectorial, transfusion and congenital are considered the main transmission mechanisms in human Chagas disease. Alternative mechanisms are accidental, oral and by organ transplantation. Other hypothetic mechanisms could be by other vectors, sexual, criminal and by means of marsupial anal secretions. The present accorded strategies for prevention are: CONGENITAL: early case detection and immediate treatment. If possible, start during the pre natal period, throughout mothers serology, performing parasitological tests in the new born from positive women. For positive cases, immediate treatment; for those negative babies, conventional serology at the 8th month, treating specifically those with positive results. ACCIDENTAL TRANSMISSION: Rigorous training and utilization of protection equipments. IF accident occurs, immediate disinfection, conventional serology and beginning of specific treatment by ten days. Revision of the serology after 30 days: if positive, extend the treatment until the total dose (60 days or more). ORGAN TRANSPLANTATION: previous serology for donor and receptor. When the former is infected and the last negative, cancel the surgery or install the specific treatment by ten days before the surgery for the donor, followed by the receptor during ten days after the transplantation. ORAL TRANSMISSION: Specific measures are not available, food hygiene is recommended, including the cooking of meats delivered from possible reservoirs. Nowadays, the detection and immediate treatment of the case is recommended, followed by active research of new cases around the detected one.
Revista da Sociedade Brasileira de Medicina Tropical 01/2011; 44 Suppl 2:68-72. · 0.93 Impact Factor
[show abstract][hide abstract] ABSTRACT: After controlling Triatoma infestans in Brazil, other species of triatomine that were considered minor in the transmission of Chagas disease became important. The persistence of Triatoma brasiliensis in Northeastern Brazil, associated with reinfection of domestic environments recently sprayed with pyrethroids, may be a signal of susceptibility alteration of this species to this insecticide. Specimens of T. brasiliensis from the municipality of Tauá, state of Ceará, were captured before and one year after spraying. They were submitted to bioassays using deltamethrin. The LD50 ranged from 0.19-0.33 ng of deltamethrin/nymph. The resistance ratio among samples from Tauá varied from 1.16-1.79 in the samples captured before the spraying and 1.00-1.74 in the samples captured one year after spraying, demonstrating that the two populations were equally susceptible to deltamethrin. The small difference in susceptibility between the two captures suggests that T. brasiliensis obtained in the second capture are from new invasions of the domestic environment and that the insecticide did not select resistant individuals. Therefore, it is suggested that T. brasiliensis control be carried out supplementing the regular use of pyrethroids with complementary measures, such as improvement of the dwellings and health education.
Memórias do Instituto Oswaldo Cruz 05/2010; 105(3):348-52. · 1.36 Impact Factor
[show abstract][hide abstract] ABSTRACT: Investigation of the food source of triatomines helps in understanding the biology of these insects, and also helps to infer their importance in transmitting Trypanosoma cruzi to humans.
The present study aimed to use the precipitin reaction to record the food source of triatomines from 54 municipalities in the central-western region of the State of Minas Gerais, as well as their natural infection by flagellates similar to Trypanosoma cruzi.
From July 2003 to March 2007, 416 insects were evaluated, all from the species Panstrongylus megistus. Among all these occurrences, birds (70%) and humans (22.5%) were the major blood sources. Sixteen (3.8%) of the insects were found to be positive for flagellates similar to Trypanosoma cruzi, and eight performed hematophagia on humans.
The results show the need to increase the entomological surveillance in this region, given that the possibility of new cases of Chagas disease occurring through vector transmission was detected.
Revista da Sociedade Brasileira de Medicina Tropical 04/2010; 43(2):125-8. · 0.93 Impact Factor
[show abstract][hide abstract] ABSTRACT: Twenty-eight Chagas disease patients (CD), 22 with the indeterminate clinical form (IND) and six with the cardiac or digestive form (CARD/DIG), were treated with benznidazole and underwent clinical and laboratorial analysis before (IND and CARD/DIG) and nine years after [patients after treatment (CDt), patients with the indeterminate clinical form at treatment onset (INDt) and with the cardiac or digestive form at treatment onset (CARD/DIGt)] treatment. The data demonstrate that 82.1% of CDt patients (23/28) remained clinically stable and 95.4% of the INDt (21/22) and 33.3% of the CARD/DIGt (2/6) patients showed unaltered physical and laboratorial examinations. The clinical evolution rate was 2%/year and was especially low in INDt patients (0.5%/year) relative to CARD/DIGt patients (7.4%/year). Positive haemoculture in treated patients was observed in 7.1% of the cases. None of the INDt (0/21) and 33.3% of the CARD/DIGt (2/6) patients displayed positive cultures. The PCR presented a positive rate significantly higher (85.2%, 23/27) than haemoculture and two samples from the same patient revealed the same result 57.7% of the patients. Conventional serology-ELISA on 16 paired samples remained positive in all individuals. Semi-quantitative ELISA highlighted significant decreases in reactivity, particularly in INDt relative to IND. Non-conventional serology-FC-ALTA-IgG, after treatment, showed positive results in all sera and 22 paired samples examined at seven and nine years after treatment, demonstrated significantly lower reactivity, particularly in INDt patients. This study was retrospective in nature, had a low number of samples and lacked an intrinsic control group, but the data corroborate other results found in the literature. The data also demonstrate that, even though a cure has not been detected in the none-treated patients, the benefits for clinical evolution were selectively observed in the group of INDt patients and did not occur for CARD/DIGt patients.
Memórias do Instituto Oswaldo Cruz 12/2009; 104(8):1139-47. · 1.36 Impact Factor
[show abstract][hide abstract] ABSTRACT: Despite the success of the Chagas Disease Control Program (PCCD) in Brazil, some endemic areas have experienced difficulty in maintaining the program's activities, especially after the health system's decentralization, since the sustainability of control measures for Chagas disease and vectors is known to depend on information and community participation. This study aimed to analyze knowledge and practices related to vectors and Chagas disease in Bambuí, Minas Gerais State, Brasil. The population's knowledge was tested with a questionnaire, accompanied by six illustrations of triatomine bugs for identification. Both adults and primary and secondary schoolchildren in rural areas of the county participated in the research. The Bambuí population showed good overall knowledge on triatomines and Chagas disease in both groups (adults and children), although the concepts were limited to preventing the insect vector from invading houses. The results emphasize the importance of educational campaigns in the context of the program as a fundamental component of community participation in Chagas disease vector control.
Cadernos de saúde pública / Ministério da Saúde, Fundação Oswaldo Cruz, Escola Nacional de Saúde Pública 09/2009; 25(8):1701-10. · 0.83 Impact Factor
[show abstract][hide abstract] ABSTRACT: This anthropological study addresses the cultural perceptions of a group of residents in the city of Bambuí, Minas Gerais State, Brazil, in relation to experience with Chagas disease and the impact of health measures on social life. The ethnographic study was based on open interviews, seeking to identify individual perceptions among 35 inhabitants of Bambuí (with and without Chagas disease) living in the region since the 1940s, when Chagas disease control activities were launched. Within a broad analysis of social perceptions concerning the effect of these health measures, the study sought to observe the cultural representations of the illness process. The study is intended to contribute to comprehensive work in health interventions, including the target population's socio-cultural characteristics. The cultural perspective plays an important role in preventing social distress.
Cadernos de saúde pública / Ministério da Saúde, Fundação Oswaldo Cruz, Escola Nacional de Saúde Pública 09/2009; 25(9):1947-56. · 0.83 Impact Factor
[show abstract][hide abstract] ABSTRACT: Strategies for controlling Chagas disease are based on spraying infested houses with pyrethroid insecticides. However, the intense use of these insecticides has promoted resistance of Triatoma infestans and, in Argentina, Bolivia and Southern Brazil, low levels of resistance have been reported. Due to the persistence of T. infestans in the state of Rio Grande do Sul (RS), we evaluated the occurrence of deltamethrin resistance in four strains from different municipalities in comparison to two susceptible strains from Brazil and one resistant strain from Bolivia. The results indicated the absence of resistance in T. infestansfrom RS.
Memórias do Instituto Oswaldo Cruz 08/2009; 104(4):668-70. · 1.36 Impact Factor
[show abstract][hide abstract] ABSTRACT: Chagas disease originated millions of years ago as an enzootic infection of wild animals and began to be transmitted to humans as an anthropozoonosis when man invaded wild ecotopes. While evidence of human infection has been found in mummies up to 9,000 years old, endemic Chagas disease became established as a zoonosis only in the last 200-300 years, as triatomines adapted to domestic environments. It is estimated that 15-16 million people are infected with Trypanosoma cruzi in Latin America, and 75-90 million are exposed to infection. Control of Chagas disease must be undertaken by interrupting its transmission by vectors and blood transfusions, improving housing and areas surrounding dwellings, providing sanitation education for exposed populations and treating acute and recently infected chronic cases. These measures should be complemented by surveillance and primary, secondary and tertiary care.
Memórias do Instituto Oswaldo Cruz 07/2009; 104 Suppl 1:31-40. · 1.36 Impact Factor