Application of WHO International Biological Reference Standards to evaluate commercial serological tests for chronic Chagas disease.

BACKGROUND Chagas disease, resulting from Trypanosoma cruzi infections, continues to be a health concern mainly in Latin American countries where the parasite is endemic. The laboratory diagnosis of a chronic infection is determined through serological assays for antibodies against T. cruzi and several tests are available that differ in key components, formats and methodologies. To date, no single test meets the criteria of a gold standard. The situation is further complicated by the difficulties associated with performance comparisons between different immunoassays or methodologies executed at different times and geographical areas. OBJECTIVE To improve the diagnosis of Chagas disease, the WHO coordinated the development of two International Biological Reference Standards for antibodies against anti-T. cruzi: NIBSC 09/186 and NIBSC 09/188 that respectively represent geographical regions with the highest prevalence of TcII and TcI lineages of the parasite. METHODS The principle goal of this study was to verify the behavior of these standards when assayed by several commercially available serological tests that employ different methods to capture and detect human anti-T. cruzi antibodies. FINDINGS AND MAIN CONCLUSIONS The results reinforce the recommendation that these standards be considered for performance evaluations of commercialised immunoassays and should be an integral step in the development of new test components or assay paradigms.

Indoor Dust as a Source of Virulent Strains of the Agents of Cryptococcosis in the Rio Negro Micro-Region of the Brazilian Amazon.

Cryptococcosis, a potentially fatal mycosis in humans, is acquired via exposure to exogenous environmental sources. This study aimed to investigate the frequency, genetic diversity, and virulence of cryptococcal strains isolated from indoor dust in the Rio Negro micro-region of the Brazilian Amazon. A total of 8.9% of the studied houses were positive, recovering nine Cryptococcus neoformans VNI and 16 C. gattii VGII isolates, revealing an endemic pattern in domestic microenvironments. The International Society for Human and Animal Mycology (ISHAM) consensus multilocus sequence typing (MLST) scheme for the C. neoformans/C. gattii species complexes identified two sequence types (STs), ST93 and ST5, amongst C. neoformans isolates and six STs amongst C. gattii isolates, including the Vancouver Island Outbreak ST7 (VGIIa) and ST20 (VGIIb), the Australian ST5, and ST264, ST268 and ST445, being unique to the studied region. Virulence studies in the Galleria mellonella model showed that five C. gattii strains and one C. neoformans strain showed a similar pathogenic potential to the highly virulent Vancouver Island outbreak strain CDR265 (VGIIa). The findings of this study indicate that humans can be exposed to the agents of cryptococcosis via house dust, forming the basis for future studies to analyze the impact of early and continuous exposure to indoor dust on the development of subclinical or clinical infections.

Morphological Aspects of Antennal Sensilla of the Rhodnius brethesi Matta, 1919 (Hemiptera: Reduviidae) from the Negro River, Amazon Region of Brazil.

Studies conducted in river Ererê located in the left margin of Negro River, municipality of Barcelos, state of Amazonas, have confirmed that Rhodnius brethesi has as its natural habitat the palm tree Leopoldinia piassaba. By scanning electron microscopy, sensillum type was studied on the antennae of R. brethesi. The specimens used come from the field and laboratory colony. No differences were observed between R. brethesi and other Triatominae studied. In the R. brethesi antennas, differences were observed only between the antennal segments and in the dorsal and ventral portions. Trichobothria sensilla show a difference with a lamellar base, suggesting that this conformation of the base of the sensilla is a synapomorphic feature of the genus. Another important observation is that, considering that R. brethesi is a specialist, infesting only one type of palm tree, trichoidea sensilla may be involved with plant-derived odorants. The knowledge of such functions could benefit the understanding of the likely biological role of these structures in chemical communication and also provide basic information for future studies of niche recognition, since this species of triatomine is only found in the L. piassaba palm.

Human acute Chagas disease: changes in factor VII, activated protein C and hepatic enzymes from patients of oral outbreaks in Pará State (Brazilian Amazon).

Oral transmission of Chagas disease has been increasing in Latin American countries. The present study aimed to investigate changes in hepatic function, coagulation factor levels and parasite load in human acute Chagas disease (ACD) secondary to oral Trypanosoma cruzi transmission. Clinical and epidemiological findings of 102 infected individuals attended in the State of Pará from October 2013 to February 2016 were included. The most common symptoms were fever (98%), asthenia (83.3%), face and limb edema (80.4%), headache (74.5%) and myalgia (72.5%). The hepatic enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST) of 30 ACD patients were higher compared with controls, and this increase was independent of the treatment with benznidazole. Moreover, ACD individuals had higher plasma levels of activated protein C and lower levels of factor VII of the coagulation cascade. Patients with the highest parasite load had also the most increased transaminase levels. Also, ALT and AST were associated moderately (r = 0.429) and strongly (r = 0.595) with parasite load respectively. In conclusion, the present study raises the possibility that a disturbance in coagulation and hepatic function may be linked to human ACD.

Acute Chagas disease in the state of Pará, Amazon Region: is it increasing?

Acute Chagas disease (ACD) has a distinct epidemiological profile in the Amazon Region, with cases and outbreaks of Trypanosoma cruzi infection being possibly related to the ingestion of contaminated food. Data on ACD in the state of Pará retrieved from 2000 to 2016 from the Brazilian Notifiable Diseases Information System (SINAN) were evaluated. During this period, 2,030 of the 16,807 reported cases were confirmed, with a higher incidence between the months of August and December, thus characterising a seasonal pattern of acute infection, and coinciding with the higher production of "açaí", one fruit likely involved in the oral transmission of the disease. Evaluation of the absolute numbers of confirmed ACD cases secondary to oral infection suggests that infection through this route increased during the 2010-2016 period, differing from what was recorded in terms of vectorial or other infection routes. These findings point to the need of intensifying strategies to prevent or substantially reduce oral transmission.

Acute Chagas disease in the state of Pará, Amazon Region: is it increasing?

Acute Chagas disease (ACD) has a distinct epidemiological profile in the Amazon Region, with cases and outbreaks of Trypanosoma cruzi infection being possibly related to the ingestion of contaminated food. Data on ACD in the state of Pará retrieved from 2000 to 2016 from the Brazilian Notifiable Diseases Information System (SINAN) were evaluated. During this period, 2,030 of the 16,807 reported cases were confirmed, with a higher incidence between the months of August and December, thus characterising a seasonal pattern of acute infection, and coinciding with the higher production of "açaí", one fruit likely involved in the oral transmission of the disease. Evaluation of the absolute numbers of confirmed ACD cases secondary to oral infection suggests that infection through this route increased during the 2010-2016 period, differing from what was recorded in terms of vectorial or other infection routes. These findings point to the need of intensifying strategies to prevent or substantially reduce oral transmission.

Prevalence of intestinal parasites and risk factors forspecific and multiple helminth infections in a remote city of the Brazilian Amazon.

INTRODUCTION: Few studies have described the risk factors of intestinal parasitic infections in the Amazon. METHODS: A cross-sectional survey was performed in a City of the State of Amazonas (Brazil) to estimate the prevalence of intestinal parasites and determine the risk factors for helminth infections. RESULTS: Ascaris lumbricoides was the most prevalent parasite. The main risk factors determined were: not having a latrine for A. lumbricoides infection; being male and having earth or wood floors for hookworm infection; and being male for multiple helminth infections. CONCLUSIONS: We reported a high prevalence of intestinal parasites and determined some poverty-related risk factors.

Reflexões sobre o ensino online de Biossegurança à luz da Teoria da Aprendizagem Significativa / Reflections on the online learning of Biosafety based in the meaningful learning

Organizar eventos educacionais, com foco na aprendizagem, exige articulação entre planejamento, processo de ensino e avaliação. O presente manuscrito objetiva avaliar a estruturação pedagógica e os resultados no QBA/Online ­ curso de Biossegurança a distância, inserido no Moodle, oferecido aos ingressos do Instituto Oswaldo Cruz ­ à luz da Teoria da Aprendizagem Significativa (TAS), para identificar oportunidades de melhorias. Na pesquisa qualitativa, foram considerados os dados de 2760 participantes, de 2008 a 2014. A média de participação anual foi de 460, com predominância de alunos (40%). No planejamento, não foi utilizada uma fundamentação teórica-metodológica, mas considerados os aspectos contextuais do ensino e a natureza do conhecimento a ser ensinado. O conteúdo está em 12 textos. O maior índice de acertos nos testes foi de 18 questões, no único instrumento de avaliação da aprendizagem, com 20 perguntas, centradas nos temas dos textos. O curso foi bem avaliado pelos alunos. A flexibilidade do tempo/local está dentre os pontos positivos e a quantidade/tamanho dos textos, nos negativos. O diagnóstico ratificou a relevância de um curso online; necessidade de reorganização do material instrucional; e de oferta de estratégias de ensino para estimular o interesse dos alunos

Organizing educational events, focusing on learning, requires disposition between planning, teaching process and evaluation. This manuscrip tintent to evaluate pedagogical format and results in QBA/Online ­ distance learning course on Biosafety, accessed in Moodle platform, off ered to graduates from Oswaldo Cruz Institute ­ based in the Meaningful Learning Theory as to enlighten opportunities for improvement. A qualitative inquiry was performed, with 2760 participants and registered in the system, from 2008 to 2014. The average annual contribution is 460, with a predominance of students (40%). With regard toplanning, theoretical-methodological were not considered, only contextual aspects of education and the concepts of knowledge to be taught/instructed. Twelve texts were assigned. Thehighest scores rates in tests reached 18 questions, the only instrument for assessing learning, whichhas 20 questions, focusing on themes of current texts. The course was well rated by those who completed the evaluation form. Participants highlighted as positive aspects; flexibility as to time/place and as negative the large number of texts and its sizes. The analysis confirmed the benefits of online tool; the need to rearrange institutional material; and providing teaching strategies to encourage students' interest

Reflexões sobre o Ensino online de Biossegurança à luz da Teoria da Aprendizagem Significativa / Reflections on the online learning of Biosafety based in the meaningful learning

Organizar eventos educacionais, com foco na aprendizagem, exige articulação entre planejamento, processo de ensino e avaliação. O presente manuscrito objetiva avaliar a estruturação pedagógica e os resultados no QBA/Online – curso de Biossegurança a distância, inserido no Moodle, oferecido aos ingressos do Instituto Oswaldo Cruz – à luz da Teoria da Aprendizagem Significativa (TAS), para identificar oportunidades de melhorias. Na pesquisa qualitativa, foram considerados os dados de 2760 participantes, de 2008 a 2014. A média de participação anual foi de 460, com predominância de alunos (40%). No planejamento, não foi utilizada uma fundamentação teórica-metodológica, mas considerados os aspectos contextuais do ensino e a natureza do conhecimento a ser ensinado. O conteúdo está em 12 textos. O maior índice de acertos nos testes foi de 18 questões, no único instrumento de avaliação da aprendizagem, com 20 perguntas, centradas nos temas dos textos. O curso foi bem avaliado pelos alunos. A flexibilidade do tempo/local está dentre os pontos positivos e a quantidade/tamanho dos textos, nos negativos. O diagnóstico ratificou a relevância de um curso online; necessidade de reorganização do material instrucional; e de oferta de estratégias de ensino para estimular o interesse dos alunos (AU)

Organizing educational events, focusing on learning, requires disposition between planning, teaching process and evaluation. This manuscrip tintent to evaluate pedagogical format and results in QBA/Online – distance learning course on Biosafety, accessed in Moodle platform, off ered to graduates from Oswaldo Cruz Institute – based in the Meaningful Learning Theory as to enlighten opportunities for improvement. A qualitative inquiry was performed, with 2760 participants and registered in the system, from 2008 to 2014. The average annual contribution is 460, with a predominance of students (40%). With regard toplanning, theoretical-methodological were not considered, only contextual aspects of education and the concepts of knowledge to be taught/instructed. Twelve texts were assigned. Thehighest scores rates in tests reached 18 questions, the only instrument for assessing learning, whichhas 20 questions, focusing on themes of current texts. The course was well rated by those who completed the evaluation form. Participants highlighted as positive aspects; flexibility as to time/place and as negative the large number of texts and its sizes. The analysis confirmed the benefits of online tool; the need to rearrange institutional material; and providing teaching strategies to encourage students’ interest (AU)

Clinical follow-up of responses to treatment with benznidazol in Amazon: a cohort study of acute Chagas disease.

A total of 179 individuals with acute Chagas disease mainly transmitted by oral source, from Pará and Amapá State, Amazonian, Brazil were included during the period from 1988 to 2005. Blood samples were used to survey peripheral blood for T. cruzi hemoparasites by quantitative buffy coat (QBC), indirect xenodiagnosis, blood culture and serology to detection of total IgM and anti-T. cruzi IgG antibodies by indirect immunofluorescence assay (IFA) and indirect hemagglutination assay (HA). All assays were performed pre-treatment (0 days) and repeated 35 (±7) and 68 (±6) days after the initiation of treatment with benznidazol and every 6 months while remained seropositive. The endpoint of collection was performed in 2005. Total medium period of follow-up per person was 5.6 years. Also, a blood sample was collected from 72 randomly chosen treated patients to perform polimerase chain reaction (PCR) method. Proportions of subjects with negative or positive serology according to the number of years after treatment were compared. In the endpoint of follow-up we found 47 patients (26.7%) serologically negative, therefore considered cured and 5 (2.7%) exhibited mild cardiac Chagas disease. Other 132 patients had persistent positive serologic tests. The PCR carried out in 72 individuals was positive in 9.8%. Added, there was evidence of therapeutic failure immediately following treatment, as demonstrated by xenodiagnosis and blood culture methods in 2.3% and 3.5% of cases, respectively. There was a strong evidence of antibody clearing in the fourth year after treatment and continuous decrease of antibody titers. Authors suggest that control programs should apply operational researches with new drug interventions four years after the acute phase for those treated patients with persistently positive serology.

[Morbidity of Chagas disease among autochthonous patients from the Rio Negro microregion, State of Amazonas]. / Morbidade da doença de Chagas em pacientes autóctones da microrregião do Rio Negro, Estado do Amazonas.

INTRODUCTION: A seroepidemiological and clinical study was conducted on 152 autochthonous individuals living in the district of Barcelos, State of Amazonas, to evaluate the seroprevalence of Chagas infection and morbidity of Chagas disease. METHODS: The serological tests used were indirect immunofluorescence, conventional and recombinant ELISA and immunoblot (Tesa-blot). Thirty-eight patients were considered seropositive; 31 were considered serodoubtful; and 83 were considered seronegative. The 38 seropositive cases were paired with 38 seronegative controls of the same age and sex, and underwent epidemiological and clinical evaluations, electrocardiograms and echocardiograms. Twenty-nine pairs underwent radiological examinations of the esophagus. RESULTS: Seropositivity was 19.9 times more frequent among workers gathering plant materials from the forests and 10.4 times more frequent among piassaba gatherers. Eighty six point seven percent of the seropositive individuals recognized the genus Rhodnius as the local vector, while only 34.2% of the seronegative individuals recognized this. The EKG was abnormal in 36.8% of the seropositive individuals and in 21.5% of the seronegative individuals, while the echocardiogram showed abnormalities in 31.6% of the seropositive and 18.4% of the seronegative individuals. Precordialgia and palpitation were more frequent among the seropositive individuals. Clinical evaluation on the digestive system and X-ray on the esophagus did not show significant abnormalities. CONCLUSIONS: Chagas disease in the study region can be considered to be an occupational disease.

Morbidade da doença de Chagas em pacientes autóctones da microrregião do Rio Negro, Estado do Amazonas / Morbidity of Chagas disease among autochthonous patients from the Rio Negro microregion, State of Amazonas

INTRODUÇÃO: Foi realizado um estudo soroepidemiológico e clínico em 152 indivíduos residentes no município de Barcelos, Estado do Amazonas. Avaliou-se a soroprevalência da infecção chagásica e a morbidade da doença de Chagas. MÉTODOS: Os testes sorológicos foram a imunofluorescência indireta, ELISA convencional e recombinante e o Tesa-blot. Foram considerados soropositivos 38 pacientes, duvidosos 31 e soronegativos negativos 83. Os 38 casos soropositivos foram pareados com 38 controles soronegativos da mesma idade, sexo e submetidos à avaliação epidemiológica, clínica, eletro e ecocardiográfica, sendo que, 29 pares fizeram exame radiológico do esôfago. RESULTADOS: A soropositividade foi 19,9 vezes mais frequente nos trabalhadores do extrativismo em geral e 10,4 vezes mais frequente no extrativismo da piaçaba. Aplicou-se o teste de reconhecimento com o vetor local do gênero Rhodnius e 86,7 por cento dos pacientes soropositivos o reconheceram, enquanto somente 34,2 por cento dos soronegativos o fizeram. O ECG mostrou-se alterado em 36,8 por cento nos soropositivos e em 21,5 por cento nos soronegativos, enquanto o ecocardiograma mostrou alterações em 31,6 por cento nos soropositivos e 18,4 por cento nos soronegativos. Precordialgia e palpitações foram mais frequentes nos soropositivos. O estudo clínico do aparelho digestivo e radiológico do esôfago não mostrou alterações significativas. CONCLUSÕES. A doença de Chagas na região estudada pode ser considerada uma doença ocupacional.

INTRODUCTION: A seroepidemiological and clinical study was conducted on 152 autochthonous individuals living in the district of Barcelos, State of Amazonas, to evaluate the seroprevalence of Chagas infection and morbidity of Chagas disease. METHODS: The serological tests used were indirect immunofluorescence, conventional and recombinant ELISA and immunoblot (Tesa-blot). Thirty-eight patients were considered seropositive; 31 were considered serodoubtful; and 83 were considered seronegative. The 38 seropositive cases were paired with 38 seronegative controls of the same age and sex, and underwent epidemiological and clinical evaluations, electrocardiograms and echocardiograms. Twenty-nine pairs underwent radiological examinations of the esophagus. RESULTS: Seropositivity was 19.9 times more frequent among workers gathering plant materials from the forests and 10.4 times more frequent among piassaba gatherers. Eighty six point seven percent of the seropositive individuals recognized the genus Rhodnius as the local vector, while only 34.2 percent of the seronegative individuals recognized this. The EKG was abnormal in 36.8 percent of the seropositive individuals and in 21.5 percent of the seronegative individuals, while the echocardiogram showed abnormalities in 31.6 percent of the seropositive and 18.4 percent of the seronegative individuals. Precordialgia and palpitation were more frequent among the seropositive individuals. Clinical evaluation on the digestive system and X-ray on the esophagus did not show significant abnormalities. CONCLUSIONS: Chagas disease in the study region can be considered to be an occupational disease.

Chagas disease in the Amazon Region

The risk that Chagas disease becomes established as a major endemic threat in Amazonia (the world's largest tropical biome, today inhabited by over 30 million people) relates to a complex set of interacting biological and social determinants. These include intense immigration from endemic areas (possibly introducing parasites and vectors), extensive landscape transformation with uncontrolled deforestation, and the great diversity of wild Trypanosoma cruzi reservoir hosts and vectors (25 species in nine genera), which maintain intense sylvatic transmission cycles. Invasion of houses by adventitious vectors (with infection rates > 60 percent) is common, and focal adaptation of native triatomines to artificial structures has been reported. Both acute (~ 500) and chronic cases of autochthonous human Chagas disease have been documented beyond doubt in the region. Continuous, low-intensity transmission seems to occur throughout the Amazon, and generates a hypoendemic pattern with seropositivity rates of ~ 1-3 percent. Discrete foci also exist in which transmission is more intense (e.g., in localized outbreaks probably linked to oral transmission) and prevalence rates higher. Early detection-treatment of acute cases is crucial for avoiding further dispersion of endemic transmission of Chagas disease in Amazonia, and will require the involvement of malaria control and primary health care systems. Comprehensive eco-epidemiological research, including prevalence surveys or the characterization of transmission dynamics in different ecological settings, is still needed. The International Initiative for Chagas Disesae Surveillance and Prevention in the Amazon provides the framework for building up the political and scientific cooperation networks required to confront the challenge of preventing Chagas disease in Amazonia.

Chagas disease in the Amazon region.

The risk that Chagas disease becomes established as a major endemic threat in Amazonia (the world's largest tropical biome, today inhabited by over 30 million people) relates to a complex set of interacting biological and social determinants. These include intense immigration from endemic areas (possibly introducing parasites and vectors), extensive landscape transformation with uncontrolled deforestation, and the great diversity of wild Trypanosoma cruzi reservoir hosts and vectors (25 species in nine genera), which maintain intense sylvatic transmission cycles. Invasion of houses by adventitious vectors (with infection rates > 60%) is common, and focal adaptation of native triatomines to artificial structures has been reported. Both acute (approximately 500) and chronic cases of autochthonous human Chagas disease have been documented beyond doubt in the region. Continuous, low-intensity transmission seems to occur throughout the Amazon, and generates a hypoendemic pattern with seropositivity rates of approximately 1-3%. Discrete foci also exist in which transmission is more intense (e.g., in localized outbreaks probably linked to oral transmission) and prevalence rates higher. Early detection-treatment of acute cases is crucial for avoiding further dispersion of endemic transmission of Chagas disease in Amazonia, and will require the involvement of malaria control and primary health care systems. Comprehensive eco-epidemiological research, including prevalence surveys or the characterization of transmission dynamics in different ecological settings, is still needed. The International Initiative for Chagas Disease Surveillance and Prevention in the Amazon provides the framework for building up the political and scientific cooperation networks required to confront the challenge of preventing Chagas disease in Amazonia.

Morphobiological aspects of Rhodnius brethesi Matta, 1919 ( Hemiptera:Reduviidae ) from the Upper and Middle Negro River, Amazon region of Brazil: I - scanning electron microscopy

The occurrence of autochthonous cases of Chagas disease in the Amazon region of Brazil over recent decades has motivated an intensification of studies in this area. Different species of triatomines have been identified, and ten of these have be proven to be carriers of the parasite Trypanosoma cruzi or " cruzi-like " parasites. Studies conducted in the municipalities of Santa Isabel do Rio Negro and Barcelos, located on the Upper and Middle of the Negro River, microregion of Negro River, state of Amazonas have confirmed not only that Rhodnius brethesi is present in the palm tree Leopoldinia piassaba, but also that this insect was recognized by palm fiber collectors. A morphological study of eyes, inter-ocular and inter-ocellar regions, antennae, buccula, labrum, rostrum, stridulatory sulcus and feet, including the apex of the tibia, spongy fossette and ctenidium was conducted by scanning electron microscopy. The buccula and the stridulatory sulcus presented notable differences in specimens of different genera and also of different species. These data make it possible to suggest that the details presented in these structures can be included as diagnostic characteristics to be used in new dichotomous keys, thereby contributing towards studies of taxonomy and systematics and furnishing backing for comparative analysis of specimens collected from different localities.

Morphobiological aspects of Rhodnius brethesi Matta, 1919 (Hemiptera:Reduviidae) from the Upper and Middle Negro River, Amazon region of Brazil: I - scanning electron microscopy.

The occurrence of autochthonous cases of Chagas disease in the Amazon region of Brazil over recent decades has motivated an intensification of studies in this area. Different species of triatomines have been identified, and ten of these have be proven to be carriers of the parasite Trypanosoma cruzi or " cruzi-like " parasites. Studies conducted in the municipalities of Santa Isabel do Rio Negro and Barcelos, located on the Upper and Middle of the Negro River, microregion of Negro River, state of Amazonas have confirmed not only that Rhodnius brethesi is present in the palm tree Leopoldinia piassaba, but also that this insect was recognized by palm fiber collectors. A morphological study of eyes, inter-ocular and inter-ocellar regions, antennae, buccula, labrum, rostrum, stridulatory sulcus and feet, including the apex of the tibia, spongy fossette and ctenidium was conducted by scanning electron microscopy. The buccula and the stridulatory sulcus presented notable differences in specimens of different genera and also of different species. These data make it possible to suggest that the details presented in these structures can be included as diagnostic characteristics to be used in new dichotomous keys, thereby contributing towards studies of taxonomy and systematics and furnishing backing for comparative analysis of specimens collected from different localities.

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

A new conglomerate family sample of 194 dwellings with 996 resident persons were studied in the town of Barcelos, State of Amazonas, in order to re-evaluate the risk of Chagas disease. During the survey the persons were interviewed and in this occasion we showed to them a collection of Panstrongylus, Rhodnius and Triatoma, asking if they recognized and eventually have been bitten by this kind of bugs. At this time we collected 500 ul of blood in microtainer tubes from 886 interviewed persons who gave permission after informed consent. A screening test for T. cruzi antibodies based on agglutination of colored polymer particles, sensitized with three different synthetic peptides of T. cruzi (ID-PaGIA Chagas Test), showed 13.2% of sera positivity, but only 6.8% were confirmed by indirect immunofluorescence, and ELISA with purified T. cruzi antigens. Two hundred and six interviewed persons (20.7%) recognized the triatomines, as "piaçavas' lice" and 62 (30%) confirmed that have been bitten by the bugs, 25.8% of them had a positive serology for T. cruzi infection. Electrocardiographic alterations were shown in 9.3% of the seropositives and in 11.9% of the seronegative cases. This was considered not statistically significant.

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

A new conglomerate family sample of 194 dwellings with 996 resident persons were studied in the town of Barcelos, State of Amazonas, in order to re-evaluate the risk of Chagas disease. During the survey the persons were interviewed and in this occasion we showed to them a collection of Panstrongylus, Rhodnius and Triatoma, asking if they recognized and eventually have been bitten by this kind of bugs. At this time we collected 500 ul of blood in microtainer® tubes from 886 interviewed persons who gave permission after informed consent. A screening test for T. cruzi antibodies based on agglutination of colored polymer particles, sensitized with three different synthetic peptides of T. cruzi (ID-PaGIA Chagas Test)®, showed 13.2 percent of sera positivity, but only 6.8 percent were confirmed by indirect immunofluorescence, and ELISA with purified T. cruzi antigens. Two hundred and six interviewed persons (20.7 percent) recognized the triatomines, as "piaçavas' lice" and 62 (30 percent) confirmed that have been bitten by the bugs, 25.8 percent of them had a positive serology for T. cruzi infection. Electrocardiographic alterations were shown in 9.3 percent of the seropositives and in 11.9 percent of the seronegative cases. This was considered not statistically significant

Chagas disease: from bush to huts and houses: is it the case of the Brazilian Amazon?

Two of the major problems facing the Amazon - human migration from the other areas and uncontrolled deforestation - constitute the greatest risk for the establishment of endemic Chagas disease in this part of Brazil. At least 18 species of triatomines had been found in the Brazilian Amazon, 10 of them infected with Trypanosoma cruzi, associated with numerous wild reservoirs. With wide-range deforestation, wild animals will perforce be driven into other areas, with tendency for triatomines to become adapted to alternative food sources in peri and intradomicilies. Serological surveys and cross-sectional studies for Chagas disease, carried out in rural areas of the Rio Negro, in the Brazilian Amazon, showed a high level of seropositivity for T. cruzi antibodies. A strong correlation of seroreactivity with the contact of gatherers of piaçava fibers with wild triatomines could be evidenced.

Morbidade da doença de Chagas em áreas do Sertäo da Paraíba e da Caatinga do Piauí / Chaga's disease morbidity in Sertäo of Paraíba and Caatinga of Piauí

A clinical and electrocardiographic case control study was carried out with 186 pairs of persons with positive and negative serology for T. cruzi infection from the Sertäo Paraíba and in 200 seropositive cases from the region of Caatinga in the State of Piauí, North-eastern Brazil. The predominant clinical manifestations in seropositive cases in both areas were: palpitations, dyspnea on effort, precordial pain, dysphagia, odynophagia, pyrosis and intestinal constipation. The EKG abnormalities rates suggestive of chronic chagasic cardiopathy were respectively in Paraíba and Piauí: AV block 3.8 per cent and 2 per cent, RBBB III 6.4 per cent and 7 per cent, RBBB III+ LAB 10.7 per cent and 10.5 per cent, and multifocal extrasystoles 2.7 per cent and 3 per cent. Xenodiagnosis in a sample of 54 seropositive individuals in the Sert-ao of Para-iba and in 120 in the Caatinga of Piauí was revealed 13 per cent and 34 per cent positive; PCR tests in a sample of 47 seropositives in Paraíba and 101 in Piauí revealed positives in 44.6 per cent and 59.5 per cent respectively. Blood culture in LIT media of 101 seropositive cases from the Caatinga of Piauí was positive for T. cruzi in 25.7 per cent. A triatomine survey carried out in a sample of 132 domiciles and peridomiciles in the Sertäo of Paraíba and in a sample of 159 in the Caatinga of Piauí showed the following results: In Paraíba, 16 specimens of T. brasiliensis, not infected with T. cruzi, were captured. In Piauí, 750 triatomines were captured, of these 625 were examined: 49 were T. pseudomaculata, not infected with T. cruzi (19 in peridomiciles and 30 in the domiciles), and 576 were T. brasiliensis (371 in the domiciles and 205 in the peridomiciles) and of this latter specie 32 (5.5 per cent) were infected with T. cruzi (31 in the domiciles and one in the peridomicile) per cent.