Chagas Disease Control Program Research Articles

Triatomine vectors of Trypanosoma cruzi in an endemic area for Chagas disease in Northeast Brazil.

We assessed the distribution of triatomines in an endemic area for Chagas disease. This retrospective study used secondary data extracted from the Official System of the National Chagas Disease Control Program (Sistema Oficial do Programa Nacional de Controle da Doença de Chagas - SisPCDCh). A total of 7,257 (725.7 ± 221.7 per year) specimens were collected from 2013 to 2022. Most of them (6,792; 93.6%) were collected in the intradomicile and 465 (6.4%) in the peridomicile. A total of 513 (7.1%) triatomines tested positive for the presence of trypomastigote forms, similar to Trypanosoma cruzi. The spatial analysis revealed a heterogeneous distribution of triatomines across different municipalities.

Chagas disease prevalence among migrants from El Salvador in Milan: a cross- sectional study of an often-overlooked population

Background Chagas disease (CD) is considered to be highly endemic in El Salvador, where its prevalence is estimated to be 1.3–3.7%. Although more than 40,000 migrants from El Salvador are currently living in Europe (particularly in Spain and Italy), there are few data regarding the prevalence of CD in this population. The aim of this study was to evaluate the prevalence of CD among Salvadorans living in Italy. Methods A cross-sectional serological survey of CD among Salvadorans living in the metropolitan area of Milan was carried out between October 2017 and December 2019. The participants’ blood samples were tested for Trypanosoma cruzi antibodies using two different serological assays. The collected demographic data included their biological sex, province of origin, the type of housing in their country of origin, and family history of CD. Results Of the 384 subjects who voluntarily participated in the study, five (1.3%, most coming from La Paz) were positive to both serological assays and therefore conclusively diagnosed as having CD. Five other subjects had discrepant serological results but were not positive to a third assay. Three of the five subjects with a diagnosis of CD completed medical staging, one of whom had chronic disease (digestive and cardiac involvement). Conclusions The prevalence of CD among Salvadorans living in Milan is similar to that estimated by the WHO in 2010. Although they are often overlooked in CD surveys, Salvadoran migrants should be included in CD control programs in countries in which the disease is not endemic.

Dynamics of Panstrongylus megistus infestation, the primary vector of Trypanosoma cruzi in Minas Gerais, Brazil

Panstrongylus megistus is considered one of the primary species of epidemiological importance for the transmission of Chagas disease in Brazil due to its wide geographical distribution throughout the national territory, good ability to invade and colonize houses, and high rates of natural infection by the Trypanosoma cruzi. The importance of this species in Minas Gerais has been recognized since the 80s. It is responsible for the high prevalence rates of Chagas disease in the west of the state. Studies conducted in the municipality of Jaboticatubas show that P. megistus is still the most captured vector in the region, even after 40 years of uninterrupted actions of the Chagas Disease Control Program in the municipality. Despite the importance of the species, its population dynamics is little studied. Consequently, crucial genetic information such as genetic diversity and gene flow among environments have not been well characterized yet. In this context, this work presents a population genetic analysis at the microgeographic level using microsatellite markers in samples of P. megistus obtained from Jaboticatubas to better understand the infestation dynamics of the primary vector species of T. cruzi in the region. The observed and expected heterozygosity ranged from 0.26 to 0.47 and 0.47 to 0.65, respectively. Most loci presented Hardy-Weinberg disequilibrium due to the excess of homozygotes. The pairwise Fst ranged from 0.05 to 0.35, with the p value significant for all comparisons, indicating the absence of gene flow between them. The values of Fis found ranged from 0.25 to 0.52, all values of p ≤ 0.05, probably due to structured populations, inbreeding, or null alleles. The results suggest an extended stay of this species in the colonized environments, with rare dispersal to other locations. Such results differ from that observed for Triatoma brasiliensis and Triatoma dimidiata, species that present constant movement, even after colonization of the artificial environment, and are similar to the behavior of Triatoma infestans. Thus, the study reinforces the importance of continuous entomological surveillance in the areas of occurrence of P. megistus to avoid the installation and formation of new foci of household infestation in the region.

Entomological surveillance of Chagas disease in the East of Minas Gerais region, Brazil.

ABSTRACTBackground: After decentralizing the actions of the Chagas Disease Control Program (CDCP) in Brazil, municipalities were now responsible for control measures against this endemic, supervised by the Regional Health Superintendencies (RHS). We aimed to evaluate the recent entomological surveillance of Chagas disease in the Regional Health Superintendence of Governador Valadares (RHS/GV) from 2014 to 2019. Methods: Triatomines captured by residents during entomological surveillance were sent to the reference laboratory, where the species and evolutionary stages were identified, place of capture, and presence of Trypanosoma cruzi. A database was created, and the following were calculated: the rate of infection by T. cruzi (overall rate and rate by species), monthly seasonality, spatial distribution of species, number of captures, and infected triatomines/health microregions. Results: We identified 1,708 insects; 1,506 (88.2%) were triatomines, most were adult instars (n=1,469), and few were nymphs (n=37). The identified species were Triatoma vitticeps, Panstrongylus megistus, Panstrongylus diasi, Rhodnius neglectus, and Panstrongylus geniculatus. The first three were most frequently captured and distributed throughout the study area. Most bugs were captured intradomicile (72.5%), mainly in the second semester, between September and November, with an average infection rate of 41.5% (predominantly T. vitticeps, 49.2%). All municipalities sent triatomines, especially in the microregions of Governador Valadares. Conclusions: These data reinforce the need and importance of improving Chagas disease control measures in the region to establish active and participatory entomological surveillance.

Occurrence and spatial distribution of triatomines (Hemiptera: Reduviidae) in the urban area of the municipality of Montes Claros, Northern Minas Gerais, Brazil.

The north of the Brazilian state of Minas Gerais is classified as an area of high risk of vectorial transmission of Chagas disease (CD) or of reestablishing transmission in the home, but the Chagas disease control programme is disjointed. The study evaluated the occurrence, natural infection and the spatial distribution of species of triatomines associated with climatic variations in the urban area of Montes Claros, a municipality endemic to CD in the north of Minas Gerais, Brazil. Triatomine data were obtained from passive entomological surveillance actions of the Chagas Disease Control Program (Programa de Controle de Doença de Chagas-PCDCh), registered by the Zoonosis Control Center (Centro de Controle de Zoonoses-CCZ) from 2009 to 2019. A total of 277 triatomines belonging to eight species were collected, and of these, 203 insects were examined. It was found that 46.2% of triatomines were captured inside the home and 8.3% around the home. The natural infection rate was 6.9%; 14 specimens showed natural infection by Trypanosoma cruzi (12 females and 2 males), and of these, 13 were found in the home and one in an uninformed location. The number of triatomine records collected was significantly higher in the month of September (p=.01), and there was an inverse correlation between the number of triatomines and the relative humidity of the air (p<.001). It was verified that the highest triatomine densities are located in transition areas between urban infrastructure (32.12%) and pasture (25.72%). The diversity of species of triatomines infected with T.cruzi in residential units in urban areas in the municipality of Montes Claros is worrying, as it suggests a potential risk of transmission of the parasite to domestic animals and humans.

Surveillance of Chagas disease vectors in Ceará State, Northeastern Brazil

Objective : Describe the spatial distribution, temporal trend and the natural infection rates by Trypanosoma cruzi in triatomines captured in Ceara State, between 2003 and 2014. Methods : Chagas Disease Control Program data were used to describe triatomine species circulating, their distribution in the state, the capture places (intradomicile and peridomicile), and the rates of natural infection by T. cruzi, between 2003 and 2014. Results : During this period, 401,721 triatomines were captured in 89.1% of the municipalities of the State, belonging to the species Triatoma pseudomaculata (53.9%), Triatoma brasiliensis (40.5%), Rhodnius nasutus (1.9%), Panstrongylus megistus (1.5%), Panstrogylus lutzi (1.3%), Triatoma rubrofasciata (0.8%), Panstrongylus geniculatus (< 0.1%), and Triatoma petrochiae (< 0.1%). Most of the specimens were caught in peridomicile areas (83.0%), with emphasis on T. pseudomaculata and T. brasiliensis, while P. lutzi was predominant in the intradomicile. P. lutzi had the highest infection rate by T. cruzi (7.8%), while T. pseudomaculata (0.9%), T. brasiliensis (1.0%), and P. megistus (1.3%) had the lowest rates. Conclusions : The occurrence of an enzootic cycle of T. cruzi and the presence of synanthropic animals that provide a source of blood meals to triatomines increases the risk of its transmission to humans, requiring constant vigilance by the sanitary authorities.

Análise temporal das ações para o controle da doença de Chagas em Sergipe, Brasil (1998-2015)

Objetivo: Análise temporal das ações de controle da doença de Chagas de 1998 a 2015 e seu impacto no estado de Sergipe, Brasil. Métodos: Estudo retrospectivo baseado em dados secundários obtidos do Programa de Controle da Doença de Chagas (PCDCh) (municípios positivos, espécie de triatomíneo capturado, índice de infecção e controle químico) e do Projeto de Melhoria Habitacional (recursos materiais, andamento das obras e monitoramento) para avaliação das ações destes programas nos oito territórios sergipanos. Foi realizada uma análise temporal por meio do modelo Joinpoint Regression Analysis. Resultados: Foram observadas diferenças nas taxas de cobertura do programa nos diferentes territórios, sendo os municípios localizados na região do Alto Sertão os mais atendidos. Foram coletadas seis espécies de triatomineos com redução no número de espécimes no final do período, encontrados principalmente fora da área litoranea do Estado. A maior taxa de infecção foi encontrada em Panstrongylus lutzi. Houve recursos importantes para melhoria habitacional em todos os territórios, no entanto a execução não foi satisfatória para a maioria. Conclusão: Apesar das fragilidades observadas no Programa, houve avanços importantes no controle da doença de Chagas. Todavia, faz-se necessário retomar as atividades, tendo em vista que existem condições necessárias para que a doença possa se disseminar por conta dos vetores e dos reservatórios ainda pouco estudados.

Epidemiological and clinical characteristics of Trypanosoma cruzi infection in dogs (Canis lupus familiaris) from a Chagas Disease-Endemic Urban Area in Colombia

In the last few years, an unusual increase in the number of acute Chagas disease outbreaks, presumably due to oral transmission, has been reported in urban areas in Santander, Colombia. Given the importance of dogs (Canis lupus familiaris) as reservoir hosts and sentinels of T. cruzi infection across different regions of America, we carried out a serological and molecular survey on T. cruzi infection in 215 dogs from the metropolitan area of Bucaramanga, Santander. Serological detection was carried out using enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescence antibody test (IFAT), and indirect hemagglutination assay (IHA), while molecular detection was done using a nested PCR (nPCR), targeting the microsatellite region of T. cruzi nuclear DNA. Animals were defined as seropositive when at least two of the three serological tests were positive, and only these animals were evaluated with the nPCR. To discriminate DTU TcI from other DTUs, a multiplex PCR was performed in the T. cruzi-positive samples. Additionally, clinical and hematological traits were evaluated in these hosts. The dog sera showed a seropositivity rate of 27.9 % (60/215), of which 43.3 % (26/60) were positive for nPCR. Statistical analysis indicated that T. cruzi seropositive in dogs was associated with specific socioeconomic sectors and a lack of garbage collection in these municipalities. Hematological analyses showed that T. cruzi infection was associated with anemia and platelet alterations but not with alterations of aspartate aminotransferase (ASAT) and creatine kinase myocardial band (CK-MB). The high seroprevalence of infection and active circulation of T. cruzi I (TcI) in dogs reflect the risk of infection to humans in this area, which should be taken into consideration when Chagas disease control programs are implemented. In addition, T. cruzi infection may take a toll on dog health, which should be considered during dog care and management.

Perfil entomológico da doença de Chagas no município de Potengi – CE, Brasil

Este estudo objetivou determinar o perfil entomológico da doença de Chagas em áreas rurais e periurbanas de Potengi – CE e a infecção de triatomíneos pelo Trypanosoma cruzi. Dados secundários foram obtidos da 20ª Coordenadoria Regional de Saúde do Programa de Controle da Doença de Chagas, oriundos de buscas ativas dos Agentes de Combate às Endemias realizadas entre 2013 a 2015. Verificou-se que 69,23% dos domicílios pesquisados encontravam-se infestados por triatomíneos, sendo 1.150 exemplares capturados no peridomicílio e 145 no intradomicílio. Triatoma pseudomaculata, T. brasiliensis, Panstrongylus lutzi e Rhodnius nasutus foram identificadas, sendo T. pseudomaculata com maior prevalência, seguida por T. brasiliensis. Dentre os triatomíneos capturados 1,34% estavam infectados com Trypanosoma cruzi, dos quais Triatoma pseudomaculata teve maior representatividade de infecção. A infestação triatomínica em residências e anexos no município de Potengi demonstra colonização por estes insetos e adaptação ao ambiente doméstico, sendo necessárias melhorias na vigilância epidemiológica e controle desses vetores.

Entomological triatomine indicators in the State of Rio Grande do Norte, Brazil.

This study aimed to describe the main entomological triatomine-related indicators in the western mesoregion of Rio Grande do Norte. This is a descriptive cross-sectional retrospective study developed on a historical analysis of information on the triatomine capture carried out by the Chagas Disease Control Program, from 2008 to 2013. Five species were captured, of which the Triatoma brasiliensis and Triatoma pseudomaculata, by occupying the domestic and peridomestic environment, sequentially, and Panstrongylus lutzi by the highest rate of natural infection. A prevalence of nymphs among the captured specimens, a higher triatominal density in the peridomicile, infestation, colonization and natural infection rates of 5.6%, 49.6% and 0.8%, respectively, a significant difference in the distribution of specimens between the municipalities investigated and lack of declining infestation and colonization rates between 2009 and 2012 was observed. Findings suggest the need for continuous surveillance, facilitated by the association between field teams and communities, with emphasis on the proposal of health education for the recognition and notification of triatomines by the population.

Triatomine Fauna and Recent Epidemiological Dynamics of Chagas Disease in an Endemic Area of Northeast Brazil.

Updated information of the dispersion dynamics of Chagas disease (CD) and a systemic analysis of these data will aid the early identification of areas that are vulnerable to transmission and enable efficient intervention. This work synthesized spatiotemporal information regarding triatomine fauna and analyzed this information in combination with the results from serological tests to elucidate the epidemiological panorama of CD in the state of Sergipe, Brazil. This is a retrospective analytical study that utilized information from the database of the National Chagas Disease Control Program. Between 2010 and 2016, 838 triatomines of eight species, namely, Panstrongylus geniculatus, which was first recorded in the state of Sergipe, Panstrongylus lutzi, P. megistus, Triatoma brasiliensis, T. pseudomaculata, T. tibiamaculata, T. melanocephala, and Rhodnius neglectus, were collected. Optical microscopy revealed that 13.2% of triatomines examined were infected by Trypanosoma cruzi-like flagellates. The distribution of triatomines exhibits an expanding south-central to northern dispersion, with a preference for semiarid and agreste areas and occasional observations in humid coastal areas due to anthropogenic actions reflected in the environment. Of the human cases analyzed from 2012 to 2016, 8.3% (191/2316) presented positive serology for Trypanosoma cruzi, and this proportion showed a gradual increase in the southern center of the state and new notifications in coastal regions. There is a need for intensification and continuity of the measures adopted by the Chagas Disease Control Program in Sergipe, identifying new priority areas for intervention and preferential ecotopes of the vectors, considering the occurrence of positive triatomines intradomicilliary and a source of new triatomines in the peridomiciles.

Youth participatory research and evaluation to inform a Chagas disease prevention program in Ecuador

This qualitative study engaged a group of young people in participatory research and evaluation activities in order to study to what extent engaging youth in health interventions can inform research and evaluation processes. We applied a youth participatory research and evaluation approach (PRE) to inform research and evaluation on the impact of a Chagas disease control program in southern Ecuador. Our main interest was to examine the methodological contributions of PRE to knowledge sharing for health intervention planning in the context of global health and neglected tropical diseases. The results of this study suggest that by demystifying research and evaluation practices and rendering them accessible and relevant, marginalized youth can develop critical and reflexive thinking skills that could be useful for decision-making on health promotion. Our findings also reveal the potential of youth as active participants in project development in ways that enhance, validate, and improve health interventions. Young people are interested in learning about and sharing local knowledge that can benefit research and evaluation processes. Despite the numerous strengths demonstrated by PRE, the inherent complexities of international development, such as cultural differences, asymmetrical power relations, and the ongoing challenges of sustainability, remain.

Insect vectors of Chagas disease (Trypanosoma cruzi) in Northeastern Brazil.

Chagas disease remains a public health problem in the rural and urban areas of 19 countries in the Americas. The aim of the present study was to investigate the Trypanosoma cruzi infection rate of triatomines collected from both intra- and peridomiciliary areas in eleven municipalities of Southeastern Ceará, Brazil, from 2009 to 2015. A total of 32,364 triatomine specimens, including nymphs and adults, were collected, and 31,736 (98.06%) of these were examined. More nymphs were collected than adults, and the greatest number of triatomines (n = 8,548) was collected in 2010, for which the infection rate was 1.3%, with the highest rate of infections observed for specimens from Quixere. The species collected during the study were identified as Triatoma pseudomaculata, Triatoma brasiliensis, Panstrongylus megistus, Panstrongylus lutzi, and Rhodnius nasutus, with T. pseudomaculata being the most abundant (n = 19,962). These results verify the presence of triatomines in both intra- and peridomiciliary areas, thereby ensuring persistence of the pathogen and consequently, the disease, as the presence of infected vectors in households is an important risk factor. According to these findings, the Chagas Disease Control Program should intensify its efforts in order to prevent the spread of the disease.

Molecular and serological detection of Trypanosoma cruzi in dogs (Canis lupus familiaris) suggests potential transmission risk in areas of recent acute Chagas disease outbreaks in Colombia

Chagas disease is a zoonotic infection widely distributed in tropical and subtropical regions of America, including more than 50% of the Colombian territory. In the last years, an increase of outbreaks of acute Chagas disease has been observed in the east of the country due to environmental changes and mammal movements toward human settlements. Given the importance of dogs (Canis lupus familiaris) as reservoir hosts and sentinels of Trypanosoma cruzi infection across different regions of America, in this study we reported a serological and molecular detection of T. cruzi infection in 242 dogs from an endemic area of Meta department (East of Colombia), with recent emergence of acute Chagas disease outbreaks. The distribution of T. cruzi infection in dogs was not homogeneous, ranging from 0–41.4% and 0–5.1% in different sampling sectors, through serological (ELISA/IFAT) and molecular methods (conventional and real time PCR), respectively. Statistical analysis indicated that dog infection was associated with specific sampling sectors. Our results show a moderate seroprevalence of infection and active circulation of T. cruzi in dogs from this zone, which suggest areas with potential risk of infection to human that must be taken into consideration when Chagas disease control programs need to be implemented.

Chagas Disease by Oral Transmission: Cardiovascular Manifestations

Introduction: Chagas disease is the most common cause of myocarditis in South, Central and parts of North America. More than 10million Latin Americans carry the protozoan parasite Trypanosoma cruzi, 25 millions of people at risk to acquire the disease and at least one million of them will die. Transmission of parasitosis habitually depends on the participation of infected triatomines. However, acute disease caused by the accidental ingestion of contamined food, either by feces of triatomines or anal secretion of marsupials has received considerable attention recently. A sparse number of outbreaks of orally acquired human Chagas disease have been reported from Brazil, Argentina, Colombia and Venezuela. The findings in multiple outbreaks established the absence of Romana’s sign or any external point of T. cruzi entrance, presence of simultaneous onset of Chagas disease acute symptoms in members of the same family or community. The clinical manifestations are prolonged fever, dyspnea, myalgias, headache, facial and limb edema. The cardiovascular findings are myocarditis, acute congestive failure, arrhythmias, and sudden death with high mortality rate estimated at 8-35%. Diagnosis can be made by direct methods, serologic techniques, inoculation in mice of culture blood, and polymerase chain reaction. In the follow up of these patients to prevent Chagas cardiomyopathy, it is important to perform echocardiographic and electrocardiographic evaluation to keep a close eye on systolic and diastolic biventricular function and abnormalities in 12-lead electrocardiogram in asymptomatic patients. Treatment of this disease use nitro derivates compounds, to avoid the parasite proliferation but aren’t able to eliminate the entire population of T.cruzi. Conclusion: Changes in the strategy of Chagas disease control programs are mandatory; which until now are limited to vector control activities in rural Latin American communities in endemic areas.

Chagas Disease Has Not Been Controlled in Ecuador.

Chagas Disease Has Not Been Controlled in Ecuador.

Markers for the population genetics studies of Triatoma sordida (Hemiptera: Reduviidae).

BackgroundTriatoma sordida, a vector of Trypanosoma cruzi, is native of Brazil, Bolivia, Paraguay, Argentina, and Uruguay, and occurs primarily in peridomiciles. Currently, it is the species most frequently captured by the Chagas Disease Control Program in Brazil. For this reason, population genetic studies attract great interest, as they can provide further information about the dispersal and household invasion processes of this species. In the absence of suitable markers, the objective of this study was to test the cross amplification of microsatellite primers.Findings23 primers were tested for microsatellite loci already described for other species of the genus Triatoma sp. Forty four specimens of T. sordida captured in the north of Minas Gerais were used to validate the use of standardized loci for population genetic analyses. It was possible to amplify 10 of the 23 loci tested for T. sordida.ConclusionsThis is the first study that provides 10 microsatellite markers for population analysis of this triatomine species. Cross-amplification of primers can be used among other phylogenetically related species whose loci are already available for study.

Positive deviance study to inform a Chagas disease control program in southern Ecuador.

Chagas disease is caused by Trypanosoma cruzi, which is mainly transmitted by the faeces of triatomine insects that find favourable environments in poorly constructed houses. Previous studies have documented persistent triatomine infestation in houses in the province of Loja in southern Ecuador despite repeated insecticide and educational interventions. We aim to develop a sustainable strategy for the interruption of Chagas disease transmission by promoting living environments that are designed to prevent colonisation of rural houses by triatomines. This study used positive deviance to inform the design of an anti-triatomine prototype house by identifying knowledge, attitudes and practices used by families that have remained triatomine-free (2010-2012). Positive deviants reported practices that included maintenance of structural elements of the house, fumigation of dwellings and animal shelters, sweeping with "insect repellent" plants and relocation of domestic animals away from the house, among others. Participants favoured construction materials that do not drastically differ from those currently used (adobe walls and tile roofs). They also expressed their belief in a clear connection between a clean house and health. The family's economic dynamics affect space use and must be considered in the prototype's design. Overall, the results indicate a positive climate for the introduction of housing improvements as a protective measure against Chagas disease in this region.

Prevalence of Chagas disease in pregnant women and congenital transmission of Trypanosoma cruzi in Brazil: a systematic review and meta-analysis.

To estimate the prevalence of Chagas disease in pregnant women and the risk of congenital transmission of Trypanosoma cruzi infection in Brazil, through a systematic review and meta-analysis. We searched electronic databases, grey literature and reference lists of included publications to identify epidemiological studies on the prevalence of Chagas disease in pregnant women and on the congenital transmission rate of T. cruzi infection in Brazil published between January 1980 and June 2013. Pooled estimates and 95% confidence intervals (95% CIs) were calculated using fixed- and random-effects models. Sixteen articles were included - 12 studies on the prevalence of Chagas disease in pregnant women (549,359 pregnant women) and nine on congenital transmission rates (1687 children born to infected mothers). Prevalence of Chagas disease in pregnant women ranged from 0.1% to 8.5%, and congenital transmission rates from 0% to 5.2%. The pooled prevalence of Chagas disease among pregnant women across studies was 1.1% (95% CI: 0.6-2.0); the pooled congenital transmission rate was 1.7% (95% CI: 0.9-3.1). In 2010, 34,629 pregnant women were estimated to be infected with T. cruzi, and 312-1073 children born (mean: 589 cases) with congenital infection. Congenital Chagas disease is a neglected public health problem in Brazil. Systematic congenital Chagas disease control programs through routine prenatal screening for T. cruzi should be widely implemented in Brazil's endemic areas, to identify infected pregnant women and newborns at risk of congenital infection.

Evaluation of the Chagas disease control program in Açucena Municipality, Rio Doce Valley, State of Minas Gerais, Brazil.

Açucena Municipality, Rio Doce Valley, State of Minas Gerais, Brazil temporarily (2001-2005) interrupted epidemiological surveillance for Chagas disease. The objective of this work was to evaluate the Chagas Disease Control Program (CDCP) in Açucena and to offer suggestions for improving local epidemiological surveillance. This study was conducted in three phases: I) a serological investigation of schoolchildren aged 5 to 15 years using an enzyme-linked immunosorbent assay (ELISA) test performed on blood collected on filter paper followed by ELISA, indirect immunofluorescence (IIF) and indirect hemaglutination (IHA) on venous blood for borderline cases and those in the gray zone of reactivity; II) vector evaluation using the data obtained by local health agents during 2006-2010; and III) examination by ELISA, IIF and IHA of serum samples from the inhabitants of houses where infected Triatoma vitticeps was found and evaluation of their knowledge about Chagas disease. Five individuals had inconclusive results in the ELISA screening but were seronegative for Chagas disease. The triatomine evaluation revealed the presence of three species: Triatoma vitticeps, Panstrongylus megistus and Panstrongylus diasi. Triatoma vitticeps was the most prevalent and widespread, with a higher (67%) index of Trypanosoma cruzi flagellates and evidence of colonization. Most of the inhabitants of the infested houses recognized triatomines and had basic knowledge about Chagas disease. Although T. vitticeps is not clearly associated with Chagas disease transmission, these results highlight the importance of maintaining CDCP in endemic areas and the need for greater emphasis on epidemiological surveillance, especially in areas with important vectorial changes or that have been modified by human intervention.