JM Ramsey; CJ Schofield
Most Latin American countries are making dramatic progress in controlling Chagas disease, through a series of national and international initiatives focusing on elimination of domestic populations of Triatominae, improved screening of blood donors, and clinical support and treatment of persons infected with Trypanosoma cruzi. Some countries, particularly Uruguay, Chile and Brazil, are sufficiently advanced in their programmes to initiate detailed planning of the subsequent phases of Chagas di...
Full Text Available Most Latin American countries are making dramatic progress in controlling Chagas disease, through a series of national and international initiatives focusing on elimination of domestic populations of Triatominae, improved screening of blood donors, and clinical support and treatment of persons infected with Trypanosoma cruzi. Some countries, particularly Uruguay, Chile and Brazil, are sufficiently advanced in their programmes to initiate detailed planning of the subsequent phases of Chagas disease control, while others such as Peru, Ecuador, and Mexico, are currently applying only the initial phases of the control campaigns. In this review, we seek to provide a brief history of the campaigns as a basis for discussion of future interventions. Our aim is to relate operational needs to the underlying biological aspects that have made Chagas disease so serious in Latin America but have also revealed the epidemiological vulnerability of this disease.
Claudio Ricardo Lazzari
Full Text Available Many arthropod species have adopted vertebrate blood as their main food source. Blood is rich in nutrients and, except for the presence of parasites, sterile. However, this food source is not freely available, nor is obtaining it devoid of risk. It circulates inside vessels hidden underneath the skin of mobile hosts that are able to defend themselves and even predate the insects that try to feed on them. Thus, the haematophagous lifestyle is associated with major morphological, physiological and behavioural adaptations that have accumulated throughout the evolutionary history of the various lineages of blood-sucking arthropods. These adaptations have significant consequences for the evolution of parasites as well as for the epidemiology of vector-transmitted diseases. In this review article, we analyse various aspects of the behaviour of triatomine bugs to illustrate how each behavioural trait represents a particular adaptation to their close association with their hosts, which may easily turn into predators. Our aim is to offer to the reader an up-to-date integrative perspective on the behaviour of Chagas disease vectors and to propose new research avenues to encourage both young and experienced colleagues to explore this aspect of triatomine biology.
AC Silveira; MC Vinhaes
The control of the vector-borne transmission of Chagas disease in Brazil was organized as a national program in 1975, when two large entomological and sero-epidemiological surveys were conducted in the country in order to identify areas at highest risk of transmission and to guide inerventions regarding the chemical treatment of domestic vectors of the disease. The authors present the baseline data gathered through these studies and compare them with more recent data. The evaluation performed...
Juárez M Patricia; Mijailovsky Sergio J; Girotti Juan R; Figueiras Alicia
Abstract Background The triatomine bugs are vectors of the protozoan parasite Trypanosoma cruzi, the causative agent of Chagas disease. Aggregation behavior plays an important role in their survival by facilitating the location of refuges and cohesion of aggregates, helping to keep them safely assembled into shelters during daylight time, when they are vulnerable to predators. There are evidences that aggregation is mediated by thigmotaxis, by volatile cues from their faeces, and by hexane-ex...
Levy, Michael Z.; Barbu, Corentin M.; Castillo-Neyra, Ricardo; Quispe-Machaca, Victor R.; Ancca-Juarez, Jenny; Escalante-Mejia, Patricia; Borrini-Mayori, Katty; Niemierko, Malwina; Mabud, Tarub S.; Behrman, Jere R.; Naquira-Velarde, Cesar
Modern cities represent one of the fastest growing ecosystems on the planet. Urbanization occurs in stages; each stage characterized by a distinct habitat that may be more or less susceptible to the establishment of disease vector populations and the transmission of vector-borne pathogens. We performed longitudinal entomological and epidemiological surveys in households along a 1900 × 125 m transect of Arequipa, Peru, a major city of nearly one million inhabitants, in which the transmission of Trypanosoma cruzi, the aetiological agent of Chagas disease, by the insect vector Triatoma infestans, is an ongoing problem. The transect spans a cline of urban development from established communities to land invasions. We find that the vector is tracking the development of the city, and the parasite, in turn, is tracking the dispersal of the vector. New urbanizations are free of vector infestation for decades. T. cruzi transmission is very recent and concentrated in more established communities. The increase in land tenure security during the course of urbanization, if not accompanied by reasonable and enforceable zoning codes, initiates an influx of construction materials, people and animals that creates fertile conditions for epidemics of some vector-borne diseases. PMID:24990681
A. M. Oliveira Filho
Full Text Available After a large scale field trial performed in central Brazil envisaging the control of Chagas' disease vectors in an endemic area colonized by Triatoma infestans and T. sordida the cost-effectiveness analysis for each insecticide/formulation was performed. It considered the operational costs and the prices of insecticides and formulations, related to the activity and persistence of each one. The end point was considered to be less than 90% of domicilliary unitis (house + annexes free of infestation. The results showed good cost-effectiveness for a slow-release emulsifiable suspension (SRES based on PVA and containing malathion as active ingredient, as well as for the pyrethroids tested in this assay-cyfluthrin, cypermethrin, deltamethrin and permethrin.
Mougabure-Cueto, Gastón; Picollo, María Inés
Chagas disease is a chronic parasitic infection restricted to America. The disease is caused by the protozoa Trypanosoma cruzi, which is transmitted to human through the feces of infected triatomine insects. Because no treatment is available for the chronic forms of the disease, vector chemical control represents the best way to reduce the incidence of the disease. Chemical control has been based principally on spraying dwellings with insecticide formulations and led to the reduction of triatomine distribution and consequent interruption of disease transmission in several areas from endemic region. However, in the last decade it has been repeatedly reported the presence triatomnes, mainly Triatoma infestans, after spraying with pyrethroid insecticides, which was associated to evolution to insecticide resistance. In this paper the evolution of insecticide resistance in triatomines is reviewed. The insecticide resistance was detected in 1970s in Rhodnius prolixus and 1990s in R. prolixus and T. infestans, but not until the 2000s resistance to pyrthroids in T. infestans associated to control failures was described in Argentina and Bolivia. The main resistance mechanisms (i.e. enhanced metabolism, altered site of action and reduced penetration) were described in the T. infestans resistant to pyrethrods. Different resistant profiles were demonstrated suggesting independent origin of the different resistant foci of Argentina and Bolivia. The deltamethrin resistance in T. infestans was showed to be controlled by semi-dominant, autosomally inherited factors. Reproductive and developmental costs were also demonstrated for the resistant T. infestans. A discussion about resistance and tolerance concepts and the persistence of T. infestans in Gran Chaco region are presented. In addition, theoretical concepts related to toxicological, evolutionary and ecological aspects of insecticide resistance are discussed in order to understand the particular scenario of pyrethroid
Chagas disease is caused by a parasite. It is common in Latin America but not in the United States. ... nose, the bite wound or a cut. The disease can also spread through contaminated food, a blood ...
Full Text Available Heavy domestic and peridomestic infestations of Triatoma infestans were controlled in two villages in southern Bolivia by the application of deltamethrin SC25 (2.5% suspension concentrate at a target dose of 25 mg a.i./m². Actual applied dose was monitored by HPLC analysis of filter papers placed at various heights on the house walls, and was shown to range from 0 to 59.6 about a mean of 28.5 mg a.i./m². Wall bioassays showed high mortality of T. infestans during the first month after the application of deltamethrin. Mortality declined to zero as summer temperatures increased, but reappeared with the onset of the following winter. In contrast, knockdown was apparent throughout the trial, showing no discernible temperature dependence. House infestation rates, measured by manual sampling and use of paper sheets to collect bug faeces, declined from 79% at the beginning of the trial to zero at the 6 month evaluation. All but one of the houses were still free of T. infestans at the final evaluation 12 months after spraying, although a small number of bugs were found at this time in 5 of 355 peridomestic dependencies. Comparative cost studies endorse the recommendation of large-scale application of deltamethrin, or pyrethroid of similar cost-effectiveness, as a means to eliminate domestic T. infestans populations in order to interrupt transmission of Chagas disease
Monsalve, Yoman; Panzera, Francisco; Herrera, Leidi; Triana-Chávez, Omar; Gómez-Palacio, Andrés
The emerging vector of Chagas disease, Triatoma maculata (Hemiptera, Reduviidae), is one of the most widely distributed Triatoma species in northern South America. Despite its increasing relevance as a vector, no consistent picture of the magnitude of genetic and phenetic diversity has yet been developed. Here, several populations of T. maculata from eleven Colombia and Venezuela localities were analyzed based on the morphometry of wings and the mitochondrial NADH dehydrogenase subunit 4 (ND4) gene sequences. Our results showed clear morphometric and genetic differences among Colombian and Venezuelan populations, indicating high intraspecific diversity. Inter-population divergence is suggested related to East Cordillera in Colombia. Analyses of other populations from Colombia, Venezuela, and Brazil from distinct eco-geographic regions are still needed to understand its systematics and phylogeography as well as its actual role as a vector of Chagas disease. PMID:27232127
Ribeiro, J.M.C.; Schwarz, Alexandra; Francischetti, I.M.B.
Roč. 52, č. 3 (2015), s. 351-358. ISSN 0022-2585 R&D Projects: GA MŠk LH12002; GA ČR GPP302/11/P798 Institutional support: RVO:60077344 Keywords : Chagas disease * vector biology * saliva ry gland * transcriptome * medical entomology Subject RIV: FN - Epidemiology, Contagious Diseases ; Clinical Immunology Impact factor: 1.953, year: 2014
Jane Costa; Marcelo Lorenzo
Despite the relevant achievements in the control of the main Chagas disease vectors Triatoma infestans and Rhodnius prolixus, several factors still promote the risk of infection. The disease is a real threat to the poor rural regions of several countries in Latin America. The current situation in Brazil requires renewed attention due to its high diversity of triatomine species and to the rapid and drastic environmental changes that are occurring. Using the biology, behaviour and diversity of ...
Cunha, Leonardo Rodrigues; de Oliveria Cudischevitch, Cecília; Carneiro, Alan Brito; Macedo, Gustavo Bartholomeu; Lannes, Denise; da Silva-Neto, Mário Alberto Cardoso
We evaluate a new approach to teaching the basic biochemistry mechanisms that regulate the biology of Triatominae, major vectors of "Trypanosoma cruzi," the causative agent of Chagas disease. We have designed and used a comic book, "Carlos Chagas: 100 years after a hero's discovery" containing scientific information…
C. I. Abramson; E. Aldana; E. Sulbaran
The main vector of Chagas disease in Venezuela was exposed to the odors of citral, cinnamon and ruda. Cinnamon was found to stop the life cycle of Rhodnius prolixus relative to untreated animals. Citral and ruda also influenced the life cycle but not to the extent of animals exposed to cinnamon. We suggest that future research be directed toward using cinnamon in field and toxicity tests.
Fabio Faria da Mota
Full Text Available BACKGROUND: Chagas disease is a trypanosomiasis whose agent is the protozoan parasite Trypanosoma cruzi, which is transmitted to humans by hematophagous bugs known as triatomines. Even though insecticide treatments allow effective control of these bugs in most Latin American countries where Chagas disease is endemic, the disease still affects a large proportion of the population of South America. The features of the disease in humans have been extensively studied, and the genome of the parasite has been sequenced, but no effective drug is yet available to treat Chagas disease. The digestive tract of the insect vectors in which T. cruzi develops has been much less well investigated than blood from its human hosts and constitutes a dynamic environment with very different conditions. Thus, we investigated the composition of the predominant bacterial species of the microbiota in insect vectors from Rhodnius, Triatoma, Panstrongylus and Dipetalogaster genera. METHODOLOGY/PRINCIPAL FINDINGS: Microbiota of triatomine guts were investigated using cultivation-independent methods, i.e., phylogenetic analysis of 16s rDNA using denaturing gradient gel electrophoresis (DGGE and cloned-based sequencing. The Chao index showed that the diversity of bacterial species in triatomine guts is low, comprising fewer than 20 predominant species, and that these species vary between insect species. The analyses showed that Serratia predominates in Rhodnius, Arsenophonus predominates in Triatoma and Panstrongylus, while Candidatus Rohrkolberia predominates in Dipetalogaster. CONCLUSIONS/SIGNIFICANCE: The microbiota of triatomine guts represents one of the factors that may interfere with T. cruzi transmission and virulence in humans. The knowledge of its composition according to insect species is important for designing measures of biological control for T. cruzi. We found that the predominant species of the bacterial microbiota in triatomines form a group of low
Kathryn Rosecrans; Gabriela Cruz-Martin; Ashley King; Eric Dumonteil
BACKGROUND: Chagas disease is a vector-borne parasitic disease of major public health importance. Current prevention efforts are based on triatomine vector control to reduce transmission to humans. Success of vector control interventions depends on their acceptability and value to affected communities. We aimed to identify opportunities for and barriers to improved vector control strategies in the Yucatan peninsula, Mexico. METHODOLOGY/PRINCIPAL FINDINGS: We employed a sequence of qualitative...
Full Text Available BACKGROUND: Chagas disease is a vector-borne parasitic disease of major public health importance. Current prevention efforts are based on triatomine vector control to reduce transmission to humans. Success of vector control interventions depends on their acceptability and value to affected communities. We aimed to identify opportunities for and barriers to improved vector control strategies in the Yucatan peninsula, Mexico. METHODOLOGY/PRINCIPAL FINDINGS: We employed a sequence of qualitative and quantitative research methods to investigate knowledge, attitudes and practices surrounding Chagas disease, triatomines and vector control in three rural communities. Our combined data show that community members are well aware of triatomines and are knowledgeable about their habits. However, most have a limited understanding of the transmission dynamics and clinical manifestations of Chagas disease. While triatomine control is not a priority for community members, they frequently use domestic insecticide products including insecticide spray, mosquito coils and plug-in repellents. Families spend about $32 US per year on these products. Alternative methods such as yard cleaning and window screens are perceived as desirable and potentially more effective. Screens are nonetheless described as unaffordable, in spite of a cost comparable to the average annual spending on insecticide products. CONCLUSION/SIGNIFICANCE: Further education campaigns and possibly financing schemes may lead families to redirect their current vector control spending from insecticide products to window screens. Also, synergism with mosquito control efforts should be further explored to motivate community involvement and ensure sustainability of Chagas disease vector control.
Luiz Henrique Conde SANGENIS
Full Text Available SUMMARY Chagas disease (CD is an endemic anthropozoonosis from Latin America of which the main means of transmission is the contact of skin lesions or mucosa with the feces of triatomine bugs infected by Trypanosoma cruzi. In this article, we describe the first acute CD case acquired by vector transmission in the Rio de Janeiro State and confirmed by parasitological, serological and PCR tests. The patient presented acute cardiomyopathy and pericardial effusion without cardiac tamponade. Together with fever and malaise, a 3 cm wide erythematous, non-pruritic, papule compatible with a "chagoma" was found on his left wrist. This case report draws attention to the possible transmission of CD by non-domiciled native vectors in non-endemic areas. Therefore, acute CD should be included in the diagnostic workout of febrile diseases and acute myopericarditis in Rio de Janeiro.
Bethânia A. Avelar-Freitas
Full Text Available Control of Chagas disease is based on insecticide spraying in domiciles in order to exterminate triatomine populations. However, since the vectors differ in susceptibility to currently used insecticides, the screening of the toxic potential of Brazilian flora may identify new molecules lethal to triatomines. This study evaluated the toxicity of ethanolic extract of Ageratum fastigiatum (Gardner R.M. King & H. Rob., Asteraceae, on Rhodnius nasutus, a known vector of Chagas disease. Ethanolic extracts of the aerial parts of A. fastigiatum were prepared at 25 and 50 mg/mL concentrations, and 5 µL was applied to fifth-instar nymphs of R. nasutus (n=30. Controls included nymphs that were treated with 5 µL ethanol (n=30 or left untreated (n=30. The percentage of dead insects in each group was observed at 24, 48, 72, 96 and 120 h after application. The extracts of A. fastigiatum showed a mortality rate of about 37% and 77% after 120 h, at concentrations of 25 and 50 mg/mL, respectively. In control groups, the mortality rate remained under 7%. The extract of A. fastigiatum contains a coumarin, a molecule with recognized toxicity in insects, and which may be responsible for killing the triatomines.
Pelosse, Perrine; Kribs-Zaleta, Christopher M.; Ginoux, Marine; Rabinovich, Jorge E; Gourbière, Sébastien; Menu, Frédéric
Insects are known to display strategies that spread the risk of encountering unfavorable conditions, thereby decreasing the extinction probability of genetic lineages in unpredictable environments. To what extent these strategies influence the epidemiology and evolution of vector-borne diseases in stochastic environments is largely unknown. In triatomines, the vectors of the parasite Trypanosoma cruzi, the etiological agent of Chagas' disease, juvenile development time varies between individu...
Yevstigneyeva, Violetta; Camara-Mejia, Javier; Dumonteil, Eric
Background Chagas disease is a tropical parasitic disease affecting about 10 million people, mostly in the Americas, and transmitted mainly by triatomine bugs. Insect vector control with indoor residual insecticides and the promotion of housing improvement is the main control intervention. The success of such interventions relies on their acceptance and appropriation by communities, which depends on their knowledge and perceptions of both the disease and the vector. In this study, we investig...
Violetta Yevstigneyeva; Javier Camara-Mejia; Eric Dumonteil
Chagas disease is a tropical parasitic disease affecting about 10 million people, mostly in the Americas, and transmitted mainly by triatomine bugs. Insect vector control with indoor residual insecticides and the promotion of housing improvement is the main control intervention. The success of such interventions relies on their acceptance and appropriation by communities, which depends on their knowledge and perceptions of both the disease and the vector. In this study, we investigated school...
Full Text Available The authors report the case of a female infant with Group III (or Grade III megaesophagus secondary to vector-borne Chagas disease, resulting in severe malnutrition that reversed after surgery (Heller technique. The infant was then treated with the antiparasitic drug benznidazole, and the infection was cured, as demonstrated serologically and parasitologically. After follow-up of several years without evidence of disease, with satisfactory weight and height development, the patient had her first child at age 23, in whom serological tests for Chagas disease yielded negative results. Thirty years after the initial examination, the patient's electrocardiogram, echocardiogram, and chest radiography remained normal.
Full Text Available Chagas disease is a tropical parasitic disease affecting about 10 million people, mostly in the Americas, and transmitted mainly by triatomine bugs. Insect vector control with indoor residual insecticides and the promotion of housing improvement is the main control intervention. The success of such interventions relies on their acceptance and appropriation by communities, which depends on their knowledge and perceptions of both the disease and the vector. In this study, we investigated school-aged children's knowledge and perception on triatomine vectors and Chagas disease to further understand how communities view this vector and the disease in Yucatan, Mexico.We performed an analysis of children's drawings on the theme of triatomines and their house in several rural villages, to explore in an open-ended manner their views, understanding and misconceptions. A total of 261 drawings were collected from children ages 6-12 from four villages. We found that children are very familiar with triatomine vectors, and know very well many aspects of their biology and ecology, and in particular their blood-feeding habits. On the other hand, their drawings suggest that the role of triatomines as vectors of a chronic and severe cardiac disease is less understood, and the main perceived health threat appears limited to the bite itself, as previously observed in adults.These results have important implications for the specific design of future education materials and campaigns, and for the promotion of the inclusion of children in raising Chagas disease awareness in these endemic communities.
Full Text Available Although Brazil was declared free from Chagas disease transmission by the domestic vector Triatoma infestans, human acute cases are still being registered based on transmission by native triatomine species. For a better understanding of transmission risk, the geographic distribution of Brazilian triatomines was analyzed. Sixteen out of 62 Brazilian species that both occur in >20 municipalities and present synanthropic tendencies were modeled based on their ecological niches. Panstrongylus geniculatus and P. megistus showed broad ecological ranges, but most of the species sort out by the biome in which they are distributed: Rhodnius pictipes and R. robustus in the Amazon; R. neglectus, Triatoma sordida, and T. costalimai in the Cerrado; R. nasutus, P. lutzi, T. brasiliensis, T. pseudomaculata, T. melanocephala, and T. petrocchiae in the Caatinga; T. rubrovaria in the southern pampas; T. tibiamaculata and T. vitticeps in the Atlantic Forest. Although most occurrences were recorded in open areas (Cerrado and Caatinga, our results show that all environmental conditions in the country are favorable to one or more of the species analyzed, such that almost nowhere is Chagas transmission risk negligible.
Durvasula Ravi V
Full Text Available Abstract Background Paratransgenesis is an approach to reducing arthropod vector competence using genetically modified symbionts. When applied to control of Chagas disease, the symbiont bacterium Rhodococcus rhodnii, resident in the gut lumen of the triatomine vector Rhodnius prolixus (Hemiptera: Reduviidae, is transformed to export cecropin A, an insect immune peptide. Cecropin A is active against Trypanosoma cruzi, the causative agent of Chagas disease. While proof of concept has been achieved in laboratory studies, a rigorous and comprehensive risk assessment is required prior to consideration of field release. An important part of this assessment involves estimating probability of transgene horizontal transfer to environmental organisms (HGT. This article presents a two-part risk assessment methodology: a theoretical model predicting HGT in the gut of R. prolixus from the genetically transformed symbiont R. rhodnii to a closely related non-target bacterium, Gordona rubropertinctus, in the absence of selection pressure, and a series of laboratory trials designed to test the model. Results The model predicted an HGT frequency of less than 1.14 × 10-16 per 100,000 generations at the 99% certainty level. The model was iterated twenty times, with the mean of the ten highest outputs evaluated at the 99% certainty level. Laboratory trials indicated no horizontal gene transfer, supporting the conclusions of the model. Conclusions The model treats HGT as a composite event, the probability of which is determined by the joint probability of three independent events: gene transfer through the modalities of transformation, transduction, and conjugation. Genes are represented in matrices and Monte Carlo method and Markov chain analysis are used to simulate and evaluate environmental conditions. The model is intended as a risk assessment instrument and predicts HGT frequency of less than 1.14 × 10-16 per 100,000 generations. With laboratory studies that
Full Text Available 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.
Waleckx, Etienne; Camara-Mejia, Javier; Ramirez-Sierra, Maria Jesus; Cruz-Chan, Vladimir; Rosado-Vallado, Miguel; Vazquez-Narvaez, Santos; Najera-Vazquez, Rosario; Gourbière, Sébastien; Dumonteil, Eric
Background Non-domiciliated (intrusive) triatomine vectors remain a challenge for the sustainability of Chagas disease vector control as these triatomines are able to transiently (re-)infest houses. One of the best-characterized examples is Triatoma dimidiata from the Yucatan peninsula, Mexico, where adult insects seasonally infest houses between March and July. Methods We focused our study on three rural villages in the state of Yucatan, Mexico, in which we performed a situation analysis as a first step before the implementation of an ecohealth (ecosystem approach to health) vector control intervention. Results The identification of the key determinants affecting the transient invasion of human dwellings by T. dimidiata was performed by exploring associations between bug presence and qualitative and quantitative variables describing the ecological, biological and social context of the communities. We then used a participatory action research approach for implementation and evaluation of a control strategy based on window insect screens to reduce house infestation by T. dimidiata. Conclusions This ecohealth approach may represent a valuable alternative to vertically-organized insecticide spraying. Further evaluation may confirm that it is sustainable and provides effective control (in the sense of limiting infestation of human dwellings and vector/human contacts) of intrusive triatomines in the region. PMID:25604765
Waleckx, Etienne; Gourbière, Sébastien; Dumonteil, Eric
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. PMID:25993504
Khatchikian, Camilo E.; Foley, Erica A.; Barbu, Corentin M.; Hwang, Josephine; Ancca-Juárez, Jenny; Borrini-Mayori, Katty; Quıspe-Machaca, Victor R.; Naquira, Cesar; Brisson, Dustin; Levy, Michael Z.
Chagas disease is a vector-borne disease endemic in Latin America. Triatoma infestans, a common vector of this disease, has recently expanded its range into rapidly developing cities of Latin America. We aim to identify the environmental features that affect the colonization and dispersal of T. infestans in an urban environment. We amplified 13 commonly used microsatellites from 180 T. infestans samples collected from a sampled transect in the city of Arequipa, Peru, in 2007 and 2011. We assessed the clustering of subpopulations and the effect of distance, sampling year, and city block location on genetic distance among pairs of insects. Despite evidence of genetic similarity, the majority of city blocks are characterized by one dominant insect genotype, suggesting the existence of barriers to dispersal. Our analyses show that streets represent an important barrier to the colonization and dispersion of T. infestans in Arequipa. The genetic data describe a T. infestans infestation history characterized by persistent local dispersal and occasional long-distance migration events that partially parallels the history of urban development. PMID:25646757
Camilo E Khatchikian
Full Text Available Chagas disease is a vector-borne disease endemic in Latin America. Triatoma infestans, a common vector of this disease, has recently expanded its range into rapidly developing cities of Latin America. We aim to identify the environmental features that affect the colonization and dispersal of T. infestans in an urban environment. We amplified 13 commonly used microsatellites from 180 T. infestans samples collected from a sampled transect in the city of Arequipa, Peru, in 2007 and 2011. We assessed the clustering of subpopulations and the effect of distance, sampling year, and city block location on genetic distance among pairs of insects. Despite evidence of genetic similarity, the majority of city blocks are characterized by one dominant insect genotype, suggesting the existence of barriers to dispersal. Our analyses show that streets represent an important barrier to the colonization and dispersion of T. infestans in Arequipa. The genetic data describe a T. infestans infestation history characterized by persistent local dispersal and occasional long-distance migration events that partially parallels the history of urban development.
Anis Rassi; Joffre Marcondes de Rezende; Anis Rassi Junior
The authors report the case of a female infant with Group III (or Grade III) megaesophagus secondary to vector-borne Chagas disease, resulting in severe malnutrition that reversed after surgery (Heller technique). The infant was then treated with the antiparasitic drug benznidazole, and the infection was cured, as demonstrated serologically and parasitologically. After follow-up of several years without evidence of disease, with satisfactory weight and height development, the patient had her ...
Campos-Soto, Ricardo; Ortiz, Sylvia; Cordova, Ivan; Bruneau, Nicole; Botto-Mahan, Carezza; Solari, Aldo
Chagas disease, which ranks among the world's most neglected diseases, is a chronic, systemic, parasitic infection caused by the protozoan Trypanosoma cruzi. Mepraia species are the wild vectors of this parasite in Chile. Host-parasite interactions can occur at several levels, such as co-speciation and ecological host fitting, among others. Thus, we are exploring the interactions between T. cruzi circulating in naturally infected Mepraia species in all areas endemic of Chile. We evaluated T. cruzi infection rates of 27 different haplotypes of the wild Mepraia species and identified their parasite genotypes using minicircle PCR amplification and hybridization tests with genotype-specific DNA probes. Infection rates were lower in northern Chile where Mepraia gajardoi circulates (10-35%); in central Chile, Mepraia spinolai is most abundant, and infection rates varied in space and time (0-55%). T. cruzi discrete typing units (DTUs) TcI, TcII, TcV, and Tc VI were detected. Mixed infections with two or more DTUs are frequently found in highly infected insects. T. cruzi DTUs have distinct, but not exclusive, ecological and epidemiological associations with their hosts. T. cruzi infection rates of M. spinolai were higher than in M. gajardoi, but the presence of mixed infection with more than one T. cruzi DTU was the same. The same T. cruzi DTUs (TcI, TcII, TcV, and TcVI) were found circulating in both vector species, even though TcI was not equally distributed. These results suggest that T. cruzi DTUs are not associated with any of the two genetically related vector species nor with the geographic area. The T. cruzi vectors interactions are discussed in terms of old and recent events. By exploring T. cruzi DTUs present in Mepraia haplotypes and species from northern to central Chile, we open the analysis on these invertebrate host-parasite interactions. PMID:26771702
Santiago, Paula Beatriz; Assumpção, Teresa C. F.; de Araújo, Carla Nunes; Bastos, Izabela Marques Dourado; Neves, David; da Silva, Ionizete Garcia; Charneau, Sébastien; Queiroz, Rayner Myr L.; Raiol, Tainá; Oliveira, João Victor de Araújo; de Sousa, Marcelo Valle; Calvo, Eric; Ribeiro, José M. C.; Santana, Jaime M.
Background Triatomines are hematophagous insects that act as vectors of Chagas disease. Rhodnius neglectus is one of these kissing bugs found, contributing to the transmission of this American trypanosomiasis. The saliva of hematophagous arthropods contains bioactive molecules responsible for counteracting host haemostatic, inflammatory, and immune responses. Methods/Principal Findings Next generation sequencing and mass spectrometry-based protein identification were performed to investigate the content of triatomine R. neglectus saliva. We deposited 4,230 coding DNA sequences (CDS) in GenBank. A set of 636 CDS of proteins of putative secretory nature was extracted from the assembled reads, 73 of them confirmed by proteomic analysis. The sialome of R. neglectus was characterized and serine protease transcripts detected. The presence of ubiquitous protein families was revealed, including lipocalins, serine protease inhibitors, and antigen-5. Metalloproteases, disintegrins, and odorant binding protein families were less abundant. Conclusions/Significance The data presented improve our understanding of hematophagous arthropod sialomes, and aid in understanding hematophagy and the complex interplay among vectors and their vertebrate hosts. PMID:27129103
This podcast is designed to inform health care providers about Chagas disease, diagnosis, and treatment and to assist in identifying infected patients. Created: 4/3/2008 by National Center for Zoonotic, Vector-Borne, and Enteric Diseases (NCZVED). Date Released: 4/8/2008.
Insect control with insecticides and houses that are less likely to have high insect populations will help control the spread of the disease. Blood banks in Central and South America screen donors for ...
Janine M Ramsey
Full Text Available Chagas disease is one of the most important yet neglected parasitic diseases in Mexico and is transmitted by Triatominae. Nineteen of the 31 Mexican triatomine species have been consistently found to invade human houses and all have been found to be naturally infected with Trypanosoma cruzi. The present paper aims to produce a state-of-knowledge atlas of Mexican triatomines and analyse their geographic associations with T. cruzi, human demographics and landscape modification. Ecological niche models (ENMs were constructed for the 19 species with more than 10 records in North America, as well as for T. cruzi. The 2010 Mexican national census and the 2007 National Forestry Inventory were used to analyse overlap patterns with ENMs. Niche breadth was greatest in species from the semiarid Nearctic Region, whereas species richness was associated with topographic heterogeneity in the Neotropical Region, particularly along the Pacific Coast. Three species, Triatoma longipennis, Triatoma mexicana and Triatoma barberi, overlapped with the greatest numbers of human communities, but these communities had the lowest rural/urban population ratios. Triatomine vectors have urbanised in most regions, demonstrating a high tolerance to human-modified habitats and broadened historical ranges, exposing more than 88% of the Mexican population and leaving few areas in Mexico without the potential for T. cruzi transmission.
Lowenberger, Carl; Rivera Pomar, Rolando; Monteiro, Fernando A.; Minx, Patrick; Spieth, John; Bernardo Carvalho, A.; Panzera, Francisco; Lawson, Daniel; Torres, Andre Q.; Ribeiro, Jose M. C.; Sorgine, Marcos H. F.; Waterhouse, Robert M; Montague, Michael J.; Abad Franch, Fernando; Alves Bezerra, Michele
Rhodnius prolixus not only has served as a model organism for the study of insect physiology, but also is a major vector of Chagas disease, an illness that affects approximately seven million people worldwide. We sequenced the genome of R. prolixus, generated assembled sequences covering 95% of the genome (similar to 702 Mb), including 15,456 putative protein-coding genes, and completed comprehensive genomic analyses of this obligate blood-feeding insect. Although immune-deficiency (IMD)-medi...
Hernández, Jaime; Núñez, Ignacia; Bacigalupo, Antonella; PEDRO E. CATTAN
Background Chagas disease is caused by the protozoan Trypanosoma cruzi, which is transmitted to mammal hosts by triatomine insect vectors. The goal of this study was to model the spatial distribution of triatomine species in an endemic area. Methods Vector’s locations were obtained with a rural householders’ survey. This information was combined with environmental data obtained from remote sensors, land use maps and topographic SRTM data, using the machine learning algorithm Random Forests to...
Pacheco-Tucuch, Freddy Santiago; Ramirez-Sierra, Maria Jesus; Gourbière, Sébastien; Dumonteil, Eric
Triatoma dimidiata is one of the primary vectors of Chagas disease. We previously documented the spatio-temporal infestation of houses by this species in the Yucatan peninsula, Mexico, and found that non-domiciliated triatomines were specifically attracted to houses. However, the factors mediating this attraction remained unclear. Artificial light has been known for a long time to attract many insect species, and therefore may contribute to the spread of different vector-borne diseases. Also, based on the collection of different species of triatomines with light traps, several authors have suggested that light might attract triatomines to houses, but the role of artificial light in house infestation has never been clearly demonstrated and quantified. Here we performed a spatial analysis of house infestation pattern by T. dimidiata in relation to the distribution of artificial light sources in three different villages from the Yucatan peninsula, Mexico. In all three villages, infested houses were significantly closer to public street light sources than non-infested houses (18.0 ± 0.6 vs 22.6 ± 0.4 m), and street lights rather than domestic lights were associated with house infestation. Accordingly, houses closer to a public street lights were 1.64 times more likely to be infested than houses further away (OR, CI95% 1.23-2.18). Behavioral experiments using a dual-choice chamber further confirmed that adult male and females were attracted to white light during their nocturnal activity. Attraction was also dependent on light color and decreased with increasing wavelength. While public lighting is usually associated with increased development, these data clearly show that it also directly contributes to house infestation by non-domiciliated T. dimidiata. PMID:22558384
Mesk, Mohammed; Mahdjoub, Tewfik; Gourbière, Sébastien; Rabinovich, Jorge E; Menu, Frédéric
Demographic processes and spatial dispersal of Triatoma dimidiata, a triatomine species vector of Chagas disease, are modeled by integrodifference equations to estimate invasion capacity of this species under different ecological conditions. The application of the theory of orthogonal polynomials and the steepest descent method applied to these equations, allow a good approximation of the abundance of the adult female population and the invasion speed. We show that: (1) under the same mean conditions of demography and dispersal, periodic spatial dispersal results in an invasion speed 2.5 times larger than the invasion speed when spatial dispersal is continuous; (2) when the invasion speed of periodic spatial dispersal is correlated to adverse demographic conditions, it is 34.7% higher as compared to a periodic dispersal that is correlated to good demographic conditions. From our results we conclude, in terms of triatomine population control, that the invasive success of T. dimidiata may be most sensitive to the probability of transition from juvenile to adult stage. We discuss our main theoretical predictions in the light of observed data in different triatomines species found in the literature. PMID:26807809
Full Text Available Reported are observations on spontaneous occurring morphogenetic juvenilization in laboratory populations of vector species of Chagas disease. Two general effects have been observed: arrested development and uncoordinated development. These are manifested by supernumerary nymphs (6th stage, intermediate nymphal-adult stages, badly deformed adults developed from 5th instar nymphs, uncoordinated development manifested by grotesque forms of adults, supernumerary adults unable to complete metamorphosis and complete supernumerary adults produced by 6th stage nymphs. The reoccurrence of insects with identical grades of juvenilization in the population is an indication that this is a genetic trait that might be inherited. The factors responsible for morphogenetic juvenilization cannot be transmitted through the juvenilized insects because they are sterile, than they were transmitted through normal insects probably as a recessive or a group recessive factors. The spontaneous morphogenetic juvenilization observed in laboratory populations has a striking similarity to juvenilizing effects induced by application of juvenile hormone analogues, described in the literature and also obtained in our laboratory in a study to be published. Thus it is suggested that both; the altered phenotypes occurring in wild populations and their "phenocopies" induced by the application of juvenile hormone analogues are products of gene controlled identical reactions.
Mabel L Taracena
Full Text Available Technologies based on RNA interference may be used for insect control. Sustainable strategies are needed to control vectors of Chagas disease such as Rhodnius prolixus. The insect microbiota can be modified to deliver molecules to the gut. Here, Escherichia coli HT115(DE3 expressing dsRNA for the Rhodnius heme-binding protein (RHBP and for catalase (CAT were fed to nymphs and adult triatomine stages. RHBP is an egg protein and CAT is an antioxidant enzyme expressed in all tissues by all developmental stages. The RNA interference effect was systemic and temporal. Concentrations of E. coli HT115(DE3 above 3.35 × 10(7 CFU/mL produced a significant RHBP and CAT gene knockdown in nymphs and adults. RHBP expression in the fat body was reduced by 99% three days after feeding, returning to normal levels 10 days after feeding. CAT expression was reduced by 99% and 96% in the ovary and the posterior midgut, respectively, five days after ingestion. Mortality rates increased by 24-30% in first instars fed RHBP and CAT bacteria. Molting rates were reduced by 100% in first instars and 80% in third instars fed bacteria producing RHBP or CAT dsRNA. Oviposition was reduced by 43% (RHBP and 84% (CAT. Embryogenesis was arrested in 16% (RHBP and 20% (CAT of laid eggs. Feeding females 105 CFU/mL of the natural symbiont, Rhodococcus rhodnii, transformed to express RHBP-specific hairpin RNA reduced RHBP expression by 89% and reduced oviposition. Modifying the insect microbiota to induce systemic RNAi in R. prolixus may result in a paratransgenic strategy for sustainable vector control.
May-Concha, Irving; Guerenstein, Pablo G; Ramsey, Janine M; Rojas, Julio C; Catalá, Silvia
Triatoma dimidiata (Latreille) is a species complex that spans North, Central, and South America and which is a key vector of all known discrete typing units (DTU) of Trypanosoma cruzi, the etiologic agent of Chagas disease. Morphological and genetic studies indicate that T. dimidiata is a species complex with three principal haplogroups (hg) in Mexico. Different markers and traits are still inconclusive regarding if other morphological differentiation may indicate probable behavioral and vectorial divergences within this complex. In this paper we compared the antennae of three Mexican haplogroups (previously verified by molecular markers ND4 and ITS-2) and discussed possible relationships with their capacity to disperse and colonized new habitats. The abundance of each type of sensillum (bristles, basiconics, thick- and thin-walled trichoids) on the antennae of the three haplogroups, were measured under light microscopy and compared using Kruskal-Wallis non-parametric and multivariate non-parametric analyses. Discriminant analyses indicate significant differences among the antennal phenotype of haplogroups either for adults and some nymphal stages, indicating consistency of the character to analyze intraspecific variability within the complex. The present study shows that the adult antennal pedicel of the T. dimidiata complex have abundant chemosensory sensilla, according with good capacity for dispersal and invasion of different habitats also related to their high capacity to adapt to conserved as well as modified habitats. However, the numerical differences among the haplogroups are suggesting variations in that capacity. The results here presented support the evidence of T. dimidiata as a species complex but show females and males in a different way. Given the close link between the bug's sensory system and its habitat and host-seeking behavior, AP characterization could be useful to complement genetic, neurological and ethological studies of the closely
Full Text Available Insects are known to display strategies that spread the risk of encountering unfavorable conditions, thereby decreasing the extinction probability of genetic lineages in unpredictable environments. To what extent these strategies influence the epidemiology and evolution of vector-borne diseases in stochastic environments is largely unknown. In triatomines, the vectors of the parasite Trypanosoma cruzi, the etiological agent of Chagas' disease, juvenile development time varies between individuals and such variation most likely decreases the extinction risk of vector populations in stochastic environments. We developed a simplified multi-stage vector-borne SI epidemiological model to investigate how vector risk-spreading strategies and environmental stochasticity influence the prevalence and evolution of a parasite. This model is based on available knowledge on triatomine biodemography, but its conceptual outcomes apply, to a certain extent, to other vector-borne diseases. Model comparisons between deterministic and stochastic settings led to the conclusion that environmental stochasticity, vector risk-spreading strategies (in particular an increase in the length and variability of development time and their interaction have drastic consequences on vector population dynamics, disease prevalence, and the relative short-term evolution of parasite virulence. Our work shows that stochastic environments and associated risk-spreading strategies can increase the prevalence of vector-borne diseases and favor the invasion of more virulent parasite strains on relatively short evolutionary timescales. This study raises new questions and challenges in a context of increasingly unpredictable environmental variations as a result of global climate change and human interventions such as habitat destruction or vector control.
Pelosse, Perrine; Kribs-Zaleta, Christopher M; Ginoux, Marine; Rabinovich, Jorge E; Gourbière, Sébastien; Menu, Frédéric
Insects are known to display strategies that spread the risk of encountering unfavorable conditions, thereby decreasing the extinction probability of genetic lineages in unpredictable environments. To what extent these strategies influence the epidemiology and evolution of vector-borne diseases in stochastic environments is largely unknown. In triatomines, the vectors of the parasite Trypanosoma cruzi, the etiological agent of Chagas' disease, juvenile development time varies between individuals and such variation most likely decreases the extinction risk of vector populations in stochastic environments. We developed a simplified multi-stage vector-borne SI epidemiological model to investigate how vector risk-spreading strategies and environmental stochasticity influence the prevalence and evolution of a parasite. This model is based on available knowledge on triatomine biodemography, but its conceptual outcomes apply, to a certain extent, to other vector-borne diseases. Model comparisons between deterministic and stochastic settings led to the conclusion that environmental stochasticity, vector risk-spreading strategies (in particular an increase in the length and variability of development time) and their interaction have drastic consequences on vector population dynamics, disease prevalence, and the relative short-term evolution of parasite virulence. Our work shows that stochastic environments and associated risk-spreading strategies can increase the prevalence of vector-borne diseases and favor the invasion of more virulent parasite strains on relatively short evolutionary timescales. This study raises new questions and challenges in a context of increasingly unpredictable environmental variations as a result of global climate change and human interventions such as habitat destruction or vector control. PMID:23951018
Castillo-Neyra, Ricardo; Barbu, Corentin M.; Salazar, Renzo; Borrini, Katty; Naquira, Cesar; Levy, Michael Z.
Chagas disease affects millions of people in Latin America. The control of this vector-borne disease focuses on halting transmission by reducing or eliminating insect vector populations. Most transmission of Trypanosoma cruzi, the causative agent of Chagas disease, involves insects living within or very close to households and feeding mostly on domestic animals. As animal hosts can be intermittently present it is important to understand how host availability can modify transmission risk to humans and to characterize the host-seeking dispersal of triatomine vectors on a very fine scale. We used a semi-field system with motion-detection cameras to characterize the dispersal of Triatoma infestans, and compare the behavior of vector populations in the constant presence of hosts (guinea pigs), and after the removal of the hosts. The emigration rate – net insect population decline in original refuge – following host removal was on average 19.7% of insects per 10 days compared to 10.2% in constant host populations (p = 0.029). However, dispersal of T. infestans occurred in both directions, towards and away from the initial location of the hosts. The majority of insects that moved towards the original location of guinea pigs remained there for 4 weeks. Oviposition and mortality were observed and analyzed in the context of insect dispersal, but only mortality was higher in the group where animal hosts were removed (p-value vector control. Removing domestic animals in infested areas increases vector dispersal from the first day of host removal. The implications of these patterns of vector dispersal in a field setting are not yet known but could result in movement towards human rooms. PMID:25569228
M. A. Miles
Full Text Available Trypanosoma cruzi infected Rhodnius robustus and/or Rhodnius pictipes were commonly found, in large numbers, in the Brazilian Amazonian palms Maximiliana regia ("inajá", Acrocomia sclerocarpa ("mucajá" and Orbignya speciosa ("babaçu". The common opossum, Didelphis marsupialis, was the animal most frequently associated with triatomine infested palms. R. pictipes, frequently light-attracted into houses from palm trees, was the probable source of an acute case of Chagas' disease in the vicinity of Belém. It is considered that triatomine infested palms are likely to cause some cases of acute Chagas' disease in the States of Amazonas and Rondônia. Possible control methods are suggested.Rhodnius robustus e/ou Rhodnius pictipes, infectados com Trypanosoma cruzi foram comumente encontrados, em grande numero, nas palmeiras Maximiliana regia (inaja, Acrocomia sclerocarpa (mucaja e Orbignya speciosa (babacu na Amazonia brasileira. O marsupial Didelphis marsupialis foi o animal encontrado mais frequentemente nas palmeiras associadas a alta prevalencia de triatomineos. R. pictipes que e atraido pela luz nas residencias de palmeiras vizinhas, provavelmente e a fonte de um caso agudo de doenca de Chagas nas vizinhancas de Belem. Sugere-se que as palmeiras albergando triatomineos poderiam ser relacionadas com infeccoes humanas de doenca de Chagas nos Estados de Amazonas e Rondonia. Sugere-se, tambem, possiveis metodos de controle.
Full Text Available Reported are observations on spontaneous occurring morphogenetic juvenilization in laboratory populations of vector species of Chagas disease. Two general effects have been observed: arrested development and uncoordinated development. These are manifested by supernumerary nymphs (6th stage, intermediate nymphal-adult stages, badly deformed adults developed from 5th instar nymphs, uncoordinated development manifested by grotesque forms of adults, supernumerary adults unable to complete metamorphosis and complete supernumerary adults produced by 6th stage nymphs. The reoccurrence of insects with identical grades of juvenilization in the population is an indication that this is a genetic trait that might be inherited. The factors responsible for morphogenetic juvenilization cannot be transmitted through the juvenilized insects because they are sterile, than they were transmitted through normal insects probably as a recessive or a group recessive factors. The spontaneous morphogenetic juvenilization observed in laboratory populations has a striking similarity to juvenilizing effects induced by application of juvenile hormone analogues, described in the literature and also obtained in our laboratory in a study to be published. Thus it is suggested that both; the altered phenotypes occurring in wild populations and their "phenocopies" induced by the application of juvenile hormone analogues are products of gene controlled identical reactions.São relatadas observações sobre a ocorrência espontâea de juvenilização morfogenética em populações de espécies transmissoras da doença de Chagas, mantidas no laboratório. Dois efeitos gerais foram observados: a interrupção e a descoordenação do desenvolvimento. Tais efeitos são manifestados: 1 por ninfas supernumerárias (6º estádio, 2 por estágios intermediários (ninfa-adulto, 3 por adultos sensivelmente deformados, provenientes de ninfas do 5º estágio, 4 pelo desenvolvimento d
Romero, Eder Lilia; Morilla, Maria Jose
Over several thousand years, the flagellated Trypanosome cruzi-causative agent of Chagas disease-developed a complex life cycle between the reduviidae vectors and its human hosts. Due to their silent and hidden location, the intracellular amastigotes are mainly responsible for the nearly 50,000 annual deaths caused by the chronic chagasic cardiomyopathy. Chagas disease is the most important parasitic disease in the Americas, though treatments have not evolved towards a more efficient pharmacotherapy that (i) eradicates the scarce amastigotes present at the indeterminate/chronic form and (ii) employs less toxic drugs than benznidazole or nifurtimox. Nano-drug delivery systems (nanoDDS) represent useful means to selectively deliver the drug to intracellular targets. However, preclinical research in Chagas must be extended in order to improve the chances of a clinical implementation. The stages involved in this process are (i) selection of the appropriate drug for a specific parasite, (ii) development of a drug-loaded nanoDDS structure that displays the adequate pharmacokinetics, biodistribution and intracellular transit and (iii) selection of the right parasite form to target and the right stage of the disease for the treatment to be started. In this review we will critically overview the few research works published in the last 20years in the context of nanotechnology and Chagas diseases and highlight the gaps in knowledge towards the design of more efficient medicines to address this endemic. PMID:19941920
Gürtler, Ricardo E; Yadon, Zaida E
This article provides an overview of three research projects which designed and implemented innovative interventions for Chagas disease vector control in Bolivia, Guatemala and Mexico. The research initiative was based on sound principles of community-based ecosystem management (ecohealth), integrated vector management, and interdisciplinary analysis. The initial situational analysis achieved a better understanding of ecological, biological and social determinants of domestic infestation. The key factors identified included: housing quality; type of peridomestic habitats; presence and abundance of domestic dogs, chickens and synanthropic rodents; proximity to public lights; location in the periphery of the village. In Bolivia, plastering of mud walls with appropriate local materials and regular cleaning of beds and of clothes next to the walls, substantially decreased domestic infestation and abundance of the insect vector Triatoma infestans. The Guatemalan project revealed close links between house infestation by rodents and Triatoma dimidiata, and vector infection with Trypanosoma cruzi. A novel community-operated rodent control program significantly reduced rodent infestation and bug infection. In Mexico, large-scale implementation of window screens translated into promising reductions in domestic infestation. A multi-pronged approach including community mobilisation and empowerment, intersectoral cooperation and adhesion to integrated vector management principles may be the key to sustainable vector and disease control in the affected regions. PMID:25604759
Yoshioka, Kota; Nakamura, Jiro; Pérez, Byron; Tercero, Doribel; Pérez, Lenin; Tabaru, Yuichiro
Chagas disease is one of the most serious health problems in Latin America. Because the disease is transmitted mainly by triatomine vectors, a three-phase vector control strategy was used to reduce its vector-borne transmission. In Nicaragua, we implemented an indoor insecticide spraying program in five northern departments to reduce house infestation by Triatoma dimidiata. The spraying program was performed in two rounds. After each round, we conducted entomological evaluation to compare the vector infestation level before and after spraying. A total of 66,200 and 44,683 houses were sprayed in the first and second spraying rounds, respectively. The entomological evaluation showed that the proportion of houses infested by T. dimidiata was reduced from 17.0% to 3.0% after the first spraying, which was statistically significant (P < 0.0001). However, the second spraying round did not demonstrate clear effectiveness. Space-time analysis revealed that reinfestation of T. dimidiata is more likely to occur in clusters where the pre-spray infestation level is high. Here we discuss how large-scale insecticide spraying is neither effective nor affordable when T. dimidiata is widely distributed at low infestation levels. Further challenges involve research on T. dimidiata reinfestation, diversification of vector control strategies, and implementation of sustainable vector surveillance. PMID:26416118
Lescure, François-Xavier; Canestri, Ana; Melliez, Hugues; Jauréguiberry, Stéphane; Develoux, Michel; Dorent, Richard; Guiard-Schmid, Jean-Baptiste; Bonnard, Philippe; Ajana, Faïza; Rolla, Valeria; Carlier, Yves; Gay, Frederick; Elghouzzi, Marie-Hélène; Danis, Martin; Pialoux, Gilles
Chagas disease (CD) is endemic to Latin America; its prevalence is highest in Bolivia. CD is sometimes seen in the United States and Canada among migrants from Latin America, whereas it is rare in Europe. We report 9 cases of imported CD in France from 2004 to 2006.
Full Text Available BACKGROUND: Chagas disease, caused by Trypanosoma cruzi, remains a serious public health concern in many areas of Latin America, including México. It is also endemic in Texas with an autochthonous canine cycle, abundant vectors (Triatoma species in many counties, and established domestic and peridomestic cycles which make competent reservoirs available throughout the state. Yet, Chagas disease is not reportable in Texas, blood donor screening is not mandatory, and the serological profiles of human and canine populations remain unknown. The purpose of this analysis was to provide a formal risk assessment, including risk maps, which recommends the removal of these lacunae. METHODS AND FINDINGS: The spatial relative risk of the establishment of autochthonous Chagas disease cycles in Texas was assessed using a five-stage analysis. 1. Ecological risk for Chagas disease was established at a fine spatial resolution using a maximum entropy algorithm that takes as input occurrence points of vectors and environmental layers. The analysis was restricted to triatomine vector species for which new data were generated through field collection and through collation of post-1960 museum records in both México and the United States with sufficiently low georeferenced error to be admissible given the spatial resolution of the analysis (1 arc-minute. The new data extended the distribution of vector species to 10 new Texas counties. The models predicted that Triatoma gerstaeckeri has a large region of contiguous suitable habitat in the southern United States and México, T. lecticularia has a diffuse suitable habitat distribution along both coasts of the same region, and T. sanguisuga has a disjoint suitable habitat distribution along the coasts of the United States. The ecological risk is highest in south Texas. 2. Incidence-based relative risk was computed at the county level using the Bayesian Besag-York-Mollié model and post-1960 T. cruzi incidence data. This
Mesquita, Rafael D; Vionette-Amaral, Raquel J; Lowenberger, Carl; Rivera-Pomar, Rolando; Monteiro, Fernando A; Minx, Patrick; Spieth, John; Carvalho, A Bernardo; Panzera, Francisco; Lawson, Daniel; Torres, André Q; Ribeiro, Jose M C; Sorgine, Marcos H F; Waterhouse, Robert M; Montague, Michael J; Abad-Franch, Fernando; Alves-Bezerra, Michele; Amaral, Laurence R; Araujo, Helena M; Araujo, Ricardo N; Aravind, L; Atella, Georgia C; Azambuja, Patricia; Berni, Mateus; Bittencourt-Cunha, Paula R; Braz, Gloria R C; Calderón-Fernández, Gustavo; Carareto, Claudia M A; Christensen, Mikkel B; Costa, Igor R; Costa, Samara G; Dansa, Marilvia; Daumas-Filho, Carlos R O; De-Paula, Iron F; Dias, Felipe A; Dimopoulos, George; Emrich, Scott J; Esponda-Behrens, Natalia; Fampa, Patricia; Fernandez-Medina, Rita D; da Fonseca, Rodrigo N; Fontenele, Marcio; Fronick, Catrina; Fulton, Lucinda A; Gandara, Ana Caroline; Garcia, Eloi S; Genta, Fernando A; Giraldo-Calderón, Gloria I; Gomes, Bruno; Gondim, Katia C; Granzotto, Adriana; Guarneri, Alessandra A; Guigó, Roderic; Harry, Myriam; Hughes, Daniel S T; Jablonka, Willy; Jacquin-Joly, Emmanuelle; Juárez, M Patricia; Koerich, Leonardo B; Lange, Angela B; Latorre-Estivalis, José Manuel; Lavore, Andrés; Lawrence, Gena G; Lazoski, Cristiano; Lazzari, Claudio R; Lopes, Raphael R; Lorenzo, Marcelo G; Lugon, Magda D; Majerowicz, David; Marcet, Paula L; Mariotti, Marco; Masuda, Hatisaburo; Megy, Karine; Melo, Ana C A; Missirlis, Fanis; Mota, Theo; Noriega, Fernando G; Nouzova, Marcela; Nunes, Rodrigo D; Oliveira, Raquel L L; Oliveira-Silveira, Gilbert; Ons, Sheila; Orchard, Ian; Pagola, Lucia; Paiva-Silva, Gabriela O; Pascual, Agustina; Pavan, Marcio G; Pedrini, Nicolás; Peixoto, Alexandre A; Pereira, Marcos H; Pike, Andrew; Polycarpo, Carla; Prosdocimi, Francisco; Ribeiro-Rodrigues, Rodrigo; Robertson, Hugh M; Salerno, Ana Paula; Salmon, Didier; Santesmasses, Didac; Schama, Renata; Seabra-Junior, Eloy S; Silva-Cardoso, Livia; Silva-Neto, Mario A C; Souza-Gomes, Matheus; Sterkel, Marcos; Taracena, Mabel L; Tojo, Marta; Tu, Zhijian Jake; Tubio, Jose M C; Ursic-Bedoya, Raul; Venancio, Thiago M; Walter-Nuno, Ana Beatriz; Wilson, Derek; Warren, Wesley C; Wilson, Richard K; Huebner, Erwin; Dotson, Ellen M; Oliveira, Pedro L
Rhodnius prolixus not only has served as a model organism for the study of insect physiology, but also is a major vector of Chagas disease, an illness that affects approximately seven million people worldwide. We sequenced the genome of R. prolixus, generated assembled sequences covering 95% of the genome (∼ 702 Mb), including 15,456 putative protein-coding genes, and completed comprehensive genomic analyses of this obligate blood-feeding insect. Although immune-deficiency (IMD)-mediated immune responses were observed, R. prolixus putatively lacks key components of the IMD pathway, suggesting a reorganization of the canonical immune signaling network. Although both Toll and IMD effectors controlled intestinal microbiota, neither affected Trypanosoma cruzi, the causal agent of Chagas disease, implying the existence of evasion or tolerance mechanisms. R. prolixus has experienced an extensive loss of selenoprotein genes, with its repertoire reduced to only two proteins, one of which is a selenocysteine-based glutathione peroxidase, the first found in insects. The genome contained actively transcribed, horizontally transferred genes from Wolbachia sp., which showed evidence of codon use evolution toward the insect use pattern. Comparative protein analyses revealed many lineage-specific expansions and putative gene absences in R. prolixus, including tandem expansions of genes related to chemoreception, feeding, and digestion that possibly contributed to the evolution of a blood-feeding lifestyle. The genome assembly and these associated analyses provide critical information on the physiology and evolution of this important vector species and should be instrumental for the development of innovative disease control methods. PMID:26627243
Vaidian, Anil K; Louis M Weiss; Tanowitz, Herbert B.
Chagas' disease caused by Trypanosoma cruzi is an opportunistic infection in the setting of HIV/AIDS. Some individuals with HIV and chronic T. cruzi infection may experience a reactivation, which is most commonly manifested by meningoencephalitis. A reactivation myocarditis is the second most common manifestation. These presentations may be difficult to distinguish from toxoplasmosis in individuals with HIV/AIDS. The overlap of HIV and Trypanosoma cruzi infection occurs not only in endemic ar...
Roca-Acevedo, G; Picollo, M I; Capriotti, N; Sierra, I; Santo-Orihuela, P L
Chagas disease is a zoonosis transmitted to man by blood-sucking triatomine bugs found in the Americas. Triatoma infestans (Klug, 1834) is the main vector of Chagas' disease in Argentina. The control of this illness relies heavily on vector control through the use of insecticide. However, resistance to pyrethroid insecticides associated with ineffective field treatments has been increasingly reported in T. infestans from Argentina and Bolivia. There are few reports on the expression and causes of resistance in eggs of resistant populations, and even fewer studies on insecticide resistance throughout embryonic development. In this study, we explore the biochemical and molecular mechanisms potentially associated with the deltamethrin resistance assessed in the developing eggs of the Argentinean (Campo Largo) and Bolivian (Entre Ríos) T. infestans populations.We found measurable activity of monooxigenases and pyrethroid esterases throughout embryonic development. The pyrethroid esterase activity grew steadily throughout development in all the studied populations and was highest in eggs 12 d old. Mean enzyme activity increased from 13.6 to 16.3 and 22.2 picomol 7-hydroxycoumarin/min (7-OHC) in eggs of 4-, 7-, and 12 d old from the susceptible reference bug colony. Mean activity of resistant populations increased from 16.0 to 25.9 picomol 7-OHC/min in eggs of 4- to 12 d old in Entre Ríos population, and from 15.9 to 28.9 picomol 7-OHC/min in Campo Largo population. Molecular analysis of susceptible and resistant developing eggs detected L1014F mutation in both resistant populations, but no L925I mutation was found in any of the studied populations.Higher esterase activity and L1014F presence justify the resistance to pyrethroid throughout developing eggs of both studied T. infestans populations. The description of resistance profiles including resistance mechanisms involved will allow a rational design of campaigns for the control of Chagas disease transmission
Chacón, F; Bacigalupo, A; Quiroga, J F; Ferreira, A; Cattan, P E; Ramírez-Toloza, G
American trypanosomiasis is a chronic disease transmitted mainly by vectors. The hematophagous triatomine vectors transmit Trypanosoma cruzi to a wide variety of mammals, which usually are their food source. This study determined the feeding profile of Mepraia spinolai, a sylvatic triatomine vector, present in endemic areas of Chile. Vectors were captured in the north-central area of Chile. Samples of intestinal contents were analyzed by an Enzyme-linked immunosorbent assay (ELISA) that identifies and discriminates the presence of serum antigens from Homo sapiens and nine animal species (Canis familiaris, Felis catus, Capra hircus, Mus musculus, Gallus gallus, Octodon degus, Thylamys elegans, Phyllotis darwini and Oryctolagus cuniculus). Our data indicate the most frequent feeding source in this area was P. darwini, followed by O. degus, O. cuniculus, M. musculus, G. gallus, T. elegans, C. familiaris, F. catus and C. hircus. Mixed food sources were also identified. PMID:27349188
Ivy Hurwitz; Annabeth Fieck; Nichole Klein; Christo Jose; Angray Kang; Ravi Durvasula
Chagas disease results from infection with the parasite Trypanosoma cruzi. This disease remains a significant cause of morbidity and mortality in central and south America. Chagas disease now exists and is detected worldwide because of human migration. Control of Chagas disease has relied mainly on vector eradication however, the development of insect resistance to pesticides, coupled with cost and adverse health effects of insecticide treatments, has prompted our group to investigate novel m...
Medone, Paula; Ceccarelli, Soledad; Parham, Paul E; Figuera, Andreína; Rabinovich, Jorge E
Chagas disease, caused by the parasite Trypanosoma cruzi, is the most important vector-borne disease in Latin America. The vectors are insects belonging to the Triatominae (Hemiptera, Reduviidae), and are widely distributed in the Americas. Here, we assess the implications of climatic projections for 2050 on the geographical footprint of two of the main Chagas disease vectors: Rhodnius prolixus (tropical species) and Triatoma infestans (temperate species). We estimated the epidemiological implications of current to future transitions in the climatic niche in terms of changes in the force of infection (FOI) on the rural population of two countries: Venezuela (tropical) and Argentina (temperate). The climatic projections for 2050 showed heterogeneous impact on the climatic niches of both vector species, with a decreasing trend of suitability of areas that are currently at high-to-moderate transmission risk. Consequently, climatic projections affected differently the FOI for Chagas disease in Venezuela and Argentina. Despite the heterogeneous results, our main conclusions point out a decreasing trend in the number of new cases of Tr. cruzi human infections per year between current and future conditions using a climatic niche approach. PMID:25688019
Marcelo CM Castro
Full Text Available Adult triatomines occasionally fly into artificially lit premises in Amazonia. This can result in Trypanosoma cruzi transmission to humans either by direct contact or via foodstuff contamination, but the frequency of such behaviour has not been quantified. To address this issue, a light-trap was set 45 m above ground in primary rainforest near Manaus, state of Amazonas, Brazil and operated monthly for three consecutive nights over the course of one year (432 trap-hours. The most commonly caught reduviids were triatomines, including 38 Panstrongylus geniculatus, nine Panstrongylus lignarius, three Panstrongylus rufotuberculatus, five Rhodnius robustus, two Rhodnius pictipes, one Rhodnius amazonicus and 17 Eratyrus mucronatus. Males were collected more frequently than females. The only month without any catches was May. Attraction of most of the known local T. cruzi vectors to artificial light sources is common and year-round in the Amazon rainforest, implying that they may often invade premises built near forest edges and thus become involved in disease transmission. Consequently, effective Chagas disease prevention in Amazonia will require integrating entomological surveillance with the currently used epidemiological surveillance.
Yamagata, Yoichi; Nakagawa, Jun
The Southern Cone Initiative (Iniciativa de Salud del Cono Sur, INCOSUR) to control domestic transmission of Trypanosoma cruzi is a substantial achievement based on the enthusiasm of the scientific community, effective strategies, leadership, and cost-effectiveness. INCOSUR triggered the launch of other regional initiatives in Central America and in the Andean and Amazon regions, which have all made progress. The Central American Initiative targeted the elimination of an imported triatomine bug (Rhodnius prolixus) and the control of a widespread native species (Triatoma dimidiata), and faced constraints such as a small scientific community, the difficulty in controlling a native species, and a vector control programme that had fragmented under a decentralized health system. International organizations such as the Japan International Cooperation Agency (JICA) have played an important role in bridging the gaps between fragmented organizational resources. Guatemala achieved virtual elimination of R. prolixus and ;reduction of Tri. Dimidiata and El Salvador and Honduras revitalized their national programmes. The programme also revealed new challenges. Tri. dimidiata control needs to cover a large geographic area efficiently with stratification, quality control, community mobilization, and information management. Stakeholders such as the National Chagas Program, the local health system and their communities, as well as local government must share responsibilities to continue comprehensive vector control. PMID:16735164
Zermoglio, Paula F; Martin-Herrou, Hadrien; Bignon, Yohan; Lazzari, Claudio R
Insect repellents are known since many decades ago and constitute a major tool for personal protection against the biting of mosquitoes. Despite their wide use, the understanding of why and how repellents repel is relatively recent. In particular, the question about to what extent insects other than mosquitoes are repulsed by repellents remains open. We developed a series of bioassays aimed to test the performance of well established as well as potential repellent molecules on the Chagas disease vector Rhodnius prolixus. Besides testing their ability to prevent biting, we tested the way in which they act, i.e., by obstructing the detection of attractive odours or by themselves. By using three different experimental protocols (host-biting, open-loop orientation to odours and heat-triggered proboscis extension response) we show that DEET repels bugs both in the presence and in the absence of host-associated odours but only at the highest quantities tested. Piperidine was effective with or without a host and icaridine only repelled in the absence of a living host. Three other molecules recently proposed as potential repellents due to their affinity to the Ir40a(+) receptor (which is also activated by DEET) did not evoke significant repellency. Our work provides novel experimental tools and sheds light on the mechanism behind repellency in haematophagous bugs. PMID:26210345
Marco Paulo Tomaz Barbosa
Full Text Available Sudden death is one of the most characteristic phenomena of Chagas disease, and approximately one-third of infected patients develop life-threatening heart disease, including malignant ventricular arrhythmias. Fibrotic lesions secondary to chronic cardiomyopathy produce arrhythmogenic substrates that lead to the appearance and maintenance of ventricular arrhythmias. The objective of this study is to discuss the main clinical and epidemiological aspects of ventricular arrhythmias in Chagas disease, the specific workups and treatments for these abnormalities, and the breakthroughs needed to determine a more effective approach to these arrhythmias. A literature review was performed via a search of the PubMed database from 1965 to May 31, 2014 for studies of patients with Chagas disease. Clinical management of patients with chronic Chagas disease begins with proper clinical stratification and the identification of individuals at a higher risk of sudden cardiac death. Once a patient develops malignant ventricular arrhythmia, the therapeutic approach aims to prevent the recurrence of arrhythmias and sudden cardiac death by the use of implantable cardioverter defibrillators, antiarrhythmic drugs, or both. In select cases, invasive ablation of the reentrant circuit causing tachycardia may be useful. Ventricular arrhythmias are important manifestations of Chagas cardiomyopathy. This review highlights the absence of high-quality evidence regarding the treatment of ventricular arrhythmias in Chagas disease. Recognizing high-risk patients who require specific therapies, especially invasive procedures such as the implantation of cardioverter defibrillators and ablative approaches, is a major challenge in clinical practice.
Full Text Available A triatomine survey was conducted in three rural settlements of Nicaragua (Santa Rosa, Quebrada Honda and Poneloya where Chagas' disease is endemic, to determine rates of house infestation, evaluate the housing condition and to asess the performance of the María sensor box in detection of domestic vectors. A total of 184 households were selected and vectors were sought by the methods of timed manual capture and by sensor boxes. The sole vectors species found in this study was Triatoma dimidiata. Of the examined bugs 50, 60 and 33%, in the respective communities, were infected with T. cruzi. The rates of house infestation as determined by manual capture and sensor boxes were respectively, 48.3% and 54.2% in Santa Rosa, 29.8% and 51.2% in Quebrada Honda and in Poneloya 3.8 and 5.9% with significant difference between the methods in Quebrada Honda. When compared with the manual capture, the Maria sensor box detected vectors in 71.4% of positive houses in two of the communities but also was able to detect bugs in 39.3% and 41.1% of houses where manual capture had been negative. Housing condition was evaluated according to three structural parameters, in this way, in the first community 79.2% of houses were classified as bad, 20.8% as regular; in the second one 42.5% were bad and 57.5% regular, whereas in the third 62.5% of the houses were regular. Rates of infestation did not differ greatly between the different housing conditions. Our results show that the sensor box is as efficient as manual capture and could be implemented in our country.Se efectuó una encuesta de vectores de la enfermedad de Chagas en tres comunidades endémicas de Nicaragua (Santa Rosa, Quebrada Honda y Poneloya para medir las tasas de infestación domiciliar, evaluar la condición de las viviendas, y determinar la eficacia del biosensor María para detectar los vectores domésticos. Se seleccionaron un total de 184 casas y los vectores se buscaron por los métodos de captura
Hugo Marcelo Aguilar
Full Text Available 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 (~ 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%. 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.
Dulce Maria Bustamante
Full Text Available The associations between the presence of triatomines and environmental variables were studied using correlation analysis and logistic regression models for a sample of villages in the south-eastern provinces of Guatemala. Information on the presence of Triatoma dimidiata, T. nitida and Rhodnius prolixus came from entomological surveys carried out by the Ministry of Health of Guatemala as part of its vector control programme. Environmental information for each village was extracted from digital thematic maps developed by the Ministry of Agriculture. The presence of T. nitida was found to be significantly associated with the average minimum temperature. The odds of presence of T. nitida in a village decreased as the average minimum temperature increased. T. nitida exists at altitudes above 1000 m above sea level in temperate regions. The presence of R. prolixus showed a significant positive association with maximum absolute temperature and relative humidity. The logistic regression model for R. prolixus showed a good fit and predicted suitable habitats in the provinces of Chiquimula, Zacapa and Jalapa, which agrees with the known distribution of the species. Habitat partitioning between R. prolixus and T. dimidiata is suggested by their significant and opposite associations with maximum absolute temperature. Improved models to predict suitable habitats for T. dimidiata hold promise for spatial targeting of integrated vector management.
Bustamante, Dulce Maria; Monroy, Maria Carlota; Rodas, Antonieta Guadalupe; Juarez, Jaime Abraham; Malone, John B
The associations between the presence of triatomines and environmental variables were studied using correlation analysis and logistic regression models for a sample of villages in the south-eastern provinces of Guatemala. Information on the presence of Triatoma dimidiata, T. nitida and Rhodnius prolixus came from entomological surveys carried out by the Ministry of Health of Guatemala as part of its vector control programme. Environmental information for each village was extracted from digital thematic maps developed by the Ministry of Agriculture. The presence of T. nitida was found to be significantly associated with the average minimum temperature. The odds of presence of T. nitida in a village decreased as the average minimum temperature increased. T. nitida exists at altitudes above 1000 m above sea level in temperate regions. The presence of R. prolixus showed a significant positive association with maximum absolute temperature and relative humidity. The logistic regression model for R. prolixus showed a good fit and predicted suitable habitats in the provinces of Chiquimula, Zacapa and Jalapa, which agrees with the known distribution of the species. Habitat partitioning between R. prolixus and T. dimidiata is suggested by their significant and opposite associations with maximum absolute temperature. Improved models to predict suitable habitats for T. dimidiata hold promise for spatial targeting of integrated vector management. PMID:18686245
Parra-Henao, Gabriel; Quirós-Gómez, Oscar; Jaramillo-O, Nicolas; Cardona, Ángela Segura
Triatomadimidiata(Hemiptera: Reduviidae) is a secondary vector ofTrypanosoma cruziin Colombia and represents an important epidemiological risk mainly in the central and oriental regions of the country where it occupies sylvatic, peridomestic, and intradomestic ecotopes, and because of this complex distribution, its distribution and abundance could be conditioned by environmental factors. In this work, we explored the relationship betweenT. dimidiatadistribution and environmental factors in the northwest, northeast, and central zones of Colombia and developed predictive models of infestation in the country. The associations between the presence ofT. dimidiataand environmental variables were studied using logistic regression models and ecological niche modeling for a sample of villages in Colombia. The analysis was based on the information collected in field about the presence ofT. dimidiataand the environmental data for each village extracted from remote sensing images. The presence ofTriatoma dimidiata(Latreille, 1811) was found to be significantly associated with the maximum vegetation index, minimum land surface temperature (LST), and the digital elevation for the statistical model. Temperature seasonality, annual precipitation, and vegetation index were the variables that most influenced the ecological niche model ofT. dimidiatadistribution. The logistic regression model showed a good fit and predicted suitable habitats in the Andean and Caribbean regions, which agrees with the known distribution of the species, but predicted suitable habitats in the Pacific and Orinoco regions proposing new areas of research. Improved models to predict suitable habitats forT. dimidiatahold promise for spatial targeting of integrated vector management. PMID:26856910
Costa, Camila M; Sousa, Marcelo V; Ricart, Carlos André O; Santana, Jaime M; Teixeira, Antonio R L; Roepstorff, Peter; Charneau, Sébastien
The triatomine bugs are obligatory haematophagous organisms that act as vectors of Chagas disease by transmitting the protozoan Trypanosoma cruzi. Their feeding success is strongly related to salivary proteins that allow these insects to access blood by counteracting host haemostatic mechanisms....... Proteomic studies were performed on saliva from the Amazonian triatomine bugs: Rhodnius brethesi and R. robustus, species epidemiologically relevant in the transmission of T. cruzi. Initially, salivary proteins were separated by two-dimensional gel electrophoresis (2-DE). The average number of spots of the...
Carter, Yvonne L.; Juliano, Jonathan J; Montgomery, Susan P.; Qvarnstrom, Yvonne
Acute Chagas disease is rarely recognized, and the risk for acquiring the disease is undefined in travelers to Central America. We describe a case of acute Chagas disease in a traveler to Costa Rica and highlight the need for increased awareness of this infection in travelers to Chagas-endemic areas.
Full Text Available Triatoma dimidiata is the most important Chagas disease insect vector in Central America as this species is primarily responsible for Trypanosoma cruzi transmission to humans, the protozoan parasite that causes Chagas disease. T. dimidiata sensu lato is a genetically diverse assemblage of taxa and effective vector control requires a clear understanding of the geographic distribution and epidemiological importance of its taxa. The nuclear ribosomal internal transcribed spacer 2 (ITS-2 is frequently used to infer the systematics of triatomines. However, oftentimes amplification and sequencing of ITS-2 fails, likely due to both the large polymerase chain reaction (PCR product and polymerase slippage near the 5' end. To overcome these challenges we have designed new primers that amplify only the 3'-most 200 base pairs of ITS-2. This region distinguishes the ITS-2 group for 100% of known T. dimidiata haplotypes. Furthermore, we have developed a PCR-restriction fragment length polymorphism (RFLP approach to determine the ITS-2 group, greatly reducing, but not eliminating, the number of amplified products that need to be sequenced. Although there are limitations with this new PCR-RFLP approach, its use will help with understanding the geographic distribution of T. dimidiata taxa and can facilitate other studies characterising the taxa, e.g. their ecology, evolution and epidemiological importance, thus improving vector control.
Rita de Cássia Moreira de Souza
Full Text Available Introduction Biological collections are depositories of information on different species and contribute to the knowledge, protection, conservation and maintenance of biodiversity. Methods A list of triatomine species currently included in the Collection of Chagas Disease Vectors (FIOCRUZ-COLVEC was prepared from the database made available by the Reference Center on Environmental Information. Results COLVEC curatorship houses 4,778 specimens of triatomines, of which 811 come from other American countries (Argentina, Bolivia, Colombia, Costa Rica, the United States of America, Guatemala, Mexico, Peru, Uruguay and Venezuela and 3,967 are autochthonous from Brazil. Altogether, 56 species of Chagas disease vectors are represented in the COLVEC: two species of the Tribe Cavernicolini Usinger, 1944; fifteen species of the tribe Rhodniini Pinto, 1926, of which 12 are of the genus Rhodnius and 3 are of the genus Psamolestes; and 39 species of the tribe Triatomini Jeannel, 1919, represented by the genus Dipetalogaster, two species of the genus Eratyrus, two of the genus Meccus, seven of the genus Panstrongylus and 27 of the genus Triatoma. Conclusions This list provides important data on the diversity of triatomines currently included in COLVEC, including the expanded area of Panstrongylus lutzi occurrence in the municipalities Pirapora and Januária, State of Minas Gerais. The maintenance and expansion of the collection ensures the preservation of biodiversity and further studies.
Biological Control of the Chagas Disease Vector Triatoma infestans with the Entomopathogenic Fungus Beauveria bassiana Combined with an Aggregation Cue: Field, Laboratory and Mathematical Modeling Assessment.
Full Text Available Current Chagas disease vector control strategies, based on chemical insecticide spraying, are growingly threatened by the emergence of pyrethroid-resistant Triatoma infestans populations in the Gran Chaco region of South America.We have already shown that the entomopathogenic fungus Beauveria bassiana has the ability to breach the insect cuticle and is effective both against pyrethroid-susceptible and pyrethroid-resistant T. infestans, in laboratory as well as field assays. It is also known that T. infestans cuticle lipids play a major role as contact aggregation pheromones. We estimated the effectiveness of pheromone-based infection boxes containing B. bassiana spores to kill indoor bugs, and its effect on the vector population dynamics. Laboratory assays were performed to estimate the effect of fungal infection on female reproductive parameters. The effect of insect exuviae as an aggregation signal in the performance of the infection boxes was estimated both in the laboratory and in the field. We developed a stage-specific matrix model of T. infestans to describe the fungal infection effects on insect population dynamics, and to analyze the performance of the biopesticide device in vector biological control.The pheromone-containing infective box is a promising new tool against indoor populations of this Chagas disease vector, with the number of boxes per house being the main driver of the reduction of the total domestic bug population. This ecologically safe approach is the first proven alternative to chemical insecticides in the control of T. infestans. The advantageous reduction in vector population by delayed-action fungal biopesticides in a contained environment is here shown supported by mathematical modeling.
Schofield, C J; Apt, W; Miles, M A
Chagas disease probably affects over half a million people in Chile, principally in rural communities in the fertile valleys of the arid 'norte chico' region, north of Santiago. The main domestic vector is Triatoma infestans, but Triatoma spinolai, although mainly in rocky sylvatic and peridomestic ecotopes, also invades houses. Since the Spanish invasion in the sixteenth century, and particularly during the last 100 years, the endemic region has suffered an ecological breakdown, largely due to excessive timbering and over-grazing, which has led to a denuded landscape with severe loss of agricultural productivity. This breakdown, combined with uneconomically sized farms and poor marketing, exacerbates the poverty of the rural communities. As in other similar areas of Latin America, the combination of poverty and poor education discourages improvements in housing which would reduce the risk of vector-transmitted Chagas disease. This paper reviews the historical and ecological background of the endemic region of Chile, both as a basis for further work, and as a point of comparison with other endemic areas. The review attempts to show how the current status of Chagas disease is likely to be maintained through its association with poor quality housing, poverty and ecological degradation, drawing parallels with other endemic++ areas and suggesting ways by which the ecological damage might be reversed. PMID:6821391
According to 1997 entomological and sero-epidemiological data, the transmission of Chagas disease has been interrupted in Uruguay; this has been certified by an independent commission appointed by the Pan American Health Organization/World Health Organization (PAHO/WHO). Transmission of Chagas disease, which is endemic in Uruguay, is via the vector Triatoma infestans or through transfusion with infected blood. In 1983, T. infestans lived in dwellings in 80% of Uruguay; in 1996, in all departments except Tacuarembo, house infestation rates decreased to below 0.1% (a reduction equivalent to 95%). The vector is found around the home, rather than in it, in Tacuarembo; therefore, its presence does not have any significance for transmission. The number of infected blood donors is now negligible, and there is 100% coverage via compulsory blood screening. Uruguay is the first Southern Cone country to have achieved the goals established by the Ministries of Health of Argentina, Bolivia, Brazil, Chile, Paraguay, and Uruguay to eliminate the transmission of Chagas disease. PMID:12321803
Marilanda Ferreira Bellini; Rosana Silistino-Souza; Marileila Varella-Garcia; Maria Tercília Vilela Azeredo-Oliveira; Ana Elizabete Silva
The etiologic agent of Chagas Disease is the Trypanosoma cruzi, transmitted through blood-sucking insect vectors of the Triatominae subfamily, representing one of the most serious public health concerns in Latin America. There are geographic variations in the prevalence of clinical forms and morbidity of Chagas disease, likely due to genetic variation of the T. cruzi and the host genetic and environmental features. Increasing evidence has supported that inflammatory cytokines and chemokines a...
Dalva Marli V. Wanderley
In the first half of this century - a period of expanding coffee cultivation - there was a close relationship between the growth of cleared spaces, the domestication of triatomines, and the establishment of Chagas' disease in the state of São Paulo. However, the initiation of control mesuares in 1950 coincided with a period characterized by a progressive reversal of the conditions that had facilitated the establishment of Chagas' disease in the first place. Alterations were taking place in th...
Marti, Gerardo A; Lastra, Claudia C López; Pelizza, Sebastian A; García, Juan J
A survey for entomopathogenic fungi of the Chagas disease vector Triatoma infestans was conducted in two provinces of Argentina from March-December 2003. Field-collected insects that died in the laboratory were individually maintained in moist chamber and incubated at 22 degrees C. Triatominae adults infected with the fungus Paecilomyces lilacinus were found at El Quebracho (27 degrees 34'S-64 degrees 31'W), Santiago del Estero province, Argentina, in December 2003. Paecilomyces lilacinus was cultured and isolated from infected insects in SDAY, PYG and MEA media. Pathogenicity tests were conducted and positive results were recorded. The median survival time (MST) of T. infestans exposed to a P. lilacinus conidial suspension was 12.8 days, and 100% mortality occurred at 30 days post-treatment. This is the first record of natural infection caused by P. lilacinus in T. infestans in the world. PMID:17123036
Risk factors for intradomiciliary infestation by the Chagas disease vector Triatoma dimidiatain Jutiapa, Guatemala Factores de riesgo para la infestación intradomiciliaria por el vector de la enfermedad de Chagas, Triatoma dimidiata, en Jutiapa, Guatemala
Dulce Maria Bustamante
Full Text Available Seventeen variables were evaluated as possible risk factors for the intradomiciliary infestation with Triatoma dimidiata in 644 houses in Jutiapa, Guatemala. During 2004 the houses were assessed for vector presence and evaluated for hygiene, cluttering, material comfort, construction conditions and number of inhabitants, among other factors. Chi-square analysis detected significant associations between vector presence and eight variables related to domestic sanitary and construction conditions. Log-linear models showed that regardless of the age of the house, the odds of vector presence were 4.3 and 10 times lower in houses with a good socioeconomic status compared with poor and very poor houses respectively. Log-linear models also pointed to a greater chance of vector presence when walls lacked plastering (3.85 times or walls had low quality-incomplete plastering (4.56 times, compared with walls that were completely plastered. Control strategies against T. dimidiata should include the introduction of better-quality but inexpensive plastering formulations and better sanitation practices should also be promoted among the population. Such control strategies should not only reduce or eliminate infestation, but also prevent vector reinfestation.Seiscientas cuarenta y cuatro casas en Jutiapa, Guatemala fueron encuestadas en el año 2004 para buscar el vector de la enfermedad de Chagas Triatoma dimidiata. Diecisiete variables relacionadas con las condiciones estructurales y de higiene de las casas fueron registradas y evaluadas como factores de riesgo para la infestación intradomiciliar con T. dimidiata. Análisis chi-cuadrado detectaron asociaciones significativas entre la presencia del vector y 8 de estas variables. En modelos log-lineares se detectó, que sin importar la antigüedad de la casa, las posibilidades de presencia del vector fueron 4,3 y 10 veces más bajas en casas con un buen estado socioeconómico que en casas pobres o muy pobres
The increasing number of autochthonous cases of Chagas disease in the Amazon since the 1970s has led to fear that the disease may become a new public health problem in the region. This transformation in the disease's epidemiological pattern in the Amazon can be explained by environmental and social changes in the last 30 years. The current article draws on the sociological theory of perverse effects to explain these changes as the unwanted result of the shift from the "inward" development model prevailing until the 1970s to the "outward" model that we know as globalization, oriented by industrial forces and international trade. The current article highlights the implementation of five new patterns in agriculture, cattle-raising, mining, lumbering, and urban occupation that have generated changes in the environment and the traditional indigenous habitat and have led to migratory flows, deforestation, sedentary living, the presence of domestic animals, and changes in the habitat that facilitate colonization of human dwellings by vectors and the domestic and work-related transmission of the disease. The expansion of Chagas disease is thus a perverse effect of the globalization process in the Amazon. PMID:17308715
Full Text Available Chagas' disease, caused by the protozoan parasite Trypanosoma cruzi, represents a major public health problem in most of the American continent. As transmission of the parasite is being interrupted in most of South America, the disease remains endemic in various areas of Mexico. We review here some of the information gathered in recent years. Seroprevalence of T. cruzi infection in humans remains relatively high in some areas, and there has been a general increase in the number of chronic cases reported to health authorities in recent years. In fact, chronic chagasic cardiomyopathy appears to be affecting a large number of patients with heart disease, but many cases may be misreported because of the unspecific nature of the clinical symptoms. Epidemiological monitoring of vector and reservoir populations, as well as of human cases is helping focus on endemic areas, but a better coordination and development of these efforts is still needed. Recent studies of parasite biology are in agreement with previous work showing the great diversity of parasite characteristics, and support the need for a regional approach to this zoonosis. Strong and continuing support from health and academic authorities is thus still needed to further improve our understanding of Chagas' disease in Mexico and implement efficient control programs.
Jose Rodrigues Coura
Full Text Available From an epidemiological point of view, Chagas disease and its reservoirs and vectors can present the following characteristics: (i enzooty, maintained by wild animals and vectors, with broad occurrence from southern United States of America (USA to southern Argentina and Chile (42ºN 49ºS, (ii anthropozoonosis, when man invades the wild ecotope and becomes infected with Trypanosoma cruzi from wild animals or vectors or when the vectors and wild animals, especially marsupials, invade the human domicile and infect man, (iii zoonosis-amphixenosis and exchanged infection between animals and humans by domestic vectors in endemic areas and (iv zooanthroponosis, infection that is transmitted from man to animals, by means of domestic vectors, which is the rarest situation in areas endemic for Chagas disease. The characteristics of Chagas disease as an enzooty of wild animals and as an anthropozoonosis are seen most frequently in the Brazilian Amazon and in the Pan-Amazon region as a whole, where there are 33 species of six genera of wild animals: Marsupialia, Chiroptera, Rodentia, Edentata (Xenarthra, Carnivora and Primata and 27 species of triatomines, most of which infected with T. cruzi . These conditions place the resident populations of this area or its visitors - tourists, hunters, fishermen and especially the people whose livelihood involves plant extraction - at risk of being affected by Chagas disease. On the other hand, there has been an exponential increase in the acute cases of Chagas disease in that region through oral transmission of T. cruzi , causing outbreaks of the disease. In four seroepidemiological surveys that were carried out in areas of the microregion of the Negro River, state of Amazonas, in 1991, 1993, 1997 and 2010, we found large numbers of people who were serologically positive for T. cruzi infection. The majority of them and/or their relatives worked in piassava extraction and had come into contact with and were stung by
Full Text Available Studies that explicitly and specifically take into account the spatial dimension within the study of eco-epidemiological systems remain rare. Our approach of modelling the spatial and/or temporal properties of the entomological and/or epidemiological data before their mapping with possible explanatory variables, objectively underline the significant patterns at different scales. The domiciliary and peri-domiciliary presence and abundance of juvenile and adult vectors of the Chagas disease (Triatoma sordida and Panstrongylus geniculatus in Bahia state in northeast Brazil, has been modelled by automatically identifying significant multi-scale spatial patterns of the entomological data by the application and adaptation of the spatial modelling methodology proposed by Dray et al. (2006 and based on principal coordinate analysis of neighbour matrices. We found that entomological data can be modelled by a set of eigenvectors that present a significant Moran’s I index of spatial autocorrelation. The models for juvenile and adult vectors are defined by 28 and 32 eigenvectors that explain 82.3% and 79.9%, respectively, of the total data variances. The results support insect presence as the outcome both of a local scale “near-to-near” dispersal and an infestation from the wild, surrounding environment that produces a higher insect density at the village periphery.
Antonio C. Campos de Carvalho
Full Text Available Chagas disease which is caused by the parasite Trypanosoma cruzi is an important cause of cardiomyopathy in Latin America. In later stages chagasic cardiomyopathy is associated with congestive heart failure which is often refractory to medical therapy. In these individuals heart transplantation has been attempted. However, this procedure is fraught with many problems attributable to the surgery and the postsurgical administration of immunosuppressive drugs. Studies in mice suggest that the transplantation of bone-marrow-derived cells ameliorates the inflammation and fibrosis in the heart associated with this infection. Cardiac magnetic resonance imaging reveals that bone marrow transplantation ameliorates the infection induced right ventricular enlargement. On the basis of these animal studies the safety of autologous bone marrow transplantation has been assessed in patients with chagasic end-stage heart disease. The initial results are encouraging and more studies need to be performed.
Full Text Available Chagas disease, caused by the protozoan Trypanosoma cruzi, is endemic in Latin America and affects ca. 10 million people worldwide. About 30% of Chagas disease patients develop chronic Chagas disease cardiomyopathy (CCC, a particularly lethal inflammatory cardiomyopathy that occurs decades after the initial infection, while most patients remain asymptomatic. Mortality rate is higher than that of noninflammatory cardiomyopathy. CCC heart lesions present a Th1 T-cell-rich myocarditis, with cardiomyocyte hypertrophy and prominent fibrosis. Data suggest that the myocarditis plays a major pathogenetic role in disease progression. Major unmet goals include the thorough understanding of disease pathogenesis and therapeutic targets and identification of prognostic genetic factors. Chagas disease thus remains a neglected disease, with no vaccines or antiparasitic drugs proven efficient in chronically infected adults, when most patients are diagnosed. Both familial aggregation of CCC cases and the fact that only 30% of infected patients develop CCC suggest there might be a genetic component to disease susceptibility. Moreover, previous case-control studies have identified some genes associated to human susceptibility to CCC. In this paper, we will review the immunopathogenesis and genetics of Chagas disease, highlighting studies that shed light on the differential progression of Chagas disease patients to CCC.
Angela M Bayer
Full Text Available BACKGROUND: Chagas disease is one of the most important neglected tropical diseases in the Americas. Vectorborne transmission of Chagas disease has been historically rare in urban settings. However, in marginal communities near the city of Arequipa, Peru, urban transmission cycles have become established. We examined the history of migration and settlement patterns in these communities, and their connections to Chagas disease transmission. METHODOLOGY/PRINCIPAL FINDINGS: This was a qualitative study that employed focus group discussions and in-depth interviews. Five focus groups and 50 in-depth interviews were carried out with 94 community members from three shantytowns and two traditional towns near Arequipa, Peru. Focus groups utilized participatory methodologies to explore the community's mobility patterns and the historical and current presence of triatomine vectors. In-depth interviews based on event history calendars explored participants' migration patterns and experience with Chagas disease and vectors. Focus group data were analyzed using participatory analysis methodologies, and interview data were coded and analyzed using a grounded theory approach. Entomologic data were provided by an ongoing vector control campaign. We found that migrants to shantytowns in Arequipa were unlikely to have brought triatomines to the city upon arrival. Frequent seasonal moves, however, took shantytown residents to valleys surrounding Arequipa where vectors are prevalent. In addition, the pattern of settlement of shantytowns and the practice of raising domestic animals by residents creates a favorable environment for vector proliferation and dispersal. Finally, we uncovered a phenomenon of population loss and replacement by low-income migrants in one traditional town, which created the human settlement pattern of a new shantytown within this traditional community. CONCLUSIONS/SIGNIFICANCE: The pattern of human migration is therefore an important
Full Text Available Immunosuppression, which has become an increasingly relevant clinical condition in the last 50 years, modifies the natural history of Trypanosoma cruzi infection in most patients with Chagas disease. The main goal in this setting is to prevent the consequences of reactivation of T. cruzi infection by close monitoring. We analyze the relationship between Chagas disease and three immunosuppressant conditions, including a description of clinical cases seen at our center, a brief review of the literature, and recommendations for the management of these patients based on our experience and on the data in the literature. T. cruzi infection is considered an opportunistic parasitic infection indicative of AIDS, and clinical manifestations of reactivation are more severe than in acute Chagas disease. Parasitemia is the most important defining feature of reactivation. Treatment with benznidazole and/or nifurtimox is strongly recommended in such cases. It seems reasonable to administer trypanocidal treatment only to asymptomatic immunosuppressed patients with detectable parasitemia, and/or patients with clinically defined reactivation. Specific treatment for Chagas disease does not appear to be related to a higher incidence of neoplasms, and a direct role of T. cruzi in the etiology of neoplastic disease has not been confirmed. Systemic immunosuppressive diseases or immunosuppressants can modify the natural course of T. cruzi infection. Immunosuppressive doses of corticosteroids have not been associated with higher rates of reactivation of Chagas disease. Despite a lack of evidence-based data, treatment with benznidazole or nifurtimox should be initiated before immunosuppression where possible to reduce the risk of reactivation. Timely antiparasitic treatment with benznidazole and nifurtimox (or with posaconazole in cases of therapeutic failure has proven to be highly effective in preventing Chagas disease reactivation, even if such treatment has not been
Marchant, A; Mougel, F; Almeida, C; Jacquin-Joly, E; Costa, J; Harry, M
High throughput sequencing (HTS) provides new research opportunities for work on non-model organisms, such as differential expression studies between populations exposed to different environmental conditions. However, such transcriptomic studies first require the production of a reference assembly. The choice of sampling procedure, sequencing strategy and assembly workflow is crucial. To develop a reliable reference transcriptome for Triatoma brasiliensis, the major Chagas disease vector in Northeastern Brazil, different de novo assembly protocols were generated using various datasets and software. Both 454 and Illumina sequencing technologies were applied on RNA extracted from antennae and mouthparts from single or pooled individuals. The 454 library yielded 278 Mb. Fifteen Illumina libraries were constructed and yielded nearly 360 million RNA-seq single reads and 46 million RNA-seq paired-end reads for nearly 45 Gb. For the 454 reads, we used three assemblers, Newbler, CAP3 and/or MIRA and for the Illumina reads, the Trinity assembler. Ten assembly workflows were compared using these programs separately or in combination. To compare the assemblies obtained, quantitative and qualitative criteria were used, including contig length, N50, contig number and the percentage of chimeric contigs. Completeness of the assemblies was estimated using the CEGMA pipeline. The best assembly (57,657 contigs, completeness of 80 %, assembly leading to recommend the use of (1) a single individual with large representation of biological tissues, (2) merging both long reads and short paired-end Illumina reads, (3) several assemblers in order to combine the specific advantages of each. PMID:25233990
C.J. Schofield; J.C.P. Dias
Chagas disease transmission can be effetively interrupted by insecticidal control of its triatomine bug vectors. We present here a simple model comparing the costs and benefits of such a programme, designed to eliminate domestic populations of Triatoma infestans throughout its known area of distribution over the seven southernmost countries of Latin America. The model has been simplified to require only four financial estimates relating to the unit cost of housing spraying and benefits due to...
An initiative to interrupt the transmission of Chagas disease in Central America was launched at a meeting held October 22-24, 1997, in Tegucigalpa, Honduras. Sponsored by the UNDP/World Bank/WHO Special Program for Research and Training in Tropical Diseases (TDR), the meeting was attended by government delegates from Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and Panama. The initiative was launched within the framework of Resolution 13 of the Meeting of Ministers of Health of the Central American Countries, held in Belize in September 1997. Detailed plans of activities were prepared for each country for the period 1998-2001, for approval by the various ministries of health, while operational, epidemiological, and entomological research priorities were also agreed upon. Research projects to help improve disease control will be sponsored by TDR. The first meeting of the Technical Intergovernment Commission established to meet annually to assess progress in control activities will occur in October 1998 in Guatemala. Vector and infection rate data are briefly presented on each country represented at the meeting. PMID:12348564
Carlos N Ibarra-Cerdeña
Full Text Available The niche conservatism hypothesis states that related species diverge in niche characteristics at lower rates than expected, given their lineage divergence. Here we analyze whether niche conservatism is a common pattern among vector species (Hemiptera: Reduviidae: Triatominae of Trypanosoma cruzi that inhabit North and Central America, a highly heterogeneous landmass in terms of environmental gradients. Mitochondrial and nuclear loci were used in a multi-locus phylogenetic framework to reconstruct phylogenetic relationships among species and estimate time of divergence of selected clades to draw biogeographic inferences. Then, we estimated similarity between the ecological niche of sister species and tested the niche conservatism hypothesis using our best estimate of phylogeny. Triatoma is not monophyletic. A primary clade with all North and Central American (NCA triatomine species from the genera Triatoma, Dipetalogaster, and Panstrongylus, was consistently recovered. Nearctic species within the NCA clade (T. p. protracta, T. r. rubida diverged during the Pliocene, whereas the Neotropical species (T. phyllosoma, T. longipennis, T. dimidiata complex are estimated to have diverged more recently, during the Pleistocene. The hypothesis of niche conservatism could not be rejected for any of six sister species pairs. Niche similarity between sister species best fits a retention model. While this framework is used here to infer niche evolution, it has a direct impact on spatial vector dynamics driven by human population movements, expansion of transportation networks and climate change scenarios.
Dalva Marli V. Wanderley
Full Text Available In the first half of this century - a period of expanding coffee cultivation - there was a close relationship between the growth of cleared spaces, the domestication of triatomines, and the establishment of Chagas' disease in the state of São Paulo. However, the initiation of control mesuares in 1950 coincided with a period characterized by a progressive reversal of the conditions that had facilitated the establishment of Chagas' disease in the first place. Alterations were taking place in the agricultural environment, rural areas were becoming depopulated, and low-grade housing was being destroyed. Natural transmission of the endemic was interrupted in the mid-1970's, following the elimination of Triatoma infestans from homes. Subsequently, however, a challenge emerged from two extradomiciliary species, Triatoma sordida and Panstrongylus megistus. The invasive character of these species made it necessary to investigate their possible repercussions on human populations and to set up permanent programs of epidemiological surveillance involving direct participation by local populations.O presente estudo analisa as relações entre a expansão dos espaços abertos, a domiciliação triatomínea e a instalação da doença de Chagas no Estado de São Paulo durante a expansão da cultura cafeeira, na primeira metade do século. No período pós-50, o início das ações de controle coincide com a desestruturação das relações facilitadoras para a instalação da doença de Chagas, através da alteração do espaço agrário, êxodo rural e destruição de domicílios de pior qualidade. A partir da interrupção da transmissão natural da endemia, em meados da década de 70, conseqüência da eliminação de Triatoma infestans dos domicílios, enfrenta-se o desafio das populações triatomíneas extradomiciliares - Triatoma sordida e Panstrongylus megistus -, cujo caráter invasivo tem requerido a investigação das possíveis repercuss
Bermudez, José; Davies, Carolina; Simonazzi, Analía; Real, Juan Pablo; Palma, Santiago
One of the most significant health problems in the American continent in terms of human health, and socioeconomic impact is Chagas disease, caused by the protozoan parasite Trypanosoma cruzi. Infection was originally transmitted by reduviid insects, congenitally from mother to fetus, and by oral ingestion in sylvatic/rural environments, but blood transfusions, organ transplants, laboratory accidents, and sharing of contaminated syringes also contribute to modern day transmission. Likewise, Chagas disease used to be endemic from Northern Mexico to Argentina, but migrations have earned it global. The parasite has a complex life cycle, infecting different species, and invading a variety of cells - including muscle and nerve cells of the heart and gastrointestinal tract - in the mammalian host. Human infection outcome is a potentially fatal cardiomyopathy, and gastrointestinal tract lesions. In absence of a vaccine, vector control and treatment of patients are the only tools to control the disease. Unfortunately, the only drugs now available for Chagas' disease, Nifurtimox and Benznidazole, are relatively toxic for adult patients, and require prolonged administration. Benznidazole is the first choice for Chagas disease treatment due to its lower side effects than Nifurtimox. However, different strategies are being sought to overcome Benznidazole's toxicity including shorter or intermittent administration schedules-either alone or in combination with other drugs. In addition, a long list of compounds has shown trypanocidal activity, ranging from natural products to specially designed molecules, re-purposing drugs commercialized to treat other maladies, and homeopathy. In the present review, we will briefly summarize the upturns of current treatment of Chagas disease, discuss the increment on research and scientific publications about this topic, and give an overview of the state-of-the-art research aiming to produce an alternative medication to treat T. cruzi infection
Rodríguez-Planes, L I; Vazquez-Prokopec, G M; Cecere, M C; Canale, D M; Gürtler, R E
The control of nondomiciliated triatomine species adapted to peridomestic habitats represents a challenge because they are connected to sylvatic colonies, and pyrethroid insecticides have limited effects outdoors. The effects of residual insecticide spraying have rarely been assessed on secondary triatomines. Triatoma garciabesi (Carcavallo, Martinez, Cichero, Prosen & Ronderos, 1967) is a nontarget vector that inhabits the dry western Chaco region, and a member of the Triatoma sordida Stål 1859 complex. Little is known on the capacity of T. garciabesi to invade and establish viable domestic or peridomestic colonies, and on its response to residual insecticide sprays directed against Triatoma infestans Klug 1834. The presence and abundance of triatomines were assessed by timed manual collections annually or biannually (spring and fall) during 10 yr after a community-wide insecticide spraying campaign and selective insecticide sprays directed against T. infestans in a rural village of northwestern Argentina. T. garciabesi mainly occupied peridomestic habitats associated with chickens, and was unable to colonize human sleeping quarters. Trees with chickens occurred in nearly all houses and were infested in >25% of the occasions. The abundance of bugs at house-compound level was best explained by a generalized estimating equation model that included selective insecticide sprays during the previous semester (negative effects), chicken abundance (positive effects), seasonality, and their interactions. Our results suggest that insecticide applications targeting T. infestans affected the abundance of T. garciabesi, and reduced the likelihood of future infestation. PMID:26490000
This report provides a review and analysis of the research landscape for three diseases - Chagas disease, human African trypanosomiasis and leishmaniasis - that disproportionately afflict poor and remote populations with limited access to health services. It represents the work of the disease reference group on Chagas Disease, Human African Trypanosomiasis and Leishmaniasis (DRG3) which was established to identify key research priorities through review of research evidence and input from stakeholders' consultations. The diseases, which are caused by related protozoan parasites, are described in terms of their epidemiology and diseases burden, clinical forms and pathogenesis, HIV coinfection, diagnosis, drugs and drug resistance, vaccines, vector control, and health-care interventions. Priority areas for research are identified based on criteria such as public health relevance, benefit and impact on poor populations and equity, and feasibility. The priorities are found in the areas of diagnostics, drugs, vector control, asymptomatic infection, economic analysis of treatment and vector control methods, and in some specific issues such as surveillance methods or transmission-blocking vaccines for particular diseases. This report will be useful to researchers, policy and decision-makers, funding bodies, implementation organizations, and civil society. This is one of ten disease and thematic reference group reports that have come out of the TDR Think Tank, all of which have contributed to the development of the Global Report for Research on Infectious Diseases of Poverty, available at: www.who.int/tdr/stewardship/global_report/en/index.html. PMID:23484340
Background: There is scarce information on myocardial perfusion abnormalities and on the coronary vasomotor condition in Chagas disease patients. Aims: To assess regional perfusion abnormalities and the coronary vasomotor response of patients in the chronic phase of Chagas disease. Methods: With the use of 99mTc-sestamibi SPECT imaging and cold pressor test and intracoronary acetylcoline (ACH) perfusion, we studied 9 patients aged 42,6±12 years, 4 males, in the chronic stage of Chagas disease (5 with the indeterminate form and 4 with heart lesion) with normal coronary arteries. Vasomotor responses to intracoronary increasing doses of ACH and to a single dose of nitroglycerine (NTG) were assessed with digital quantitative angiography. Regional myocardial perfusion was evaluated at rest and after cold pressor test by a semi quantitative score analysis in an 18-segment model with 99mTc-sestamibi SPECT images. Results were expressed as mean ± 2SD. Differences between continuous variables were measured by two tails Student's t test for paired variables and the significance level was set at 5 %. Results: All patients had regional perfusion defects and abnormal vasomotor response. The diameter of the left anterior descending artery decreased 34% from a basal diameter of 3.66∫0.95 mm down to 2.42±0.74 mm after maximal response to ACH (p<0.002). NTG infusion augmented its diameter to 3.86±0.77 mm (p<0.0002) that is a 60% increase from post ACH diameter. Myocardial perfusion score was 1∫2.66 at rest and 6.22±3.6 after cold pressor test (p<0.0001). Conclusions: This group of patients in the chronic phase of Chagas disease showed an abnormal vasoconstrictive response to intracoronary ACH and cold-induced perfusion defects suggesting that endothelial dysfunction plays a role in the pathophysiology of chronic Chagas heart disease
José Rodrigues Coura
Full Text Available Chagas disease, in the Amazon Region as elsewhere, can be considered an enzootic disease of wild animals or an anthropozoonosis, an accidental disease of humans that is acquired when humans penetrate a wild ecosystem or when wild triatomines invade human dwellings attracted by light or searching for human blood. The risk of endemic Chagas disease in the Amazon Region is associated with the following phenomena: (i extensive deforestation associated with the displacement of wild mammals, which are the normal sources of blood for triatomines, (ii adaptation of wild triatomines to human dwellings due to the need for a new source of blood for feeding and (iii uncontrolled migration of human populations and domestic animals that are already infected with Trypanosoma cruzi from areas endemic for Chagas disease to the Amazon Region. Several outbreaks of severe acute cases of Chagas disease, as well as chronic cases, have been described in the Amazon Region. Control measures targeted to avoiding endemic Chagas disease in the Amazon Region should be the following: improving health education in communities, training public health officials and communities for vector and Chagas disease surveillance and training local physicians to recognise and treat acute and chronic cases of Chagas diseases as soon as possible.
Full Text Available Chagas disease results from infection with the parasite Trypanosoma cruzi. This disease remains a significant cause of morbidity and mortality in central and south America. Chagas disease now exists and is detected worldwide because of human migration. Control of Chagas disease has relied mainly on vector eradication however, the development of insect resistance to pesticides, coupled with cost and adverse health effects of insecticide treatments, has prompted our group to investigate novel methods of transmission control. Our laboratory has been instrumental in the development of the paratransgenic strategy to control vectorial transmission of T. cruzi. In this paper, we discuss various components of the paratransgenic approach. Specifically, we describe classes of molecules that can serve as effectors, including antimicrobial peptides, endoglucanases, and highly specific single chain antibodies that target surface glycoprotein tags on the surface of T. cruzi. Furthermore, we address evolving concepts related to field dispersal of engineered bacteria as part of the paratransgenic control strategy and attendant risk assessment evaluation.
Gürtler, Ricardo E.; Ceballos, Leonardo A.; Ordóñez-Krasnowski, Paula; Leonardo A Lanati; Stariolo, Raúl; Kitron, Uriel
Background Understanding the factors that affect the host-feeding preferences of triatomine bugs is crucial for estimating transmission risks and predicting the effects of control tactics targeting domestic animals. We tested whether Triatoma infestans bugs prefer to feed on dogs vs. chickens and on dogs vs. cats and whether vector density modified host choices and other vital rates under natural conditions. Methodology Two host choice experiments were conducted in small caged huts with two r...
Ricardo E Gürtler
Full Text Available BACKGROUND: Understanding the factors that affect the host-feeding preferences of triatomine bugs is crucial for estimating transmission risks and predicting the effects of control tactics targeting domestic animals. We tested whether Triatoma infestans bugs prefer to feed on dogs vs. chickens and on dogs vs. cats and whether vector density modified host choices and other vital rates under natural conditions. METHODOLOGY: Two host choice experiments were conducted in small caged huts with two rooms between which bugs could move freely. Matched pairs of dog-chicken (six and dog-cat (three were assigned randomly to two levels of vector abundance and exposed to starved bugs during three nights. Bloodmeals from 1,160 bugs were tested by a direct enzyme-linked immunosorbent assay. PRINCIPAL FINDINGS: Conditional logistic regression showed that dogs were highly preferred over chickens or cats and that vector density modified host-feeding choices. The relative risk of a bug being blood-engorged increased significantly when it fed only on dog rather than chicken or cat. Bugs achieved higher post-exposure weight at higher vector densities and successive occasions, more so if they fed on a dog rather than on a cat. CONCLUSIONS: Our findings strongly refute the hypothesis that T. infestans prefers to blood-feed on chickens rather than dogs. An increase in dog or cat availability or accessibility will increase the rate of bug feeding on them and exert strong non-linear effects on R(0. When combined with between-dog heterogeneities in exposure, infection, and infectiousness, the strong bug preference for dogs can be exploited to target dogs in general, and even the specific individuals that account for most of the risk, with topical lotions or insecticide-impregnated collars to turn them into baited lethal traps or use them as transmission or infestation sentinels based on their immune response to Trypanosoma cruzi or bug salivary antigens.
Reinaldo B. Bestetti
Full Text Available Abstract The scientific construction of chronic Chagas heart disease (CCHD started in 1910 when Carlos Chagas highlighted the presence of cardiac arrhythmia during physical examination of patients with chronic Chagas disease, and described a case of heart failure associated with myocardial inflammation and nests of parasites at autopsy. He described sudden cardiac death associated with arrhythmias in 1911, and its association with complete AV block detected by Jacquet's polygraph as Chagas reported in 1912. Chagas showed the presence of myocardial fibrosis underlying the clinical picture of CCHD in 1916, he presented a full characterization of the clinical aspects of CCHD in 1922. In 1928, Chagas detected fibrosis of the conductive system, and pointed out the presence of marked cardiomegaly at the chest X-Ray associated with minimal symptomatology. The use of serological reaction to diagnose CCHD was put into clinical practice in 1936, after Chagas' death, which along with the 12-lead ECG, revealed the epidemiological importance of CCHD in 1945. In 1953, the long period between initial infection and appearance of CCHD was established, whereas the annual incidence of CCHD from patients with the indeterminate form of the disease was established in 1956. The use of heart catheterization in 1965, exercise stress testing in 1973, Holter monitoring in 1975, Electrophysiologic testing in 1973, echocardiography in 1975, endomyocardial biopsy in 1981, and Magnetic Resonance Imaging in 1995, added to the fundamental clinical aspects of CCHD as described by Carlos Chagas.
Rebecca Click Lambert
Full Text Available To determine the risk for Chagas disease (American trypanosomiasis in the United States, the characteristics that make the triatomine vector effective and the areas most at risk for transmission were delineated. In addition, the status of Chagas disease awareness among physicians in areas with a potential risk for the disease was determined. A geographical information system (GIS was used to analyze three triatomine species within the United States known to harbor Trypanosoma cruzi and that exhibit qualities of domesticity. An analysis of the minimum temperature threshold for increased triatomine activity delineates the current population at increased risk, and by incorporating temperature predictions for 2030, the population at risk under a future climate scenario was also delineated. Considering both environmental and social factors, a vignette-based physician survey, based on the results of the GIS analysis, was used to gauge the level of awareness of Chagas disease within the delineated higher risk range. The current area at increased risk for Chagas disease includes much of the southern United States, and the higher risk range is expected to expand into the central United States based upon the 1°C (1.8°F increase in temperature predicted by the Intergovernmental Panel on Climate Change (IPCC by the year 2030. Survey results indicate a limited consideration of Chagas disease during differential diagnosis, illustrating that the low number of Chagas disease cases discovered in the United States may be attributable to a lack of disease awareness as opposed to a lack of disease threat. This study combines GIS and survey analyses to evaluate the role that temperature variability and disease awareness among physicians play in the potential emergence of Chagas disease in the United States. This approach indicates that there is a potential for Chagas disease to emerge in the United States.
Angheben, Andrea; Boix, Lucia; Buonfrate, Dora; Gobbi, Federico; Bisoffi, Zeno; Pupella, Simonetta; Gandini, Giorgio; Aprili, Giuseppe
In the last decades, increasing international migration and travel from Latin America to Europe have favoured the emergence of tropical diseases outside their "historical" boundaries. Chagas disease, a zoonosis endemic in rural areas of Central and South America represents a clear example of this phenomenon. In the absence of the vector, one of the potential modes of transmission of Chagas disease in non-endemic regions is through blood and blood products. As most patients with Chagas disease are asymptomatic and unaware of their condition, in case of blood donation they can inadvertently represent a serious threat to the safety of the blood supply in non-endemic areas. Since the first cases of transfusion-transmitted Chagas disease were described in the last years, non-endemic countries began to develop ad hoc strategies to prevent and control the spread of the infection. United States, Spain, United Kingdom and France first recognised the need for Trypanosoma cruzi screening in at-risk blood donors. In this review, we trace an up-to-date perspective on Chagas disease, describing its peculiar features, from epidemiological, pathological, clinical and diagnostic points of view. Moreover, we describe the possible transmission of Chagas disease through blood or blood products and the current strategies for its control, focusing on non-endemic areas. PMID:26513769
visualice. En niños menores de 10 años con infección crónica reciente el NF durante 60 días ha dado buenos resultados al igual que en el BNZ a dosis de 5mg/kg día por 60 días en niños de 6-12 años con la forma indeterminada. En adultos el itraconazol a dosis de 6 mg/kg al día por 120 días, repartido en dos dosis ha permitido una curación del 60%. El BNZ a dosis de 5mg/kg día por 30 días ha demostrado disminuir las alteraciones electrocardiográ-ficas nuevas de los cardiopatas crónicos. Es importante señalar que por lo general en el período crónico no hay negativización de la serología convencional y el criterio de curación se debe basar en dos o más de los siguientes parametros, que se deben mantener así por varios años y siempre que no exista posibilidad de reinfección: 1 Negativización del xenodiagnóstico 2 Negativización de los hemocultivos 3 Viraje del PCR de (+ a (- 4 Viraje de los anticuerpos líticos de (+ a (- 5 Mejoría clínica y del ECG. Especialmente en cardiopatías recientes.Up to day, it is accepted that human Chagas disease must be treated in any of its evolution periods , with the only exception of the chronical terminal phase In the acute clinical period infection of less than two months and in the biological period with demonstration of parasites in fresh blood smears, stick drop, with positive conventional serology and positive IgM. Treatment is with nifurtimox (NF 8-10 mg/kg per day in adults and 15 mg/kg per day in children for 60-90 days. The dosis is given in three daily intakes. The clinical and serology cure 60%. In Brazil where this drug is not used benznidazol (BNZ is prescribed at dosis of 5 mg/kg per day for adults and 5-10 mg/kg per day in children during 60 days. In congenital infection therapy must be applied as soon as the dignosis is confirmed by clinic and demonstration of parasites at fresh blood, smear microstraut, etc. In the new born often the dignosis is done when he has the chronic period of the infection
Full Text Available We proposed to investigate subclinical cognitive impairment secondary to chronic Chagas' disease (CCD. No similar study was previously done. The neuropsychological performance of 45 chronic Chagasic patients and 26 matched controls (age, education place and years of residency in endemic area was compared using the Mini Mental State Exam (MMSE, Weschler Memory Scale (WMS and the Weschler Adult Intelligent Scale (WAIS. Non-parametric tests and Chi2 were used to compare group means and multivariate statistics in two way frequency tables for measures of independence and association of categorical variables with the disease. Results: Chagasic patients showed lower MMSE scores (p<004, poor orientation (p<.004, and attention (p<.007. Lower WMS MQ were associated with CCD (Chi2 5.9; p<.01; Fisher test p<.02. Lower WAIS IQ were associated with CCD (Chi2 6.3, p<.01; Fisher test p<.01 being the digit symbol (p<.03, picture completion (p<.03, picture arrangement (p<.01 and object assembly (p<.03 subtests the most affected. The impairment in non-verbal reasoning, speed of information processing, problem solving, learning and sequencing observed in chronic Chagas disease patients resembles the cognitive dysfunction associated with white matter disease.
Conners, Erin E; Vinetz, Joseph M; Weeks, John R; Brouwer, Kimberly C
Human migration has been identified as a potential factor for increased Chagas disease risk and has transformed the disease from a Latin American problem to a global one. We conducted a systematic review of the scientific literature between 2004-2014 in order to: summarize recent seroprevalence estimates of Chagas disease among Latin American migrants, in both endemic and non-endemic settings; compare seroprevalence estimates in migrants to countrywide prevalence estimates; and identify risk factors for Chagas disease among migrants. A total of 320 studies were screened and 23 studies were included. We found evidence that the prevalence of Chagas disease is higher than expected in some migrant groups and that reliance on blood donor screening prevalence estimates underestimates the burden of disease. Overall there is a dearth of high quality epidemiologic studies on the prevalence of Chagas disease in migrants, especially among intra-regional migrants within Latin America. Given that this zoonotic disease cannot likely be eradicated, improved surveillance and reporting is vital to continuing control efforts. More accurate health surveillance of both Latin American migrants and the Chagas disease burden will help countries appropriately scale up their response to this chronic disease. Overall, improved estimates of Chagas disease among migrants would likely serve to highlight the real need for better screening, diagnostics, and treatment of individuals living with the disease. PMID:26777312
The Chagas disease domestic transmission cycle in Guatemala: Parasite-vector switches and lack of mitochondrial co-diversification between Triatoma dimidiata and Trypanosoma cruzi subpopulations suggest non-vectorial parasite dispersal across the Motagua valley.
Pennington, Pamela M; Messenger, Louisa Alexandra; Reina, Jeffrey; Juárez, José G; Lawrence, Gena G; Dotson, Ellen M; Llewellyn, Martin S; Cordón-Rosales, Celia
Parasites transmitted by insects must adapt to their vectors and reservoirs. Chagas disease, an American zoonosis caused by Trypanosoma cruzi, is transmitted by several species of triatomines. In Central America, Triatoma dimidiata is a widely dispersed vector found in sylvatic and domestic habitats, with distinct populations across the endemic region of Guatemala. Our aim was to test the strength of association between vector and parasite genetic divergence in domestic environments. Microsatellite (MS) loci were used to characterize parasites isolated from T. dimidiata (n=112) collected in domestic environments. Moderate genetic differentiation was observed between parasites north and south of the Motagua Valley, an ancient biogeographic barrier (FST 0.138, p=0.009). Slightly reduced genotypic diversity and increased heterozygosity in the north (Allelic richness (Ar)=1.00-6.05, FIS -0.03) compared to the south (Ar=1.47-6.30, FIS 0.022) suggest either a selective or demographic process during parasite dispersal. Based on parasite genotypes and geographic distribution, 15 vector specimens and their parasite isolates were selected for mitochondrial co-diversification analysis. Genetic variability and phylogenetic congruence were determined with mitochondrial DNA sequences (10 parasite maxicircle gene fragments and triatomine ND4+CYT b). A Mantel test as well as phylogenetic, network and principal coordinates analyses supported at least three T. dimidiata haplogroups separated by geographic distance across the Motagua Valley. Maxicircle sequences showed low T. cruzi genetic variability (π nucleotide diversity 0.00098) with no evidence of co-diversification with the vector, having multiple host switches across the valley. Sylvatic Didelphis marsupialis captured across the Motagua Valley were found to be infected with T. cruzi strains sharing MS genotypes with parasites isolated from domiciliated triatomines. The current parasite distribution in domestic environments
Full Text Available While the former part of this back-to-back paper dealt with the identification of multi-scale spatial patterns associated with the presence, abundance and dispersion of the insect vectors (Triatominae of Chagas disease, this latter part examines the need for pattern characterisation by means of detailed data on environmental, residential, peri-domiciliary and human behaviour. The study site was, in both cases, a single village situated in Bahia, Brazil, wherefrom the data were collected through field observation and a standardised questionnaire, while the environmental characteristics were derived from satellite images and landscape characterisation. Following this, factorial analysis of mixed group (FAMG, an exploratory data analysis method, was applied to “mine” the huge dataset in a hierarchical way and to evaluate the relative impact of different factors such as the surrounding environment, the domiciliary/peri-domiciliary space properties and the presence of domestic animals. In the study village, five principal “districts” associated with different possible causes of infestation were identified. The results favour the role of depressions of the ground surface due to collapse of karstic subsoil (dolines and open rock faces as infestation sources, vector attraction by outdoor lighting, risk of insect domiciliation in dwellings constructed without finishing materials and associated with apparent disorder. Ultimately, this study not only provides the basic information needed for decision-making and specification of vector control in the study village, but offers also a knowledge-base for more general control strategies in the region.
Roux, Emmanuel; de Fátima Venâncio, Annamaria; Girres, Jean-François; Romaña, Christine A
While the former part of this back-to-back paper dealt with the identification of multi-scale spatial patterns associated with the presence, abundance and dispersion of the insect vectors (Triatominae) of Chagas disease, this latter part examines the need for pattern characterisation by means of detailed data on environmental, residential, peri-domiciliary and human behaviour. The study site was, in both cases, a single village situated in Bahia, Brazil, wherefrom the data were collected through field observation and a standardised questionnaire, while the environmental characteristics were derived from satellite images and landscape characterisation. Following this, factorial analysis of mixed group (FAMG), an exploratory data analysis method, was applied to "mine" the huge dataset in a hierarchical way and to evaluate the relative impact of different factors such as the surrounding environment, the domiciliary/peri-domiciliary space properties and the presence of domestic animals. In the study village, five principal "districts" associated with different possible causes of infestation were identified. The results favour the role of depressions of the ground surface due to collapse of karstic subsoil (dolines) and open rock faces as infestation sources, vector attraction by outdoor lighting, risk of insect domiciliation in dwellings constructed without finishing materials and associated with apparent disorder. Ultimately, this study not only provides the basic information needed for decision-making and specification of vector control in the study village, but offers also a knowledge-base for more general control strategies in the region. PMID:22109863
C. J. Schofield
Full Text Available Chagas disease transmission can be effetively interrupted by insecticidal control of its triatomine bug vectors. We present here a simple model comparing the costs and benefits of such a programme, designed to eliminate domestic populations of Triatoma infestans throughout its known area of distribution over the seven southernmost countries of Latin America. The model has been simplified to require only four financial estimates relating to the unit cost of housing spraying and benefits due to avoidance of premature death in the acute phase of the disease, avoidance of supportive treatment and care in the chronic phase of the disease, and avoidance of corrective digestive and cardiac surgery. Exceptfor these direct medical costs, al other potential benefits have been ignored. Nevertheless, the model shows that the direct financial benefits of such a programme would far outweigh the costs, and the project would support a remarkably high internal rate of return under the least optimistic estimates.
Márcio C. Vinhaes
Full Text Available Sumariam-se os dados da Fundação Nacional de Saúde (FNS sobre o estado atual dos vetores da doença de Chagas no Brasil, verificando-se que após vinte anos de controle químico continuado houve franca redução dos índices triatomínico-tripanosômicos, particularmente para esp��cies como Triatoma infestans e Panstrongylus megistus. Em paralelo, dados de sorologia escolar, de internações e de mortalidade pela doença indicam descenso nas taxas de incidência e impacto médico social da protozoose, restando áreas mais preocupantes, como o Nordeste e resíduos de T. infestans. Impõe-se urgente uma vigilância epidemiológica efetiva, a ser realizada por estados e municípios ante o processo de descentralização da FNS.This article presents the current situation for Chagas disease vectors in Brazil, based on data from the Brazilian National Health Foundation (FNS. Over the course of the last 20 years, continuous chemical control has resulted in a clear reduction of triatomine densities and Trypanosoma cruzi in Brazilian dwellings. Results have been particularly promising in relation to Triatoma infestans and Panstrongylus megistus, considered the most important species in the past. In parallel, data from school serological surveys, hospitalized patients, and mortality records show an important decrease in the disease. Nevertheless, some areas of the Brazilian Northeast and some residual foci of Triatoma infestans and Panstrongylus megistus remain as major challenges for public health authorities, requiring effective epidemiological surveillance. States and municipalities are required to assume this task at present, as the traditional Brazilian National Health Foundation is undergoing decentralization.
de Noya, Belkisyolé Alarcón; Díaz-Bello, Zoraida; Colmenares, Cecilia; Ruiz-Guevara, Raiza; Mauriello, Luciano; Muñoz-Calderón, Arturo; Noya, Oscar
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. PMID:25946155
Belkisyolé Alarcón de Noya
Full Text Available 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.
Full Text Available Chagas disease is a major public health problem in Bolivia. In the city of Cochabamba, 58% of the population lives in peripheral urban districts ("popular zones" where the infection prevalence is extremely high. From 1995 to 1999, we studied the demographics of Chagas infections in children from five to 13 years old (n = 2218 from the South zone (SZ and North zone (NZ districts, which differ in social, environmental, and agricultural conditions. Information gathered from these districts demonstrates qualitative and quantitative evidence for the active transmission of Trypanosoma cruzi in urban Cochabamba. Seropositivity was high in both zones (25% in SZ and 19% in NZ. We observed a high risk of infection in children from five to nine years old in SZ, but in NZ, a higher risk occurred in children aged 10-13, with odds ratio for infection three times higher in NZ than in SZ. This difference was not due to triatomine density, since more than 1,000 Triatoma infestans were captured in both zones, but was possibly secondary to the vector infection rate (79% in SZ and 37% in NZ. Electrocardiogram abnormalities were found to be prevalent in children and pre-adolescents (SZ = 40%, NZ = 17%, indicating that under continuous exposure to infection and re-infection, a severe form of the disease may develop early in life. This work demonstrates that T. cruzi infection should also be considered an urban health problem and is not restricted to the rural areas and small villages of Bolivia.
Full Text Available American trypanosomiasis or Chagas disease, caused by Trypanosoma cruzi, occurs between triatomine vectors and mammals, including man. T. cruzi has 150 Ma in America with almost 10 million of infected people today. The overlapping of its wild and domestic ecotopes is increasing. The host-parasite imbrications has been discerned by the study of infection patterns, transmissibility and transmission cycles in natural and laboratory models, through to parasitological and molecular tests. This article describes specific parasite niches, as plant biocenosis or biological corridors between domestic and wild ecotopes and helps distinguish Chagas disease risks and the borderline between wild and domestic transmission cycles, with emphasis on Venezuelan studies.
... mainly, in rural areas of Latin America where poverty is widespread). Chagas disease ( T. cruzi infection) is ... Prevention 1600 Clifton Rd. Atlanta, GA 30329-4027, USA 800-CDC-INFO (800-232-4636) TTY: (888) ...
Arce-Fonseca, Minerva; Rios-Castro, Martha; Carrillo-Sánchez, Silvia del Carmen; Martínez-Cruz, Mariana; Rodríguez-Morales, Olivia
Chagas disease is a zoonosis caused by Trypanosoma cruzi in which the most affected organ is the heart. Conventional chemotherapy has a very low effectiveness; despite recent efforts, there is currently no better or more effective treatment available. DNA vaccines provide a new alternative for both prevention and treatment of a variety of infectious disorders, including Chagas disease. Recombinant DNA technology has allowed some vaccines to be developed using recombinant proteins or virus-lik...
Granjon, Elodie; Dichtel-Danjoy, Marie-Laure; Saba, Esber; Sabino, Ester; Campos de Oliveira, Lea; Zrein, Maan
Background Chagas disease is due to the parasite Trypanosoma cruzi, a protist disseminated by a Triatome vector. This disease is endemic to Latin America and considered by WHO as one of the 17 world’s neglected diseases. In Europe and in North America, imported cases are also detected, due to migration of population outside of the endemic region. Diagnosis of T. cruzi infection is usually made indirectly by the detection of specific antibodies to T. cruzi antigens. Following initial diagnosti...
Cruz, Jader Santos; Santos-Miranda, Artur; Sales-Junior, Policarpo Ademar; Monti-Rocha, Renata; Campos, Paula Peixoto; Machado, Fabiana Simão; Roman-Campos, Danilo
Chagas disease, caused by the triatominae Trypanosoma cruzi, is one of the leading causes of heart malfunctioning in Latin America. The cardiac phenotype is observed in 20-30% of infected people 10-40 years after their primary infection. The cardiac complications during Chagas disease range from cardiac arrhythmias to heart failure, with important involvement of the right ventricle. Interestingly, no studies have evaluated the electrical properties of right ventricle myocytes during Chagas disease and correlated them to parasite persistence. Taking advantage of a murine model of Chagas disease, we studied the histological and electrical properties of right ventricle in acute (30 days postinfection [dpi]) and chronic phases (90 dpi) of infected mice with the Colombian strain of T. cruzi and their correlation to parasite persistence. We observed an increase in collagen deposition and inflammatory infiltrate at both 30 and 90 dpi. Furthermore, using reverse transcriptase polymerase chain reaction, we detected parasites at 90 dpi in right and left ventricles. In addition, we observed action potential prolongation and reduced transient outward K(+) current and L-type Ca(2+) current at 30 and 90 dpi. Taking together, our results demonstrate that T. cruzi infection leads to important modifications in electrical properties associated with inflammatory infiltrate and parasite persistence in mice right ventricle, suggesting a causal role between inflammation, parasite persistence, and altered cardiomyocyte function in Chagas disease. Thus, arrhythmias observed in Chagas disease may be partially related to altered electrical function in right ventricle. PMID:26976879
Edison Reis Lopes
Full Text Available The autonomic nervous system and especially the intracardiac autonomic nervous system is involved in Chagas' disease. Ganglionitis and periganglionitis were noted in three groups ofpatients dying with Chagas'disease: 1 Those in heart failure; 2 Those dying a sudden, non violent death and; 3 Those dying as a consequence ofaccidents or homicide. Hearts in the threegroups also revealed myocarditis and scattered involvement of intramyocardial ganglion cells as well as lesions of myelinic and unmyelinic fibers ascribable to Chagas'disease. In mice with experimentally induced Chagas' disease weobserved more intensive neuronal lesions of the cardiac ganglia in the acute phase of infection. Perhaps neuronal loss has a role in the pathogenesis of Chagas cardiomyopathy. However based on our own experience and on other data from the literature we conclude that the loss of neurones is not the main factor responsible for the manifestations exhibited by chronic chagasic patients. On the other hand the neuronal lesions may have played a role in the sudden death ofone group of patients with Chagas'disease but is difficult to explain the group of patients who did not die sudderly but instead progressed to cardiac failure.
Haberland, Annekathrin; Saravia, Silvia Gilka Munoz; Wallukat, Gerd; Ziebig, Reinhard; Schimke, Ingolf
Chagas disease, caused by Trypanosoma cruzi infection, is ranked as the most serious parasitic disease in Latin America and has huge potential to become a worldwide problem, due to increasing migration, and international tourism, as well as infectant transfer by blood contact and transfusion, intrauterine transfer, and organ transplantation. Nearly 30% of chronically-infected patients become symptomatic, often with a latency of 10-30 years, developing life-threatening complications. Of those, nearly 90% develop Chagas heart disease, while the others manifest gastrointestinal disease and neuronal disorders. Besides interrupting the infection cycle and chemo therapeutic infectant elimination, starting therapy early in symptomatic patients is important for counteracting the disease. This would be essentially supported by optimized patient management, involving risk assessment, early diagnosis and monitoring of the disease and its treatment. From economic and logistic viewpoints, the tools of laboratory medicine should be especially able to guarantee this. After summarizing the basics of chronic Chagas disease, such as the epidemiological data, the pathogenetic mechanisms thought to drive symptomatic Chagas disease and also treatment options, we present tools of laboratory medicine that address patient diagnosis, risk assessment for becoming symptomatic and guidance, focusing on autoantibody estimation for risk assessment and heart marker measurement for patient guidance. In addition, increases in levels of inflammation and oxidative stress markers in chronic Chagas disease are discussed. PMID:23045386
Franco, Thiago A; Oliveira, Daniele S; Moreira, Monica F; Leal, Walter S; Melo, Ana C A
Olfaction is one of the main sensory modalities that allow insects to interpret their environment. Several proteins, including odorant-binding proteins (OBPs) and odorant receptors (ORs), are involved in this process. Odorant receptors are ion channels formed by a binding unit OR and an odorant receptor co-receptor (Orco). The main goal of this study was to characterize the Orco gene of Rhodnius prolixus (RproOrco) and to infer its biological functions using gene silencing. The full-length RproOrco gene sequence was downloaded from VectorBase. This gene has 7 introns and is located in the genome SuperContig GL563069: 1,017,713-1,023,165. RproOrco encodes a protein of 473 amino acids, with predicted 7 transmembrane domains, and is highly expressed in the antennae during all R. prolixus developmental stages. The RNAi technique effectively silenced RproOrco, reducing the gene's expression by approximately 73%. Interestingly, the effect of gene silencing persisted for more than 100 days, indicating a prolonged effect of dsRNA that was maintained even after molting. The phenotypic effects of silencing involved the following: (1) loss of the ability to find a vertebrate host in a timely manner, (2) decreased ingested blood volume, (3) delayed and decreased molt rate, (4) increased mortality rate, and (5) decreased egg laying. Our data strongly suggest that dsOrco disrupts R. prolixus host-finding behavior, which is further reflected in the blood ingestion, molting, mortality, and egg laying data. This study clearly demonstrates that Orco is an excellent target for controlling triatomine populations. Thus, the data presented here open new possibilities for the control of vector-borne diseases. PMID:25747010
Péneau, Julie; Nguyen, Anne; Flores-Ferrer, Alheli; Blanchet, Denis; Gourbière, Sébastien
The effects of biodiversity on the transmission of infectious diseases now stand as a cornerstone of many public health policies. The upper Amazonia and Guyana shield are hot-spots of biodiversity that offer genuine opportunities to explore the relationship between the risk of transmission of Chagas disease and the diversity of its triatomine vectors. Over 730 triato-mines were light-trapped in four geomorphological landscapes shaping French-Guiana, and we determined their taxonomic status an...
Um critério de menor custo, como subsídio para a escolha do método de combate a triatomíneos vetores da Doença de Chagas A cheaper criterion in helping to select the method to combat triatomid vectors of Chaga's disease
Ubiratan Lemos dos Reis
Full Text Available Apesar da prioridade da luta antimalárica, o Serviço de Erradicação da Malária e Profilaxia da Doença de Chagas do Estado de São Paulo, não descuidou, mesmo nas fases iniciais da campanha de erradicação, do combate aos triatomíneos vetores da doença de Chagas. Não ocorrendo descontinuidade na sua profilaxia, foram encontradas inúmeras localidades não mais infestadas, especialmente nas áreas onde predomina o Triatoma infestans. Essa situação decorreu não sòmente em função dos métodos de profilaxia adotados, mas também, sem dúvida, do desenvolvimento sócio-econômico da região. Mostrou-se que a redução no número de focos e na densidade dos triatomíneos, permitiu que a desinsetização em massa das casas, passasse a ser encarada como desnecessária, aconselhando-se sua substituição pelo denominado método seletivo. Através do estudo comparativo dos custos dispendidos na realização desses dois métodos de desinsetização, estabeleceu-se uma fórmula matemática para determinar até que valor do percentual de infestação das habitações de uma área, o método seletivo, que vem sendo indicado como o mais adequado, é também o mais econômico. Conhecendo-se o custo unitário da casa pesquisada (C P e o da casa rociada (Ce, pode-se determinar o percentual de casas infestadas (Xe para o qual o custo do trabalho é o mesmo, seja para rociado total, seja para rociado seletivo, usando-se a expressão: Xe = 100 (1- Cp/Ce; para um percentual de casas infestadas menor que Xe, o método seletivo será o de menor custo.Although the antimalarial campaign always had priority, the Serviço de Erradicação de Malária e Profilaxia da Doença de Chagas of the State of São Paulo (Brazil never neglected, even at the beginning of the campaign, to fight against the triatomid vectors of Chagas' Disease. Because there was no interruption in the prophylaxis, it is not unusual at present to find several localities without triatoma
Lima, Marli M; Carvalho-Costa, Filipe A; Toma, Helena K; Borges-Pereira, José; de Oliveira, Tiago Guedes; Sarquis, Otília
Chagas disease was investigated in two new settlements of landless rural workers inhabiting prefabricated, triatomine-proof houses and in four neighboring older communities where mud huts were still well suitable for vectors. Through a cross-sectional survey and entomological assessment, we surveyed 148 houses/families in the two new settlements and in 47 houses/families in the four older localities. We determined seroprevalence of Chagas disease through IFI and Elisa (eluates) assays and searched for vectors in the domestic and peridomestic environments. Seroprevalence reached 0.6% (3/466) in the new settlements and 0.8% (1/115) in the older communities. Triatomines were not found in the new settlements, while 7 Triatoma brasiliensis, 4 T. pseudomaculata, 1 Panstrongylus lutzi, and 145 Rhodnius nasutus were collected in the older localities. In addition, a colony of T. brasiliensis (n = 55) was encountered inside a school attended by children of the region. Parasite strains isolated from the insects were characterized as T. cruzi I. Despite the low prevalence of Chagas disease in both scenarios, entomological surveillance must be strengthened and housing improvement reinforced in order to control vector transmission. The risk of infection by the vectors was lower in the settlements of improved homes, where conditions for colonization of the peridomestic environment by transmitting insects were not observed. PMID:25673077
Full Text Available El proceso de transmisión de la enfermedad de Chagas ha estado históricamente relacionado con los patrones de ocupación territorial de los asentamientos humanos. En las áreas rurales puede ocurrir más fácilmente el encuentro del vector, los agentes patógenos y los seres humanos, por las condiciones de la vivienda y la pobreza existente en estas zonas. Los procesos migratorios permanentes o estacionales han jugado un papel igualmente importante en el transporte de los vectores y en la infección de la población en las zonas urbanas. Las nuevas fronteras agrícolas del Amazonas se han establecido nuevas áreas de transmisión de la enfermedad. La atención dada a los bancos de sangre ha permitido disminuir la transmisión transfusional, pero la inmigración internacional ha cambiado la situación epidemiológica, pues en Estados Unidos y España viven miles de enfermos que habían sido infectados décadas antes y no encuentran adecuada atención. Los avances en el conocimiento y el control de la enfermedad son mostrados en el artículo, señalando las limitaciones existentes en cuanto al mejoramiento de las condiciones ambientales y de vivienda de los pobres.The historical processes involved in Chagas disease transmission relate to the patterns and conditions of human settlements, especially in rural areas, due to proximity to forest areas, where both vectors and Trypanosoma cruzi can occur, combined with precarious housing conditions and underlying poverty. However, seasonal and permanent rural-urban migration has played a major role in re-mobilizing vectors, T. cruzi, and Chagas-infected individuals. A new agricultural frontier in the Amazon has led to a new transmission pattern, especially with palm trees located close to houses. Improved blood bank surveillance has decreased transmission by blood transfusions. International migration also plays a role in Chagas disease epidemiology. The United States and Spain, where specific health
Keenan, Martine; Chaplin, Jason H
Recent clinical trials investigating treatment of chronic indeterminate Chagas disease with two re-purposed azole anti-fungal drugs, posaconazole and ravuconazole, revealed their inferiority to the current standard-of-care benznidazole and highlighted the inadequacy of the existing pre-clinical testing paradigm for this disease. A very limited number of controlled clinical trials for Chagas disease have been conducted to date. The selection of these compounds for clinical evaluation relied heavily on pre-clinical data obtained from in vitro screens and animal studies. This chapter reviews the evolution of CYP51 as a target for Trypanosoma cruzi growth inhibition and also explores the impact of clinical trial data on contemporary Chagas disease drug discovery. Advances in pre-clinical profiling assays, the current compound landscape and progress towards the identification of new drug targets to re-invigorate research are reviewed. PMID:25727705
Stephen A. Klotz; Dorn, Patricia L.; Mark Mosbacher; Schmidt, Justin O.
Eleven species of kissing bugs are found in the United States. Their home ranges may be expanding northward, perhaps as a consequence of climate change. At least eight of the species, perhaps all, are reported to harbor Trypanosoma cruzi, the parasite that causes Chagas disease. Because humans are encroaching on kissing bug habitat, there is concern for vector-transmitted Chagas disease in the United States. To date, documented autochthonous cases of Chagas in humans in the United States are ...
Entomological indices, feeding sources, and molecular identification of Triatoma phyllosoma (Hemiptera: Reduviidae) one of the main vectors of Chagas disease in the Istmo de Tehuantepec, Oaxaca, Mexico.
Villalobos, Guiehdani; Martínez-Hernández, Fernando; de la Torre, Patricia; Laclette, Juan Pedro; Espinoza, Bertha
The purpose of this study was to conduct an entomological analysis, determination of feeding sources, and molecular identification of triatomines in five communities of the Istmo de Tehuantepec, Oaxaca. The only found species in two of five searched communities (San Mateo del Mar and Tehuantepec City) was Triatoma phyllosoma. Colonization indices were high in both communities. In San Mateo del Mar, the insects were found indoors and in Tehuantepec City in peridomestic areas. The Trypanosoma cruzi infection indices were 2.1% in San Mateo del Mar and 39.4% in Tehuantepec City. This difference could be related to the high numbers of triatomine feeding on hens in the former community. In contrast, in Tehuantepec, dogs were the principal triatomine feeding sources. All nymphs and adults that were genetically analyzed belonged to the species T. phyllosoma. Low levels of genetic variation were found between vectors from both communities. PMID:21896810
Edwards, Morven S; Rench, Marcia A; Todd, Charles W; Czaicki, Nancy; Steurer, Francis J; Bern, Caryn; Montgomery, Susan P
Perinatal screening for Trypanosoma cruzi in a cohort of 4000 predominantly Hispanic women in southern Texas revealed that Chagas disease occurs with sufficient frequency (0.25%) that targeted perinatal screening should be considered to identify infected mothers and infants at risk for congenital infection. PMID:26407360
Bryan, Laura K; Hamer, Sarah A; Shaw, Sarah; Curtis-Robles, Rachel; Auckland, Lisa D; Hodo, Carolyn L; Chaffin, Keith; Rech, Raquel R
A 10-year-old Quarter Horse gelding presented to the Texas A&M University Veterinary Teaching Hospital with a six month-history of ataxia and lameness in the hind limbs. The horse was treated presumptively for equine protozoal myeloencephalitis (EPM) based on clinical signs but was ultimately euthanized after its condition worsened. Gross lesions were limited to a small area of reddening in the gray matter of the thoracic spinal cord. Histologically, trypanosome amastigotes morphologically similar to Trypanosoma cruzi, the agent of Chagas disease in humans and dogs, were sporadically detected within segments of the thoracic spinal cord surrounded by mild lymphoplasmacytic inflammation. Ancillary testing for Sarcocystis neurona, Neospora spp., Toxoplasma gondii and Leishmania spp. was negative. Conventional and real time polymerase chain reaction (PCR) of affected paraffin embedded spinal cord were positive for T. cruzi, and sequencing of the amplified T. cruzi satellite DNA PCR fragment from the horse was homologous with various clones of T. cruzi in GenBank. While canine Chagas disease cases have been widely reported in southern Texas, this is the first report of clinical T. cruzi infection in an equid with demonstrable amastigotes in the spinal cord. In contrast to previous instances of Chagas disease in the central nervous system (CNS) of dogs and humans, no inflammation or T. cruzi amastigotes were detected in the heart of the horse. Based on clinical signs, there is a potential for misdiagnosis of Chagas disease with other infectious diseases that affect the equine CNS. T. cruzi should be considered as a differential diagnosis in horses with neurologic clinical signs and histologic evidence of meningomyelitis that originate in areas where Chagas disease is present. The prevalence of T. cruzi in horses and the role of equids in the parasite life cycle require further study. PMID:26801589
In Peru, Chagas disease has an epidemiological significance in three macro-regions, one of them is the southern macro-region formed by the departments of Arequipa, Moquegua and Tacna. In 1965 a successful control was performed by house spraying insecticides, however, the persistence of the vector made it necessary for a second control plan that was implemented in 2000 and followed the guidelines of CONAL Plan, based on the elimination of Triatoma infestans and screening in blood banks.This plan was successful in Tacna and Moquegua, therefore these departments were considered free of vectorial transmission by the Pan American Health Organization. A ssimilar situation has not been achieved in the department of Arequipa because of the presence, among other factors, of rural migration to the city, in this way the urbanization of Chagas disease is a new epidemiological scenario of which we need to know more. PMID:25123876
Alicia I Hidron
Full Text Available BACKGROUND: Patients with Chagas disease have migrated to cities, where obesity, hypertension and other cardiac risk factors are common. METHODOLOGY/PRINCIPAL FINDINGS: The study included adult patients evaluated by the cardiology service in a public hospital in Santa Cruz, Bolivia. Data included risk factors for T. cruzi infection, medical history, physical examination, electrocardiogram, echocardiogram, and contact 9 months after initial data collection to ascertain mortality. Serology and PCR for Trypanosoma cruzi were performed. Of 394 participants, 251 (64% had confirmed T. cruzi infection by serology. Among seropositive participants, 109 (43% had positive results by conventional PCR; of these, 89 (82% also had positive results by real time PCR. There was a high prevalence of hypertension (64% and overweight (body mass index [BMI] >25; 67%, with no difference by T. cruzi infection status. Nearly 60% of symptomatic congestive heart failure was attributed to Chagas cardiomyopathy; mortality was also higher for seropositive than seronegative patients (p = 0.05. In multivariable models, longer residence in an endemic province, residence in a rural area and poor housing conditions were associated with T. cruzi infection. Male sex, increasing age and poor housing were independent predictors of Chagas cardiomyopathy severity. Males and participants with BMI =25 had significantly higher likelihood of positive PCR results compared to females or overweight participants. CONCLUSIONS: Chagas cardiomyopathy remains an important cause of congestive heart failure in this hospital population, and should be evaluated in the context of the epidemiological transition that has increased risk of obesity, hypertension and chronic cardiovascular disease.
Claudinei Caetano de Souza
Full Text Available An interactive media on Chagas disease was developed as an educational tool, on the context of the scientific research and dissemination actions of the National Institute of Structural Biotechnology and Medicinal Chemistry in Infectious Diseases (INBEQMeDI. Different computational resources were used either in terms of hardware and software. The media contains 13 videos that range from 30 seconds to 4 minutes, all with information about Chagas disease, showing the social and economic aspects; the research made by the INBEQMeDI group; different aspects of the disease illustrated by slides arranged in a mobile carousel, and radio programs, with funny skits. The target audience for use of this feature is students aged 10 to 17 years. Teachers of areas of science and biology, through a partnership with the Agency of Education of the State of São Paulo, will be invited to plan a strategy for media use with their students.
Full Text Available Chagas disease is a zoonotic parasitic disease well-documented throughout the Americas and transmitted primarily by triatomine 'kissing bug' vectors. In acknowledgment of the successful history of vector control programs based on community participation across Latin America, we used a citizen science approach to gain novel insight into the geographic distribution, seasonal activity, and Trypanosoma cruzi infection prevalence of kissing bugs in Texas while empowering the public with information about Chagas disease.We accepted submissions of kissing bugs encountered by the public in Texas and other states from 2013-2014 while providing educational literature about Chagas disease. In the laboratory, kissing bugs were identified to species, dissected, and tested for T. cruzi infection. A total of 1,980 triatomines were submitted to the program comprised of at least seven species, of which T. gerstaeckeri and T. sanguisuga were the most abundant (85.7% of submissions. Triatomines were most commonly collected from dog kennels and outdoor patios; Overall, 10.5% of triatomines were collected from inside the home. Triatomines were submitted from across Texas, including many counties which were not previously known to harbor kissing bugs. Kissing bugs were captured primarily throughout April-October, and peak activity occurred in June-July. Emails to our dedicated account regarding kissing bugs were more frequent in the summer months (June-August than the rest of the year. We detected T. cruzi in 63.3% of tested bugs.Citizen science is an efficient approach for generating data on the distribution, phenology, and infection prevalence of kissing bugs-vectors of the Chagas disease parasite-while educating the public and medical community.
Bonney, Kevin M.; David M. Engman
Chagas heart disease (CHD), caused by the protozoan parasite Trypanosoma cruzi, is the leading cause of infectious myocarditis in the world. The etiology of CHD is unclear and multiple mechanisms have been proposed to explain the pathogenesis of the disease. This review describes the proposed mechanisms of CHD pathogenesis and evaluates the historical significance and evidence supporting each. Although the majority of CHD-related pathologies are currently attributed to parasite persistence in...
Péneau, Julie; Nguyen, Anne; Flores-Ferrer, Alheli; Blanchet, Denis; Gourbière, Sébastien
The effects of biodiversity on the transmission of infectious diseases now stand as a cornerstone of many public health policies. The upper Amazonia and Guyana shield are hot-spots of biodiversity that offer genuine opportunities to explore the relationship between the risk of transmission of Chagas disease and the diversity of its triatomine vectors. Over 730 triatomines were light-trapped in four geomorphological landscapes shaping French-Guiana, and we determined their taxonomic status and infection by Trypanosoma cruzi. We used a model selection approach to unravel the spatial and temporal variations in species abundance, diversity and infection. The vector community in French-Guiana is typically made of one key species (Panstrongylus geniculatus) that is more abundant than three secondary species combined (Rhodnius pictipes, Panstrongylus lignarius and Eratyrus mucronatus), and four other species that complete the assemblage. Although the overall abundance of adult triatomines does not vary across French-Guiana, their diversity increases along a coastal-inland gradient. These variations unravelled a non-monotonic relationship between vector biodiversity and the risk of transmission of Chagas disease, so that intermediate biodiversity levels are associated with the lowest risks. We also observed biannual variations in triatomine abundance, representing the first report of a biannual pattern in the risk of Chagas disease transmission. Those variations were highly and negatively correlated with the average monthly rainfall. We discuss the implications of these patterns for the transmission of T. cruzi by assemblages of triatomine species, and for the dual challenge of controlling Amazonian vector communities that are made of both highly diverse and mostly intrusive species. PMID:26867025
Full Text Available The effects of biodiversity on the transmission of infectious diseases now stand as a cornerstone of many public health policies. The upper Amazonia and Guyana shield are hot-spots of biodiversity that offer genuine opportunities to explore the relationship between the risk of transmission of Chagas disease and the diversity of its triatomine vectors. Over 730 triatomines were light-trapped in four geomorphological landscapes shaping French-Guiana, and we determined their taxonomic status and infection by Trypanosoma cruzi. We used a model selection approach to unravel the spatial and temporal variations in species abundance, diversity and infection. The vector community in French-Guiana is typically made of one key species (Panstrongylus geniculatus that is more abundant than three secondary species combined (Rhodnius pictipes, Panstrongylus lignarius and Eratyrus mucronatus, and four other species that complete the assemblage. Although the overall abundance of adult triatomines does not vary across French-Guiana, their diversity increases along a coastal-inland gradient. These variations unravelled a non-monotonic relationship between vector biodiversity and the risk of transmission of Chagas disease, so that intermediate biodiversity levels are associated with the lowest risks. We also observed biannual variations in triatomine abundance, representing the first report of a biannual pattern in the risk of Chagas disease transmission. Those variations were highly and negatively correlated with the average monthly rainfall. We discuss the implications of these patterns for the transmission of T. cruzi by assemblages of triatomine species, and for the dual challenge of controlling Amazonian vector communities that are made of both highly diverse and mostly intrusive species.
Pinho, Rosa T.; Waghabi, Mariana C.; Cardillo, Fabíola; Mengel, José; Antas, Paulo R. Z.
Biomarkers or biosignature profiles have become accessible over time in population-based studies for Chagas disease. Thus, the identification of consistent and reliable indicators of the diagnosis and prognosis of patients with heart failure might facilitate the prioritization of therapeutic management to those with the highest chance of contracting this disease. The purpose of this paper is to review the recent state and the upcoming trends in biomarkers for human Chagas disease. As an emerging concept, we propose a classification of biomarkers based on plasmatic-, phenotype-, antigenic-, genetic-, and management-related candidates. The available data revisited here reveal the lessons learned thus far and the existing challenges that still lie ahead to enable biomarkers to be employed consistently in risk evaluation for this disease. There is a strong need for biomarker validation, particularly for biomarkers that are specific to the clinical forms of Chagas disease. The current failure to achieve the eradication of the transmission of this disease has produced determination to solve this validation issue. Finally, it would be strategic to develop a wide variety of biomarkers and to test them in both preclinical and clinical trials. PMID:27563302
Full Text Available The increasing number of autochthonous cases of Chagas disease in the Amazon since the 1970s has led to fear that the disease may become a new public health problem in the region. This transformation in the disease's epidemiological pattern in the Amazon can be explained by environmental and social changes in the last 30 years. The current article draws on the sociological theory of perverse effects to explain these changes as the unwanted result of the shift from the "inward" development model prevailing until the 1970s to the "outward" model that we know as globalization, oriented by industrial forces and international trade. The current article highlights the implementation of five new patterns in agriculture, cattle-raising, mining, lumbering, and urban occupation that have generated changes in the environment and the traditional indigenous habitat and have led to migratory flows, deforestation, sedentary living, the presence of domestic animals, and changes in the habitat that facilitate colonization of human dwellings by vectors and the domestic and work-related transmission of the disease. The expansion of Chagas disease is thus a perverse effect of the globalization process in the Amazon.El incremento de casos autóctonos de la enfermedad de Chagas en la Amazonia a partir de los años setenta hace temer que pueda convertirse en un novedoso problema de salud pública en la región. Este cambio del patrón epidemiológico de la enfermedad en la región amazónica debe ser explicado por las transformaciones ambientales y sociales que han ocurrido en los pasados treinta años. Este artículo utiliza la teoría sociológica de los efectos perversos para explicar esos cambios como el resultado indeseado del cambio de modelo de desarrollo "hacia adentro", que había existido hasta los años setenta, por otro "hacia fuera" que está orientado por las fuerzas de la producción y el comercio internacional que conocemos como globalización. El art
Kjos, S A; Snowden, K F; Craig, T M; Lewis, B; Ronald, N; Olson, J K
Although acute and chronic cases of canine Chagas disease have been reported from multiple areas in the southern region of the United States, little data are available on current disease occurrence patterns in endemic areas. Therefore, a study to assess frequency, geographic distribution, signalment, and clinical spectrum of Chagas disease in domestic dogs from Texas was conducted. Serology, histopathology, and clinical case records from multiple institutions for the time period 1993-2007 were analyzed. A total of 537 serologically and/or histopathologically confirmed cases were documented. Cases were reported from 48 of 254 counties within Texas, covering all major geographic regions. Forty-eight dog breeds were represented among the cases, primarily in the sporting and working groups. In histopathologically confirmed cases, acute death occurred in 42%, approximately half of which were ecoregions of Texas, affecting a broad range of dog breeds and age groups. PMID:18255233
Full Text Available Chagas' disease, caused by the protozoan parasite Trypanosoma cruzi, represents a major public health problem in most of the American continent. As transmission of the parasite is being interrupted in most of South America, the disease remains endemic in various areas of Mexico. We review here some of the information gathered in recent years. Seroprevalence of T. cruzi infection in humans remains relatively high in some areas, and there has been a general increase in the number of chronic cases reported to health authorities in recent years. In fact, chronic chagasic cardiomyopathy appears to be affecting a large number of patients with heart disease, but many cases may be misreported because of the unspecific nature of the clinical symptoms. Epidemiological monitoring of vector and reservoir populations, as well as of human cases is helping focus on endemic areas, but a better coordination and development of these efforts is still needed. Recent studies of parasite biology are in agreement with previous work showing the great diversity of parasite characteristics, and support the need for a regional approach to this zoonosis. Strong and continuing support from health and academic authorities is thus still needed to further improve our understanding of Chagas' disease in Mexico and implement efficient control programs.La enfermedad de Chagas, causada por el parásito protozoario Trypanosoma cruzi, constituye un importante problema de salud pública en el continente americano. La transmisión del parásito se ha ido interrumpiendo en la mayor parte de América del Sur, pero la enfermedad sigue siendo endémica en varias regiones de México. En este artículo se revisa la información más reciente sobre dicha enfermedad. La seroprevalencia de la infección por T. cruzi se ha mantenido a niveles relativamente altos en algunas regiones, y se observa un aumento general en el número de casos reportados a las autoridades de salud en los últimos a
Janine M Ramsey
Full Text Available BACKGROUND: Given current neglect for Chagas disease in public health programs in Mexico, future healthcare and economic development policies will need a more robust model to analyze costs and impacts of timely clinical attention of infected populations. METHODOLOGY/PRINCIPAL FINDINGS: A Markov decision model was constructed to simulate the natural history of a Chagas disease cohort in Mexico and to project the associated short and long-term clinical outcomes and corresponding costs. The lifetime cost for a timely diagnosed and treated Chagas disease patient is US$ 10,160, while the cost for an undiagnosed individual is US$ 11,877. The cost of a diagnosed and treated case increases 24-fold from early acute to indeterminate stage. The major cost component for lifetime cost was working days lost, between 44% and 75%, depending on the program scenario for timely diagnosis and treatment. CONCLUSIONS/SIGNIFICANCE: In the long term, it is cheaper to diagnose and treat chagasic patients early, instead of doing nothing. This finding by itself argues for the need to shift current policy, in order to prioritize and attend this neglected disease for the benefit of social and economic development, which implies including treatment drugs in the national formularies. Present results are even more relevant, if one considers that timely diagnosis and treatment can arrest clinical progression and enhance a chronic patient's quality of life.
Hanley, J.; Stevens-Goodnight, S.; Kulkarni, S.; Bustamante, D.; Fytilis, N.; Goff, P.; Monroy, C.; Morrissey, L. A.; Orantes, L.; Stevens, L.; Dorn, P.; Lucero, D.; Rios, J.; Rizzo, D. M.
The goal of our NSF-sponsored Division of Behavioral and Cognitive Sciences grant is to create a multidisciplinary approach to develop spatially explicit models of vector-borne disease risk using Chagas disease as our model. Chagas disease is a parasitic disease endemic to Latin America that afflicts an estimated 10 million people. The causative agent (Trypanosoma cruzi) is most commonly transmitted to humans by blood feeding triatomine insect vectors. Our objectives are: (1) advance knowledge on the multiple interacting factors affecting the transmission of Chagas disease, and (2) provide next generation genomic and spatial analysis tools applicable to the study of other vector-borne diseases worldwide. This funding is a collaborative effort between the RSENR (UVM), the School of Engineering (UVM), the Department of Biology (UVM), the Department of Biological Sciences (Loyola (New Orleans)) and the Laboratory of Applied Entomology and Parasitology (Universidad de San Carlos). Throughout this five-year study, multi-educational groups (i.e., high school, undergraduate, graduate, and postdoctoral) will be trained in systems modeling. This systems approach challenges students to incorporate environmental, social, and economic as well as technical aspects and enables modelers to simulate and visualize topics that would either be too expensive, complex or difficult to study directly (Yasar and Landau 2003). We launch this research by developing a set of multi-scale, epidemiological models of Chagas disease risk using STELLA® software v.9.1.3 (isee systems, inc., Lebanon, NH). We use this particular system dynamics software as a starting point because of its simple graphical user interface (e.g., behavior-over-time graphs, stock/flow diagrams, and causal loops). To date, high school and undergraduate students have created a set of multi-scale (i.e., homestead, village, and regional) disease models. Modeling the system at multiple spatial scales forces recognition that
Nisimura, Lindice Mitie; Estato, Vanessa; de Souza, Elen Mello; Reis, Patricia A.; Lessa, Marcos Adriano; de Castro-Faria-Neto, Hugo Caire; Pereira, Mirian Claudia de Souza; Tibiriçá, Eduardo; Garzoni, Luciana Ribeiro
Cardiomyopathy is the main clinical form of Chagas disease (CD); however, cerebral manifestations, such as meningoencephalitis, ischemic stroke and cognitive impairment, can also occur. The aim of the present study was to investigate functional microvascular alterations and oxidative stress in the brain of mice in acute CD. Acute CD was induced in Swiss Webster mice (SWM) with the Y strain of Trypanosoma cruzi (T. cruzi). Cerebral functional capillary density (the number of spontaneously perf...
Anis Rassi Jr
Full Text Available Chagas heart disease (CHD results from infection with the protozoan parasite Trypanosoma cruzi and is the leading cause of infectious myocarditis worldwide. It poses a substantial public health burden due to high morbidity and mortality. CHD is also the most serious and frequent manifestation of chronic Chagas disease and appears in 20-40% of infected individuals between 10-30 years after the original acute infection. In recent decades, numerous clinical and experimental investigations have shown that a low-grade but incessant parasitism, along with an accompanying immunological response [either parasite-driven (most likely or autoimmune-mediated], plays an important role in producing myocardial damage in CHD. At the same time, primary neuronal damage and microvascular dysfunction have been described as ancillary pathogenic mechanisms. Conduction system disturbances, atrial and ventricular arrhythmias, congestive heart failure, systemic and pulmonary thromboembolism and sudden cardiac death are the most common clinical manifestations of chronic Chagas cardiomyopathy. Management of CHD aims to relieve symptoms, identify markers of unfavourable prognosis and treat those individuals at increased risk of disease progression or death. This article reviews the pathophysiology of myocardial damage, discusses the value of current risk stratification models and proposes an algorithm to guide mortality risk assessment and therapeutic decision-making in patients with CHD.
Pedro Emmanuel Alvarenga Americano do Brasil; Sergio Salles Xavier; Marcelo Teixeira Holanda; Alejandro Marcel Hasslocher-Moreno; José Ueleres Braga
Abstract: INTRODUCTION With the globalization of Chagas disease, unexperienced health care providers may have difficulties in identifying which patients should be examined for this condition. This study aimed to develop and validate a diagnostic clinical prediction model for chronic Chagas disease. METHODS This diagnostic cohort study included consecutive volunteers suspected to have chronic Chagas disease. The clinical information was blindly compared to serological tests results, and a ...
Full Text Available Chagas disease, named after Carlos Chagas, who first described it in 1909, exists only on the American Continent. It is caused by a parasite, Trypanosoma cruzi, which is transmitted to humans by blood-sucking triatomine bugs and via blood transfusion. Chagas disease has two successive phases: acute and chronic. The acute phase lasts six-eight weeks. Several years after entering the chronic phase, 20-35% of infected individuals, depending on the geographical area, will develop irreversible lesions of the autonomous nervous system in the heart, oesophagus and colon, and of the peripheral nervous system. Data on the prevalence and distribution of Chagas disease improved in quality during the 1980s as a result of the demographically representative cross-sectional studies in countries where accurate information was not previously available. A group of experts met in Brasilia in 1979 and devised standard protocols to carry out countrywide prevalence studies on human T. cruzi infection and triatomine house infestation. Thanks to a coordinated multi-country programme in the Southern Cone countries, the transmission of Chagas disease by vectors and via blood transfusion was interrupted in Uruguay in 1997, in Chile in 1999 and in Brazil in 2006; thus, the incidence of new infections by T. cruzi across the South American continent has decreased by 70%. Similar multi-country initiatives have been launched in the Andean countries and in Central America and rapid progress has been reported towards the goal of interrupting the transmission of Chagas disease, as requested by a 1998 Resolution of the World Health Assembly. The cost-benefit analysis of investment in the vector control programme in Brazil indicates that there are savings of US$17 in medical care and disabilities for each dollar spent on prevention, showing that the programme is a health investment with very high return. Many well-known research institutions in Latin America were key elements of a
Gabrielle C Hunter
Full Text Available BACKGROUND: Chagas disease is endemic in the rural areas of southern Peru and a growing urban problem in the regional capital of Arequipa, population ∼860,000. It is unclear how to implement cost-effective screening programs across a large urban and periurban environment. METHODS: We compared four alternative screening strategies in 18 periurban communities, testing individuals in houses with 1 infected vectors; 2 high vector densities; 3 low vector densities; and 4 no vectors. Vector data were obtained from routine Ministry of Health insecticide application campaigns. We performed ring case detection (radius of 15 m around seropositive individuals, and collected data on costs of implementation for each strategy. RESULTS: Infection was detected in 21 of 923 (2.28% participants. Cases had lived more time on average in rural places than non-cases (7.20 years versus 3.31 years, respectively. Significant risk factors on univariate logistic regression for infection were age (OR 1.02; p = 0.041, time lived in a rural location (OR 1.04; p = 0.022, and time lived in an infested area (OR 1.04; p = 0.008. No multivariate model with these variables fit the data better than a simple model including only the time lived in an area with triatomine bugs. There was no significant difference in prevalence across the screening strategies; however a self-assessment of disease risk may have biased participation, inflating prevalence among residents of houses where no infestation was detected. Testing houses with infected-vectors was least expensive. Ring case detection yielded four secondary cases in only one community, possibly due to vector-borne transmission in this community, apparently absent in the others. CONCLUSIONS: Targeted screening for urban Chagas disease is promising in areas with ongoing vector-borne transmission; however, these pockets of epidemic transmission remain difficult to detect a priori. The flexibility to adapt to the
Adriana dos Santos
Full Text Available Introduction 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. Methods 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. Results 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. Conclusions 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.
Goff, P.; Hulse, A.; Harder, H. R.; Pierce, L. A.; Rizzo, D.; Hanley, J.; Orantes, L.; Stevens, L.; Justi, S.; Monroy, C.
A computational simulation has been designed as an investigative case study by high school students to introduce system dynamics modeling into high school curriculum. This case study approach leads users through the forensics necessary to diagnose an unknown disease in a Central American village. This disease, Chagas, is endemic to 21 Latin American countries. The CDC estimates that of the 110 million people living in areas with the disease, 8 million are infected, with as many as 300,000 US cases. Chagas is caused by the protozoan parasite, Trypanosoma cruzi, and is spread via blood feeding insect (vectors), that feed on vertebrates and live in crevasses in the walls and roofs of adobe homes. One-third of the infected people will develop chronic Chagas who are asymptomatic for years before their heart or GI tract become enlarged resulting in death. The case study has three parts. Students play the role of WHO field investigators and work collaboratively to: 1) use genetics to identify the host(s) and vector of the disease 2) use a STELLA™ SIR (Susceptible, Infected, Recovered) system dynamics model to study Chagas at the village scale and 3) develop management strategies. The simulations identify mitigation strategies known as Ecohealth Interventions (e.g., home improvements using local materials) to help stakeholders test and compare multiple optima. High school students collaborated with researchers from the University of Vermont, Loyola University and Universidad de San Carlos, Guatemala, working in labs, interviewing researchers, and incorporating mulitple field data as part of a NSF-funded multiyear grant. The model displays stable equilibria of hosts, vectors, and disease-states. Sensitivity analyses show measures of household condition and presence of vertebrates were significant leverage points, supporting other findings by the University research team. The village-scale model explores multiple solutions to disease mitigation for the purpose of producing
A Triatoma maculata (Hemiptera, Reduviidae, Triatominae population from Roraima, Amazon region, Brazil, has some bionomic characteristics of a potential Chagas disease vector Uma população de Triatoma maculata (Hemiptera, Reduviidae, Triatominae proveniente de Roraima, Amazônia, Brasil, possui algumas características bionômicas de vetor potencial de doença de Chagas
José Francisco Luitgards-Moura
Full Text Available Even though Chagas disease is rare in the Brazilian Amazon, the conditions for the establishment of domiciliated cycles prevail in many areas where triatomines are of frequent occurrence. In Roraima, a previous serological and entomological survey in three agricultural settlements showed the existence of all transmission cycle elements, i.e., individuals infected by Trypanosoma cruzi, triatomine species previously found harboring T. cruzi in the broader Amazon region of neighboring countries and, domicile/ peridomicile conditions favorable to triatomine colonization. Triatoma maculata was the most frequent species, found in chicken houses in the peridomicile and sporadically within residences. Aiming to investigate the possibility of T. maculata to possess the potentiality to transmit T. cruzi in the area, bionomic characteristics were studied under laboratory conditions. These were feeding frequency, time for defecation after a blood meal, time elapsed in voluntary fasting pre- and pos-ecdysis, moulting time periods, pre-oviposition and oviposition periods and index of oviposition, incubation period, egg viability, longevity and mortality rate. Results show that the Passarão population of T. maculata should be considered a potential vector of T. cruzi since it shows a capacity to infest artificial ecotopes in the peridomicile, to carry out large number of meals during the nymphal cycle, to have a relatively short developmental cycle capable of producing 2.9 generations/year, to blood source eclecticism, to defecate immediately after the blood meal while still on the host and to the fact that has been previously found naturally infected by T.cruzi.A doença de Chagas é de rara ocorrência na Região Amazônica Brasileira, onde contudo as condições para o estabelecimento de ciclos domésticos existem. Um estudo previamente realizado em áreas de colonização agrícola no Estado de Roraima, mostrou a possibilidade de ciclos autóctones de
presence of T. cruzi in blood, explored in fresh smears by serial micro-hematocrite and/or by xenodiagnosis, was the only criterion to define infection in NB. All NB were followed up by direct agglutination (DA with or without 2 mercaptoethanol (DA-w2ME, DA-wo2ME and IIF in order to establish the specific antibody kinetics. Clinical studies on NB with T. cruzi infection include routine laboratory tests. Benznidazole (3 to 7 mg/kg/day and, in 1 case, nifurtimox (15 mg/kg/day were employed as therapeutic agents. T. cruzi infection was confirmed in 149 PW (15.9%, table I. These chagasic mothers delivered 6 chagasic NB (CCHD-NB, (4%. Diagnosis of congenital Chagas' disease accounted for a total of 12 NB out of the 968 studied. 4 out of them were positive by both micro-hematocrite and blood smears and 7 by micro-hematocrite alone. Xenodiagnosis was performed in 2 NB resulting positive in both cases, table II. The most usual clinical findings included hepatomegaly (present in all cases, splenomegaly 8/12, jaundice 10/12 and prematurity 5/12, table 3. Laboratory findings showed anemia to be of hypochromic microcytic type in all cases. Other laboratory findings included lymphocytosis, normal erythrosedimentation, slight to moderate increase of transaminases in all cases, and elevated indirect bilirrubin in cases with jaundice, table 4. Analysis of cerebro spinal fluid in 6 CCh-NB revealed the presence of T. cruzi in 2 cases, plus abnormal cytochemical content in one of them, table 4. The serological reactions of infected and treated NB became negative between 4th and 8th month in all but 1 case that remained positive until 14th, fig. 1. A close correlation was found between DA and IIF. DA-w2ME liter showed a significant drop during the initial phase of the controls. Benznidazole was successful in 11 out of the 12 CCh-NB. The remaining NB was effectively treated with nifurtimox. Therapeutic tolerance was satisfactory for both agents. These observations showed that congenital Chagas
Daniel P. Cardinali
Full Text Available Chagas' disease is a severe health problem in Latin America, causing approximately 50 000 deaths a year, with approximately 18 million infected people. About 25-30% of the patients infected with Trypanosoma cruzi develop the chronic form of the disease. The protective response against T. cruzi depends on both innate and acquired immunity involving macrophages, natural killer cells, T and B lymphocytes, and the production of proinflammatory Th-1 cytokines. In addition, an increased nitric oxide (NO production in macrophages leading to effective microbicidal action is needed to control parasitemia. Melatonin is detectable in T. cruzi and may play a role in promoting infection whereas, when administered in high doses during the acute phase of T. cruzi infection, it can decrease parasitemia while reducing NO production. During chronic disease progression, the sustained oxidative stress concomitant to myocardial damage could be reduced by administering melatonin. It is hypothesized that the coordinated administration of a melatonin agonist like the MT1/MT2 agonist ramelteon, that lacks antioxidant activity and may not affect NO production during the acute phase, and of melatonin in doses high enough to decrease oxidative damage, to preserve mitochondrial and to prevent cardiomyopathy during the chronic phase, could be a novel add-on treatment of Chagas´ disease.
C. Miguel Pinto; Sofía Ocaña-Mayorga; Tapia, Elicio E.; Lobos, Simón E.; Zurita, Alejandra P.; Fernanda Aguirre-Villacís; Amber MacDonald; Anita G Villacís; Luciana Lima; Teixeira, Marta M. G.; Mario J Grijalva; Perkins, Susan L.
The generalist parasite Trypanosoma cruzi has two phylogenetic lineages associated almost exclusively with bats-Trypanosoma cruzi Tcbat and the subspecies T. c. marinkellei. We present new information on the genetic variation, geographic distribution, host associations, and potential vectors of these lineages. We conducted field surveys of bats and triatomines in southern Ecuador, a country endemic for Chagas disease, and screened for trypanosomes by microscopy and PCR. We identified parasite...
Renata Trotta Barroso Ferreira; Aline Martins Melandre; Maria Luiza Cabral; Maria Regina Branquinho; Paola Cardarelli-Leite
Abstract: INTRODUCTION: Before 2004, the occurrence of acute Chagas disease (ACD) by oral transmission associated with food was scarcely known or investigated. Originally sporadic and circumstantial, ACD occurrences have now become frequent in the Amazon region, with recently related outbreaks spreading to several Brazilian states. These cases are associated with the consumption of açai juice by waste reservoir animals or insect vectors infected with Trypanosoma cruzi in endemic areas. Altho...
José Rodrigues Coura
Full Text Available At least eighteen species of triatominae have been found in the Brazilian Amazon, nine of them naturally infected with Trypanosoma cruzi or "cruzi-like" trypanosomes and associated with numerous wild reservoirs. Despite the small number of human cases of Chagas' disease described to date in the Brazilian Amazon the risk that the disease will become endemic in this area is increasing for the following reasons: a uncontrolled deforestation and colonization altering the ecological balance between reservoir hosts and wild vectors; b the adaptation of reservoir hosts of T.cruzi and wild vectors to peripheral and intradomiciliary areas, as the sole feeding alternative; c migration of infected human population from endemic areas, accompanied by domestic reservoir hosts (dogs and cats or accidentally carrying in their baggage vectors already adapted to the domestic habitat. In short, risks that Chagas' disease will become endemic to the Amazon appear to be linked to the transposition of the wild cycle to the domestic cycle in that area or to transfer of the domestic cycle from endemic areas to the Amazon.Pelo menos dezoito espécies de triatomíneos foram encontradas na Amazônia brasileira, nove das quais infectadas com Trypanosoma cruzi ou semelhante ("cruzi-like", associadas com numerosos reservatórios silvestres. A despeito do pequeno número de casos humanos da doença de Chagas descritos até agora na Amazônia brasileira, o risco que essa doença se torne endêmica é cada vez maior, pelas seguintes razões: a desmatamentos e colonização descontrolados, alterando o balanço entre reservatórios e vetores; b adaptação de reservatórios e vetores silvestres com T.cruzi ao peridomicílio, como única alternativa alimentar; c migração de populações humanas infectadas com T.cruzi acompanhadas de reservatórios domésticos (cães e gatos ou de vetores de suas regiões de origem na bagagem, já adaptados ao domicílio. Em resumo, o risco de que
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The increasing number of autochthonous cases of Chagas disease in the Amazon since the 1970s has led to fear that the disease may become a new public health problem in the region. This transformation in the disease's epidemiological pattern in the Amazon can be explained by environmental and social changes in the last 30 years. The current article draws on the sociological theory of perverse effects to explain these changes as the unwanted result of the shift from the "inward" development mod...
Full Text Available Carlos Chagas related in more than two 200 cases, what he called "nervous forms" of trypanosomiasis, that is neurological manifestations from central origin (idiotism, infantilism, pseudo-bulbar paralysis, aphasia, cerebellar ataxia, atetosis, espostic or paralytic diplegia, disbasia. At that time Chagas expressed his concepts as follows: "In relation to the frequency of trypanosomiasis nervous forms we have performed many observations which allow us to state that this disease is the one which causes the largest number of organic affections of the central nervous system, in human pathology". We are plenty convinced by Chagas's statement. By experiments on animals of laboratory we have very often noticed a rather varied neurological symptomatology, being worth point out identical syndromes to those observed by Chagas. Our autopsy material non-rarely include chronic Chagas cases presenting a most varied symtomatology. Among them we have named only three cases of discerebral nanism, a rather rare affection in other parts of the world and relatively frequent in our material. The fact which we have demonstrated, i.e., a relatively great decreasing of number of nervous cells in the peripheral system could happen in the central nervous system as well. Provided that there are only two quantitative works on neuron number diminishing in the central nervous system in mice and rats we decline to go into further details about central neuropathies in man. We emphasized the necessity to perform researches on this field by means of intimate collaboration between clinicians and pathologists, as the only way to confirm on scientific basis all that was observed by the panoramic and genial vision of Carlos Chagas.
Soto, Hugo; Tibaduiza, Tania; Montilla, Marleny; Triana, Omar; Suárez, Diana Carolina; Torres Torres, Mariela; Arias, María Teresa; Lugo, Ligia
Colombia recorded 11 cases of acute Chagas disease and 80 cases of oral contamination with Trypanosoma cruzi. The current study analyzes the entomological and parasitological characteristics of the outbreak in Aguachica, Cesar Department, in 2010. An interdisciplinary group of health professionals and regional university personnel conducted the laboratory tests in the patients and the investigation of the transmission focus. Eleven cases of acute Chagas diseases were detected in a single family in a dwelling with domiciliated triatomines and Rhodnius pallescens, Pantrongylus geniculatus, Eratyrus cuspidatus, and two Didelphis marsupialis opossums infected with T. cruzi in Attalea butyracea and Elaeis oleifera palm trees in the urban area of Aguachica. The study analyzes the role of R. pallescens and palm trees in the wild cycle of T. cruzi and in oral transmission of Chagas disease. Sporadic incursions by wild R. pallescens, P. geniculatus, and E. cuspidatus from the nearby palm trees into human dwellings may cause increasingly frequent outbreaks of oral Chagas disease. PMID:24896050
Pinazo, Maria-Jesus; Gascon, Joaquim
There are currently two major factors that have modified the epidemiology of Chagas disease in the last decades: climate change and migration flows. In this new scenario, there are new challenges to control and prevent Trypanosoma cruzi infection in endemic countries, such as the control of a wider distribution of triatomine vectors or the reinforcement of vertical transmission programs. In non-endemic areas, few countries are aware of the emergence of this new disease and have established changes in their health systems. To address this new public health challenge, the priorities should be control programs to avoid new cases of T. cruzi infection acquired through vertical transmission, blood transfusion or organ transplant. In both, endemic and non-endemic areas, the international community and all the actors involved in Chagas disease must join efforts mainly in two directions: better management of the infection in affected individuals and more research to cover the knowledge gap mainly in physiopathology, diagnosis and treatment. PMID:26187358
Janine M Ramsey
Full Text Available Traditional methods for Chagas disease prevention are targeted at domestic vector reduction, as well as control of transfusion and maternal-fetal transmission. Population connectivity of Trypanosoma cruzi-infected vectors and hosts, among sylvatic, ecotone and domestic habitats could jeopardize targeted efforts to reduce human exposure. This connectivity was evaluated in a Mexican community with reports of high vector infestation, human infection, and Chagas disease, surrounded by agricultural and natural areas. We surveyed bats, rodents, and triatomines in dry and rainy seasons in three adjacent habitats (domestic, ecotone, sylvatic, and measured T. cruzi prevalence, and host feeding sources of triatomines. Of 12 bat and 7 rodent species, no bat tested positive for T. cruzi, but all rodent species tested positive in at least one season or habitat. Highest T. cruzi infection prevalence was found in the rodents, Baiomys musculus and Neotoma mexicana. In general, parasite prevalence was not related to habitat or season, although the sylvatic habitat had higher infection prevalence than by chance, during the dry season. Wild and domestic mammals were identified as bloodmeals of T. pallidipennis, with 9% of individuals having mixed human (4.8% single human and other mammal species in bloodmeals, especially in the dry season; these vectors tested >50% positive for T. cruzi. Overall, ecological connectivity is broad across this matrix, based on high rodent community similarity, vector and T. cruzi presence. Cost-effective T. cruzi, vector control strategies and Chagas disease transmission prevention will need to consider continuous potential for parasite movement over the entire landscape. This study provides clear evidence that these strategies will need to include reservoir/host species in at least ecotones, in addition to domestic habitats.
Full Text Available La enfermedad de Chagas es producida por el parásito Trypanosoma cruzi, el cual afecta tanto a seres humanos como a animales, en particular mamíferos marsupiales y placentarios. Las vías de transmisión son diversas, siendo una de las más importantes la vía vectorial, en la que participan insectos infectados con este parásito, animales y humanos. En este artículo de revisión discutimos los postulados sobre la vía de transmisión oral, los hallazgos de T. cruzi en momias de América y especialmente en las del norte de Chile. Presentamos además información que apunta a que la enfermedad de Chagas estuvo presente mucho antes de la conquista europea y de la construcción de viviendas de adobe. Comentamos las hipótesis sobre el vector domiciliado más importante de Sudamérica, Triatoma infestans, su antigüedad en la costa de Arica y los reportes más recientes de otros vectores silvestres. También se discute la información relacionada a la participación en el ciclo de T. cruzi de distintos mamíferos silvestres de Chile y asimismo proponemos el estudio paleoparasitológico en restos zooarqueológicos para conocer las especies de mamíferos reservónos de T. cruzi en la antigüedad.Chagas diseases is produced by a parasite named Trypanosoma cruzi, that affects humans and other marsupial and placental mammals. Transmission routes are diverse, but the most important transmission is the vector route, which involves the triatomine insects, wild and domestic infected animáis, and humans. Here we review the data about oral transmission route and the evidences of the etiological agent (Trypanosoma cruzi of Chagas disease in pre-Columbian American mummies, making a critical review of the infection in northern Chile. Moreover, we comment on the hypotheses suggested in relation to the most important vector of the infection in South América Triatoma infestans, its antiquity in the Arica coast, and the recent reports about other wild infected
Full Text Available Leptin is produced primarily by adipocytes. Although originally associated with the central regulation of satiety and energy metabolism, increasing evidence indicates that leptin may be an important mediator in cardiovascular pathophysiology. The aim of the present study was to investigate plasma leptin levels in patient with Chagas' heart disease and their relation to different forms of the disease. We studied 52 chagasic patients and 30 controls matched for age and body mass index. All subjects underwent anthropometric, leptin and N-terminal pro-brain natriuretic peptide (NT-proBNP measurements and were evaluated by echocardiography, 12-lead electrocardiogram (ECG, and chest X-ray. All patients had fasting blood samples taken between 8:00 and 9:00 am. Chagasic patients were divided into 3 groups: group I (indeterminate form, IF group consisted of 24 subjects with 2 positive serologic reactions for Chagas' disease and no cardiac involvement as evaluated by chest X-rays, ECG and two-dimensional echocardiography; group II (showing ECG abnormalities and normal left ventricular systolic function, ECG group consisted of 14 patients; group III consisted of 14 patients with congestive heart failure (CHF group and left ventricular dysfunction. Serum leptin levels were significantly lower (P < 0.001 in the CHF group (1.4 ± 0.8 ng/mL when compared to the IF group (5.3 ± 5.3 ng/mL, ECG group (9.7 ± 10.7 ng/mL, and control group (8.1 ± 7.8 ng/mL. NT-proBNP levels were significantly higher (P < 0.001 in the CHF group (831.8 ± 800.1 pg/mL when compared to the IF group (53.2 ± 33.3 pg/mL, ECG group (83.3 ± 57.4 pg/mL, and control group (32 ± 22.7 pg/mL. Patients with Chagas' disease and an advanced stage of CHF have high levels of NT-ProBNP andlow plasma levels of leptin. One or more leptin-suppressing mechanisms may operate in chagasic patients.
Leon Rodriguez, Daniel A; Carmona, F. David; Echeverría, Luis Eduardo; González, Clara Isabel; Martin, Javier
Chagas disease is a parasitic disorder caused by the infection with the flagellated protozoan Trypanosoma cruzi. According to the World Health Organization, more than six million people are currently infected in endemic regions. Genetic factors have been proposed to influence predisposition to infection and development of severe clinical phenotypes like chronic Chagas cardiomyopathy (CCC). Interleukin 18 (IL18) encodes a proinflammatory cytokine that has been proposed to be involved in controlling T. cruzi infection. In this study, we analyzed the possible role of six IL18 gene variants (rs5744258, rs360722, rs2043055, rs187238, rs1946518 and rs360719), which cover most of the variation within the locus, in the susceptibility to infection by T. cruzi and/or CCC. In total, 1,171 individuals from a Colombian region endemic for Chagas disease, classified as seronegative (n = 595), seropositive asymptomatic (n = 175) and CCC (n = 401), were genotyped using TaqMan probes. Significant associations with T. cruzi infection were observed when comparing seronegative and seropositive individuals for rs187238 (P = 2.18E-03, OR = 0.77), rs360719 (P = 1.49E-03, OR = 0.76), rs2043055 (P = 2.52E-03, OR = 1.29), and rs1946518 (P = 0.0162, OR = 1.22). However, dependence analyses suggested that the association was mainly driven by the polymorphism rs360719. This variant is located within the promoter region of the IL18 gene, and it has been described that it creates a binding site for the transcription factor OCT-1 affecting IL-18 expression levels. In addition, no evidence of association was observed between any of the analyzed IL18 gene polymorphisms and the development of CCC. In summary, our data suggest that genetic variation within the promoter region of IL18 is directly involved in the susceptibility to infection by T. cruzi, which provides novel insight into disease pathophysiology and adds new perspectives to achieve a more effective disease control. PMID:27027876
Simone Frédérique Brenière
Full Text Available A cross section of a human population (501 individuals selected at random, and living in a Bolivian community, highly endemic for Chagas disease, was investigated combining together clinical, parasitological and molecular approaches. Conventional serology and polymerase chain reaction (PCR indicated an active transmission of the infection, a high seroprevalence (43.3% ranging from around 12% in 45 years, and a high sensitivity (83.8% and specificity of PCR. Abnormal ECG tracing was predominant in chagasic patients and was already present among individuals younger than 13 years. SAPA (shed acute phase antigen recombinant protein and the synthetic peptide R-13 were used as antigens in ELISA tests. The reactivity of SAPA was strongly associated to Trypanosoma cruzi infection and independent of the age of the patients but was not suitable neither for universal serodiagnosis nor for discrimination of specific phases of Chagas infection. Anti-R-13 response was observed in 27.5% only in chagasic patients. Moreover, anti-R13 reactivity was associated with early infection and not to cardiac pathology. This result questioned previous studies, which considered the anti-R-13 response as a marker of chronic Chagas heart disease. The major clonets 20 and 39 (belonging to Trypanosoma cruzi I and T. cruzi II respectively which circulate in equal proportions in vectors of the studied area, were identified in patients' blood by PCR. Clonet 39 was selected over clonet 20 in the circulation whatever the age of the patient. The only factor related to strain detected in patients' blood, was the anti-R-13 reactivity: 37% of the patients infected by clonet 39 (94 cases had anti-R13 antibodies contrasting with only 6% of the patients without clonet 39 (16 cases.
Rafael M. Ortí-Lucas
Full Text Available Background. The prevalence of Chagas disease in endemic countries varies with the kind of vector involved and the socioeconomic conditions of the population of origin. Due to recent immigration it is an emerging public health problem in Europe, especially in those countries which receive immigrant populations with a high prevalence of carriers. The study reviews the impact of the disease on Bolivian immigrants living in Europe, the preventive measures and regulations applied in European countries, and their repercussion on possible stigmatization of certain population groups. Methods. The Bolivian immigrant population resident in 2012 was estimated and the affected population in different European countries was calculated with data on carrier prevalence that were recently published. The preventive measures and regulations available in Europe were also reviewed. MEDLINE-PubMed, GoPubMed, and Embase were consulted for the literature review. Results. The Bolivian immigrant population has the highest prevalence of Chagas carriers (6.7%–25% compared to the overall Latin American population (1.3%–2.4%. Only in Spain, France, Belgium, UK, Portugal, Italy, Switzerland, The Netherlands, and Germany, preventive measures are applied to this population. The established regulations are insufficient and completely different criteria are applied in the different countries and this could reflect a certain degree of stigmatization.
Roca Saumell, Carme; Soriano-Arandes, Antoni; Solsona Díaz, Lluís; Gascón Brustenga, Joaquim
Chagas disease is caused by the protozoan Trypanosoma cruzi. Although it is commonly transmitted by an insect vector in continental Latin-America, in recent decades, due migration, has been diagnosed in other countries such Spain, the European country with a largest immigrant population of Latin American. For a long time, the patient remains asymptomatic, but some years after this stage, the symptoms can be serious (dilated cardiomyopathy, megacolon, megaesophagus). In addition, detection in pregnant women has a high priority because of the route of vertical transmission. Several specific guidelines about Chagas disease has been developed on the Banks of blood, maternal hospitals, HIV co-infection, organ transplant. But due to the detection of lack of information to primary care professionals, we consider to will be useful this document written and agreed to by family phisicians, pediatricians and specialists in International Health. PMID:25704793
The importance of Chagas' disease - a histic and haematic parasitosis endemic in extensive areas of Latin America, with 60 million people exposed to it and 20 million infected - stems from the high sickness and mortality rates affecting mainly rural and fringe populations. Nevertheless, progressive urbanization of the disease due to population migration and blood transfusion is being observed. The authors studied 56 cases of patients with Chagas' disease, 45 of whom were detected asymptomatically when donating blood by immunoserological reactions involving complement fixation and haemagglutination. Radiotracers were used to explore ventricular function in 56 cases; oesophageal transit in 29 cases; the upper urinary tract in 25 cases; and bladder function in 22 cases. All four procedures were applied to 19 patients. In 40 patients a study was made of the left and right ventricular function, the left being found altered in 17% of the cases, the right ventricular function in 22% and both in 25%. In 26 cases (65%) anomalies were encountered in at least one of the two ventricles. Oesophageal transit was altered in 20 patients, 16 of them asymptomatically. In 6 of them it was prolonged, in 4 it was adynamic and in 10 cases uncoordinated. The upper urinary tract showed abnormalities (pyelic dilation, pyelo-ureteral dyskinesia, ureteral dyskinesia, ureteral dilation and/or vesico-ureteral reflux) in 22 patients, in all cases asymptomatically. Bladder function was abnormal in 18 asymptomatic patients, basically represented by a residual decompensated cystopathy with a hypotonicity of different degrees. Of the 45 patients without symptoms detected when donating blood, there was alteration of ventricular function in 49%, of oesophageal transit in 68%, of the upper urinary tract in 90%, and of bladder function in 78%, with an overall figure of 66% abnormal examinations from 106 radioisotopic studies
João Carlos P. Dias
The feasibility and most important ecological aspects of vectorial Chagas' disease control are discussed. The spread and maintenance of this disease involve multiple ecological and sociopolitical factors that must be taken into account when control programs are planned, executed and evaluated. In spite of its complexity, Chagas disease can be controlled using methods that target specific mechanisms of transmission, the most important being vectorial and transfusional. Major ecological problem...
Gubler, D J
Vector-borne diseases have been the scourge of man and animals since the beginning of time. Historically, these are the diseases that caused the great plagues such as the 'Black Death' in Europe in the 14th Century and the epidemics of yellow fever that plagued the development of the New World. Others, such as Nagana, contributed to the lack of development in Africa for many years. At the turn of the 20th Century, vector-borne diseases were among the most serious public and animal health problems in the world. For the most part, these diseases were controlled by the middle of the 20th Century through the application of knowledge about their natural history along with the judicious use of DDT (dichlorodiphenyltrichloroethane) and other residual insecticides to interrupt the transmission cycle between arthropod and vertebrate host. However, this success initiated a period of complacency in the 1960s and 1970s, which resulted in the redirection of resources away from prevention and control of vector-borne diseases. The 1970s was also a time in which there were major changes to public health policy. Global trends, combined with changes in animal husbandry, urbanisation, modern transportation and globalisation, have resulted in a global re-emergence of epidemic vector-borne diseases affecting both humans and animals over the past 30 years. PMID:20128467
O. M. Genovese
Full Text Available Seventy five patients with the diagnosis of chronic Chagas' disease were studied by employing EPs techniques. Two of them had delayed arrival of the signal to the Erb's point and one to the spinal cord when looking at SEPs. TWo patients had increment of the time interval between waves 1st and IIIrd, when studying PEATs. These findings were interpreted as due to peripheral nerve fibers damage, a feature described in previous papers. The, most striking finding was the prolonged time interval between waves N13 and N20 (SEPs found in two patients and between waves IIIrd and Vth (PEAT seen in 7 affected subjects. These observations suggested the development of some sort of CNS involvement, perhaps related to myelin damage, in patients who reached the chronic state of the infection.
Lopes, E R; Marquez, J O; da Costa Neto, B; Menezes, A A; Chapadeiro, M E
The frequency of strokes was studied in chronic chagasic and years of age, non-chagasic patients, older than 15 coming to necropsy in Uberaba, from 1979 than 1988. The study consisted of paired sex and age matched controls. Two hundred and eight pairs were analysed. Either ischemic or hemorrhagic strokes were found in 41 (19.7%) of the chagasics and in 55 (26.4%) of the non-chagasic, a difference not significant at the level of 5%. Twelve (75%) of the former had infarcts and 4 (25%) had brain hemorrhage; five (31.3%) of the non-chagasics had ischemic strokes and 11 (68.7%) had hemorrhagic strokes. The differences were significant to the level of 5%. The results indicate a high frequency of ischemic strokes in human Chagas' disease and demonstrate a lesser frequency of hemorrhagic stroke in chagasics when compared with non-chagasics. PMID:1841424
Morocoima, Antonio; Carrasco, Hernán J; Boadas, Johanna; Chique, José David; Herrera, Leidi; Urdaneta-Morales, Servio
Trypanosoma cruzi, etiological agent of Chagas' disease, was isolated from armadillos (Dasypus novemcinctus novemcinctus) captured in rural communities Northeastern Venezuela from Nueva Esparta State (no endemic for Chagas' disease), Monagas and Anzoátegui States (endemics). The isolates, genetically typed by PCR-RFLP as belonging to the TcIII DTU, have demonstrated in murine model heterogenic parasitemia, mortality and histotropism with marked parasitism in cardiac, skeletal, and smooth myocytes that showed correlation with lymphobasophilic inflammatory infiltrates. Our finding of T. cruzi infected armadillos in Isla Margarita (Nueva Esparta State), together with reports of triatomine vectors in this region, the accentuated synanthropy of armadillos, intense economic activity, migration due to tourism and the lack of environmental education programs all of them represent risks that could cause the emergence of Chagas' disease in this area. This is the first report of the TcIII DTU in Northeastern Venezuela, thus widening the geographic distribution of this DTU. PMID:22902748
Sandra Maria Alkmim-Oliveira
Full Text Available Introduction Determining the genetic similarities among Trypanosoma cruzi populations isolated from different hosts and vectors is very important to clarify the epidemiology of Chagas disease. Methods An epidemiological study was conducted in a Brazilian endemic area for Chagas disease, including 76 chronic chagasic individuals (96.1% with an indeterminate form; 46.1% with positive hemoculture. Results T. cruzi I (TcI was isolated from one child and TcII was found in the remaining (97.1% subjects. Low-stringency single-specific-primer-polymerase chain reaction (LSSP-PCR showed high heterogeneity among TcII populations (46% of shared bands; however, high similarities (80-100% among pairs of mothers/children, siblings, or cousins were detected. Conclusions LSSP-PCR showed potential for identifying similar parasite populations among individuals with close kinship in epidemiological studies of Chagas disease.
Andrade, Jadelson Pinheiro de; Marin Neto, Jose Antonio; Paola, Angelo Amato Vincenzo de; Vilas-Boas, Fábio; Oliveira, Glaucia Maria Moraes; Bacal, Fernando; Bocchi, Edimar Alcides; Almeida, Dirceu Rodrigues; Fragata Filho, Abilio Augusto; Moreira, Maria da Consolação Vieira; Xavier, Sergio Salles; Oliveira Junior, Wilson Alves de; Dias, João Carlos Pinto
Much has been achieved in one century after Carlos Chagas' discovery. However, there is surely much to be done in the next decades. At present, we are witnessing many remarkable efforts to monitor the epidemiology of the disease, to better understand the biology of the T. cruzi and its interaction with human beings as well as the pathogenesis and pathophysiology of the complications in the chronic phase, and deal more appropriately and effectively with late cardiac and digestive manifestations. Although the vector and transfusion-derived transmission of the disease has been controlled in many countries, there remains a pressing need for sustained surveillance of the measures that led to this achievement. It is also necessary to adopt initiatives that enable appropriate management of social and medical conditions resulting from the migration of infected individuals to countries where the disease formerly did not exist. It's also necessary to standardize the most reliable methods of detection of infection with T. cruzi, not only for diagnosis purposes, but more crucially, as a cure criterion. The etiological treatment of millions of patients in the chronic stage of the disease is also to be unraveled. A renewed interest in this area is observed, including prospects of studies focusing on the association of drugs with benznidazole. We also wait for full evidence of the actual effectiveness of the etiological treatment to impact favorably on the natural history of the disease in its chronic phase. Eventually, cardiologists are primarily responsible for improving the clinical management of their patients with Chagas' disease, judiciously prescribing drugs and interventions that respect, as much as possible, the peculiar pathophysiology of the disease, wasting no plausible therapeutic opportunities. PMID:21789345
The unprecedented emergence of important public health and veterinary zoonoses is usually a result of exponential population growth and globalization of human activities. I characterized Chagas' disease as an emergent zoonosis in the Caracas Valley (Venezuela) due to the following findings: the presence of reservoirs (Didelphis marsupialis, Rattus rattus) and vectors (Panstrongylus geniculatus, Panstrongylus rufotuberculatus) infected with Trypanosoma cruzi in urbanized or marginalized areas; the elevated contact between P. geniculatus and human beings detected by parasitological and molecular examinations of triatomine feces demonstrated the possibility of transmission risks; a study of outbreaks of urban Chagas' disease reported the first proven case of oral transmission of T. cruzi to human beings; the risk of transmission of glandular metacyclic stages from marsupials by experimental ocular and oral instillation; mice genitalia infected with T. cruzi contaminated blood resulted in the formation of amastigotes very close to the lumen suggesting that there may be a possibility of infection via their release into the urine and thence to the exterior; the ubiquitous histotropism and histopathology of T. cruzi was demonstrated using a mouse model; the presence of experimental T. cruzi pseudocysts in adipose, bone-cartilage, and eye tissue indicated a potential risk for transplants. Socio-sanitary programs that include improvements in housing, vector control, and access to medical treatment, as well as strategies aimed at combating social inequalities, poverty, and underdevelopment should be undertaken in those areas where zoonoses are most prevalent. Disciplines, such as Ecology, Epidemiology, Medical Entomology, Human and Veterinary Medicine, Environmental Studies, Public Health, Social and Political Studies, Immunology, Microbiology, and Pharmacology could all provide important contributions that aim to reduce the occurrence of factors governing the spread of
Guimaro, M.C.; Alves, R. J. V.; Rose, E.; Sousa, A.O.; Rosa, A.D.; Hecht, M.M.; Sousa, M.V.; Andrade, R.R.; Vital, T.; Plachý, Jiří; Nitz, N.; Hejnar, Jiří; Gomes, C.C.; Teixeira, A.R.L.
Roč. 8, č. 12 (2014). ISSN 1935-2735 Institutional support: RVO:68378050 Keywords : Chagas disease * inbred chicken * adoptive transfer of immunity Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.446, year: 2014
José Manuel Ramos
Full Text Available INTRODUCTION: Publications are often used as a measure of success in research work. Chagas disease occurs in Central and Southern America. However, during the past years, the disease has been occurring outside Latin America due to migration from endemic zones. This article describes a bibliometric review of the literature on Chagas disease research indexed in PubMed during a 70-year period. METHODS: Medline was used via the PubMed online service of the U.S. National Library of Medicine from 1940 to 2009. The search strategy was: Chagas disease [MeSH] OR Trypanosoma cruzi [MeSH]. RESULTS: A total of 13,989 references were retrieved. The number of publications increased steadily over time from 1,361 (1940-1969 to 5,430 (2000-2009 (coefficient of determination for linear fit, R²=0.910. Eight journals contained 25% of the Chagas disease literature. Of the publications, 64.2% came from endemic countries. Brazil was the predominant country (37%, followed by the United States (17.6% and Argentina (14%. The ranking in production changed when the number of publications was normalized by estimated cases of Chagas disease (Panama and Uruguay, population (Argentina and Uruguay, and gross domestic product (Bolivia and Brazil. CONCLUSIONS: Several Latin American countries, where the prevalence of T. cruzi infection was not very high, were the main producers of the Chagas disease literature, after adjusting for economic and population indexes. The countries with more estimated cases of Chagas disease produced less research on Chagas disease than some developed countries.
Fred Luciano Neves Santos
Full Text Available INTRODUCTION: Control strategies to eliminate the transmission of Chagas disease by insect vectors have significantly decreased the number of reported acute cases in Brazil. However, data regarding the incidence and distribution of acute Chagas disease cases in the State of Pernambuco are unavailable in the literature. METHODS: A geographical information system was used to delineate the spatiotemporal distribution profile of the cases from 2002 to 2013 in 185 municipalities of Pernambuco based on the municipality where notification occurred. The results were presented in digital maps generated by the TerraView software (INPE. RESULTS: A total of 302 cases of acute disease were recorded in 37.8% of the municipalities, for a total of 0.13 cases per 1,000,000 inhabitants per year. Out of the 302 cases, 99.3% were reported between 2002 and 2006. The most affected municipalities were Carnaubeira da Penha, Mirandiba and Terra Nova. The risk maps showed a significant decrease in the number of notifications and a concentration of cases in the Midwest region. CONCLUSIONS: This study highlights a significant decrease in new cases of acute Chagas disease in Pernambuco starting in 2006 when Brazil received an international certification for the interruption of vectorial transmission by Triatoma infestans. However, control strategies should still be encouraged because other triatomine species can also transmit the parasite; moreover, other transmission modes must not be neglected.
Full Text Available 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 cruziinfection 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.
Guedes, Paulo Marcos Matta; de Andrade, Cléber Mesquita; Nunes, Daniela Ferreira; de Sena Pereira, Nathalie; Queiroga, Tamyres Bernadete Dantas; Machado-Coelho, George Luiz Lins; Nascimento, Manuela Sales Lima; Do-Valle-Matta, Maria Adelaide; da Câmara, Antônia Cláudia Jácome; Chiari, Egler; Galvão, Lúcia Maria da Cunha
Ischemic strokes have been implicated as a cause of death in Chagas disease patients. Inflammation has been recognized as a key component in all ischemic processes, including the intravascular events triggered by vessel interruption, brain damage and repair. In this study, we evaluated the association between inflammatory markers and the death risk (DR) and stroke risk (SR) of patients with different clinical forms of chronic Chagas disease. The mRNA expression levels of cytokines, transcript...
Full Text Available Abstract Background Experimental studies demonstrate that infection with trypanosoma cruzi causes vasculitis. The inflammatory lesion process could hypothetically lead to decreased distensibility of large and small arteries in advanced Chagas' disease. We tested this hypothesis. Methods and results We evaluated carotid-femoral pulse-wave velocity (PWV in 53 Chagas' disease patients compared with 31 healthy volunteers (control group. The 53 patients were classified into 3 groups: 1 16 with indeterminate form of Chagas' disease; 2 18 with Chagas' disease, electrocardiographic abnormalities, and normal systolic function; 3 19 with Chagas' disease, systolic dysfunction, and mild-to-moderate congestive heart failure. No difference was noted between the 4 groups regarding carotid-femoral PWV (8.4 ± 1.1 vs 8.2 ± 1.5 vs 8.2 ± 1.4 vs 8.7 ± 1.6 m/s, P = 0.6 or pulse pressure (39.5 ± 7.6 vs 39.3 ± 8.1 vs 39.5 ± 7.4 vs 39.7 ± 6.9 mm Hg, P = 0.9. A positive, significant, similar correlation occurred between PWV and age in patients with Chagas' disease (r = 0.42, P = 0.002, in controls (r = 0.48, P = 0.006, and also between PWV and systolic blood pressure in both groups (patients with Chagas' disease, r = 0.38, P = 0.005; healthy subjects, r = 0.36, P = 0.043. Conclusion Carotid femoral pulse-wave velocity is not modified in patients with Chagas' disease, suggesting that elastic properties of large arteries are not affected in this disorder.
Full Text Available INTRODUCTION: A descriptive, entomological and seroepidemiological study on Chagas disease was conducted in a place of recent occupation on the outskirts of Cochabamba, Bolivia: Avaroa/Primer de Mayo (population:3,000, where the socio-economic level is low and no control measures have been made available. METHODS: The immunofluorescent antibody test (IFAT was used for IgG and IgM anti-Trypanosoma cruzi antibodies in filter paper bloodspot eluates from 128 subjects (73 females, 55 males selected by systematic sampling. Concerning each subject age, gender, birthplace, occupation, duration of residence and building materials used in their houses were recorded. Vectors were captured both in domestic and peridomestic environments. RESULTS: Seropositive, 12.5% (16/128: females, 15.1% (11/73; males, 9.1% (5/55. Average time of residence: 6.1 years for the whole population sample and 7.4 years for the seropositive subjects. Most houses had adobe walls (76.7% , n= 30, galvanized iron rooves (86.7% and earthen floors (53.4% 80% of the walls had crevices. One hundred forty seven specimens of Triatoma infestans were captured, of which 104 (70.7% were domestic, and 1 peridomestic Triatoma sordida. Precipitin host identification: birds, 67.5%; humans, 27.8%; rodents, 11.9%; dogs, 8.7%; cats, 1.6%. House infestation and density indices were 53.3 and 493.0 respectively. We found 21 (14.3% specimens of T. infestans infected with trypanosomes, 18 (85.7% of which in domestic environments. DISCUSSION: The elements for the vector transmission of Chagas disease are present in Avaroa/Primer de Mayo and the ancient custom of keeping guinea pigs indoors adds to the risk of human infection. In neighboring Cochabamba, due to substandard quality control, contaminated blood transfusions are not infrequent, which further aggravates the spread of Chagas disease. Prompt action to check the transmission of this infection, involving additionally the congenital and transfusional
Pedro Emmanuel Alvarenga Americano do Brasil
Full Text Available Abstract: INTRODUCTION With the globalization of Chagas disease, unexperienced health care providers may have difficulties in identifying which patients should be examined for this condition. This study aimed to develop and validate a diagnostic clinical prediction model for chronic Chagas disease. METHODS This diagnostic cohort study included consecutive volunteers suspected to have chronic Chagas disease. The clinical information was blindly compared to serological tests results, and a logistic regression model was fit and validated. RESULTS The development cohort included 602 patients, and the validation cohort included 138 patients. The Chagas disease prevalence was 19.9%. Sex, age, referral from blood bank, history of living in a rural area, recognizing the kissing bug, systemic hypertension, number of siblings with Chagas disease, number of relatives with a history of stroke, ECG with low voltage, anterosuperior divisional block, pathologic Q wave, right bundle branch block, and any kind of extrasystole were included in the final model. Calibration and discrimination in the development and validation cohorts (ROC AUC 0.904 and 0.912, respectively were good. Sensitivity and specificity analyses showed that specificity reaches at least 95% above the predicted 43% risk, while sensitivity is at least 95% below the predicted 7% risk. Net benefit decision curves favor the model across all thresholds. CONCLUSIONS: A nomogram and an online calculator (available at http://shiny.ipec.fiocruz.br:3838/pedrobrasil/chronic_chagas_disease_prediction/ were developed to aid in individual risk estimation.
José Rodrigues Coura
Full Text Available This study consists of a broad review on what is known and what should be improved regarding knowledge of Chagas disease, not only through analysis on the main studies published on the topics discussed, but to a large extent based on experience of this subject, acquired over the past 50 years (1961-2011. Among the subjects covered, we highlight the pathogenesis and evolution of infection by Trypanosoma cruzi, drugs in use and new strategies for treating Chagas disease; the serological tests for the diagnosis and the controls of cure the infection; the regional variations in prevalence, morbidity and response to treatment of the disease; the importance of metacyclogenesis of T. cruzi in different species of triatomines and its capacity to transmit Chagas infection; the risks of adaptation of wild triatomines to human dwellings; the morbidity and need for a surveillance and control program for Chagas disease in the Amazon region and the need to prioritize initiatives for controlling Chagas disease in Latin America and Mexico and in non-endemic countries, which is today a major international dilemma. Finally, we raise the need for to create a new initiative for controlling Chagas disease in the Gran Chaco, which involves parts of Argentina, Bolivia and Paraguay.
Pineda, Vanessa; Montalvo, Edilma; Alvarez, Dayra; Santamaría, Ana María; Calzada, Jose Eduardo; Saldaña, Azael
The sylvatic triatomine Rhodnius pallescens is considered to be the most important and widespread vector of Trypanosoma cruzi and Trypanosoma rangeli in Panama. However, its behavior and biological characteristics have only been partially investigated. Thus, to achieve sustainable and efficient control over Chagas disease in Panama, a better understanding of the ecology and biology of R. pallescens is essential. In this study we evaluated R. pallescens host feeding sources using a dot-blot assay, and the trypanosome infection index by PCR analysis in a Chagas disease endemic area of central Panama. It was found that in peridomestic palm trees, 20.3% of the examined bugs had fed on opossums (Didelphis marsupialis). However, we observed an increased anthropophagy (25.4%) for those bugs collected inside houses. Considering the domestic and peridomestic habitats as a whole, the proportion of collected R. pallescens infected with trypanosomes was 87.4%. In the two habitats the predominant infection was with T. cruzi (80-90%). Between 47-51% of the analyzed triatomines were infected with T. rangeli. Mixed infections (40-51%) were also detected. These findings provide a better basis for the implementation of a rational control and surveillance program for Chagas disease in regions where R. pallescens is endemic. PMID:18488091
Full Text Available Triatoma dimidiata, currently the major Central American vector of Trypanosoma cruzi, the parasite that causes Chagas disease, inhabits caves throughout the region. This research investigates the possibility that cave dwelling T. dimidiata might transmit the parasite to humans and links the blood meal sources of cave vectors to cultural practices that differ among locations.We determined the blood meal sources of twenty-four T. dimidiata collected from two locations in Guatemala and one in Belize where human interactions with the caves differ. Blood meal sources were determined by cloning and sequencing PCR products amplified from DNA extracted from the vector abdomen using primers specific for the vertebrate 12S mitochondrial gene. The blood meal sources were inferred by ≥ 99% identity with published sequences. We found 70% of cave-collected T. dimidiata positive for human DNA. The vectors had fed on 10 additional vertebrates with a variety of relationships to humans, including companion animal (dog, food animals (pig, sheep/goat, wild animals (duck, two bat, two opossum species and commensal animals (mouse, rat. Vectors from all locations fed on humans and commensal animals. The blood meal sources differ among locations, as well as the likelihood of feeding on dog and food animals. Vectors from one location were tested for T. cruzi infection, and 30% (3/10 tested positive, including two positive for human blood meals.Cave dwelling Chagas disease vectors feed on humans and commensal animals as well as dog, food animals and wild animals. Blood meal sources were related to human uses of the caves. We caution that just as T. dimidiata in caves may pose an epidemiological risk, there may be other situations where risk is thought to be minimal, but is not.
Granjon, Elodie; Dichtel-Danjoy, Marie-Laure; Saba, Esber; Sabino, Ester; Campos de Oliveira, Lea; Zrein, Maan
Background Chagas disease is due to the parasite Trypanosoma cruzi, a protist disseminated by a Triatome vector. This disease is endemic to Latin America and considered by WHO as one of the 17 world’s neglected diseases. In Europe and in North America, imported cases are also detected, due to migration of population outside of the endemic region. Diagnosis of T. cruzi infection is usually made indirectly by the detection of specific antibodies to T. cruzi antigens. Following initial diagnostic evaluation or screening test (qualifying or discarding blood donation), a confirmation test is performed for samples initially reactive. The test presented in this study aims at the confirmation/refutation of the infectious status of human blood samples and will permit taking appropriate clinical measures. Methodology/Principal Findings We designed a novel array of twelve antigens and printed these antigens onto 96-well plates. We tested 248 positive samples T. cruzi, 94 unscreened blood donors’ samples from non-endemic area, 49 seronegative blood donors, 7 false-positive and 3 doubtful samples. The observed reactivities were analyzed to propose a decision-tree algorithm that correctly classifies all the samples, with the potential to discriminate false-positive results and sticky samples. We observed that antibodies levels (Sum of all antigens) was significantly higher for PCR positive than for PCR negative samples in all studied groups with Multi-cruzi. Conclusion/Significance The results described in this study indicate that the Multi-cruzi improves the serological confirmation of Chagas disease. Moreover the “sum of all antigens” detected by Multi-cruzi could reflect parasitemia level in patients–like PCR signals does—and could serve as an indicator of parasite clearance in longitudinal follow-ups. Validation of this assay is still required on an independent large collection of well characterized samples including typical false-reactive samples such as
Full Text Available A new multiplex assay platform was evaluated to detect Trypanosoma cruzi infection using the recombinant antigens CRA, FRA, CRAFRA fusion and parasite lysate. The antigens presented different sensitivity and specificity in a singleplex test when compared to a serial dilution of two pools comprising 10 positive serum samples and one pool of 10 negative samples. The recombinant protein CRA presented lower sensitivity (55% in contrast to the 100% specificity and sensitivity of FRA, CRAFRA and T. cruzi lysate. These antigens also showed good results in a duplex test and the duplex test with CRAFRA/T. cruzi lysate showed better performance with 100% specificity and sensitivity, as well as a lower cut-off value in comparison to the other duplex test, FRA/T. cruzi lysate. Hence, when the antigens were used in duplex format, both tests showed decreased cut-off values and no interference between different bead sets, resulting in increasing sensitivity and specificity. The results of these multiplex tests show that they could be an alternative to singleplex detection for Chagas disease, and also indicate the necessity of using multiplex diagnostic tools to increase the sensitivity and specificity for diagnostic tests. Emerging data from the T. cruzi genome and from its ORFeome project will also allow the identification of new antigens for this disease detection application.
Foti, Leonardo; Fonseca, Bruna de Paula Fonseca e; Nascimento, Lilian Dias; Marques, Christiane de Fatima Silva; da Silva, Edmilson Domingos; Duarte, Cesar Augusto Barros; Probst, Christian M; Goldenberg, Samuel; Pinto, Antônio Gomes; Krieger, Marco Aurélio
A new multiplex assay platform was evaluated to detect Trypanosoma cruzi infection using the recombinant antigens CRA, FRA, CRAFRA fusion and parasite lysate. The antigens presented different sensitivity and specificity in a singleplex test when compared to a serial dilution of two pools comprising 10 positive serum samples and one pool of 10 negative samples. The recombinant protein CRA presented lower sensitivity (55%) in contrast to the 100% specificity and sensitivity of FRA, CRAFRA and T. cruzi lysate. These antigens also showed good results in a duplex test and the duplex test with CRAFRA/T. cruzi lysate showed better performance with 100% specificity and sensitivity, as well as a lower cut-off value in comparison to the other duplex test, FRA/T. cruzi lysate. Hence, when the antigens were used in duplex format, both tests showed decreased cut-off values and no interference between different bead sets, resulting in increasing sensitivity and specificity. The results of these multiplex tests show that they could be an alternative to singleplex detection for Chagas disease, and also indicate the necessity of using multiplex diagnostic tools to increase the sensitivity and specificity for diagnostic tests. Emerging data from the T. cruzi genome and from its ORFeome project will also allow the identification of new antigens for this disease detection application. PMID:19753468
Magalhães, Luisa M. D.; Villani, Fernanda N. A.; Nunes, Maria do Carmo P.; Gollob, Kenneth J.; Rocha, Manoel O. C.; Dutra, Walderez O.
This study was designed to investigate whether the expression of interleukin 17 (IL-17) is associated with the indeterminate or cardiac clinical forms of Chagas disease and whether IL-17 expression can be correlated with patients' cardiac function. Our results demonstrated that cardiac Chagas patients have a lower intensity of expression of IL-17 by total lymphocytes and lower frequency of circulating T helper 17 cells. Correlative analysis showed that high IL-17 expression was associated wit...
Carlos Chagas was born on 9 July 1878 in the farm "Bon Retiro" located close to the City of Oliveira in the interior of the State of Minas Gerais, Brazil. He started his medical studies in 1897 at the School of Medicine of Rio de Janeiro. In the late XIX century, the works by Louis Pasteur and Robert Koch induced a change in the medical paradigm with emphasis in experimental demonstrations of the causal link between microbes and disease. During the same years in Germany appeared the pathological concept of disease, linking organic lesions with symptoms. All these innovations were adopted by the reforms of the medical schools in Brazil and influenced the scientific formation of Chagas. Chagas completed his medical studies between 1897 and 1903 and his examinations during these years were always ranked with high grades. Oswaldo Cruz accepted Chagas as a doctoral candidate and directed his thesis on "Hematological studies of Malaria" which was received with honors by the examiners. In 1903 the director appointed Chagas as research assistant at the Institute. In those years, the Institute of Manguinhos, under the direction of Oswaldo Cruz, initiated a process of institutional growth and gathered a distinguished group of Brazilian and foreign scientists. In 1907, he was requested to investigate and control a malaria outbreak in Lassance, Minas Gerais. In this moment Chagas could not have imagined that this field research was the beginning of one of the most notable medical discoveries. Chagas was, at the age of 28, a Research Assistant at the Institute of Manguinhos and was studying a new flagellate parasite isolated from triatomine insects captured in the State of Minas Gerais. Chagas made his discoveries in this order: first the causal agent, then the vector and finally the human cases. These notable discoveries were carried out by Chagas in twenty months. At the age of 33 Chagas had completed his discoveries and published the scientific articles that gave him world
Golding, N.; Wilson, AL; Moyes, CL; Cano, J.; Pigott, DM; Velayudhan, R; Brooker, SJ; Smith, DL; Hay, SI; Lindsay, SW
Background Vector-borne diseases cause a significant proportion of the overall burden of disease across the globe, accounting for over 10 % of the burden of infectious diseases. Despite the availability of effective interventions for many of these diseases, a lack of resources prevents their effective control. Many existing vector control interventions are known to be effective against multiple diseases, so combining vector control programmes to simultaneously tackle several diseases could of...
Higa, Leticia H; Corral, Ricardo S; Morilla, María José; Romero, Eder L; Petray, Patricia B
Archaeosomes (ARC), vesicles made from lipids extracted from Archaea, display strong adjuvant properties. In this study, we evaluated the ability of the highly stable ARC formulated from total polar lipids of a new Halorubrum tebenquichense strain found in Argentinean Patagonia, to act as adjuvant for soluble parasite antigens in developing prophylactic vaccine against the intracellular protozoan T. cruzi, the etiologic agent of Chagas disease. We demonstrated for the first time that C3H/HeN mice subcutaneously immunized with trypanosomal antigens entrapped in these ARC (ARC-TcAg) rapidly developed higher levels of circulating T. cruzi antibodies than those measured in the sera from animals receiving the antigen alone. Enhanced humoral responses elicited by ARC-TcAg presented a dominant IgG2a antibody isotype, usually associated with Th1-type immunity and resistance against T. cruzi. More importantly, ARC-TcAg-vaccinated mice displayed reduced parasitemia during early infection and were protected against an otherwise lethal challenge with the virulent Tulahuén strain of the parasite. Our findings suggest that, as an adjuvant, H. tebenquichense-derived ARC may hold great potential to develop a safe and helpful vaccine against this relevant human pathogen. PMID:23291939
Full Text Available Chagas disease, named after Carlos Chagas who first described it in 1909, exists only on the American Continent. It is caused by a parasite, Trypanosoma cruzi, transmitted to humans by blood-sucking triatomine bugs and by blood transfusion. Chagas disease has two successive phases, acute and chronic. The acute phase lasts 6 to 8 weeks. After several years of starting the chronic phase, 20% to 35% of the infected individuals, depending on the geographical area will develop irreversible lesions of the autonomous nervous system in the heart, esophagus, colon and the peripheral nervous system. Data on the prevalence and distribution of Chagas disease improved in quality during the 1980's as a result of the demographically representative cross-sectional studies carried out in countries where accurate information was not available. A group of experts met in Brasília in 1979 and devised standard protocols to carry out countrywide prevalence studies on human T. cruzi infection and triatomine house infestation. Thanks to a coordinated multi-country program in the Southern Cone countries the transmission of Chagas disease by vectors and by blood transfusion has been interrupted in Uruguay in1997, in Chile in 1999, and in 8 of the 12 endemic states of Brazil in 2000 and so the incidence of new infections by T. cruzi in the whole continent has decreased by 70%. Similar control multi-country initiatives have been launched in the Andean countries and in Central America and rapid progress has been recorded to ensure the interruption of the transmission of Chagas disease by 2005 as requested by a Resolution of the World Health Assembly approved in 1998. The cost-benefit analysis of the investments of the vector control program in Brazil indicate that there are savings of US$17 in medical care and disabilities for each dollar spent on prevention, showing that the program is a health investment with good return. Since the inception in 1979 of the Steering
Luiz Fernando Junqueira Junior
Full Text Available INTRODUCTION: Exclusive or associated lesions in various structures of the autonomic nervous system occur in the chronic forms of Chagas disease. In the indeterminate form, the lesions are absent or mild, whereas in the exclusive or combined heart and digestive disease forms, they are often more pronounced. Depending on their severity these lesions can result mainly in cardiac parasympathetic dysfunction but also in sympathetic dysfunction of variable degrees. Despite the key autonomic effect on cardiovascular functioning, the pathophysiological and clinical significance of the cardiac autonomic dysfunction in Chagas disease remains unknown. METHODS: Review of data on the cardiac autonomic dysfunction in Chagas disease and their potential consequences, and considerations supporting the possible relationship between this disturbance and general or cardiovascular clinical and functional adverse outcomes. RESULTS: We hypothesise that possible consequences that cardiac dysautonomia might variably occasion or predispose in Chagas disease include: transient or sustained arrhythmias, sudden cardiac death, adverse overall and cardiovascular prognosis with enhanced morbidity and mortality, an inability of the cardiovascular system to adjust to functional demands and/or respond to internal or external stimuli by adjusting heart rate and other hemodynamic variables, and immunomodulatory and cognitive disturbances. CONCLUSIONS: Impaired cardiac autonomic modulation in Chagas disease might not be a mere epiphenomenon without significance. Indirect evidences point for a likely important role of this alteration as a primary predisposing or triggering cause or mediator favouring the development of subtle or evident secondary cardiovascular functional disturbances and clinical consequences, and influencing adverse outcomes.
Rocha, Juan Stuardo Yazlle
A brief overview of the evolution of knowledge about Chagas disease since its discovery by Carlos Chagas in 1909 until the mid-1940s is presented. The trajectory of physician Pedreira de Freitas and his growing involvement in research in the area led to his contributions to laboratory diagnosis - which lent consistency and security to epidemiological surveys of Chagas disease - and the redefinition of the scale of the disease in Brazil and the Americas with its terrible social and economic impact. His proposal for the disease prevention model - based on selective purging in the application of insecticide - was adopted nationally and internationally and made it possible to bring the disease under control in Brazil and other countries. He devoted himself with equal intensity to enhancing the teaching of medical practices in the community and was a pioneer in the implementation of preventive medicine in medical education in Brazil. PMID:27557035
Pays, J F
In 2006 the Pan American Health Organisation (PAHO) roughly estimated the prevalence of Chagas disease or American Human Trypanosomiasis, due to Trypanosoma cruzi, still to be eight million cases. The migration of people from the country into towns has resulted, in recent decades, in the urbanisation of this rural disease. Up to the mid-20th century, the epidemiology of the disease was closely linked to the extreme poverty of the peasant population and to their housing, the rancho, which offers a suitable habitat for the vectors and encourages their proliferation. A further barrier has recently been crossed with the arrival in non-endemic areas of numerous seropositive individuals. We shall draw attention in this article to the main clinical signs and to the manner of progression of the disease as well as to the problems posed by treatment of the different phases of this unique condition. It is not fanciful to describe it as resembling an adventure story, because of the place and manner of its discovery and of how the disease unfolds. PMID:20131420
Halperin, Anthony; Pajuelo, Monica; Tornheim, Jeffrey A; Vu, Nancy; Carnero, Andrés M; Galdos-Cardenas, Gerson; Ferrufino, Lisbeth; Camacho, Marilyn; Justiniano, Juan; Colanzi, Rony; Bowman, Natalie M; Morris, Tiffany; MacDougall, Hamish; Bern, Caryn; Moore, Steven T; Gilman, Robert H
Autonomic dysfunction is common in Chagas disease and diabetes. Patients with either condition complicated by cardiac autonomic dysfunction face increased mortality, but no clinical predictors of autonomic dysfunction exist. Pupillary light reflexes (PLRs) may identify such patients early, allowing for intensified treatment. To evaluate the significance of PLRs, adults were recruited from the outpatient endocrine, cardiology, and surgical clinics at a Bolivian teaching hospital. After testing for Chagas disease and diabetes, participants completed conventional autonomic testing (CAT) evaluating their cardiovascular responses to Valsalva, deep breathing, and orthostatic changes. PLRs were measured using specially designed goggles, then CAT and PLRs were compared as measures of autonomic dysfunction. This study analyzed 163 adults, including 96 with Chagas disease, 35 patients with diabetes, and 32 controls. PLRs were not significantly different between Chagas disease patients and controls. Patients with diabetes had longer latency to onset of pupil constriction, slower maximum constriction velocities, and smaller orthostatic ratios than nonpatients with diabetes. PLRs correlated poorly with CAT results. A PLR-based clinical risk score demonstrated a 2.27-fold increased likelihood of diabetes complicated by autonomic dysfunction compared with the combination of blood tests, CAT, and PLRs (sensitivity 87.9%, specificity 61.3%). PLRs represent a promising tool for evaluating subclinical neuropathy in patients with diabetes without symptomatic autonomic dysfunction. Pupillometry does not have a role in the evaluation of Chagas disease patients. PMID:27044564
Pedroso, Enio Roberto Pietra; Rezende, Nilton Alves de, E-mail: firstname.lastname@example.org [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Faculdade de Medicina; Abuhid, Ivana Moura [Instituto de Medicina Nuclear e Diagnostico Molecular, Belo Horizonte, MG (Brazil)
Background: non-invasive cardiological methods have been used for the identification of myocardial damage in Chagas disease. Objective: to verify whether the rest/stress myocardial perfusion scintigraphy is able to identify early myocardial damage in the indeterminate form of Chagas disease. Methods: eighteen patients with the indeterminate form of Chagas Disease and the same number of normal controls, paired by sex and age, underwent rest/stress myocardial scintigraphy using sestamibi-99mTc, aiming at detecting early cardiac damage. Results: the results did not show perfusion or ventricular function defects in patients at the indeterminate phase of Chagas disease and in the normal controls, except for a patient who presented signs of ventricular dysfunction in the myocardial perfusion scintigraphy with electrocardiographic gating. Conclusion: the results of this study, considering the small sample size, showed that the rest/stress myocardial scintigraphy using sestamibi-99mTc is not an effective method to detect early myocardial alterations in the indeterminate form of Chagas disease (author)
Jennifer M Manne
Full Text Available BACKGROUND: According to World Health Organization (WHO prevalence estimates, 1.1 million people in Mexico are infected with Trypanosoma cruzi, the etiologic agent of Chagas disease (CD. However, limited information is available about access to antitrypanosomal treatment. This study assesses the extent of access in Mexico, analyzes the barriers to access, and suggests strategies to overcome them. METHODS AND FINDINGS: Semi-structured in-depth interviews were conducted with 18 key informants and policymakers at the national level in Mexico. Data on CD cases, relevant policy documents and interview data were analyzed using the Flagship Framework for Pharmaceutical Policy Reform policy interventions: regulation, financing, payment, organization, and persuasion. Data showed that 3,013 cases were registered nationally from 2007-2011, representing 0.41% of total expected cases based on Mexico's national prevalence estimate. In four of five years, new registered cases were below national targets by 11-36%. Of 1,329 cases registered nationally in 2010-2011, 834 received treatment, 120 were pending treatment as of January 2012, and the treatment status of 375 was unknown. The analysis revealed that the national program mainly coordinated donation of nifurtimox and that important obstacles to access include the exclusion of antitrypanosomal medicines from the national formulary (regulation, historical exclusion of CD from the social insurance package (organization, absence of national clinical guidelines (organization, and limited provider awareness (persuasion. CONCLUSIONS: Efforts to treat CD in Mexico indicate an increased commitment to addressing this disease. Access to treatment could be advanced by improving the importation process for antitrypanosomal medicines and adding them to the national formulary, increasing education for healthcare providers, and strengthening clinical guidelines. These recommendations have important implications for other
Juan David Ramírez
Full Text Available BACKGROUND: Trypanosoma cruzi, the causative agent of Chagas disease, displays significant genetic variability revealed by six Discrete Typing Units (TcI-TcVI. In this pathology, oral transmission represents an emerging epidemiological scenario where different outbreaks associated to food/beverages consumption have been reported in Argentina, Bolivia, Brazil, Ecuador and Venezuela. In Colombia, six human oral outbreaks have been reported corroborating the importance of this transmission route. Molecular epidemiology of oral outbreaks is barely known observing the incrimination of TcI, TcII, TcIV and TcV genotypes. METHODOLOGY AND PRINCIPAL FINDINGS: High-throughput molecular characterization was conducted performing MLMT (Multilocus Microsatellite Typing and mtMLST (mitochondrial Multilocus Sequence Typing strategies on 50 clones from ten isolates. Results allowed observing the occurrence of TcI, TcIV and mixed infection of distinct TcI genotypes. Thus, a majority of specific mitochondrial haplotypes and allelic multilocus genotypes associated to the sylvatic cycle of transmission were detected in the dataset with the foreseen presence of mitochondrial haplotypes and allelic multilocus genotypes associated to the domestic cycle of transmission. CONCLUSIONS: These findings suggest the incrimination of sylvatic genotypes in the oral outbreaks occurred in Colombia. We observed patterns of super-infection and/or co-infection with a tailored association with the severe forms of myocarditis in the acute phase of the disease. The transmission dynamics of this infection route based on molecular epidemiology evidence was unraveled and the clinical and biological implications are discussed.
The TSH and T3 response to synthetic TRH was evaluated in two groups of patients: normal and with Chagas' disease, from the urban area of Sao Paulo (Brazil). Plasma T4, PBI and TSH values were within the normal range, when compared with those found in the controls: So were the thyroid uptakes of 2 and 24 hours; the basal levels of T3 where within the normal range except in three subjects whose values were higher than normal. After TRH administration the amount of TSH secretion in patients with Chagas' disease was increased when compared to normal ones, while T3 secretion was unaltered. It is suggested that in the Chagas' disease there is an increase in the pituitary TSH, while the thyroid reserve is preserved. This increase could be due to a difference in the regulation rate of TRH, which is determined by the neuronal degeneration caused by the disease itself. (author)
Shivali Gupta; Xianxiu Wan; Zago, Maria P.; Martinez Sellers, Valena C.; Silva, Trevor S.; Dadjah Assiah; Monisha Dhiman; Sonia Nuñez; Petersen, John R; Vázquez-Chagoyán, Juan C.; Jose G Estrada-Franco; Nisha Jain Garg
BACKGROUND: Chagas disease, caused by Trypanosoma cruzi, is endemic in Latin America and an emerging infectious disease in the US and Europe. We have shown TcG1, TcG2, and TcG4 antigens elicit protective immunity to T. cruzi in mice and dogs. Herein, we investigated antigenicity of the recombinant proteins in humans to determine their potential utility for the development of next generation diagnostics for screening of T. cruzi infection and Chagas disease. METHODS AND RESULTS: Sera samples f...
Full Text Available Congenital Chagas disease (CChD has been reported in different countries, mostly in Latin America. In 1987 a fatal case of CChD of second generation (CChDSG was published. Within a period of six months - 1989-1990 - two cases of CChDSG were diagnosed and studied in the city of Santiago. Two premature newborns, sons of two sisters, with moderate liver and spleen enlargement, were found to have positive serology for Chagas disease and xenodiagnoses. The mothers, urban residents all their lives, without antecedents of triatomine bugs contact or blood transfusions, showed positive serology and xenodiagnoses. Their mother (grandmother of the infants, lived 20 years in a Northern rural Chagas disease endemic locality, in a triatomine infested house. Afterwards, she moved to Santiago, where she married and has resided up to now. Serology and xenodiagnoses were also positive. All the Trypanosoma cruzi infected individuals were successfully treated with nifurtimox.
C Miguel Pinto
Full Text Available The generalist parasite Trypanosoma cruzi has two phylogenetic lineages associated almost exclusively with bats-Trypanosoma cruzi Tcbat and the subspecies T. c. marinkellei. We present new information on the genetic variation, geographic distribution, host associations, and potential vectors of these lineages. We conducted field surveys of bats and triatomines in southern Ecuador, a country endemic for Chagas disease, and screened for trypanosomes by microscopy and PCR. We identified parasites at species and genotype levels through phylogenetic approaches based on 18S ribosomal RNA (18S rRNA and cytochrome b (cytb genes and conducted a comparison of nucleotide diversity of the cytb gene. We document for the first time T. cruzi Tcbat and T. c. marinkellei in Ecuador, expanding their distribution in South America to the western side of the Andes. In addition, we found the triatomines Cavernicola pilosa and Triatoma dispar sharing shelters with bats. The comparisons of nucleotide diversity revealed a higher diversity for T. c. marinkellei than any of the T. c. cruzi genotypes associated with Chagas disease. Findings from this study increased both the number of host species and known geographical ranges of both parasites and suggest potential vectors for these two trypanosomes associated with bats in rural areas of southern Ecuador. The higher nucleotide diversity of T. c. marinkellei supports a long evolutionary relationship between T. cruzi and bats, implying that bats are the original hosts of this important parasite.
Leyria, Jimena; Fruttero, Leonardo L.; Nazar, Magalí; Canavoso, Lilián E.
In this work, we have investigated the involvement of DmCatD, a cathepsin D-like peptidase, and acid phosphatase in the process of follicular atresia of Dipetalogaster maxima, a hematophagous insect vector of Chagas’ disease. For the studies, fat bodies, ovaries and hemolymph were sampled from anautogenous females at representative days of the reproductive cycle: pre-vitellogenesis, vitellogenesis as well as early and late atresia. Real time PCR (qPCR) and western blot assays showed that DmCatD was expressed in fat bodies and ovaries at all reproductive stages, being the expression of its active form significantly higher at the atretic stages. In hemolymph samples, only the immunoreactive band compatible with pro-DmCatD was observed by western blot. Acid phosphatase activity in ovarian tissues significantly increased during follicular atresia in comparison to pre-vitellogenesis and vitellogenesis. A further enzyme characterization with inhibitors showed that the high levels of acid phosphatase activity in atretic ovaries corresponded mainly to a tyrosine phosphatase. Immunofluorescence assays demonstrated that DmCatD and tyrosine phosphatase were associated with yolk bodies in vitellogenic follicles, while in atretic stages they displayed a different cellular distribution. DmCatD and tyrosine phosphatase partially co-localized with vitellin. Moreover, their interaction was supported by FRET analysis. In vitro assays using homogenates of atretic ovaries as the enzyme source and enzyme inhibitors demonstrated that DmCatD, together with a tyrosine phosphatase, were necessary to promote the degradation of vitellin. Taken together, the results strongly suggested that both acid hydrolases play a central role in early vitellin proteolysis during the process of follicular atresia. PMID:26091289
Full Text Available Accurately defining disease distributions and calculating disease risk is an important step in the control and prevention of diseases. Geographical information systems (GIS and remote sensing technologies, with maximum entropy (Maxent ecological niche modelling computer software, were used to create predictive risk maps for Chagas disease in Bolivia. Prevalence rates were calculated from 2007 to 2009 household infection survey data for Bolivia, while environmental data were compiled from the Worldclim database and MODIS satellite imagery. Socio-economic data were obtained from the Bolivian National Institute of Statistics. Disease models identified altitudes at 500-3,500 m above the mean sea level (MSL, low annual precipitation (45-250 mm, and higher diurnal range of temperature (10-19 °C; peak 16 °C as compatible with the biological requirements of the insect vectors. Socio-economic analyses demonstrated the importance of improved housing materials and water source. Home adobe wall materials and having to fetch drinking water from rivers or wells without pump were found to be highly related to distribution of the disease by the receiver operator characteristic (ROC area under the curve (AUC (0.69 AUC, 0.67 AUC and 0.62 AUC, respectively, while areas with hardwood floors demonstrated a direct negative relationship (-0.71 AUC. This study demonstrates that Maxent modelling can be used in disease prevalence and incidence studies to provide governmental agencies with an easily learned, understandable method to define areas as either high, moderate or low risk for the disease. This information may be used in resource planning, targeting and implementation. However, access to high-resolution, sub-municipality socio-economic data (e.g. census tracts would facilitate elucidation of the relative influence of poverty-related factors on regional disease dynamics.
The morphological changes in the postmortem study of a man probably with the indeterminate form of Chagas' disease are described. The heart exhibited lesions of the epicardium, myocardium and endocardium, as well as of the conduction system, primarily small inflammatory foci. There was mild fibrosis of the myocardium, atrioventricular node, and left bundle branch (at its origin). These alterations, although mild, were similar, in quality, to those described in the other chronic forms of Chagas' disease, and suggest active lesions, with a potential for further development. In the esophagus, among other features, a striking reduction of the number of neurons was observed. (author)
Samanta Cristina das Chagas Xavier; André Luiz Rodrigues Roque; Daniele Bilac; Vitor Antônio Louzada de Araújo; Sócrates Fraga da Costa da Costa Neto; Elias Seixas Lorosa; Luiz Felipe Coutinho Ferreira da Silva; Ana Maria Jansen
BACKGROUND: The new epidemiological scenario of orally transmitted Chagas disease that has emerged in Brazil, and mainly in the Amazon region, needs to be addressed with a new and systematic focus. Belém, the capital of Pará state, reports the highest number of acute Chagas disease (ACD) cases associated with the consumption of açaí juice. METHODOLOGY/PRINCIPAL FINDINGS: The wild and domestic enzootic transmission cycles of Trypanosoma cruzi were evaluated in the two locations (Jurunas and Va...
Xavier, Samanta Cristina das Chagas; Roque, André Luiz Rodrigues; Bilac, Daniele; de Araújo, Vitor Antônio Louzada; Neto, Sócrates Fraga da Costa; Lorosa, Elias Seixas; da Silva, Luiz Felipe Coutinho Ferreira; Jansen, Ana Maria
Background The new epidemiological scenario of orally transmitted Chagas disease that has emerged in Brazil, and mainly in the Amazon region, needs to be addressed with a new and systematic focus. Belém, the capital of Pará state, reports the highest number of acute Chagas disease (ACD) cases associated with the consumption of açaí juice. Methodology/Principal Findings The wild and domestic enzootic transmission cycles of Trypanosoma cruzi were evaluated in the two locations (Jurunas and Val-...
Mario Alberto Cardoso Silva-Neto
Full Text Available Chagas disease is a severe illness, which can lead to death if the patients are not promptly treated. The disease is caused by the protozoan parasite Trypanosoma cruzi, which is mostly transmitted by a triatomine insect vector. There are 8-10 million people infected with T. cruzi in the world, but the vector-borne transmission occurs only in the Americas, especially Latin America. About 30 % of chronically infected people develop cardiac diseases and up to 10 % develop digestive, neurological or mixed disorders. Lysophosphatydilcholine (LPC is the major phospholipid component of oxidized low-density lipoproteins associated with atherosclerosis-related tissue damage. Insect-derived LPC is a powerful chemoattractant for inflammatory cells at the site of the insect bite, enhances parasite invasion, and inhibits the production of nitric oxide (NO by T. cruzi-stimulated macrophages. The recognition of the ubiquitous presence of LPC on the vector saliva, its production by the parasite itself and its presence both on patient plasma as well as its role on diverse host x parasite interaction systems lead us to compare its distribution in nature with the title of the famous Beatles song Here, There and Everywhere recorded exactly 50 years ago in 1966. Here, we review the major findings pointing out the role of such molecule as an immunosignaling modulator of Chagas disease transmission. Also, we believe that future investigation of the connection of this ubiquity and the immune role of such molecule may lead in the future to novel methods to control parasite transmission, infection and pathogenesis.
Iván Darío BRAVO-TOBAR
Full Text Available SUMMARY Chagas disease is a public health problem worldwide. The availability of diagnostic tools to predict the development of chronic Chagas cardiomyopathy is crucial to reduce morbidity and mortality. Here we analyze the prognostic value of adenosine deaminase serum activity (ADA and C-reactive protein serum levels (CRP in chagasic individuals. One hundred and ten individuals, 28 healthy and 82 chagasic patients were divided according to disease severity in phase I (n = 35, II (n = 29, and III (n = 18. A complete medical history, 12-lead electrocardiogram, chest X-ray, and M-mode echocardiogram were performed on each individual. Diagnosis of Chagas disease was confirmed by ELISA and MABA using recombinant antigens; ADA was determined spectrophotometrically and CRP by ELISA. The results have shown that CRP and ADA increased linearly in relation to disease phase, CRP being significantly higher in phase III and ADA at all phases. Also, CRP and ADA were positively correlated with echocardiographic parameters of cardiac remodeling and with electrocardiographic abnormalities, and negatively with ejection fraction. CRP and ADA were higher in patients with cardiothoracic index ≥ 50%, while ADA was higher in patients with ventricular repolarization disturbances. Finally, CRP was positively correlated with ADA. In conclusion, ADA and CRP are prognostic markers of cardiac dysfunction and remodeling in Chagas disease.
Full Text Available BACKGROUND: Chagas disease was originally reported in Panama in 1931. Currently, the best knowledge of this zoonosis is restricted to studies done in historically endemic regions. However, little is known about the distribution and epidemiology of Chagas disease in other rural areas of the country. METHODS AND FINDINGS: A cross-sectional descriptive study was carried out between May 2005 - July 2008 in four rural communities of the Santa Fe District, Veraguas Province. The study included an entomologic search to collect triatomines, bloodmeal type identification and infection rate with trypanosomes in collected vectors using a dot- blot and PCR analysis, genotyping of circulating Trypanosoma cruzi (mini-exon gene PCR analysis and the detection of chagasic antibodies among inhabitants. The vector Rhodnius pallescens was more frequently found in La Culaca and El Pantano communities (788 specimens, where it was a sporadic household visitor. These triatomines presented darker coloration and larger sizescompared with typical specimens collected in Central Panama. Triatoma dimidiata was more common in Sabaneta de El Macho (162 specimens. In one small sub-region (El Macho, 60% of the houses were colonized by this vector. Of the examined R. pallescens, 54.7.0% (88/161 had fed on Didelphis marsupialis, and 24.6% (34/138 of T. dimidiata specimens collected inside houses were positive for human blood. R. pallescens presented an infection index with T. cruzi of 17.7% (24/136, with T. rangeli of 12.5% (17/136 and 50.7% (69/136 were mixed infections. In 117 T. dimidiata domestic specimens the infection index with T. cruzi was 21.4%. Lineage I of T. cruzi was confirmed circulating in these vectors. A T. cruzi infection seroprevalence of 2.3% (24/1,056 was found in this population. CONCLUSIONS: This is the first report of Chagas disease endemicity in Santa Fe District, and it should be considered a neglected public health problem in this area of Panama.
Pacheco Raquel S
Full Text Available In the past few years, new aspects of the immunopathology of Chagas' disease have been described in immunosuppressed patients, such as fatal central nervous system lesions related to the reactivation of the parasite. This article is the first description of the genotypic characterization, at the strain level, of Trypanosoma cruzi isolated from a patient with Chagas` disease/AIDS co-infection. The presence of four hypodense lesions was observed in the cranial compute tomographic scan. The diagnosis of AIDS was assessed by the detection of anti-HIV antibodies using enzyme-linked immunosorbent assay (ELISA and Western blot techniques. The CD4+ lymphocyte counts were maintained under 200 cells/mm3 during one year demonstrating the severity of the state of immunosuppression. Chagas' disease was confirmed by serological and parasitological methods. Trypomastigote forms were visualized in a thick blood smear. The parasite isolated is genotypically similar to the CL strain. The paper reinforces that cerebral Chagas' disease can be considered as another potential opportunistic infection in AIDS resulting from the reactivation of a dormant T. cruzi infection acquired years earlier.
Montes de Oca, N V; Cabrera Alonso, C; Martínez, R; Cantelar de Francisco, N; Pérez Insueta, O
The results obtained during the serologic study for the diagnosis of Chagas' disease in 868 Nicaraguan students in the Isle of Youth are reported. Qualitative hemagglutination and indirect immunofluorescence were used. It was found that 8.5% of these students showed antibodies specific to Trypanosoma cruzi by means of this diagnostic test. PMID:2518003
Nóbrega, Aglaêr A.; Garcia, Marcio H.; Tatto, Erica; Marcos T Obara; Costa, Elenild; Sobel, Jeremy; Araujo, Wildo N.
In 2006, a total of 178 cases of acute Chagas disease were reported from the Amazonian state of Pará, Brazil. Eleven occurred in Barcarena and were confirmed by visualization of parasites on blood smears. Using cohort and case–control studies, we implicated oral transmission by consumption of açaí palm fruit.
José Rodrigues Coura
Full Text Available The pathogenesis and evolutive pattern of Chagas disease suggests that the chronic phase should be more widely treated in order to (i eliminate Trypanosoma cruzi and prevent new inflammatory foci and the extension of tissue lesions, (ii promote tissue regeneration to prevent fibrosis, (iii reverse existing fibrosis, (iv prevent cardiomyopathy, megaoesophagus and megacolon and (v reduce or eliminate cardiac block and arrhythmia. All cases of the indeterminate chronic form of Chagas disease without contraindications due to other concomitant diseases or pregnancy should be treated and not only cases involving children or recently infected cases. Patients with chronic Chagas cardiomyopathy grade II of the New York Heart Association classification should be treated with specific chemotherapy and grade III can be treated according to medical-patient decisions. We are proposing the following new strategies for chemotherapeutic treatment of the chronic phase of Chagas disease: (i repeated short-term treatments for 30 consecutive days and interval of 30-60 days for six months to one year and (ii combinations of drugs with different mechanisms of action, such as benznidazole + nifurtimox, benznidazole or nifurtimox + allopurinol or triazole antifungal agents, inhibition of sterol synthesis.
Teixeira, A.R.L.; Gomes, C.; Nitz, N.; Sousa, A.O.; Alvez, R.M.; Guimaro, M.C.; Cordeiro, C.; Bernal, F.M.; Rosa, A.C.; Hejnar, Jiří; Leonardecz, E.; Hecht, M.M.
Roč. 5, č. 3 (2011), e1000. ISSN 1935-2735 Institutional research plan: CEZ:AV0Z50520514 Keywords : Chagas disease * Trypanosoma cruzi * kDNA minicircles * inbred chicken Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.716, year: 2011
Full Text Available Chagas' disease causes degeneration and reduction of the number of intrinsic neurons of the esophageal myenteric plexus, with consequent absent or partial lower esophageal sphincter relaxation and loss of peristalsis in the esophageal body. The impairment of esophageal motility is seen mainly in the distal smooth muscle region. There is no study about esophageal striated muscle contractions in the disease. In 81 patients with heartburn (44 with esophagitis taken as controls, 51 patients with Chagas' disease (21 with esophageal dilatation and 18 patients with idiopathic achalasia (11 with esophageal dilatation we studied the amplitude, duration and area under the curve of esophageal proximal contractions. Using the manometric method and a continuous perfusion system we measured the esophageal striated muscle contractions 2 to 3 cm below the upper esophageal sphincter after swallows of a 5-ml bolus of water. There was no significant difference in striated muscle contractions between patients with heartburn and esophagitis and patients with heartburn without esophagitis. There was also no significant difference between patients with heartburn younger or older than 50 years or between men and women or in esophageal striated muscle contractions between patients with heartburn and Chagas' disease. The esophageal proximal amplitude of contractions was lower in patients with idiopathic achalasia than in patients with heartburn. In patients with Chagas' disease there was no significant difference between patients with esophageal dilatation and patients with normal esophageal diameter. Esophageal striated muscle contractions in patients with Chagas' disease have the same amplitude and duration as seen in patients with heartburn. Patients with idiopathic achalasia have a lower amplitude of contraction than patients with heartburn.
Full Text Available The most important component of the upper esophageal sphincter (UES is the cricopharyngeal muscle. During the measurement of sphincter pressure the catheter passed through the sphincter affects the pressure value. In Chagas' disease and primary achalasia there is an esophageal myenteric plexus denervation which may affect UES pressure. We measured the UES pressure of 115 patients with Chagas' disease, 28 patients with primary achalasia and 40 healthy volunteers. We used a round manometric catheter with continuous perfusion and the rapid pull-through method, performed in triplicate during apnea. Pressures were measured in four directions, and the direction with the highest pressure (anterior/posterior and the average of the four directions were measured. The highest UES pressure in Chagas' disease patients without abnormalities upon radiologic esophageal examination (N = 63 was higher than in normal volunteers (142.8 ± 47.4 mmHg vs 113.0 ± 46.0 mmHg, mean ± SD, P<0.05. There was no difference in UES pressure between patients with primary achalasia and patients with Chagas' disease and similar esophageal involvement and normal volunteers (P>0.05. There was no difference between patients with or without esophageal dilation. In the group of subjects less than 50 years of age the UES pressure of primary achalasia (N = 21 was lower than that of Chagas' disease patients with normal radiologic esophageal examination (N = 41, measured at the site with the highest pressure (109.3 ± 31.5 mmHg vs 149.6 ± 45.3 mmHg, P<0.01 and as the average of the four directions (64.2 ± 17.1 mmHg vs 83.5 ± 28.6 mmHg, P<0.05. We conclude that there is no difference in UES pressure between patients with Chagas' disease, primary achalasia and normal volunteers, except for patients with minor involvement by Chagas' disease, for whom the UES pressure at the site with the highest pressure was higher than the pressure of normal volunteers and patients with primary
Camandaroba, Edson Luiz P; Pinheiro Lima, Clarissa M; Andrade, Sonia G
Oral transmission of Trypanosoma cruzi has been suspected when epidemic episodes of acute infection were observed in areas devoid of domiciled insect vectors. Considering that the distribution of T. cruzi biodemes differs in sylvatic and domestic cycles, results of studies on biodemes can be of interest regarding oral transmission. The infectivity of T. cruzi strains of different biodemes was tested in mice subjected to infection by the digestive route (gavage). Swiss mice were infected either with the Peruvian strain (Biodeme Type I, Z2b) or the Colombian strain (Biodeme Type III, Z1, or T. cruzi I); for control, intraperitoneal inoculation was performed in a group of mice. The Colombian strain revealed a similar high infectivity and pathogenicity when either route of infection was used. However, the Peruvian strain showed contrasting levels of infectivity and pathogenicity, being high by intraperitoneal inoculation and low when the gastric route was used. The higher infectivity of the Colombian strain (Biodeme Type III) by gastric inoculation is in keeping with its role in the epidemic episodes of acute Chagas disease registered in the literature, since strains belonging to Biodeme III are most often found in sylvatic hosts. PMID:12048547
CAMANDAROBA Edson Luiz P.
Full Text Available Oral transmission of Trypanosoma cruzi has been suspected when epidemic episodes of acute infection were observed in areas devoid of domiciled insect vectors. Considering that the distribution of T. cruzi biodemes differs in sylvatic and domestic cycles, results of studies on biodemes can be of interest regarding oral transmission. The infectivity of T. cruzi strains of different biodemes was tested in mice subjected to infection by the digestive route (gavage. Swiss mice were infected either with the Peruvian strain (Biodeme Type I, Z2b or the Colombian strain (Biodeme Type III, Z1, or T. cruzi I; for control, intraperitoneal inoculation was performed in a group of mice. The Colombian strain revealed a similar high infectivity and pathogenicity when either route of infection was used. However, the Peruvian strain showed contrasting levels of infectivity and pathogenicity, being high by intraperitoneal inoculation and low when the gastric route was used. The higher infectivity of the Colombian strain (Biodeme Type III by gastric inoculation is in keeping with its role in the epidemic episodes of acute Chagas disease registered in the literature, since strains belonging to Biodeme III are most often found in sylvatic hosts.
Ogata, Haline; Teixeira, Maxelle Martins; de Sousa, Rodrigo Cunha; da Silva, Marcos Vinícius; Correia, Dalmo; Rodrigues Junior, Virmondes; Levy, Bruce David; de Paula Rogério, Alexandre
Chagas disease is caused by Trypanosoma cruzi (T. cruzi). In some patients with Chagas disease, symptoms progress to chronic chagasic cardiomyopathy. Endogenously, inflammation is resolved in the presence of lipid mediators such as aspirin-triggered RvD1 (AT-RvD1) which has anti-inflammatory and pro-resolution effects. Here, we demonstrated, for the first time, the effects of AT-RvD1 on T. cruzi antigen-stimulated peripheral blood mononuclear cells (PBMCs) from patients with Chagas heart disease. The levels of IFN-γ, TNF-α, IL-10, and IL-13 increased in PBMCs from cardiac-form Chagas patients in stage B1 (patients with fewer heart abnormalities) stimulated with T. cruzi antigen compared to those in non-stimulated PBMCs. AT-RvD1 reduced the IFN-γ concentrations in PBMCs from patients with Chagas disease stimulated with T. cruzi antigen compared to stimulated with T. cruzi antigen cells. AT-RvD1 treatment resulted in no observable changes in TNF-α, IL-10, and IL-13 levels. AT-RvD1 significantly decreased the percentage of necrotic cells and caused a significant reduction in the proliferation rate of T. cruzi antigen-stimulated PBMCs from patients with Chagas disease. These findings demonstrate that AT-RvD1 modulates the immune response in Chagas disease patients and might have potential to be used as an alternative approach for slowing the development of further heart damage. PMID:26927755
Valdez-Tah, Alba; Huicochea-Gómez, Laura; Ortega-Canto, Judith; Nazar-Beutelspacher, Austreberta; Ramsey, Janine M
Vector-borne transmission of Trypanosoma cruzi (VBTTc) is dependent on the concomitant interaction between biological and environmental hazard over the entire landscape, and human vulnerability. Representations and practices of health-disease-care-seeking and territorial appropriation and use were analyzed for VBTTc in a qualitative ethnographic study in the Zoh-Laguna landscape, Campeche, Mexico. In-depth interviews and participatory observation explored representations and practices regarding ethno-ecological knowledge related to vector-transmission, health-disease-care-seeking, and land use processes. The population has a broad knowledge of biting insects, which they believe are all most abundant in the rainy season; the community´s proximity to natural areas is perceived as a barrier to control their abundance. Triatomines are mostly recognized by men, who have detailed knowledge regarding their occurrence and association with mammals in non-domestic fragments, where they report being bitten. Women emphasize the dermal consequences of triatomine bites, but have little knowledge about the disease. Triatomine bites and the chinchoma are "normalized" events which are treated using home remedies, if at all. The neglected condition of Chagas disease in Mexican public health policies, livelihoods which are dependent on primary production, and gender-related knowledge (or lack thereof) are structural circumstances which influence the environment and inhabitants´ living conditions; in turn, these trigger triatomine-human contact. The most important landscape practices producing vulnerability are the activities and mobility within and between landscape fragments causing greater exposure of inhabitants primarily in the dry season. A landscape approach to understanding vulnerability components of VBTTc from health-disease-care-seeking perspectives and based on territorial appropriation and use, is essential where there is continuous movement of vectors between and
Full Text Available Vector-borne transmission of Trypanosoma cruzi (VBTTc is dependent on the concomitant interaction between biological and environmental hazard over the entire landscape, and human vulnerability. Representations and practices of health-disease-care-seeking and territorial appropriation and use were analyzed for VBTTc in a qualitative ethnographic study in the Zoh-Laguna landscape, Campeche, Mexico. In-depth interviews and participatory observation explored representations and practices regarding ethno-ecological knowledge related to vector-transmission, health-disease-care-seeking, and land use processes. The population has a broad knowledge of biting insects, which they believe are all most abundant in the rainy season; the community´s proximity to natural areas is perceived as a barrier to control their abundance. Triatomines are mostly recognized by men, who have detailed knowledge regarding their occurrence and association with mammals in non-domestic fragments, where they report being bitten. Women emphasize the dermal consequences of triatomine bites, but have little knowledge about the disease. Triatomine bites and the chinchoma are "normalized" events which are treated using home remedies, if at all. The neglected condition of Chagas disease in Mexican public health policies, livelihoods which are dependent on primary production, and gender-related knowledge (or lack thereof are structural circumstances which influence the environment and inhabitants´ living conditions; in turn, these trigger triatomine-human contact. The most important landscape practices producing vulnerability are the activities and mobility within and between landscape fragments causing greater exposure of inhabitants primarily in the dry season. A landscape approach to understanding vulnerability components of VBTTc from health-disease-care-seeking perspectives and based on territorial appropriation and use, is essential where there is continuous movement of vectors
Ceccarelli, Soledad; Rabinovich, Jorge E
We analyzed the possible effects of global climate change on the potential geographic distribution in Venezuela of five species of triatomines (Eratyrus mucronatus (Stal, 1859), Panstrongylus geniculatus (Latreille, 1811), Rhodnius prolixus (Stål, 1859), Rhodnius robustus (Larrousse, 1927), and Triatoma maculata (Erichson, 1848)), vectors of Trypanosoma cruzi, the etiological agent of Chagas disease. To obtain the future potential geographic distributions, expressed as climatic niche suitability, we modeled the presences of these species using two IPCC (Intergovernmental Panel on Climate Change) future emission scenarios of global climate change (A1B and B1), the Global Climate model CSIRO Mark 3.0, and three periods of future projections (years 2020, 2060, and 2080). After estimating with the MaxEnt software the future climatic niche suitability for each species, scenario, and period of future projections, we estimated a series of indexes of Venezuela's vulnerability at the county, state, and country level, measured as the number of people exposed due to the changes in the geographical distribution of the five triatomine species analyzed. Despite that this is not a measure of the risk of Chagas disease transmission, we conclude that possible future effects of global climate change on the Venezuelan population vulnerability show a slightly decreasing trend, even taking into account future population growth; we can expect fewer locations in Venezuela where an average Venezuelan citizen would be exposed to triatomines in the next 50-70 yr. PMID:26336258
Full Text Available Abstract Background Chagas disease is a health threat for many people, mostly those living in Latin America. One of the most important problems in treatment is the limitation of existing drugs. Prodigiosin, produced by Serratia marcescens (Rhodnius prolixus endosymbiont, belongs to the red-pigmented bacterial prodiginine family, which displays numerous biological activities, including antibacterial, antifungal, antiprotozoal, antimalarial, immunosuppressive, and anticancer properties. Here we describe its effects on Trypanosoma cruzi mitochondria belonging to Tc I and Tc II. Results Parasites exposed to prodigiosin altered the mitochondrial function and oxidative phosphorylation could not have a normal course, probably by inhibition of complex III. Prodigiosin did not produce cytotoxic effects in lymphocytes and Vero cells and has better effects than benznidazole. Our data suggest that the action of prodigiosin on the parasites is mediated by mitochondrial structural and functional disruptions that could lead the parasites to an apoptotic-like cell death process. Conclusions Here, we propose a potentially useful trypanocidal agent derived from knowledge of an important aspect of the natural life cycle of the parasite: the vector-parasite interaction. Our results indicate that prodigiosin could be a good candidate for the treatment of Chagas disease.
Ivy Hurwitz, Annabeth Fieck, Amber Read, Heidi Hillesland, Nichole Klein, Angray Kang, Ravi Durvasula
Full Text Available Conventional methodologies to control vector borne diseases with chemical pesticides are often associated with environmental toxicity, adverse effects on human health and the emergence of insect resistance. In the paratransgenic strategy, symbiotic or commensal microbes of host insects are transformed to express gene products that interfere with pathogen transmission. These genetically altered microbes are re-introduced back to the insect where expression of the engineered molecules decreases the host's ability to transmit the pathogen. We have successfully utilized this strategy to reduce carriage rates of Trypanosoma cruzi, the causative agent of Chagas disease, in the triatomine bug, Rhodnius prolixus, and are currently developing this methodology to control the transmission of Leishmania donovani by the sand fly Phlebotomus argentipes. Several effector molecules, including antimicrobial peptides and highly specific single chain antibodies, are currently being explored for their anti-parasite activities in these two systems. In preparation for eventual field use, we are actively engaged in risk assessment studies addressing the issue of horizontal gene transfer from the modified bacteria to environmental microbes.
Posada, Elizabeth; Pell, Christopher; Angulo, Nataly; Pinazo, María Jesús; Gimeno, Faust; Elizalde, Ignasi; Gysels, Marjolein; Muñoz, Jose; Pool, Robert; Gascón, Joaquim
Due to international migration, Chagas disease, endemic in Latin America, has become more common in non-endemic areas. Chronic Chagas disease can cause damage to the digestive system leading to constipation. However, a range of factors influences constipation and a better understanding of the role of non-Chagas related factors is required to improve management of Chagas-related digestive problems. This study explores perceptions of constipation and changes in food and exercise habits amongst Bolivians in Barcelona, Spain. Bolivian migrants attending the Tropical Medicine Unit (Hospital Clínic, Barcelona) were interviewed about their food habits in Spain and Bolivia, migratory experience, work and leisure activities. Chagas seropositive participants also received radiological examinations. Bolivian migrants experienced dietary changes, influenced by work-related factors, which included reductions in quantities of food and liquid consumed. Almost half the participants reported changes in digestive rhythm since arriving in Spain. Constipation, which was common, in some cases was only recounted during interviews. Bolivian migrants' constipation may be associated with chronic Chagas disease or migration-related dietary changes. Careful questioning using the Rome III criteria is however required to ensure its diagnosis. Radiological studies are also required to confirm the role of Chagas disease and identify potentially serious intestinal damage. PMID:24038501
Elsa L Segura
quantify exposure to risk factors and seropositivity. Odds ratios with 95% confidence intervals and Mantel-Haenszel chi-squared tests were obtained. Multivariate analysis was performed with unconditional logistic regression, variables included in the model were those that had a p-value up to 0.20 in the bivariate analysis. The etiologic fraction in the exposed was also obtained. RESULTS: The prevalence of Chagas disease was between 0 and 2.8%. Jurisdictions at a higher risk were Tuxpan, Panuco and Cordoba; Orizaba showed no risk. The main household risk factors were palma/zacate (palmtree, grass leaves roof and walls, dirt floor, the presence of the vector, and ventilation. CONCLUSIONS: Epidemiological surveillance should emphasize health education, housing improvement, and use of insecticides.
Santos, Fred Luciano Neves; de Souza, Wayner Vieira; Barros, Michelle da Silva; Nakazawa, Mineo; Krieger, Marco Aurélio; Gomes, Yara de Miranda
There is a significant heterogeneity in reported performance of serological assays for Chagas disease diagnosis. The conventional serology testing in laboratory diagnosis and in blood banks is unsatisfactory because of a high number of inconclusive and misclassified results. We aimed to assess the quality of four commercially available enzyme-linked immunosorbent assay tests for their ability to detect Trypanosoma cruzi antibodies in 685 sera samples. Cross-reactivity was assessed by using 748 sera from patients with unrelated diseases. Initially, we found that the reactivity index against T. cruzi antigen was statistically higher in sera from Chagas disease patients compared with those from non-chagasic patients, supporting the notion that all evaluated tests have a good discriminatory ability toward the diagnosis of T. cruzi infection in patients in the chronic phase of the disease. Although all tests were similarly sensitive for diagnosing T. cruzi infection, there were significant variations in terms of specificity and cross-reactivity among them. Indeed, we obtained divergent results when testing sera from patient with unrelated diseases, particularly leishmaniasis, with the levels of cross-reactivity being higher in tests using whole T. cruzi extracts compared with those using recombinant proteins. Our data suggest that all four tests may be used for the laboratory diagnosis and routine blood screening diagnose for Chagas disease. We also emphasize that, despite their general good performance, caution is needed when analyzing the results when these tests are performed in areas where other diseases, particularly leishmaniasis, are endemic. PMID:26976886
Milena B. P. Soares; LAIN PONTES-DE-CARVALHO; RICARDO RIBEIRO-DOS-SANTOS
Chagas' disease is a major health problem in Latin America, where it constitutes one of the leading causes of heart failure. About one fourth of Trypanosoma cruzi-infected individuals develop chronic chagasic cardiomyopathy (CChC), the most severe form of the disease. CChC is histologically characterized by the presence of multifocal inflammatory infiltrates in the heart, composed mainly by mononuclear cells, usually adhered to myocytes and leading to myocytolysis, and frequently by interstit...
Ana Laura Carbajal-de-la-Fuente
Full Text Available The Special Programme for Research and Training in Tropical Diseases (TDR is an independent global programme of scientific collaboration cosponsored by the United Nations Children's Fund, the United Nations Development Program, the World Bank, and the World Health Organization. TDR's strategy is based on stewardship for research on infectious diseases of poverty, empowerment of endemic countries, research on neglected priority needs, and the promotion of scientific collaboration influencing global efforts to combat major tropical diseases. In 2001, in view of the achievements obtained in the reduction of transmission of Chagas disease through the Southern Cone Initiative and the improvement in Chagas disease control activities in some countries of the Andean and the Central American Initiatives, TDR transferred the Chagas Disease Implementation Research Programme (CIRP to the Communicable Diseases Unit of the Pan American Health Organization (CD/PAHO. This paper presents a scientometric evaluation of the 73 projects from 18 Latin American and European countries that were granted by CIRP/PAHO/TDR between 1997 and 2007. We analyzed all final reports of the funded projects and scientific publications, technical reports, and human resource training activities derived from them. Results about the number of projects funded, countries and institutions involved, gender analysis, number of published papers in indexed scientific journals, main topics funded, patents inscribed, and triatomine species studied are presented and discussed. The results indicate that CIRP/PAHO/TDR initiative has contributed significantly, over the 1997-2007 period, to Chagas disease knowledge as well as to the individual and institutional-building capacity.
The authors present a case of Chagas'disease as tumor-like lesion of the brain, in a patient with Aids, simulating the lesions most frequently found in these patients, as toxoplasmosis, lymphoma and cryptococcosis. Furthermore, the case reported have peculiarity to be the only with lesion documented in cerebellum, and unusual due to be secondary by reactivation of chronic Chagas disease. Moreover, emphasize analysis of cerebrospinal fluid with realization of sorologic tests to Chagas's disease, as simple as effective method, to make use of biopsy with stereotaxia in unfinished cases and bad evolution. Finally, after a wide world literature review about Chagas'disease as a tumor-like lesion of the brain, emphasizing this publication as the first written in a radiology journal of specialty. (author). 40 refs., 3 figs., 1 tab
Chagas disease (AD) was described by Carlos Chagas in 1909. It is caused by a parasite T. cruzi, transmitted by bugs, by blood transfusion, vertical and orally. The DC has two phases: acute and chronic. The evolution to the cardiac form occurs in about 30% of chronic cases and is the largest cause of mortality in chronic Chagas disease. The aim of this study was to Chagas' disease in patients of Tocantins, compared with other heart patients and asymptomatic from the standpoint of non-invasive exams using radiant energies such as echocardiography and ECG and RX. The descriptive study included 80 patients, 20 chronic form of Chagas disease, 20 indeterminate, 20 with other heart diseases, and 20 controls. There was a prevalence of 9.5% of chagasic patients treated in outpatient cardiology at Araguaina Tocantins, and 7.3% in chronic and 2.21% in the indeterminate. Of the chronic patients in the study 50% had mega esophagus and megacolon 4 (20%). Most patients had no family history of AD, nor was a smoker or drinker. Major electrocardiographic abnormalities found refer to driving. The evaluation of ICT, the chronic chagasic showed that increased by 40% of patients, 40% had esophageal changes and 20% of patients had megacolon s. The echocardiogram was abnormal in 42%). 27% of patients had EF below 55% changed. Changes in segmental contractility and Asynchrony septum were found in 80% of chronic Chagas disease. In 80% of the patients was observed diastolic dysfunction. The valvular changes occurred in 75%. Electrocardiographic abnormalities occurred in 80% of patients with CCC, while the other heart had ECG changes. Arterial hypertension had an incidence of 45% in patients with CCC and 40% in FCI. The systolic and diastolic ventricular dysfunction was more prevalent in groups that had an abnormal ECG and arrhythmia. Observed that the group of chagasic decreased ejection fraction is correlated to a higher incidence of arrhythmias besides diastolic dysfunction and related
Maria Esther Carvalho
American trypanosomiasis in the state of São Paulo, Brazil, during the period when there was a state effort to control the vector. Data from the municipality of Taquarituba, administrative region of Sorocaba, which was then important in the epidemiology of Chagas disease in that region, were analyzed. Despite the government efforts started in the 1950s, domiciliary triatomines were still being captured in that region during the 1970s. METHODS: Population samples were selected from five localities of Taquarituba. Age, sex, birthplace, and time of residence in the house being occupied at the time of the interview, were recorded. Probit analysis is used to assess a possible relationship between age and seropositivity, the latter taken as indicative of the risk of transmission. RESULTS: Blood from Taquarituba native people represented 62.9% of the samples examined (n = 2.784 and 62.4% of all seropositives (n = 380. Overall proportion of seropositives was 13.6% with no significant difference between genders (p = 0.538. Children under 6 years of age were not seropovitive, Seropositivity increased from 2.7% in the age group 6-9 years to 30.6% in the age group 30-39 years. By using probit analysis, an age-seropositivity relationship was found within these groups. CONCLUSIONS: The results of serological tests pointed to an association between the actions taken against Triatoma infestans and the decline and eventual control of the transmission of Chagas disease in the late 1960s.
Morilla, Maria Jose; Romero, Eder Lilia
Chagas disease is a neglected parasitic infection caused by the protozoan Trypanosoma cruzi. After a mostly clinically silent acute phase, the disease becomes a lifelong chronic condition that can lead to chronic heart failure and thromboembolic phenomena followed by sudden death. Antichagasic treatment is only effective in the acute phase but fails to eradicate the intracellular form of parasites and causes severe toxicity in adults. Although conventional oral benznidazol is not a safe and efficient drug to cure chronic adult patients, current preclinical data is insufficient to envisage if conventional antichagasic treatment could be realistically improved by a nanomedical approach. This review will discuss how nanomedicines could help to improve the performance of therapeutics, vaccines and diagnosis of Chagas disease. PMID:25707979
Regina Maia de Souza; Vicente Amato Neto
Using the indirect hemagglutination (IH), indirect immunofluorescence (IIF) and enzyme linked immunosorbent assay (ELISA) tests for the diagnosis of Chagas disease, 4000 serum samples were examined. This study was conducted with different purposes: clinical interest, research support and parasitological monitoring of those patients with Chagas disease who were treated with heart transplantations. The tests occurred without patient selection and in accordance with the medical requests. The res...
José Rodrigues Coura; Angela Cristina Verissimo Junqueira; Cristina Maria Giordano; Ilra Renata Komoda Funatsu
At least eighteen species of triatominae have been found in the Brazilian Amazon, nine of them naturally infected with Trypanosoma cruzi or "cruzi-like" trypanosomes and associated with numerous wild reservoirs. Despite the small number of human cases of Chagas' disease described to date in the Brazilian Amazon the risk that the disease will become endemic in this area is increasing for the following reasons: a) uncontrolled deforestation and colonization altering the ecological balance betwe...
Full text: Chagas disease remains a leading public health concern throughout much of Central and South America. Over 16 million people were infected with Trypanosoma cruzi, the causative agent of Chagas Disease, and further 100 million were at risk, prior to the initiation of the regional vector control initiatives. With neither a cure nor vaccine available, control relies heavily on strategies that eliminate the domestic triatomine vectors of T. cruzi. Insecticide-based strategies have had initial success but are limited by problems of cost, sustainability, and the inability to control non-domiciliated bug populations. Extra-domiciliary bug populations present the risk of re-invading human dwellings in the absence of continued use of chemicals. For the past 10 years, our group has developed a novel strategy to render bugs incapable of T. cruzi transmission. This approach, termed paratransgenesis, involves genetic manipulation of symbiotic bacteria resident in the gut lumen of the bug, to export molecules that are toxic to T. cruzi. Triatomines disperse the symbiotic bacteria to their progeny via fecal contamination. Nymphs that probe feces of adult bugs rapidly establish gut infections with the symbiont. We have exploited the biology of bacterial transfer amongst triatomines to create a synthetic paste termed CRUZIGARD for field delivery of engineered bacteria. Viewed as an integrated control strategy, this method would complement and ensure the sustainability of the ongoing insecticide-based initiatives. The strategy is designed to completely block transmission by targeting bug populations that prove resilient to conventional methods. The novel concept of the auto-propagation of a transmission-blocking agent is based on the natural and efficient dispersal of genetically altered bacteria through lateral spread of fecal material in bug colonies, making it cost-effective and sustainable. Significant barriers still exist to field use of this technology. The efficacy
Di Girolamo, Chiara; Martelli, Giulia; Ciannameo, Anna; Vocale, Caterina; Fini, Marco; Stefanini, Angelo; Landini, Maria Paola; Viale, Pierluigi; Verucchi, Gabriella
Global processes have brought about a substantial change in the epidemiological landscape of Chagas disease, spreading it to non-endemic areas. Italy is the second country in Europe in terms of Latin American migrants and expected infection rate. Given that scenario, the Bologna University Teaching Hospital undertaken a study aimed at providing preliminary data on the prevalence and investigating the knowledge and the subjective perceptions of Chagas disease, migration pathways and other relevant ill-health experiences. A cross-sectional study was undertaken in association with an ethnographic research. Between November 2010 and May 2013 Chagas disease testing was offered to people who attended the hospital and data were collected to investigate the broader socio-demographic and cultural factors. 151 individuals were screened for anti T. cruzi antibodies; 12 of them, 10 Bolivians and 2 Argentinians, were seroreactive, resulting in an overall prevalence of 7.94 %. Both the quantitative and the qualitative analysis revealed a degree of heterogeneity in terms of knowledge and perceptions of the disease as well as of migration pathways. The results are comparable with those reported by previous studies with similar characteristics and highlight the relevance of such public health issue in a non-endemic context. Moreover, the interdisciplinary approach has greatly helped to unveil the complex social and cultural implications of Chagas disease, to explain the subjective ill-health experiences, and to understand the ways in which the broader socio-economic and cultural context affects an intervention and its potential for success or failure. PMID:25935443
Silvia M Ayub-Ferreira
Full Text Available Sudden death has been considered the main cause of death in patients with Chagas heart disease. Nevertheless, this information comes from a period before the introduction of drugs that changed the natural history of heart failure. We sought to study the mode of death of patients with heart failure caused by Chagas heart disease, comparing with non-Chagas cardiomyopathy.We examined the REMADHE trial and grouped patients according to etiology (Chagas vs non-Chagas and mode of death. The primary end-point was all-cause, heart failure and sudden death mortality; 342 patients were analyzed and 185 (54.1% died. Death occurred in 56.4% Chagas patients and 53.7% non-Chagas patients. The cumulative incidence of all-cause mortality and heart failure mortality was significantly higher in Chagas patients compared to non-Chagas. There was no difference in the cumulative incidence of sudden death mortality between the two groups. In the Cox regression model, Chagas etiology (HR 2.76; CI 1.34-5.69; p = 0.006, LVEDD (left ventricular end diastolic diameter (HR 1.07; CI 1.04-1.10; p<0.001, creatinine clearance (HR 0.98; CI 0.97-0.99; p = 0.006 and use of amiodarone (HR 3.05; CI 1.47-6.34; p = 0.003 were independently associated with heart failure mortality. LVEDD (HR 1.04; CI 1.01-1.07; p = 0.005 and use of beta-blocker (HR 0.52; CI 0.34-0.94; p = 0.014 were independently associated with sudden death mortality.In severe Chagas heart disease, progressive heart failure is the most important mode of death. These data challenge the current understanding of Chagas heart disease and may have implications in the selection of treatment choices, considering the mode of death.ClinicalTrials.gov NCT00505050 (REMADHE.
José Rodrigues Coura
Full Text Available 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.
Ludmila; Rodrigues; Pinto; Ferreira; Amanda; Farage; Frade; Monique; Andrade; Baron; Isabela; Cunha; Navarro; Jorge; Kalil; Christophe; Chevillard; Edecio; Cunha-Neto
Chagas disease cardiomyopathy(CCC), the main consequence of Trypanosoma cruzi(T.cruzi) infection, is an inflammatory cardiomyopathy that develops in up to 30% of infected individuals. The heart inflammation in CCC patients is characterized by a Th1 T cell-rich myocarditis with increased production of interferon(IFN)-γ, produced by the CCC myocardial infiltrate and detected at high levels in the periphery. IFN-γ has a central role in the cardiomyocyte signaling during both acute and chronic phases of T.cruzi infection. In this review, we have chosen to focus in its pleiotropic mode of action during CCC, which may ultimately be the strongest driver towards pathological remodeling and heart failure. We describe here the antiparasitic protective and pathogenic dual role of IFN-γ in Chagas disease.
Ferreira, Ludmila Rodrigues Pinto; Frade, Amanda Farage; Baron, Monique Andrade; Navarro, Isabela Cunha; Kalil, Jorge; Chevillard, Christophe; Cunha-Neto, Edecio
Chagas disease cardiomyopathy (CCC), the main consequence of Trypanosoma cruzi (T.cruzi) infection, is an inflammatory cardiomyopathy that develops in up to 30% of infected individuals. The heart inflammation in CCC patients is characterized by a Th1 T cell-rich myocarditis with increased production of interferon (IFN)-γ, produced by the CCC myocardial infiltrate and detected at high levels in the periphery. IFN-γ has a central role in the cardiomyocyte signaling during both acute and chronic phases of T.cruzi infection. In this review, we have chosen to focus in its pleiotropic mode of action during CCC, which may ultimately be the strongest driver towards pathological remodeling and heart failure. We describe here the antiparasitic protective and pathogenic dual role of IFN-γ in Chagas disease. PMID:25228957