101
|
Ramírez JD, Montilla M, Cucunubá ZM, Floréz AC, Zambrano P, Guhl F. Molecular epidemiology of human oral Chagas disease outbreaks in Colombia. PLoS Negl Trop Dis 2013; 7:e2041. [PMID: 23437405 PMCID: PMC3578743 DOI: 10.1371/journal.pntd.0002041] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Accepted: 12/14/2012] [Indexed: 11/18/2022] Open
Abstract
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. Chagas disease represents a serious health problem affecting more than 10 million people in the Americas. The oral transmission route has emerged as a new epidemiological scenario that needs to be considered in prevention and control strategies. Herein was developed a high-resolution molecular characterization using mtMLST and MLMT tools in order to unravel the molecular epidemiology and transmission dynamics drivers in six well-characterized human oral outbreaks in Colombia. We observed the majority of clones typed as TcI and one clone as TcIV. The analysis of mitochondrial haplotypes allowed us to observe a high frequency of sylvatic haplotypes and a low proportion of domestic haplotypes. Likewise, a tailored allelic profile by each outbreak was observed. Our results suggest that sylvatic populations of T. cruzi are the causative agents of Chagas disease oral outbreaks and these findings should help to pursue new initiatives of control and prevention in those areas where domiciliated vectorial transmission has been interrupted.
Collapse
Affiliation(s)
- Juan David Ramírez
- Centro de Investigaciones en Microbiología y Parasitología Tropical (CIMPAT), Universidad de Los Andes, Bogotá, Colombia
| | - Marleny Montilla
- Grupo de Parasitología, Instituto Nacional de Salud, Bogotá, Colombia
| | - Zulma M. Cucunubá
- Grupo de Parasitología, Instituto Nacional de Salud, Bogotá, Colombia
| | | | - Pilar Zambrano
- Subdirección de Vigilancia y Control en Salud Pública, Instituto Nacional de Salud, Bogotá, Colombia
| | - Felipe Guhl
- Centro de Investigaciones en Microbiología y Parasitología Tropical (CIMPAT), Universidad de Los Andes, Bogotá, Colombia
- * E-mail:
| |
Collapse
|
102
|
Basso B. Modulation of immune response in experimental Chagas disease. World J Exp Med 2013; 3:1-10. [PMID: 24520540 PMCID: PMC3905588 DOI: 10.5493/wjem.v3.i1.1] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 01/07/2013] [Accepted: 02/06/2013] [Indexed: 02/06/2023] Open
Abstract
Trypanosoma cruzi (T. cruzi), the etiological agent of Chagas disease, affects nearly 18 million people in Latin America and 90 million are at risk of infection. The parasite presents two stages of medical importance in the host, the amastigote, intracellular replicating form, and the extracellular trypomastigote, the infective form. Thus infection by T. cruzi induces a complex immune response that involves effectors and regulatory mechanisms. That is why control of the infection requires a strong humoral and cellular immune response; hence, the outcome of host-parasite interaction in the early stages of infection is extremely important. A critical event during this period of the infection is innate immune response, in which the macrophage’s role is vital. Thus, after being phagocytized, the parasite is able to develop intracellularly; however, during later periods, these cells induce its elimination by means of toxic metabolites. In turn, as the infection progresses, adaptive immune response mechanisms are triggered through the TH1 and TH2 responses. Finally, T. cruzi, like other protozoa such as Leishmania and Toxoplasma, have numerous evasive mechanisms to the immune response that make it possible to spread around the host. In our Laboratory we have developed a vaccination model in mice with Trypanosoma rangeli, nonpathogenic to humans, which modulates the immune response to infection by T. cruzi, thus protecting them. Vaccinated animals showed an important innate response (modulation of NO and other metabolites, cytokines, activation of macrophages), a strong adaptive cellular response and significant increase in specific antibodies. The modulation caused early elimination of the parasites, low parasitaemia, the absence of histological lesions and high survival rates. Even though progress has been made in the knowledge of some of these mechanisms, new studies must be conducted which could target further prophylactic and therapeutic trials against T. cruzi infection.
Collapse
|
103
|
Moreira OC, Ramírez JD, Velázquez E, Melo MFAD, Lima-Ferreira C, Guhl F, Sosa-Estani S, Marin-Neto JA, Morillo CA, Britto C. Towards the establishment of a consensus real-time qPCR to monitor Trypanosoma cruzi parasitemia in patients with chronic Chagas disease cardiomyopathy: a substudy from the BENEFIT trial. Acta Trop 2013; 125:23-31. [PMID: 22982466 DOI: 10.1016/j.actatropica.2012.08.020] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 07/10/2012] [Accepted: 08/22/2012] [Indexed: 12/16/2022]
Abstract
Quantitative real-time PCR (qPCR) is an accurate method to quantify Trypanosoma cruzi DNA and can be used to follow-up parasitemia in Chagas disease (CD) patients undergoing chemotherapy. The Benznidazole Evaluation for Interrupting Trypanosomiasis (BENEFIT) study is an international, multicenter, randomized, double-blinded and placebo-controlled clinical trial to evaluate the efficacy of benznidazole (BZ) treatment in patients with chronic Chagas cardiomyopathy (CCC). One important question to be addressed concerns the effectiveness of BZ in reducing overall parasite load in CCC patients, even in the absence of parasitological cure. This report describes the evaluation of multiple procedures for DNA extraction and qPCR-based protocols aiming to establish a standardized methodology for the absolute quantification of T. cruzi DNA in Guanidine-EDTA blood (GEB) samples. A panel of five primer sets directed to the T. cruzi nuclear satellite DNA repeats (Sat-DNA) and to the minicircle DNA conserved regions (kDNA) was compared in either SYBR Green or TaqMan systems. Standard curve parameters such as, amplification efficiency, coefficient of determination and intercept were evaluated, as well as different procedures to generate standard samples containing pre-established T. cruzi DNA concentration. Initially, each primer set was assayed in a SYBR Green qPCR to estimate parasite load in GEB samples from chronic Chagas disease patients. The results achieved from Bayesian transmutability analysis elected the primer sets Cruzi1/Cruzi2 (p=0.0031) and Diaz7/Diaz8 (p=0.0023) coupled to the QIAamp DNA Kit extraction protocol (silica gel column), as the most suitable for monitoring parasitemia in these patients. Comparison between the parasite burden of 150 GEB samples of BENEFIT patients from Argentina, Brazil and Colombia, prior to drug/placebo administration, was performed using Cruzi1/Cruzi2 primers in a SYBR Green approach. The median parasitemia found in patients from Argentina and Colombia (1.93 and 2.31 parasite equivalents/mL, respectively) was around 20 times higher than the one estimated for the Brazilian patients (0.1 parasite equivalents/mL). This difference could be in part due to the complexity of T. cruzi genetic diversity, which is a factor possibly implicated in different clinical presentations of the disease and/or influencing parasitemia levels in infected individuals from different regions of Latin America. The results of SYBR Green qPCR assays herein presented prove this methodology to be more cost efficient than the alternative use of internal fluorogenic probes. In addition, its sensitivity and reproducibility are shown to be adequate to detect low parasitemia burden in patients with chronic Chagas disease.
Collapse
Affiliation(s)
- Otacilio C Moreira
- Instituto Federal de Educação, Ciência e Tecnologia do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | | | | | | | | | | | | | | | | |
Collapse
|
104
|
Abstract
Parasitic infections of the central nervous system (CNS) include two broad categories of infectious organisms: single-celled protozoa and multicellular metazoa. The protozoal infections include malaria, American trypanosomiasis, human African trypanosomiasis, toxoplasmosis, amebiasis, microsporidiasis, and leishmaniasis. The metazoal infections are grouped into flatworms, which include trematoda and cestoda, and roundworms or nematoda. Trematoda infections include schistosomiasis and paragonimiasis. Cestoda infections include cysticercosis, coenurosis, hydatidosis, and sparganosis. Nematoda infections include gnathostomiasis, angiostrongyliasis, toxocariasis, strongyloidiasis, filariasis, baylisascariasis, dracunculiasis, micronemiasis, and lagochilascariasis. The most common route of CNS invasion is through the blood. In some cases, the parasite invades the olfactory neuroepithelium in the nasal mucosa and penetrates the brain via the subarachnoid space or reaches the CNS through neural foramina of the skull base around the cranial nerves or vessels. The neuropathological changes vary greatly, depending on the type and size of the parasite, geographical strain variations in parasitic virulence, immune evasion by the parasite, and differences in host immune response. Congestion of the leptomeninges, cerebral edema, hemorrhage, thrombosis, vasculitis, necrosis, calcification, abscesses, meningeal and perivascular polymorphonuclear and mononuclear inflammatory infiltrate, microglial nodules, gliosis, granulomas, and fibrosis can be found affecting isolated or multiple regions of the CNS, or even diffusely spread. Some infections may be present as an expanding mass lesion. The parasites can be identified by conventional histology, immunohistochemistry, in situ hybridization, and PCR.
Collapse
Affiliation(s)
- José Eymard Homem Pittella
- Pathology Service, Hospital das Clínicas, Medical Faculty of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
| |
Collapse
|
105
|
Pavan MG, Mesquita RD, Lawrence GG, Lazoski C, Dotson EM, Abubucker S, Mitreva M, Randall-Maher J, Monteiro FA. A nuclear single-nucleotide polymorphism (SNP) potentially useful for the separation of Rhodnius prolixus from members of the Rhodnius robustus cryptic species complex (Hemiptera: Reduviidae). INFECTION GENETICS AND EVOLUTION 2012; 14:426-33. [PMID: 23219914 DOI: 10.1016/j.meegid.2012.10.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 10/16/2012] [Accepted: 10/23/2012] [Indexed: 12/31/2022]
Abstract
The design and application of rational strategies that rely on accurate species identification are pivotal for effective vector control. When morphological identification of the target vector species is impractical, the use of molecular markers is required. Here we describe a non-coding, single-copy nuclear DNA fragment that contains a single-nucleotide polymorphism (SNP) with the potential to distinguish the important domestic Chagas disease vector, Rhodnius prolixus, from members of the four sylvatic Rhodnius robustus cryptic species complex. A total of 96 primer pairs obtained from whole genome shotgun sequencing of the R. prolixus genome (12,626 random reads) were tested on 43 R. prolixus and R. robustus s.l. samples. One of the seven amplicons selected (AmpG) presented a SNP, potentially diagnostic for R. prolixus, on the 280th site. The diagnostic nature of this SNP was then confirmed based on the analysis of 154 R. prolixus and R. robustus s.l. samples representing the widest possible geographic coverage. The results of a 60% majority-rule Bayesian consensus tree and a median-joining network constructed based on the genetic variability observed reveal the paraphyletic nature of the R. robustus species complex, with respect to R. prolixus. The AmpG region is located in the fourth intron of the Transmembrane protein 165 gene, which seems to be in the R. prolixus X chromosome. Other possible chromosomal locations of the AmpG region in the R. prolixus genome are also presented and discussed.
Collapse
Affiliation(s)
- Márcio G Pavan
- Laboratório de Sistemáticae Bioquímica, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | | | | | | | | | | | | | | | | |
Collapse
|
106
|
Morocoima A, Carrasco HJ, Boadas J, Chique JD, Herrera L, Urdaneta-Morales S. Trypanosoma cruzi III from armadillos (Dasypus novemcinctus novemcinctus) from Northeastern Venezuela and its biological behavior in murine model. Risk of emergency of Chagas’ disease. Exp Parasitol 2012; 132:341-7. [DOI: 10.1016/j.exppara.2012.08.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 06/18/2012] [Accepted: 08/01/2012] [Indexed: 11/16/2022]
|
107
|
Caldas IS, da Matta Guedes PM, dos Santos FM, de Figueiredo Diniz L, Martins TAF, da Silva do Nascimento AF, Azevedo MA, de Lima WG, Neto RMN, Torres RM, Talvani A, Bahia MT. Myocardial scars correlate with eletrocardiographic changes in chronic Trypanosoma cruzi infection for dogs treated with Benznidazole. Trop Med Int Health 2012; 18:75-84. [PMID: 23107306 DOI: 10.1111/tmi.12002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVES The cardiac form of Chagas disease is evidenced by a progressive cardiac inflammation that leads to myocarditis, fibrosis and electrocardiographic (ECG) conduction abnormalities. Considering these characteristics, the aim of this study was to prospectively evaluate the early ECG changes in dogs that were experimentally inoculated with Benznidazole (Bz)-susceptibly (Berenice-78) and Bz-resistant (VL-10, and AAS) Trypanosoma cruzi strains and, later, evaluate the efficacy of Bz treatment for preventing these ECG alterations. METHODS Electrocardiographic changes of treated and untreated animals were prospectively evaluated for up to 270 days after infection, at which point collagen (right atrium) quantification was performed. RESULTS All infected dogs had a high intensity of heart fibrosis (4616.00 ± 1715.82 collagen/74931 μm(2) in dogs infected with Berenice-78 strain, 5839.2 ± 1423.49 collagen/74931 μm(2) in infected by AAS and 6294.40 ± 896.04 collagen/74931 μm(2) in animals infected with VL-10 strain), while 78.57% of all infected dogs showed ECG alterations. Bz Therapy reduced or prevented fibrosis in Bz-susceptible Berenice-78 (2813.00 ± 607.13 collagen/74931 μm(2) ) and Bz-resistant AAS strains (4024 ± 1272.44 collagen/74931 μm(2) ), coincident with only 10% de ECG alterations at 270 days. However, in those animals infected with a Bz-resistant VL-10 strain, specific treatment did not alter collagen deposition (6749.5 ± 1596.35 collagen/74931 μm(2) ) and there was first atrioventricular block and chamber overload at 120 and 270 days after infection, with 75% abnormal ECG exams. CONCLUSIONS These findings indicate that an effective antiparasitic treatment in the early stage of Chagas disease can lead to a significant reduction in the frequency and severity of the parasite-induced cardiac disease, even if parasites are not completely eliminated.
Collapse
Affiliation(s)
- Ivo Santana Caldas
- Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Minas Gerais, Brazil
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
108
|
Nogueira LG, Santos RHB, Ianni BM, Fiorelli AI, Mairena EC, Benvenuti LA, Frade A, Donadi E, Dias F, Saba B, Wang HTL, Fragata A, Sampaio M, Hirata MH, Buck P, Mady C, Bocchi EA, Stolf NA, Kalil J, Cunha-Neto E. Myocardial chemokine expression and intensity of myocarditis in Chagas cardiomyopathy are controlled by polymorphisms in CXCL9 and CXCL10. PLoS Negl Trop Dis 2012; 6:e1867. [PMID: 23150742 PMCID: PMC3493616 DOI: 10.1371/journal.pntd.0001867] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 09/03/2012] [Indexed: 01/24/2023] Open
Abstract
Background Chronic Chagas cardiomyopathy (CCC), a life-threatening inflammatory dilated cardiomyopathy, affects 30% of the approximately 8 million patients infected by Trypanosoma cruzi. Even though the Th1 T cell-rich myocarditis plays a pivotal role in CCC pathogenesis, little is known about the factors controlling inflammatory cell migration to CCC myocardium. Methods and Results Using confocal immunofluorescence and quantitative PCR, we studied cell surface staining and gene expression of the CXCR3, CCR4, CCR5, CCR7, CCR8 receptors and their chemokine ligands in myocardial samples from end-stage CCC patients. CCR5+, CXCR3+, CCR4+, CCL5+ and CXCL9+ mononuclear cells were observed in CCC myocardium. mRNA expression of the chemokines CCL5, CXCL9, CXCL10, CCL17, CCL19 and their receptors was upregulated in CCC myocardium. CXCL9 mRNA expression directly correlated with the intensity of myocarditis, as well as with mRNA expression of CXCR3, CCR4, CCR5, CCR7, CCR8 and their ligands. We also analyzed single-nucleotide polymorphisms for genes encoding the most highly expressed chemokines and receptors in a cohort of Chagas disease patients. CCC patients with ventricular dysfunction displayed reduced genotypic frequencies of CXCL9 rs10336 CC, CXCL10 rs3921 GG, and increased CCR5 rs1799988CC as compared to those without dysfunction. Significantly, myocardial samples from CCC patients carrying the CXCL9/CXCL10 genotypes associated to a lower risk displayed a 2–6 fold reduction in mRNA expression of CXCL9, CXCL10, and other chemokines and receptors, along with reduced intensity of myocarditis, as compared to those with other CXCL9/CXCL10 genotypes. Conclusions Results may indicate that genotypes associated to reduced risk in closely linked CXCL9 and CXCL10 genes may modulate local expression of the chemokines themselves, and simultaneously affect myocardial expression of other key chemokines as well as intensity of myocarditis. Taken together our results may suggest that CXCL9 and CXCL10 are master regulators of myocardial inflammatory cell migration, perhaps affecting clinical progression to the life-threatening form of CCC. Chronic Chagas cardiomyopathy (CCC) is an inflammatory heart disease that affects millions in Latin America, and in growing numbers in USA and Europe. Survival among CCC patients is shorter than among patients with cardiomyopathy of non-inflammatory etiology. This suggests that the inflammatory cell influx plays an important pathogenic role in CCC. However, little is known about the factors that maintain this myocardial inflammation. We hypothesized that Th1 T cell-attracting chemokines, involved in driving leukocyte migration, could play a role in myocardial inflammation. Herein, we have analyzed expression of several chemokines and receptors in heart tissue from patients with CCC and controls. We found inflammatory cells expressing chemokines and receptors consistent with Th1 T cell influx into CCC myocardium. mRNA expression levels of the chemokine CXCL9 correlated with inflammation. We also studied whether genetic variations in these genes could be associated to CCC development. Polymorphisms in CXCL9, CXCL10 and CCR5 were associated to differential risk of progression to the more severe form of CCC. Polymorphisms of CXCL9 and CXCL10 were also associated to the intensity of myocardial inflammation and chemokine expression. These results suggest that such chemokines may be master regulators of myocardial inflammatory cell migration, perhaps affecting clinical progression to severe CCC.
Collapse
Affiliation(s)
- Luciana Gabriel Nogueira
- Laboratory of Immunology, Heart Institute (InCor), School of Medicine, University of São Paulo, São Paulo, Brazil
- Division of Clinical Immunology and Allergy, School of Medicine, University of São Paulo, São Paulo, Brazil
- Institute for Investigation in Immunology (iii), INCT, São Paulo, Brazil
| | | | - Barbara Maria Ianni
- Myocardiopathies Unit, Heart Institute (InCor), School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Alfredo Inácio Fiorelli
- Divison of Surgery, Heart Institute (InCor), School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Eliane Conti Mairena
- Laboratory of Immunology, Heart Institute (InCor), School of Medicine, University of São Paulo, São Paulo, Brazil
- Division of Clinical Immunology and Allergy, School of Medicine, University of São Paulo, São Paulo, Brazil
- Institute for Investigation in Immunology (iii), INCT, São Paulo, Brazil
| | - Luiz Alberto Benvenuti
- Divison of Pathology, Heart Institute (InCor), School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Amanda Frade
- Laboratory of Immunology, Heart Institute (InCor), School of Medicine, University of São Paulo, São Paulo, Brazil
- Division of Clinical Immunology and Allergy, School of Medicine, University of São Paulo, São Paulo, Brazil
- Institute for Investigation in Immunology (iii), INCT, São Paulo, Brazil
| | - Eduardo Donadi
- School of Medicine of Ribeirão Preto (FMRP), University of São Paulo, São Paulo, Brazil
| | - Fabrício Dias
- School of Medicine of Ribeirão Preto (FMRP), University of São Paulo, São Paulo, Brazil
| | - Bruno Saba
- Dante Pazzanese Institute of Cardiology and Heart Failure Unit, São Paulo, Brazil
| | - Hui-Tzu Lin Wang
- Dante Pazzanese Institute of Cardiology and Heart Failure Unit, São Paulo, Brazil
| | - Abilio Fragata
- Dante Pazzanese Institute of Cardiology and Heart Failure Unit, São Paulo, Brazil
| | - Marcelo Sampaio
- Dante Pazzanese Institute of Cardiology and Heart Failure Unit, São Paulo, Brazil
| | | | - Paula Buck
- Myocardiopathies Unit, Heart Institute (InCor), School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Charles Mady
- Myocardiopathies Unit, Heart Institute (InCor), School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Edimar Alcides Bocchi
- Transplantation and Heart Failure Unit, Heart Institute (InCor), School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Noedir Antonio Stolf
- Divison of Surgery, Heart Institute (InCor), School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Jorge Kalil
- Laboratory of Immunology, Heart Institute (InCor), School of Medicine, University of São Paulo, São Paulo, Brazil
- Division of Clinical Immunology and Allergy, School of Medicine, University of São Paulo, São Paulo, Brazil
- Institute for Investigation in Immunology (iii), INCT, São Paulo, Brazil
| | - Edecio Cunha-Neto
- Laboratory of Immunology, Heart Institute (InCor), School of Medicine, University of São Paulo, São Paulo, Brazil
- Division of Clinical Immunology and Allergy, School of Medicine, University of São Paulo, São Paulo, Brazil
- Institute for Investigation in Immunology (iii), INCT, São Paulo, Brazil
- * E-mail:
| |
Collapse
|
109
|
Does orchiectomy enhance the immune-stimulatory effects of melatonin during experimental Chagas’ disease? Res Vet Sci 2012; 93:819-25. [DOI: 10.1016/j.rvsc.2011.09.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 08/15/2011] [Accepted: 09/26/2011] [Indexed: 01/03/2023]
|
110
|
Congenital and oral transmission of American trypanosomiasis: an overview of physiopathogenic aspects. Parasitology 2012; 140:147-59. [PMID: 23010131 DOI: 10.1017/s0031182012001394] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Chagas disease or American trypanosomiasis is a pathology affecting about 8-11 million people in Mexico, Central America, and South America, more than 300 000 persons in the United States as well as an indeterminate number of people in other non-endemic countries such as USA, Spain, Canada and Switzerland. The aetiological agent is Trypanosoma cruzi, a protozoan transmitted by multiple routes; among them, congenital route emerges as one of the most important mechanisms of spreading Chagas disease worldwide even in non-endemic countries and the oral route as the responsible of multiple outbreaks of acute Chagas disease in regions where the vectorial route has been interrupted. The aim of this review is to illustrate the recent research and advances in host-pathogen interaction making a model of how the virulence factors of the parasite would interact with the physiology and immune system components of the placental barrier and gastrointestinal tract in order to establish a response against T. cruzi infection. This review also presents the epidemiological, clinical and diagnostic features of congenital and oral Chagas disease in order to update the reader about the emerging scenarios of Chagas disease transmission.
Collapse
|
111
|
Abstract
Chagas cardiomyopathy is the most severe and life-threatening manifestation of human Chagas disease--a 'neglected' tropical disease caused by the protozoan parasite Trypanosoma cruzi. The disease is endemic in all continental Latin American countries, but has become a worldwide problem because of migration of infected individuals to developed countries, mainly in Europe and North America. Chagas cardiomyopathy results from the combined effects of persistent parasitism, parasite-driven tissue inflammation, microvascular and neurogenic dysfunction, and autoimmune responses triggered by the infection. Clinical presentation varies widely according to the extent of myocardial damage, and manifests mainly as three basic syndromes that can coexist in an individual patient: heart failure, cardiac arrhythmia, and thromboembolism. NYHA functional class, left ventricular systolic function, and nonsustained ventricular tachycardia are important prognostic markers of the risk of death. Management of Chagas cardiomyopathy focuses on the treatment of the three main syndromes. The use of β-blockers in patients with Chagas disease and heart failure is safe, well tolerated, and should be encouraged. Most specialists and international institutions now recommend specific antitrypanosomal treatment of patients with chronic Chagas disease, even in the absence of evidence obtained from randomized clinical trials. Further research on the management of patients with Chagas cardiomyopathy is necessary.
Collapse
|
112
|
Monteiro WM, Magalhães LKC, de Sá ARN, Gomes ML, Toledo MJDO, Borges L, Pires I, de Oliveira Guerra JA, Silveira H, Barbosa MDGV. Trypanosoma cruzi IV causing outbreaks of acute Chagas disease and infections by different haplotypes in the Western Brazilian Amazonia. PLoS One 2012; 7:e41284. [PMID: 22848457 PMCID: PMC3405119 DOI: 10.1371/journal.pone.0041284] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 06/19/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Chagas disease is an emergent tropical disease in the Brazilian Amazon Region, with an increasing number of cases in recent decades. In this region, the sylvatic cycle of Trypanosoma cruzi transmission, which constitutes a reservoir of parasites that might be associated with specific molecular, epidemiological and clinical traits, has been little explored. The objective of this work is to genetically characterize stocks of T. cruzi from human cases, triatomines and reservoir mammals in the State of Amazonas, in the Western Brazilian Amazon. METHODOLOGY/PRINCIPAL FINDINGS We analyzed 96 T. cruzi samples from four municipalities in distant locations of the State of Amazonas. Molecular characterization of isolated parasites from cultures in LIT medium or directly from vectors or whole human blood was performed by PCR of the non-transcribed spacer of the mini-exon and of the 24 S alfa ribosomal RNA gene, RFLP and sequencing of the mitochondrial cytochrome c oxidase subunit II (COII) gene, and by sequencing of the glucose-phosphate isomerase gene. The T. cruzi parasites from two outbreaks of acute disease were all typed as TcIV. One of the outbreaks was triggered by several haplotypes of the same DTU. TcIV also occurred in isolated cases and in Rhodnius robustus. Incongruence between mitochondrial and nuclear phylogenies is likely to be indicative of historical genetic exchange events resulting in mitochondrial introgression between TcIII and TcIV DTUs from Western Brazilian Amazon. TcI predominated among triatomines and was the unique DTU infecting marsupials. CONCLUSION/SIGNIFICANCE DTU TcIV, rarely associated with human Chagas disease in other areas of the Amazon basin, is the major strain responsible for the human infections in the Western Brazilian Amazon, occurring in outbreaks as single or mixed infections by different haplotypes.
Collapse
Affiliation(s)
- Wuelton Marcelo Monteiro
- Tropical Medicine Foundation Dr. Heitor Vieira Dourado, Manaus, Amazonas, Brazil
- University of the State of Amazonas, Manaus, Amazonas, Brazil
- Federal University of Amazonas, Manaus, Amazonas, Brazil
| | - Laylah Kelre Costa Magalhães
- Tropical Medicine Foundation Dr. Heitor Vieira Dourado, Manaus, Amazonas, Brazil
- University of the State of Amazonas, Manaus, Amazonas, Brazil
| | | | | | | | - Lara Borges
- Instituto de Higiene e Medicina Tropical, Center for Malaria Studies, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Isa Pires
- Instituto de Higiene e Medicina Tropical, Center for Malaria Studies, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Jorge Augusto de Oliveira Guerra
- Tropical Medicine Foundation Dr. Heitor Vieira Dourado, Manaus, Amazonas, Brazil
- University of the State of Amazonas, Manaus, Amazonas, Brazil
| | - Henrique Silveira
- Tropical Medicine Foundation Dr. Heitor Vieira Dourado, Manaus, Amazonas, Brazil
- Instituto de Higiene e Medicina Tropical, Center for Malaria Studies, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Maria das Graças Vale Barbosa
- Tropical Medicine Foundation Dr. Heitor Vieira Dourado, Manaus, Amazonas, Brazil
- University of the State of Amazonas, Manaus, Amazonas, Brazil
- Nilton Lins University Center, Manaus, Amazonas, Brazil
| |
Collapse
|
113
|
Coura JR, Borges-Pereira J. Chagas disease. What is known and what should be improved: a systemic review. Rev Soc Bras Med Trop 2012; 45:286-96. [PMID: 22760123 DOI: 10.1590/s0037-86822012000300002] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 05/12/2012] [Indexed: 11/22/2022] Open
Abstract
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.
Collapse
Affiliation(s)
- José Rodrigues Coura
- Laboratório de Doenças Parasitárias, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil.
| | | |
Collapse
|
114
|
Santos FM, Lima WG, Gravel AS, Martins TAF, Talvani A, Torres RM, Bahia MT. Cardiomyopathy prognosis after benznidazole treatment in chronic canine Chagas' disease. J Antimicrob Chemother 2012; 67:1987-95. [DOI: 10.1093/jac/dks135] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
115
|
Guedes PMM, Gutierrez FRS, Silva GK, Dellalibera-Joviliano R, Rodrigues GJ, Bendhack LM, Rassi A, Rassi A, Schmidt A, Maciel BC, Marin Neto JA, Silva JS. Deficient regulatory T cell activity and low frequency of IL-17-producing T cells correlate with the extent of cardiomyopathy in human Chagas' disease. PLoS Negl Trop Dis 2012; 6:e1630. [PMID: 22545173 PMCID: PMC3335880 DOI: 10.1371/journal.pntd.0001630] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Accepted: 03/09/2012] [Indexed: 11/23/2022] Open
Abstract
Background Myocardium damage during Chagas' disease results from the immunological imbalance between pro- and production of anti-inflammatory cytokines and has been explained based on the Th1–Th2 dichotomy and regulatory T cell activity. Recently, we demonstrated that IL-17 produced during experimental T. cruzi infection regulates Th1 cells differentiation and parasite induced myocarditis. Here, we investigated the role of IL-17 and regulatory T cell during human Chagas' disease. Methodology/Principal Findings First, we observed CD4+IL-17+ T cells in culture of peripheral blood mononuclear cells (PBMC) from Chagas' disease patients and we evaluated Th1, Th2, Th17 cytokine profile production in the PBMC cells from Chagas' disease patients (cardiomyopathy-free, and with mild, moderate or severe cardiomyopathy) cultured with T. cruzi antigen. Cultures of PBMC from patients with moderate and severe cardiomyopathy produced high levels of TNF-α, IFN-γ and low levels of IL-10, when compared to mild cardiomyopathy or cardiomyopathy-free patients. Flow cytometry analysis showed higher CD4+IL-17+ cells in PBMC cultured from patients without or with mild cardiomyopathy, in comparison to patients with moderate or severe cardiomyopathy. We then analyzed the presence and function of regulatory T cells in all patients. All groups of Chagas' disease patients presented the same frequency of CD4+CD25+ regulatory T cells. However, CD4+CD25+ T cells from patients with mild cardiomyopathy or cardiomyopathy-free showed higher suppressive activity than those with moderate and severe cardiomyopathy. IFN-γ levels during chronic Chagas' disease are inversely correlated to the LVEF (P = 0.007, r = −0.614), while regulatory T cell activity is directly correlated with LVEF (P = 0.022, r = 0.500). Conclusion/Significance These results indicate that reduced production of the cytokines IL-10 and IL-17 in association with high levels of IFN-γ and TNF-α is correlated with the severity of the Chagas' disease cardiomyopathy, and the immunological imbalance observed may be causally related with deficient suppressor activity of regulatory T cells that controls myocardial inflammation. Dilated cardiomyopathy is one of the clinical forms of Chagas' disease (CD) after the infection caused by the parasite Trypanosoma cruzi. Even though strategies adopted in most Latin-American countries in the last decades towards vector control have been effective in reducing the incidence of CD, active transmission is maintained in some regions, and secondary prevention approaches are still required for the infected patients, mostly because the specific anti-parasitic medications are toxic and perhaps of limited efficacy in chronically infected individuals. Moreover, there are no markers to predict the risk of developing dilated cardiomyopathy in asymptomatic, chronically infected patients, although the failure in the mechanisms that control the immune response can be involved in the development of Chagas' heart disease. In this study we show that preserved activity of regulatory T cells and the production of the cytokine IL-17 are connected with a more benign evolution of the disease, which brings a new understanding on the mechanisms associated with progression of CD.
Collapse
Affiliation(s)
- Paulo Marcos Matta Guedes
- Department of Microbiology and Parasitology, Federal University of Rio Grande do Norte, Natal, Brazil
- Department of Biochemistry and Immunology, School of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
| | - Fredy Roberto Salazar Gutierrez
- Department of Biochemistry and Immunology, School of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
- School of Medicine, University Antonio Narino, Bogota, Colombia
| | - Grace Kelly Silva
- Department of Biochemistry and Immunology, School of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
| | - Renata Dellalibera-Joviliano
- Integrated Faculty Fafibe and Department of Surgery and Anatomy, School of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
| | - Gerson Jhonatan Rodrigues
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
| | - Lusiane Maria Bendhack
- Department of Physical and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
| | - Anis Rassi
- Division of Cardiology, Anis Rassi Hospital, Goiânia, Brazil
| | - Anis Rassi
- Division of Cardiology, Anis Rassi Hospital, Goiânia, Brazil
| | - André Schmidt
- Division of Cardiology, School of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
| | - Benedito Carlos Maciel
- Division of Cardiology, School of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
| | - José Antonio Marin Neto
- Division of Cardiology, School of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
| | - João Santana Silva
- Department of Biochemistry and Immunology, School of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
- * E-mail:
| |
Collapse
|
116
|
Flórez O, Martín J, González CI. Genetic variants in the chemokines and chemokine receptors in Chagas disease. Hum Immunol 2012; 73:852-8. [PMID: 22537745 DOI: 10.1016/j.humimm.2012.04.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 04/15/2012] [Accepted: 04/16/2012] [Indexed: 01/30/2023]
Abstract
Clinical symptoms of Chagas' disease occur in 30% of the individuals infected with Trypanosoma cruzi and are characterised by heart inflammation and dysfunction. Chemokines and chemokine receptors control the migration of leukocytes during the inflammatory process and are involved in the modulation of Th1 or Th2 responses. To determine their influence, we investigated the possible role of CCL5/RANTES and CXCL8/IL8 chemokines, and CCR2 and CCR5 chemokines receptors cluster gene polymorphisms with the development of chagasic cardiomyopathy. Our study included 260 Chagas seropositive individuals (asymptomatic, n=130; cardiomyopathic, n=130) from an endemic area of Colombia. Genotyping was performed by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) and TaqMan SNP genotyping assay. We found statistically significant differences in the distribution of the CCR5 human haplogroup (HH)-A (p=0.027; OR=3.78, 95% CI=1.04-13.72). Moreover, we found that the CCR5-2733 G and CCR5-2554 T alleles are associated, respectively, with a reduced risk of susceptibility and severity to develop chagasic cardiomyopathy. No other associations were found to be significant for the other polymorphisms analysed in the CCR5, CCR2, CCL5/RANTES and CXCL8/IL8 genes. Our data suggest that the analysed chemokines and chemokine receptor genetic variants have a weak but important association with the development of chagasic cardiomyopathy in the population under study.
Collapse
Affiliation(s)
- Oscar Flórez
- Grupo de Inmunología y Epidemiología Molecular, GIEM, Facultad de Salud, Universidad Industrial de Santander, Bucaramanga, Colombia
| | | | | |
Collapse
|
117
|
Silva LC, Vicentine FPP, Herbella FAM. High resolution manometric findings in patients with Chagas' disease esophagopathy. ASIAN PAC J TROP MED 2012; 5:110-2. [PMID: 22221752 DOI: 10.1016/s1995-7645(12)60006-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 07/11/2011] [Accepted: 10/15/2011] [Indexed: 11/28/2022] Open
Abstract
OBJECTIVE To describe high resolution manometry features of a population of symptomatic patients with Chagas' disease esophagopathy (CDE). METHODS Sixteen symptomatic dysphagic patients with CDE [mean age (54.81±13.43) years, 10 women] were included in this study. All patients underwent a high resolution manometry. RESULTS Mean lower esophageal sphincter (LES) extension was (3.02±1.17) cm with a mean basal pressure of (15.25±7.00) mmHg. Residual pressure was (14.31±9.19) mmHg. Aperistalsis was found in all 16 patients. Achalasia with minimal esophageal pressurization (type 1) was present in 25% of patients and achalasia with esophageal compression (type 2) in 75%, according to the Chicago Classification. Upper esophageal sphincter (UES) mean basal pressure was (97.96±54.22) mmHg with a residual pressure of (12.95±6.42) mmHg. CONCLUSIONS Our results show that LES was hypotensive or normotensive in the majority of the patients. Impaired relaxation was found in a minority of our patients. Aperistalsis was seen in 100% of patients. UES had impaired relaxation in a significant number of patients. Further clinical study is needed to investigate whether manometric features can predict outcomes following the studies of idiopathic achalasia.
Collapse
Affiliation(s)
- Luciana C Silva
- Department of Surgery, Escola Paulista de Medicina, Federal University of Sao Paulo, Sao Paulo, Brazil
| | | | | |
Collapse
|
118
|
Coura JR, Junqueira ACV. Risks of endemicity, morbidity and perspectives regarding the control of Chagas disease in the Amazon Region. Mem Inst Oswaldo Cruz 2012; 107:145-54. [DOI: 10.1590/s0074-02762012000200001] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 02/01/2011] [Indexed: 11/21/2022] Open
|
119
|
Custer B, Agapova M, Bruhn R, Cusick R, Kamel H, Tomasulo P, Biswas H, Tobler L, Lee TH, Caglioti S, Busch M. Epidemiologic and laboratory findings from 3 years of testing United States blood donors for Trypanosoma cruzi. Transfusion 2012; 52:1901-11. [DOI: 10.1111/j.1537-2995.2012.03569.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
120
|
Martins-Melo FR, Alencar CH, Ramos AN, Heukelbach J. Epidemiology of mortality related to Chagas' disease in Brazil, 1999-2007. PLoS Negl Trop Dis 2012; 6:e1508. [PMID: 22348163 PMCID: PMC3279342 DOI: 10.1371/journal.pntd.0001508] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 12/19/2011] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Chagas' disease is an important neglected public health problem in many Latin American countries, but population-based epidemiological data are scarce. Here we present a nationwide analysis on Chagas-associated mortality, and risk factors for death from this disease. METHODOLOGY/PRINCIPAL FINDINGS We analyzed all death certificates of individuals who died between 1999 and 2007 in Brazil, based on the nationwide Mortality Information System (a total of 243 data sets with about 9 million entries). Chagas' disease was mentioned in 53,930 (0.6%) of death certificates, with 44,537 (82.6%) as an underlying cause and 9,387 (17.4%) as an associated cause of death. Acute Chagas' disease was responsible for 2.8% of deaths. The mean standardized mortality rate was 3.36/100.000 inhabitants/year. Nationwide standardized mortality rates reduced gradually, from 3.78 (1999) to 2.78 (2007) deaths/year per 100,000 inhabitants (-26.4%). Standardized mortality rates were highest in the Central-West region, ranging from 15.23 in 1999 to 9.46 in 2007 (-37.9%), with a significant negative linear trend (p = 0.001; R(2) = 82%). Proportional mortality considering multiple causes of death was 0.60%. The Central-West showed highest proportional mortality among regions (2.17%), with a significant linear negative trend, from 2.28% to 1.90% (-19.5%; p = 0.001; R(2) = 84%). There was a significant increase in the Northeast of 38.5% (p = 0.006; R(2) = 82%). Bivariable analysis on risk factors for death from Chagas' disease showed highest relative risks (RR) in older age groups (RR: 10.03; 95% CI: 9.40-10.70; p<0.001) and those residing in the Central-West region (RR: 15.01; 95% CI: 3.90-16.22; p<0.001). In logistic regression analysis, age ≥30 years (adjusted OR: 10.81; 95% CI: 10.03-10.65; p<0.001) and residence in one of the three high risk states Minas Gerais, Goiás or the Federal District (adjusted OR: 5.12; 95% CI: 5.03-5.22, p<0.001) maintained important independent risk factors for death by Chagas' disease. CONCLUSIONS/SIGNIFICANCE This is the first nationwide population-based study on Chagas mortality in Brazil, considering multiple causes of death. Despite the decline of mortality associated with Chagas' disease in Brazil, the disease remains a serious public health problem with marked regional differences.
Collapse
Affiliation(s)
| | - Carlos Henrique Alencar
- Department of Community Health, School of Medicine, Federal University of Ceará, Fortaleza, Brazil
| | - Alberto Novaes Ramos
- Department of Community Health, School of Medicine, Federal University of Ceará, Fortaleza, Brazil
| | - Jorg Heukelbach
- Department of Community Health, School of Medicine, Federal University of Ceará, Fortaleza, Brazil
- School of Public Health, Tropical Medicine and Rehabilitation Sciences, Anton Breinl Centre for Public Health and Tropical Medicine, James Cook University, Townsville, Australia
| |
Collapse
|
121
|
Coutinho CF, Souza-Santos R, Lima MM. Combining geospatial analysis and exploratory study of triatomine ecology to evaluate the risk of Chagas disease in a rural locality. Acta Trop 2012; 121:30-3. [PMID: 22015423 DOI: 10.1016/j.actatropica.2011.10.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 09/20/2011] [Accepted: 10/06/2011] [Indexed: 10/16/2022]
Abstract
The use of geo-spatial analysis to anticipate transmission risk for Chagas disease was tested in a rural area of northeast Brazil in an approach that combined geo-referencing and exploratory study of triatomine infestation, including related elements such as the environment and hosts. A total of 617 triatomine specimens, mainly Triatoma brasiliensis, were captured, exhibiting an overall T. cruzi positivity of 44.4%. Layer analysis indicated that the greatest transmission risk to man was associated with woodpiles. The buffer area generated contained uninhabited dwellings teeming with bats and positive bugs. Other locations outside the buffer, near uninhabited dwellings housing cattle, contained colonies of triatomines harboring T. cruzi. The results indicate that local residents' activities themselves favor the development of risk areas for Chagas disease.
Collapse
|
122
|
Dixit SS, Upadhayaya RS, Chattopadhyaya J. New parasite inhibitors encompassing novel conformationally-locked 5′-acyl sulfamoyl adenosines. Org Biomol Chem 2012; 10:6121-9. [DOI: 10.1039/c2ob25879j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
123
|
Zingales B, Miles MA, Campbell DA, Tibayrenc M, Macedo AM, Teixeira MMG, Schijman AG, Llewellyn MS, Lages-Silva E, Machado CR, Andrade SG, Sturm NR. The revised Trypanosoma cruzi subspecific nomenclature: rationale, epidemiological relevance and research applications. INFECTION GENETICS AND EVOLUTION 2011; 12:240-53. [PMID: 22226704 DOI: 10.1016/j.meegid.2011.12.009] [Citation(s) in RCA: 610] [Impact Index Per Article: 46.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 12/16/2011] [Indexed: 10/14/2022]
Abstract
The protozoan Trypanosoma cruzi, its mammalian reservoirs, and vectors have existed in nature for millions of years. The human infection, named Chagas disease, is a major public health problem for Latin America. T. cruzi is genetically highly diverse and the understanding of the population structure of this parasite is critical because of the links to transmission cycles and disease. At present, T. cruzi is partitioned into six discrete typing units (DTUs), TcI-TcVI. Here we focus on the current status of taxonomy-related areas such as population structure, phylogeographical and eco-epidemiological features, and the correlation of DTU with natural and experimental infection. We also summarize methods for DTU genotyping, available for widespread use in endemic areas. For the immediate future multilocus sequence typing is likely to be the gold standard for population studies. We conclude that greater advances in our knowledge on pathogenic and epidemiological features of these parasites are expected in the coming decade through the comparative analysis of the genomes from isolates of various DTUs.
Collapse
Affiliation(s)
- Bianca Zingales
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Avenida Professor Lineu Prestes 748, 05508-000 São Paulo, SP, Brazil.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
124
|
Chuenkova MV, Pereiraperrin M. Neurodegeneration and neuroregeneration in Chagas disease. ADVANCES IN PARASITOLOGY 2011; 76:195-233. [PMID: 21884893 DOI: 10.1016/b978-0-12-385895-5.00009-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Autonomic dysfunction plays a significant role in the development of chronic Chagas disease (CD). Destruction of cardiac parasympathetic ganglia can underlie arrhythmia and heart failure, while lesions of enteric neurons in the intestinal plexuses are a direct cause of aperistalsis and megasyndromes. Neuropathology is generated by acute infection when the parasite, though not directly damaging to neuronal cells, elicits immune reactions that can become cytotoxic, inducing oxidative stress and neurodegeneration. Anti-neuronal autoimmunity may further contribute to neuropathology. Much less clear is the mechanism of subsequent neuronal regeneration in patients that survive acute infection. Morphological and functional recovery of the peripheral neurons in these patients correlates with the absence of CD clinical symptoms, while persistent neuronal deficiency is observed for the symptomatic group. The discovery that Trypanosoma cruzi trans-sialidase can moonlight as a parasite-derived neurotrophic factor (PDNF) suggests that the parasite might influence the balance between neuronal degeneration and regeneration. PDNF functionally mimics mammalian neurotrophic factors in that it binds and activates neurotrophin Trk tyrosine kinase receptors, a mechanism which prevents neurodegeneration. PDNF binding to Trk receptors triggers PI3K/Akt/GSK-3β and MAPK/Erk/CREB signalling cascades which in neurons translates into resistance to oxidative and nutritional stress, and inhibition of apoptosis, whereas in the cytoplasm of infected cells, PDNF represents a substrate-activator of the host Akt kinase, enhancing host-cell survival until completion of the intracellular cycle of the parasite. Such dual activity of PDNF provides sustained activation of survival mechanisms which, while prolonging parasite persistence in host tissues, can underlie distinct outcomes of CD.
Collapse
Affiliation(s)
- Marina V Chuenkova
- Department of Pathology and Sackler School of Graduate Students, Tufts University School of Medicine, Boston, Massachusetts, USA
| | | |
Collapse
|
125
|
Nissapatorn V, Sawangjaroen N. Parasitic infections in HIV infected individuals: diagnostic & therapeutic challenges. Indian J Med Res 2011; 134:878-97. [PMID: 22310820 PMCID: PMC3284096 DOI: 10.4103/0971-5916.92633] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Indexed: 12/30/2022] Open
Abstract
After 30 years of the human immunodeficiency virus (HIV) epidemic, parasites have been one of the most common opportunistic infections (OIs) and one of the most frequent causes of morbidity and mortality associated with HIV-infected patients. Due to severe immunosuppression, enteric parasitic pathogens in general are emerging and are OIs capable of causing diarrhoeal disease associated with HIV. Of these, Cryptosporidium parvum and Isospora belli are the two most common intestinal protozoan parasites and pose a public health problem in acquired immunodeficiency syndrome (AIDS) patients. These are the only two enteric protozoan parasites that remain in the case definition of AIDS till today. Leishmaniasis, strongyloidiasis and toxoplasmosis are the three main opportunistic causes of systemic involvements reported in HIV-infected patients. Of these, toxoplasmosis is the most important parasitic infection associated with the central nervous system. Due to its complexity in nature, toxoplasmosis is the only parasitic disease capable of not only causing focal but also disseminated forms and it has been included in AIDS-defining illnesses (ADI) ever since. With the introduction of highly active anti-retroviral therapy (HAART), cryptosporidiosis, leishmaniasis, schistosomiasis, strongyloidiasis, and toxoplasmosis are among parasitic diseases reported in association with immune reconstitution inflammatory syndrome (IRIS). This review addresses various aspects of parasitic infections in term of clinical, diagnostic and therapeutic challenges associated with HIV-infection.
Collapse
Affiliation(s)
- Veeranoot Nissapatorn
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
| | | |
Collapse
|
126
|
Cabrera G, Barría C, Fernández C, Sepúlveda S, Valenzuela L, Kemmerling U, Galanti N. DNA repair BER pathway inhibition increases cell death caused by oxidative DNA damage in Trypanosoma cruzi. J Cell Biochem 2011; 112:2189-99. [PMID: 21480362 DOI: 10.1002/jcb.23138] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Trypanosoma cruzi, a parasitic protozoan, is the etiological agent of Chagas disease, an endemic and neglected pathology in Latin America. It presents a life cycle that involves a hematophagous insect and man as well as domestic and wild mammals. The parasitic infection is not eliminated by the immune system of mammals; thus, the vertebrate host serves as a parasite reservoir. Additionally, chronic processes leading to dysfunction of the cardiac and digestive systems are observed. To establish a chronic infection some parasites should resist the oxidative damage to its DNA exerted by oxygen and nitrogen free radicals (ROS/RNS) generated in host cells. Till date there are no reports directly showing oxidative DNA damage and repair in T. cruzi. We establish that ROS/RNS generate nuclear and kinetoplastid DNA damage in T. cruzi that may be partially repaired by the parasite. Furthermore, we determined that both oxidative agents diminish T. cruzi cell viability. This effect is significantly augmented in parasites subsequently incubated with methoxyamine, a DNA base excision repair (BER) pathway inhibitor, strongly suggesting that the maintenance of T. cruzi viability is a consequence of DNA repair mechanisms.
Collapse
Affiliation(s)
- G Cabrera
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
| | | | | | | | | | | | | |
Collapse
|
127
|
Duaso J, Yanez E, Castillo C, Galanti N, Cabrera G, Corral G, Maya JD, Zulantay I, Apt W, Kemmerling U. Reorganization of extracellular matrix in placentas from women with asymptomatic chagas disease: mechanism of parasite invasion or local placental defense? J Trop Med 2011; 2012:758357. [PMID: 22007243 PMCID: PMC3189612 DOI: 10.1155/2012/758357] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 08/08/2011] [Indexed: 11/11/2022] Open
Abstract
Chagas disease, produced by the protozoan Trypanosoma cruzi (T. cruzi), is one of the most frequent endemic diseases in Latin America. In spite the fact that in the past few years T. cruzi congenital transmission has become of epidemiological importance, studies about this mechanism of infection are scarce. In order to explore some morphological aspects of this infection in the placenta, we analyzed placentas from T. cruzi-infected mothers by immunohistochemical and histochemical methods. Infection in mothers, newborns, and placentas was confirmed by PCR and by immunofluorescence in the placenta. T. cruzi-infected placentas present destruction of the syncytiotrophoblast and villous stroma, selective disorganization of the basal lamina, and disorganization of collagen I in villous stroma. Our results suggest that the parasite induces reorganization of this tissue component and in this way may regulate both inflammatory and immune responses in the host. Changes in the ECM of placental tissues, together with the immunological status of mother and fetus, and parasite load may determine the probability of congenital transmission of T. cruzi.
Collapse
Affiliation(s)
- Juan Duaso
- Programa de Anatomía y Biología del Desarrollo, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia, Región Metropolitana, 1027 Santiago de Chile, Chile
| | - Erika Yanez
- Programa de Anatomía y Biología del Desarrollo, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia, Región Metropolitana, 1027 Santiago de Chile, Chile
| | - Christian Castillo
- Programa de Anatomía y Biología del Desarrollo, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia, Región Metropolitana, 1027 Santiago de Chile, Chile
| | - Norbel Galanti
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia, Región Metropolitana, 1027 Santiago de Chile, Chile
| | - Gonzalo Cabrera
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia, Región Metropolitana, 1027 Santiago de Chile, Chile
| | - Gabriela Corral
- Servicio de Obstetricia y Ginecología, Hospital de Illapel, Independencia, IV Región, 0512 Illapel, Chile
| | - Juan Diego Maya
- Programa de Farmacología Molecular y Clínica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia, Región Metropolitana, 1027 Santiago de Chile, Chile
| | - Inés Zulantay
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia, Región Metropolitana, 1027 Santiago de Chile, Chile
| | - Werner Apt
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia, Región Metropolitana, 1027 Santiago de Chile, Chile
| | - Ulrike Kemmerling
- Programa de Anatomía y Biología del Desarrollo, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia, Región Metropolitana, 1027 Santiago de Chile, Chile
- Departamento de Estomatología, Facultad de Ciencias de la Salud, Universidad de Talca, Avenida Lircay s/n, VII Región, 3460000 Talca, Chile
| |
Collapse
|
128
|
Coura JR, Borges-Pereira J. Chronic phase of Chagas disease: why should it be treated? A comprehensive review. Mem Inst Oswaldo Cruz 2011; 106:641-5. [DOI: 10.1590/s0074-02762011000600001] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Accepted: 08/23/2011] [Indexed: 12/13/2022] Open
|
129
|
|
130
|
Marini V, Moretti E, Bermejo D, Basso B. Vaccination with Trypanosoma rangeli modulates the profiles of immunoglobulins and IL-6 at local and systemic levels in the early phase of Trypanosoma cruzi experimental infection. Mem Inst Oswaldo Cruz 2011; 106:32-7. [PMID: 21340352 DOI: 10.1590/s0074-02762011000100005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Accepted: 12/08/2010] [Indexed: 12/17/2022] Open
Abstract
In America, there are two species of Trypanosoma that can infect humans: Trypanosoma cruzi, which is responsible for Chagas disease and Trypanosoma rangeli, which is not pathogenic. We have developed a model of vaccination in mice with T. rangeli epimastigotes that protects against T. cruzi infection. The goal of this work was to study the pattern of specific immunoglobulins in the peritoneum (the site of infection) and in the sera of mice immunized with T. rangeli before and after challenge with T. cruzi. Additionally, we studied the effects triggered by antigen-antibodies binding and the levels of key cytokines involved in the humoral response, such as IL-4, IL-5 and IL-6. The immunization triggered the production of antibodies reactive with T. cruzi in peritoneal fluid (PF) and in serum, mainly IgG1 and, to a lesser magnitude, IgG2. Only immunized mice developed specific IgG3 antibodies in their peritoneal cavities. Antibodies were able to bind to the surface of the parasites and agglutinate them. Among the cytokines studied, IL-6 was elevated in PF during early infection, with higher levels in non-immunized-infected mice. The results indicate that T. rangeli vaccination against T. cruzi infection triggers a high production of specific IgG isotypes in PF and sera before infection and modulates the levels of IL-6 in PF in the early periods of infection.
Collapse
Affiliation(s)
- Vanina Marini
- Laboratorio de la Coordinación Nacional de Control de Vectores, Córdoba, Argentina
| | | | | | | |
Collapse
|
131
|
de Castro SL, Batista DGJ, Batista MM, Batista W, Daliry A, de Souza EM, Menna-Barreto RFS, Oliveira GM, Salomão K, Silva CF, Silva PB, Soeiro MDNC. Experimental Chemotherapy for Chagas Disease: A Morphological, Biochemical, and Proteomic Overview of Potential Trypanosoma cruzi Targets of Amidines Derivatives and Naphthoquinones. Mol Biol Int 2011; 2011:306928. [PMID: 22091400 PMCID: PMC3195292 DOI: 10.4061/2011/306928] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Revised: 02/25/2011] [Accepted: 03/21/2011] [Indexed: 01/31/2023] Open
Abstract
Chagas disease (CD), caused by Trypanosoma cruzi, affects approximately eight million individuals in Latin America and is emerging in nonendemic areas due to the globalisation of immigration and nonvectorial transmission routes. Although CD represents an important public health problem, resulting in high morbidity and considerable mortality rates, few investments have been allocated towards developing novel anti-T. cruzi agents. The available therapy for CD is based on two nitro derivatives (benznidazole (Bz) and nifurtimox (Nf)) developed more than four decades ago. Both are far from ideal due to substantial secondary side effects, limited efficacy against different parasite isolates, long-term therapy, and their well-known poor activity in the late chronic phase. These drawbacks justify the urgent need to identify better drugs to treat chagasic patients. Although several classes of natural and synthetic compounds have been reported to act in vitro and in vivo on T. cruzi, since the introduction of Bz and Nf, only a few drugs, such as allopurinol and a few sterol inhibitors, have moved to clinical trials. This reflects, at least in part, the absence of well-established universal protocols to screen and compare drug activity. In addition, a large number of in vitro studies have been conducted using only epimastigotes and trypomastigotes instead of evaluating compounds' activities against intracellular amastigotes, which are the reproductive forms in the vertebrate host and are thus an important determinant in the selection and identification of effective compounds for further in vivo analysis. In addition, due to pharmacokinetics and absorption, distribution, metabolism, and excretion characteristics, several compounds that were promising in vitro have not been as effective as Nf or Bz in animal models of T. cruzi infection. In the last two decades, our team has collaborated with different medicinal chemistry groups to develop preclinical studies for CD and investigate the in vitro and in vivo efficacy, toxicity, selectivity, and parasite targets of different classes of natural and synthetic compounds. Some of these results will be briefly presented, focusing primarily on diamidines and related compounds and naphthoquinone derivatives that showed the most promising efficacy against T. cruzi.
Collapse
Affiliation(s)
- Solange L. de Castro
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Denise G. J. Batista
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Marcos M. Batista
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Wanderson Batista
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Anissa Daliry
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Elen M. de Souza
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Rubem F. S. Menna-Barreto
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Gabriel M. Oliveira
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Kelly Salomão
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Cristiane F. Silva
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Patricia B. Silva
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Maria de Nazaré C. Soeiro
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| |
Collapse
|
132
|
Malafaia G, Talvani A. Nutritional Status Driving Infection by Trypanosoma cruzi: Lessons from Experimental Animals. J Trop Med 2011; 2011:981879. [PMID: 21577255 PMCID: PMC3090609 DOI: 10.1155/2011/981879] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 11/30/2010] [Accepted: 02/17/2011] [Indexed: 01/21/2023] Open
Abstract
This paper reviews the scientific knowledge about protein-energy and micronutrient malnutrition in the context of Chagas disease, especially in experimental models. The search of articles was conducted using the electronic databases of SciELO (Scientific Electronic Library Online), PubMed and MEDLINE published between 1960 and March 2010. It was possible to verify that nutritional deficiencies (protein-energy malnutrition and micronutrient malnutrition) exert a direct effect on the infection by T. cruzi. However, little is known about the immunological mechanisms involved in the relationship "nutritional deficiencies and infection by T. cruzi". A hundred years after the discovery of Chagas disease many aspects of this illness still require clarification, including the effects of nutritional deficiencies on immune and pathological mechanisms of T. cruzi infection.
Collapse
Affiliation(s)
- Guilherme Malafaia
- Departamento de Ciências Biológicas, Núcleo de Pesquisas e Estudos Ambientais e Biológicos, Instituto Federal de Educação, Ciência e Tecnologia Goiano—Campus Urutaí, Rodovia Geraldo Silva Nascimento km 2.5, 75790-000 Urutaí, GO, Brazil
| | - André Talvani
- Laboratório de Doença de Chagas, Programa de Pós-Graduação em Ciências Biológicas, Núcleo de Pesquisa em Ciências Biológicas (NUPEB), Universidade Federal de Ouro Preto (UFOP), 35400-000 Ouro Preto, MG, Brazil
| |
Collapse
|
133
|
Moretti E, Castro I, Franceschi C, Basso B. Chagas disease: serological and electrocardiographic studies in Wichi and Creole communities of Misión Nueva Pompeya, Chaco, Argentina. Mem Inst Oswaldo Cruz 2011; 105:621-7. [PMID: 20835607 DOI: 10.1590/s0074-02762010000500004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 04/13/2010] [Indexed: 11/22/2022] Open
Abstract
Chagas disease, which is caused by Trypanosoma cruzi, affects nearly 16 million people in Latin America and causes 75-90 million people to be at risk of infection. The disease is urbanizing and globalizing due to frequent migrations. There are regions of high prevalence of infection, including the north-eastern provinces of Argentina and the entire phytogeographic region known as the Gran Chaco. In the province of Chaco, Argentina, there are places inhabited by native populations such as the Wichi and Toba communities, among others. Many Creole populations resulting from miscegenation with European colonists and immigrants coexist within these communities. It has been widely accepted that in the chronic phase of the disease, between 25-30% of individuals develop some form of cardiac disease, with the right bundle-branch block being the most typical condition described so far. The aim of this work was to study the prevalence of Chagas infection and its electrocardiographic profile in the Wichi and Creole populations of Misión Nueva Pompeya, in the area known as Monte Impenetrable in Chaco, to determine the prevalence and the pattern of heart diseases produced by Chagas disease in this region.
Collapse
Affiliation(s)
- Edgardo Moretti
- Facultad de Ciencias Médicas, Universidad Nacional de Córdoba and Coordinación Nacional de Control de Vectores, Córdoba, Argentina.
| | | | | | | |
Collapse
|
134
|
Soeiro MDNC, de Castro SL. Screening of Potential anti-Trypanosoma cruzi Candidates: In Vitro and In Vivo Studies. THE OPEN MEDICINAL CHEMISTRY JOURNAL 2011; 5:21-30. [PMID: 21629508 PMCID: PMC3103897 DOI: 10.2174/1874104501105010021] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Revised: 04/21/2010] [Accepted: 05/28/2010] [Indexed: 01/21/2023]
Abstract
Chagas disease (CD), caused by the intracellular protozoan Trypanosoma cruzi, is a parasitic illness endemic in Latin America. In the centennial after CD discovery by Carlos Chagas (1909), although it still represents an important public health problem in these affected areas, the existing chemotherapy, based on benznidazole and nifurtimox (both introduced more than four decades ago), is far from being considered ideal due to substantial toxicity, variable effect on different parasite stocks and well-known poor activity on the chronic phase. CD is considered one of the major "neglected" diseases of the world, as commercial incentives are very limited to guarantee investments for developing and discovering novel drugs. In this context, our group has been pursuing, over the last years, the efficacy, selectivity, toxicity, cellular targets and mechanisms of action of new potential anti-T. cruzi candidates screened from an in-house compound library of different research groups in the area of medicinal chemistry. A brief review regarding these studies will be discussed, mainly related to the effect on T. cruzi of (i) diamidines and related compounds, (ii) natural naphthoquinone derivatives, and (iii) megazol derivatives.
Collapse
Affiliation(s)
| | - Solange Lisboa de Castro
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, 21040-900, Brazil
| |
Collapse
|
135
|
Genotype variation of Trypanosoma cruzi isolates from different Brazilian biomes. Exp Parasitol 2011; 127:308-12. [DOI: 10.1016/j.exppara.2010.07.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Revised: 07/11/2010] [Accepted: 07/20/2010] [Indexed: 11/24/2022]
|
136
|
Lee BY, Bacon KM, Connor DL, Willig AM, Bailey RR. The potential economic value of a Trypanosoma cruzi (Chagas disease) vaccine in Latin America. PLoS Negl Trop Dis 2010; 4:e916. [PMID: 21179503 PMCID: PMC3001903 DOI: 10.1371/journal.pntd.0000916] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Accepted: 11/15/2010] [Indexed: 11/18/2022] Open
Abstract
Background Chagas disease, caused by the parasite Trypanosoma cruzi (T. cruzi), is the leading etiology of non-ischemic heart disease worldwide, with Latin America bearing the majority of the burden. This substantial burden and the limitations of current interventions have motivated efforts to develop a vaccine against T. cruzi. Methodology/Principal Findings We constructed a decision analytic Markov computer simulation model to assess the potential economic value of a T. cruzi vaccine in Latin America from the societal perspective. Each simulation run calculated the incremental cost-effectiveness ratio (ICER), or the cost per disability-adjusted life year (DALY) avoided, of vaccination. Sensitivity analyses evaluated the impact of varying key model parameters such as vaccine cost (range: $0.50–$200), vaccine efficacy (range: 25%–75%), the cost of acute-phase drug treatment (range: $10–$150 to account for variations in acute-phase treatment regimens), and risk of infection (range: 1%–20%). Additional analyses determined the incremental cost of vaccinating an individual and the cost per averted congestive heart failure case. Vaccination was considered highly cost-effective when the ICER was ≤1 times the GDP/capita, still cost-effective when the ICER was between 1 and 3 times the GDP/capita, and not cost-effective when the ICER was >3 times the GDP/capita. Our results showed vaccination to be very cost-effective and often economically dominant (i.e., saving costs as well providing health benefits) for a wide range of scenarios, e.g., even when risk of infection was as low as 1% and vaccine efficacy was as low as 25%. Vaccinating an individual could likely provide net cost savings that rise substantially as risk of infection or vaccine efficacy increase. Conclusions/Significance Results indicate that a T. cruzi vaccine could provide substantial economic benefit, depending on the cost of the vaccine, and support continued efforts to develop a human vaccine. The substantial burden of Chagas disease, especially in Latin America, and the limitations of currently available treatment and control strategies have motivated the development of a Trypanosoma cruzi (T. cruzi) vaccine. Evaluating a vaccine's potential economic value early in its development can answer important questions while the vaccine's key characteristics (e.g., vaccine efficacy targets, price points, and target population) can still be altered. This can assist vaccine scientists, manufacturers, policy makers, and other decision makers in the development and implementation of the vaccine. We developed a computational economic model to determine the cost-effectiveness of introducing a T. cruzi vaccine in Latin America. Our results showed vaccination to be very cost-effective, in many cases providing both cost savings and health benefits, even at low infection risk and vaccine efficacy. Moreover, our study suggests that a vaccine may actually “pay for itself”, as even a relatively higher priced vaccine will generate net cost savings for a purchaser (e.g., a country's ministry of health). These findings support continued investments in and efforts toward the development of a human T. cruzi vaccine.
Collapse
Affiliation(s)
- Bruce Y Lee
- Public Health Computational and Operations Research, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
| | | | | | | | | |
Collapse
|
137
|
Studies toward the structural optimization of novel thiazolylhydrazone-based potent antitrypanosomal agents. Bioorg Med Chem 2010; 18:7826-35. [DOI: 10.1016/j.bmc.2010.09.056] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 09/16/2010] [Accepted: 09/22/2010] [Indexed: 11/24/2022]
|
138
|
Capriles PVSZ, Guimarães ACR, Otto TD, Miranda AB, Dardenne LE, Degrave WM. Structural modelling and comparative analysis of homologous, analogous and specific proteins from Trypanosoma cruzi versus Homo sapiens: putative drug targets for chagas' disease treatment. BMC Genomics 2010; 11:610. [PMID: 21034488 PMCID: PMC3091751 DOI: 10.1186/1471-2164-11-610] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Accepted: 10/29/2010] [Indexed: 11/25/2022] Open
Abstract
Background Trypanosoma cruzi is the etiological agent of Chagas' disease, an endemic infection that causes thousands of deaths every year in Latin America. Therapeutic options remain inefficient, demanding the search for new drugs and/or new molecular targets. Such efforts can focus on proteins that are specific to the parasite, but analogous enzymes and enzymes with a three-dimensional (3D) structure sufficiently different from the corresponding host proteins may represent equally interesting targets. In order to find these targets we used the workflows MHOLline and AnEnΠ obtaining 3D models from homologous, analogous and specific proteins of Trypanosoma cruzi versus Homo sapiens. Results We applied genome wide comparative modelling techniques to obtain 3D models for 3,286 predicted proteins of T. cruzi. In combination with comparative genome analysis to Homo sapiens, we were able to identify a subset of 397 enzyme sequences, of which 356 are homologous, 3 analogous and 38 specific to the parasite. Conclusions In this work, we present a set of 397 enzyme models of T. cruzi that can constitute potential structure-based drug targets to be investigated for the development of new strategies to fight Chagas' disease. The strategies presented here support the concept of structural analysis in conjunction with protein functional analysis as an interesting computational methodology to detect potential targets for structure-based rational drug design. For example, 2,4-dienoyl-CoA reductase (EC 1.3.1.34) and triacylglycerol lipase (EC 3.1.1.3), classified as analogous proteins in relation to H. sapiens enzymes, were identified as new potential molecular targets.
Collapse
Affiliation(s)
- Priscila V S Z Capriles
- Grupo de Modelagem Molecular de Sistemas Biológicos, Laboratório Nacional de Computação Científica, LNCC/MCT, Petrópolis, CEP 25651-075, Brazil.
| | | | | | | | | | | |
Collapse
|
139
|
Coura JR, Borges-Pereira J. Chagas disease: 100 years after its discovery. A systemic review. Acta Trop 2010; 115:5-13. [PMID: 20382097 DOI: 10.1016/j.actatropica.2010.03.008] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Accepted: 03/31/2010] [Indexed: 11/25/2022]
Abstract
Although Chagas disease was only discovered in 1909, it began millions of years ago as an enzootic disease among wild animals. Its transmission to man began accidentally as an anthropozoonosis when mankind invaded wild ecotopes. Endemic Chagas disease became established as a zoonosis over the last 200-300 years through deforestation for agriculture and livestock rearing and adaptation of triatomines to dwellings and to humans and domestic animals as food sources. When T. cruzi is transmitted to man, it invades the bloodstream and lymphatic system and lodges in muscle and heart tissue, the digestive system and phagocytic cells. Through this, it causes inflammatory lesions and an immune response, particularly mediated by CD4(+), CD8(+), IL2 and IL4, with cell and neuron destruction and fibrosis. These processes lead to blockage of the heart's conductive system, arrhythmias, heart failure, aperistalsis and dilatation of hollow viscera, especially the esophagus and colons. Chagas disease is characterized by an acute phase with or without symptoms, with (or more often without) T. cruzi penetration signs (inoculation chagoma or Romaña's sign), fever, adenomegaly, hepatosplenomegaly and patent parasitemia; and a chronic phase: indeterminate (asymptomatic, with normal electrocardiogram and heart, esophagus and colon X-rays) or cardiac, digestive or cardiac/digestive forms. There is great regional variation in the morbidity caused by Chagas disease: severe cardiac or digestive forms may occur in 10-50%, and indeterminate forms in the remaining, asymptomatic cases. The epidemiological and control characteristics of Chagas disease vary according to each country's ecological conditions and health policies.
Collapse
Affiliation(s)
- José Rodrigues Coura
- Laboratório de Doenças Parasitárias, Instituto Oswaldo Cruz-Fiocruz, Rio de Janeiro, Brazil.
| | | |
Collapse
|
140
|
Wendel S. Transfusion transmitted Chagas disease: is it really under control? Acta Trop 2010; 115:28-34. [PMID: 20044970 DOI: 10.1016/j.actatropica.2009.12.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Revised: 12/12/2009] [Accepted: 12/22/2009] [Indexed: 12/13/2022]
Abstract
Transfusion transmitted Chagas disease was recognized as a medical problem more than 50 years ago. However, little attention was paid to it by Transfusion Medicine, medical authorities or regulatory agencies as a major problem and threat (especially after the advent of HIV/AIDS); perhaps because it was mainly restricted to tropical regions, usually in less developed countries. With the intense human migratory movement from developing to developed countries, it became more common and evident. The scope of this review is to cover the main transfusional aspects of American trypanosomiasis (Chagas disease), including the main strategies to prevent it through donor questionnaires, specific serological testing and alternative methods such as leukofiltration and pathogen reduction procedures, in order to increase the blood safety in both developing and developed countries.
Collapse
|
141
|
Abad-Franch F, Santos WS, Schofield CJ. Research needs for Chagas disease prevention. Acta Trop 2010; 115:44-54. [PMID: 20227378 DOI: 10.1016/j.actatropica.2010.03.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Revised: 02/17/2010] [Accepted: 03/05/2010] [Indexed: 11/30/2022]
Abstract
We present an overview of the two main strategies for the primary (vector control) and secondary (patient care) prevention of Chagas disease (CD). We identify major advances, knowledge gaps, and key research needs in both areas. Improved specific chemotherapy, including more practical formulations (e.g., paediatric) or combinations of existing drugs, and a better understanding of pathogenesis, including the relative weights of parasite and host genetic makeup, are clearly needed. Regarding CD vectors, we find that only about 10-20% of published papers on triatomines deal directly with disease control. We pinpoint the pitfalls of the current consensus on triatomine systematics, particularly within the Triatomini, and suggest how some straightforward sampling and analytical strategies would improve research on vector ecology, naturally leading to sounder control-surveillance schemes. We conclude that sustained research on CD prevention is still crucial. In the past, it provided not only the know-how, but also the critical mass of scientists needed to foster and consolidate CD prevention programmes; in the future, both patient care and long-term vector control would nonetheless benefit from more sharply focused, problem-oriented research.
Collapse
Affiliation(s)
- Fernando Abad-Franch
- Instituto Leônidas e Maria Deane-Fiocruz Amazonia, Rua Teresina 476, 69057-070 Manaus, Amazonas, Brazil.
| | | | | |
Collapse
|
142
|
Pereira KS, Schmidt FL, Barbosa RL, Guaraldo AMA, Franco RMB, Dias VL, Passos LAC. Transmission of chagas disease (American trypanosomiasis) by food. ADVANCES IN FOOD AND NUTRITION RESEARCH 2010; 59:63-85. [PMID: 20610174 DOI: 10.1016/s1043-4526(10)59003-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
In April 2009, the centenary of the discovery of the American trypanosomiasis, or Chagas disease, was celebrated. A hundred years after the discovery, little has been invested in diagnostics and treatment because the disease affects mainly poor people in developing countries. However, some changes in the epidemiology of the disease are of great importance today. Chagas disease transmitted through food is a public health concern in all areas where there is a reservoir of Trypanosoma cruzi in wild animals (e.g., mammals and marsupials) and/or where infected triatomine bugs are in contact with human food source items (especially fruits and vegetables). Recently, several outbreaks of illness related to the ingestion of food contaminated with T. cruzi have been recorded in Brazil, Colombia, and Venezuela.
Collapse
Affiliation(s)
- Karen Signori Pereira
- Departamento de Engenharia Bioquímica, Escola de Química, Centro de Tecnologia Bloco Sala E203, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | | | | | | | | | | | | |
Collapse
|
143
|
Epting CL, Coates BM, Engman DM. Molecular mechanisms of host cell invasion by Trypanosoma cruzi. Exp Parasitol 2010; 126:283-91. [PMID: 20599990 DOI: 10.1016/j.exppara.2010.06.023] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 05/28/2010] [Accepted: 06/14/2010] [Indexed: 12/28/2022]
Abstract
The protozoan parasite Trypanosoma cruzi, the etiologic agent of Chagas disease, is an obligate intracellular protozoan pathogen. Overlapping mechanisms ensure successful infection, yet the relationship between these cellular events and clinical disease remains obscure. This review explores the process of cell invasion from the perspective of cell surface interactions, intracellular signaling, modulation of the host cytoskeleton and endosomal compartment, and the intracellular innate immune response to infection.
Collapse
Affiliation(s)
- Conrad L Epting
- Department of Pediatrics, Northwestern University, Chicago, IL 60611, USA.
| | | | | |
Collapse
|
144
|
Pérez-López FR, Chedraui P. Chagas disease in pregnancy: a non-endemic problem in a globalized world. Arch Gynecol Obstet 2010; 282:595-9. [PMID: 20559648 DOI: 10.1007/s00404-010-1553-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Accepted: 06/01/2010] [Indexed: 11/29/2022]
Abstract
BACKGROUND Chagas disease, caused by the Trypanosoma cruzi infection, is an endemic cause of morbidity and mortality in Latin America. Infection during pregnancy may increase the risk for adverse maternal-foetal outcome. METHODS Review of significant articles regarding maternal-foetal T. cruzi infection in free-vector non-endemic regions. RESULTS Vertical transmission, even in vector-free world regions, occurs in 1 out of 20 seropositive mothers. T. cruzi infection increases the risk of miscarriage, preterm birth and neonatal infection which may cause infant death or severe sequelae. Prevention of T. cruzi vertical transmission is not feasible, although early diagnosis allows appropriate treatment of newborns with a 100% efficacy. The present document will recall the importance of T. cruzi mother-to-child transmission and maternal-foetal consequences in non-endemic areas. CONCLUSION It is highly recommended that infected pregnant women in non-endemic regions be accurately assessed.
Collapse
Affiliation(s)
- Faustino R Pérez-López
- Department of Obstetrics and Gynaecology, Facultad de Medicina, Universidad de Zaragoza, Hospital Clínico de Zaragoza, Domingo Miral s/n, Zaragoza, Spain.
| | | |
Collapse
|
145
|
Bastos CJC, Aras R, Mota G, Reis F, Dias JP, de Jesus RS, Freire MS, de Araújo EG, Prazeres J, Grassi MFR. Clinical outcomes of thirteen patients with acute chagas disease acquired through oral transmission from two urban outbreaks in northeastern Brazil. PLoS Negl Trop Dis 2010; 4:e711. [PMID: 20559542 PMCID: PMC2886048 DOI: 10.1371/journal.pntd.0000711] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Accepted: 04/22/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Outbreaks of orally transmitted Trypanosoma cruzi continue to be reported in Brazil and are associated with a high mortality rate, mainly due to myocarditis. METHODS This study is a detailed report on the disease progression of acute Chagas disease in 13 patients who were infected during two micro-outbreaks in two northeastern Brazilian towns. Clinical outcomes as well as EKG and ECHO results are described, both before and after benznidazole treatment. RESULTS Fever and dyspnea were the most frequent symptoms observed. Other clinical findings included myalgia, periorbital edema, headache and systolic murmur. Two patients died of cardiac failure before receiving benznidazole treatment. EKG and ECHO findings frequently showed a disturbance in ventricular repolarization and pericardial effusion. Ventricular dysfunction (ejection fraction <55%) was present in 27.3% of patients. After treatment, EKG readings normalized in 91.7% of patients. Ventricular repolarization abnormalities persisted in 50% of the patients, while sinus bradycardia was observed in 18%. The systolic ejection fraction normalized in two out of three patients with initially depressed ventricular function, while pericardial effusion disappeared. CONCLUSIONS Myocarditis is frequently found and potentially severe in patients with acute Chagas disease. Benznidazole treatment may improve clinical symptoms, as well as EKG and ECHO findings.
Collapse
Affiliation(s)
- Claudilson J. C. Bastos
- Medicine and Human Health PhD Program, Bahian School of Medicine and Public Health, Bahia, Brazil
| | - Roque Aras
- Edgard Santos University Hospital, Federal University of Bahia, Bahia, Brazil
| | - Gildo Mota
- Edgard Santos University Hospital, Federal University of Bahia, Bahia, Brazil
| | - Francisco Reis
- Edgard Santos University Hospital, Federal University of Bahia, Bahia, Brazil
| | - Juarez Pereira Dias
- Epidemiological Surveillance Department of the Bahia Health Secretary, Bahia, Brazil
| | | | | | - Eline G. de Araújo
- Epidemiological Surveillance Department of the Bahia Health Secretary, Bahia, Brazil
| | - Juliana Prazeres
- Edgard Santos University Hospital, Federal University of Bahia, Bahia, Brazil
| | - Maria Fernanda Rios Grassi
- Medicine and Human Health PhD Program, Bahian School of Medicine and Public Health, Bahia, Brazil
- Oswaldo Cruz Foundation-FIOCRUZ, Bahia, Brazil
- * E-mail:
| |
Collapse
|
146
|
A three-dimensional multi-agent-based model for the evolution of Chagas’ disease. Biosystems 2010; 100:225-30. [DOI: 10.1016/j.biosystems.2010.03.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Accepted: 03/19/2010] [Indexed: 11/20/2022]
|
147
|
Aguilar-Garcia J, Dominguez-Pérez A, Nacarino-Mejías V, Iribarren-Marín M. Enfermedad de Chagas. Rev Clin Esp 2010; 210:e25-7. [DOI: 10.1016/j.rce.2010.02.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 02/16/2010] [Accepted: 02/23/2010] [Indexed: 10/19/2022]
|
148
|
Agapova M, Busch MP, Custer B. Cost-effectiveness of screening the US blood supply for Trypanosoma cruzi. Transfusion 2010; 50:2220-32. [DOI: 10.1111/j.1537-2995.2010.02686.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
149
|
Oliveira GMD, Masuda MO, Rocha NN, Schor N, Hooper CS, Araújo-Jorge TCD, Henriques-Pons A. Absence of Fas-L aggravates renal injury in acute Trypanosoma cruzi infection. Mem Inst Oswaldo Cruz 2010; 104:1063-71. [PMID: 20140366 DOI: 10.1590/s0074-02762009000800002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Accepted: 10/13/2009] [Indexed: 01/28/2023] Open
Abstract
Trypanosoma cruzi infection induces diverse alterations in immunocompetent cells and organs, myocarditis and congestive heart failure. However, the physiological network of disturbances imposed by the infection has not been addressed thoroughly. Regarding myocarditis induced by the infection, we observed in our previous work that Fas-L-/- mice (gld/gld) have very mild inflammatory infiltration when compared to BALB/c mice. However, all mice from both lineages die in the early acute phase. Therefore, in this work we studied the physiological connection relating arterial pressure, renal function/damage and cardiac insufficiency as causes of death. Our results show that a broader set of dysfunctions that could be classified as a cardio/anaemic/renal syndrome is more likely responsible for cardiac failure and death in both lineages. However, gld/gld mice had very early glomerular deposition of IgM and a more intense renal inflammatory response with reduced renal filtration, which is probably responsible for the premature death in the absence of significant myocarditis in gld/gld.
Collapse
|
150
|
Abad-Franch F, Ferraz G, Campos C, Palomeque FS, Grijalva MJ, Aguilar HM, Miles MA. Modeling disease vector occurrence when detection is imperfect: infestation of Amazonian palm trees by triatomine bugs at three spatial scales. PLoS Negl Trop Dis 2010; 4:e620. [PMID: 20209149 PMCID: PMC2830460 DOI: 10.1371/journal.pntd.0000620] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Accepted: 01/15/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Failure to detect a disease agent or vector where it actually occurs constitutes a serious drawback in epidemiology. In the pervasive situation where no sampling technique is perfect, the explicit analytical treatment of detection failure becomes a key step in the estimation of epidemiological parameters. We illustrate this approach with a study of Attalea palm tree infestation by Rhodnius spp. (Triatominae), the most important vectors of Chagas disease (CD) in northern South America. METHODOLOGY/PRINCIPAL FINDINGS The probability of detecting triatomines in infested palms is estimated by repeatedly sampling each palm. This knowledge is used to derive an unbiased estimate of the biologically relevant probability of palm infestation. We combine maximum-likelihood analysis and information-theoretic model selection to test the relationships between environmental covariates and infestation of 298 Amazonian palm trees over three spatial scales: region within Amazonia, landscape, and individual palm. Palm infestation estimates are high (40-60%) across regions, and well above the observed infestation rate (24%). Detection probability is higher ( approximately 0.55 on average) in the richest-soil region than elsewhere ( approximately 0.08). Infestation estimates are similar in forest and rural areas, but lower in urban landscapes. Finally, individual palm covariates (accumulated organic matter and stem height) explain most of infestation rate variation. CONCLUSIONS/SIGNIFICANCE Individual palm attributes appear as key drivers of infestation, suggesting that CD surveillance must incorporate local-scale knowledge and that peridomestic palm tree management might help lower transmission risk. Vector populations are probably denser in rich-soil sub-regions, where CD prevalence tends to be higher; this suggests a target for research on broad-scale risk mapping. Landscape-scale effects indicate that palm triatomine populations can endure deforestation in rural areas, but become rarer in heavily disturbed urban settings. Our methodological approach has wide application in infectious disease research; by improving eco-epidemiological parameter estimation, it can also significantly strengthen vector surveillance-control strategies.
Collapse
|