Chagas' disease caused by Trypanosoma cruzi is an opportunistic infection in the setting of HIV/AIDS. Some individuals with HIV and chronic T. cruzi infection may experience a reactivation, which is most commonly manifested by meningoencephalitis. A reactivation myocarditis is the second most common manifestation. These presentations may be difficult to distinguish from toxoplasmosis in individuals with HIV/AIDS. The overlap of HIV and Trypanosoma cruzi infection occurs not only in endemic areas but also in non-endemic areas of North America and Europe where the diagnosis may be even more difficult. The pathological features, diagnosis and the role of cytokines in the pathogenesis of the disease are discussed.
{"title":"Chagas' disease and AIDS.","authors":"Anil K Vaidian, Louis M Weiss, Herbert B Tanowitz","doi":"10.1186/1475-9292-3-2","DOIUrl":"https://doi.org/10.1186/1475-9292-3-2","url":null,"abstract":"<p><p>Chagas' disease caused by Trypanosoma cruzi is an opportunistic infection in the setting of HIV/AIDS. Some individuals with HIV and chronic T. cruzi infection may experience a reactivation, which is most commonly manifested by meningoencephalitis. A reactivation myocarditis is the second most common manifestation. These presentations may be difficult to distinguish from toxoplasmosis in individuals with HIV/AIDS. The overlap of HIV and Trypanosoma cruzi infection occurs not only in endemic areas but also in non-endemic areas of North America and Europe where the diagnosis may be even more difficult. The pathological features, diagnosis and the role of cytokines in the pathogenesis of the disease are discussed.</p>","PeriodicalId":17853,"journal":{"name":"Kinetoplastid Biology and Disease","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/1475-9292-3-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24518221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cristiane Quimelli Snoeijer, Gisele Fernanda Picchi, Bibiana Paula Dambrós, Mário Steindel, Samuel Goldenberg, Stênio Perdigão Fragoso, Daniel Macedo Lorenzini, Edmundo Carlos Grisard
Trypanosoma rangeli is an important hemoflagellate parasite of several mammalian species in Central and South America, sharing geographical areas, vectors and reservoirs with T. cruzi, the causative agent of Chagas disease. Thus, the occurrence of single and/or mixed infections, including in humans, must be expected and are of great importance for specific diagnosis and epidemiology. In comparison to several Trypanosomatidae species, the T. rangeli biology and genome are little known, reinforcing the needs of a gene discovery initiative. The T. rangeli transcriptome initiative aims to promote gene discovery through the generation of expressed sequence tags (ESTs) and Orestes (ORF ESTs) from both epimastigote and trypomastigote forms of the parasite, allowing further studies of the parasite biology, taxonomy and phylogeny.
{"title":"Trypanosoma rangeli Transcriptome Project: Generation and analysis of expressed sequence tags.","authors":"Cristiane Quimelli Snoeijer, Gisele Fernanda Picchi, Bibiana Paula Dambrós, Mário Steindel, Samuel Goldenberg, Stênio Perdigão Fragoso, Daniel Macedo Lorenzini, Edmundo Carlos Grisard","doi":"10.1186/1475-9292-3-1","DOIUrl":"https://doi.org/10.1186/1475-9292-3-1","url":null,"abstract":"<p><p>Trypanosoma rangeli is an important hemoflagellate parasite of several mammalian species in Central and South America, sharing geographical areas, vectors and reservoirs with T. cruzi, the causative agent of Chagas disease. Thus, the occurrence of single and/or mixed infections, including in humans, must be expected and are of great importance for specific diagnosis and epidemiology. In comparison to several Trypanosomatidae species, the T. rangeli biology and genome are little known, reinforcing the needs of a gene discovery initiative. The T. rangeli transcriptome initiative aims to promote gene discovery through the generation of expressed sequence tags (ESTs) and Orestes (ORF ESTs) from both epimastigote and trypomastigote forms of the parasite, allowing further studies of the parasite biology, taxonomy and phylogeny.</p>","PeriodicalId":17853,"journal":{"name":"Kinetoplastid Biology and Disease","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/1475-9292-3-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24518222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Véronique Hannaert, Frédéric Bringaud, Fred R Opperdoes, Paul AM Michels
Kinetoplastida are protozoan organisms that probably diverged early in evolution from other eukaryotes. They are characterized by a number of unique features with respect to their energy and carbohydrate metabolism. These organisms possess peculiar peroxisomes, called glycosomes, which play a central role in this metabolism; the organelles harbour enzymes of several catabolic and anabolic routes, including major parts of the glycolytic and pentosephosphate pathways. The kinetoplastid mitochondrion is also unusual with regard to both its structural and functional properties.In this review, we describe the unique compartmentation of metabolism in Kinetoplastida and the metabolic properties resulting from this compartmentation. We discuss the evidence for our recently proposed hypothesis that a common ancestor of Kinetoplastida and Euglenida acquired a photosynthetic alga as an endosymbiont, contrary to the earlier notion that this event occurred at a later stage of evolution, in the Euglenida lineage alone. The endosymbiont was subsequently lost from the kinetoplastid lineage but, during that process, some of its pathways of energy and carbohydrate metabolism were sequestered in the kinetoplastid peroxisomes, which consequently became glycosomes. The evolution of the kinetoplastid glycosomes and the possible selective advantages of these organelles for Kinetoplastida are discussed. We propose that the possession of glycosomes provided metabolic flexibility that has been important for the organisms to adapt easily to changing environmental conditions. It is likely that metabolic flexibility has been an important selective advantage for many kinetoplastid species during their evolution into the highly successful parasites today found in many divergent taxonomic groups.Also addressed is the evolution of the kinetoplastid mitochondrion, from a supposedly pluripotent organelle, attributed to a single endosymbiotic event that resulted in all mitochondria and hydrogenosomes of extant eukaryotes. Furthermore, indications are presented that Kinetoplastida may have acquired other enzymes of energy and carbohydrate metabolism by various lateral gene transfer events different from those that involved the algal- and alpha-proteobacterial-like endosymbionts responsible for the respective formation of the glycosomes and mitochondria.
{"title":"Evolution of energy metabolism and its compartmentation in Kinetoplastida.","authors":"Véronique Hannaert, Frédéric Bringaud, Fred R Opperdoes, Paul AM Michels","doi":"10.1186/1475-9292-2-11","DOIUrl":"10.1186/1475-9292-2-11","url":null,"abstract":"<p><p>Kinetoplastida are protozoan organisms that probably diverged early in evolution from other eukaryotes. They are characterized by a number of unique features with respect to their energy and carbohydrate metabolism. These organisms possess peculiar peroxisomes, called glycosomes, which play a central role in this metabolism; the organelles harbour enzymes of several catabolic and anabolic routes, including major parts of the glycolytic and pentosephosphate pathways. The kinetoplastid mitochondrion is also unusual with regard to both its structural and functional properties.In this review, we describe the unique compartmentation of metabolism in Kinetoplastida and the metabolic properties resulting from this compartmentation. We discuss the evidence for our recently proposed hypothesis that a common ancestor of Kinetoplastida and Euglenida acquired a photosynthetic alga as an endosymbiont, contrary to the earlier notion that this event occurred at a later stage of evolution, in the Euglenida lineage alone. The endosymbiont was subsequently lost from the kinetoplastid lineage but, during that process, some of its pathways of energy and carbohydrate metabolism were sequestered in the kinetoplastid peroxisomes, which consequently became glycosomes. The evolution of the kinetoplastid glycosomes and the possible selective advantages of these organelles for Kinetoplastida are discussed. We propose that the possession of glycosomes provided metabolic flexibility that has been important for the organisms to adapt easily to changing environmental conditions. It is likely that metabolic flexibility has been an important selective advantage for many kinetoplastid species during their evolution into the highly successful parasites today found in many divergent taxonomic groups.Also addressed is the evolution of the kinetoplastid mitochondrion, from a supposedly pluripotent organelle, attributed to a single endosymbiotic event that resulted in all mitochondria and hydrogenosomes of extant eukaryotes. Furthermore, indications are presented that Kinetoplastida may have acquired other enzymes of energy and carbohydrate metabolism by various lateral gene transfer events different from those that involved the algal- and alpha-proteobacterial-like endosymbionts responsible for the respective formation of the glycosomes and mitochondria.</p>","PeriodicalId":17853,"journal":{"name":"Kinetoplastid Biology and Disease","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC317351/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24071931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Phylogenetic analyses of the family Trypanosomatidae have been conducted using both 18S rRNA gene sequences and a variety of protein sequences. Using a variety of phylogenetic methods, 18S rRNA phylogenies indicate that the genus Trypanosoma is not monophyletic. Rather, they suggest that the American and African trypanosomes constitute distinct clades. By contrast, phylogenetic analyses of available sequences in 42 protein families gene generally supported monophyly of the genus Trypanosoma. One possible explanation for these conflicting results is poor taxon sampling in the case of protein coding genes, most of which have been sequenced for only a few species of Trypanosomatidae.
{"title":"Molecular phylogenetics of Trypanosomatidae: contrasting results from 18S rRNA and protein phylogenies.","authors":"Austin L Hughes, Helen Piontkivska","doi":"10.1186/1475-9292-2-15","DOIUrl":"https://doi.org/10.1186/1475-9292-2-15","url":null,"abstract":"<p><p>Phylogenetic analyses of the family Trypanosomatidae have been conducted using both 18S rRNA gene sequences and a variety of protein sequences. Using a variety of phylogenetic methods, 18S rRNA phylogenies indicate that the genus Trypanosoma is not monophyletic. Rather, they suggest that the American and African trypanosomes constitute distinct clades. By contrast, phylogenetic analyses of available sequences in 42 protein families gene generally supported monophyly of the genus Trypanosoma. One possible explanation for these conflicting results is poor taxon sampling in the case of protein coding genes, most of which have been sequenced for only a few species of Trypanosomatidae.</p>","PeriodicalId":17853,"journal":{"name":"Kinetoplastid Biology and Disease","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/1475-9292-2-15","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24072613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The way species and subspecies names are applied in African trypanosomes of subgenera Trypanozoon and Nannomonas is reviewed in the light of data from molecular taxonomy. In subgenus Trypanozoon the taxonomic importance of pathogenicity, host range and distribution appear to have been inflated relative to actual levels of genetic divergence. The opposite is true for subgenus Nannomonas, where current taxonomic usage badly underrepresents genetic diversity. Data from molecular characterisation studies are revealing a growing number of genotypes, which may represent distinct taxa. Unfortunately few of these genotypes are yet supported by sufficient biological data to be recognized taxonomically. But we may be missing fundamental epidemiological information, because of our inability to distinguish these trypanosomes in host blood morphologically or in tsetse by their developmental cycle. Molecular taxonomy has led the way in identifying these new genotypes and now offers the key to elucidating the biology of these organisms.
{"title":"Species concepts for trypanosomes: from morphological to molecular definitions?","authors":"Wendy Gibson","doi":"10.1186/1475-9292-2-10","DOIUrl":"https://doi.org/10.1186/1475-9292-2-10","url":null,"abstract":"<p><p>The way species and subspecies names are applied in African trypanosomes of subgenera Trypanozoon and Nannomonas is reviewed in the light of data from molecular taxonomy. In subgenus Trypanozoon the taxonomic importance of pathogenicity, host range and distribution appear to have been inflated relative to actual levels of genetic divergence. The opposite is true for subgenus Nannomonas, where current taxonomic usage badly underrepresents genetic diversity. Data from molecular characterisation studies are revealing a growing number of genotypes, which may represent distinct taxa. Unfortunately few of these genotypes are yet supported by sufficient biological data to be recognized taxonomically. But we may be missing fundamental epidemiological information, because of our inability to distinguish these trypanosomes in host blood morphologically or in tsetse by their developmental cycle. Molecular taxonomy has led the way in identifying these new genotypes and now offers the key to elucidating the biology of these organisms.</p>","PeriodicalId":17853,"journal":{"name":"Kinetoplastid Biology and Disease","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/1475-9292-2-10","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24071930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The current status of kinetoplastids phylogeny and evolution is discussed in view of the recent progresses on genomics. Some ideas on a potential framework for the evolutionary genomics of kinetoplastids are presented.
{"title":"Towards a framework for the evolutionary genomics of Kinetoplastids: what kind of data and how much?","authors":"Alberto MR Dávila, Julius Lukes;","doi":"10.1186/1475-9292-2-16","DOIUrl":"https://doi.org/10.1186/1475-9292-2-16","url":null,"abstract":"<p><p>The current status of kinetoplastids phylogeny and evolution is discussed in view of the recent progresses on genomics. Some ideas on a potential framework for the evolutionary genomics of kinetoplastids are presented.</p>","PeriodicalId":17853,"journal":{"name":"Kinetoplastid Biology and Disease","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/1475-9292-2-16","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24072612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jose Luis Gonzales, Tudor W Jones, Kim Picozzi, Hugo Ribera Cuellar
BACKGROUND: Sporadic outbreaks of bovine trypanosomiasis have been reported in Bolivia since 1996 when T. vivax and T. evansi were identified for the first time by parasitological means. However, comprehensive epidemiological information concerning T. vivax and T. evansi in the country is lacking. Current parasitological and serological diagnostic methods for trypanosomiasis have important limitations either in their sensitivity or specificity, which can result in unreliable data when applied in epidemiological studies. PCR assays are a recently developed procedure that might help to overcome the constraints of parasitological and serological assays. Therefore, the objective of this study was to evaluate PCR assays as a diagnostic tool for epidemiological studies in Bolivia. RESULTS: PCR assays for diagnosis of trypanosome infection in cattle were evaluated for their ability to detect trypanosome DNA in blood spots samples collected from cattle in four different provinces from the Bolivian lowlands and the results compared with those obtained with standard parasitological Micro Haematocrit Centrifugation Technique (MHCT) and stained smears and serological methods (Card Agglutination Test for T. evansi (CATT), and Antibody ELISAs for T. vivax and T. congolense). Kappa agreement analysis showed a significant agreement between PCR assays and results from parasitological methods but there was no agreement when PCR was compared with serological assays. Some samples from T. vivax smear positive animals were negative by PCR, therefore modifications to the PCR assay conditions were undertaken to try to improve agreement between PCR and parasitological assays. Changes in the template DNA concentration or the use of an alternative primer set resulted in improvements in the PCR detection rate, but not all the parasitologically positive samples were detected by PCR. Results from PCR assays for T. vivax and T. evansi were combined with results from parasitological and serological assays to provide information on prevalence rates for the four provinces from where the samples were obtained. CONCLUSION: The present study established evidence of the usefulness of PCR as diagnostic tool for epidemiological studies and confirmed that cattle trypanosomiasis appears to be endemic in several regions of the Bolivian lowlands.
{"title":"Evaluation of a polymerase chain reaction assay for the diagnosis of bovine trypanosomiasis and epidemiological surveillance in Bolivia.","authors":"Jose Luis Gonzales, Tudor W Jones, Kim Picozzi, Hugo Ribera Cuellar","doi":"10.1186/1475-9292-2-8","DOIUrl":"https://doi.org/10.1186/1475-9292-2-8","url":null,"abstract":"<p><p>BACKGROUND: Sporadic outbreaks of bovine trypanosomiasis have been reported in Bolivia since 1996 when T. vivax and T. evansi were identified for the first time by parasitological means. However, comprehensive epidemiological information concerning T. vivax and T. evansi in the country is lacking. Current parasitological and serological diagnostic methods for trypanosomiasis have important limitations either in their sensitivity or specificity, which can result in unreliable data when applied in epidemiological studies. PCR assays are a recently developed procedure that might help to overcome the constraints of parasitological and serological assays. Therefore, the objective of this study was to evaluate PCR assays as a diagnostic tool for epidemiological studies in Bolivia. RESULTS: PCR assays for diagnosis of trypanosome infection in cattle were evaluated for their ability to detect trypanosome DNA in blood spots samples collected from cattle in four different provinces from the Bolivian lowlands and the results compared with those obtained with standard parasitological Micro Haematocrit Centrifugation Technique (MHCT) and stained smears and serological methods (Card Agglutination Test for T. evansi (CATT), and Antibody ELISAs for T. vivax and T. congolense). Kappa agreement analysis showed a significant agreement between PCR assays and results from parasitological methods but there was no agreement when PCR was compared with serological assays. Some samples from T. vivax smear positive animals were negative by PCR, therefore modifications to the PCR assay conditions were undertaken to try to improve agreement between PCR and parasitological assays. Changes in the template DNA concentration or the use of an alternative primer set resulted in improvements in the PCR detection rate, but not all the parasitologically positive samples were detected by PCR. Results from PCR assays for T. vivax and T. evansi were combined with results from parasitological and serological assays to provide information on prevalence rates for the four provinces from where the samples were obtained. CONCLUSION: The present study established evidence of the usefulness of PCR as diagnostic tool for epidemiological studies and confirmed that cattle trypanosomiasis appears to be endemic in several regions of the Bolivian lowlands.</p>","PeriodicalId":17853,"journal":{"name":"Kinetoplastid Biology and Disease","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/1475-9292-2-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24072610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the early twentieth century, infectious diseases were a leading cause of death worldwide. Through the following years, morbidity and mortality caused by infectious diseases decreased considerably in the developed world, but not in the developing world, where infectious diseases remain an important reason for concern. For example, leishmaniosis has become into a serious Third World problem. This is mainly due to an increasing frequency of drug-resistance in Leishmania and an enhanced risk of co-infection with HIV. Drug-resistance is usually associated with an increased expression of specific P-glycoproteins involved in membrane transport. The present review summarizes information which shows that drug-resistance is also associated with changes in physiological events such as parasite infectivity, incorporation of metabolites, xenobiotics conjugation and traffic, intracellular metabolism, host-parasite interaction, parasite cell shape and promastigote-amastigote differentiation. Furthermore, these events may change in a coordinated manner. An understanding of these physiological events may be helpful for designing chemotherapeutic approaches to multiple cellular targets, identifying strategies to circumvent Leishmania drug-resistance and succesfully treating leishmaniosis.
{"title":"Physiological consequences of drug resistance in Leishmania and their relevance for chemotherapy.","authors":"Alicia Ponte-Sucre","doi":"10.1186/1475-9292-2-14","DOIUrl":"https://doi.org/10.1186/1475-9292-2-14","url":null,"abstract":"<p><p>In the early twentieth century, infectious diseases were a leading cause of death worldwide. Through the following years, morbidity and mortality caused by infectious diseases decreased considerably in the developed world, but not in the developing world, where infectious diseases remain an important reason for concern. For example, leishmaniosis has become into a serious Third World problem. This is mainly due to an increasing frequency of drug-resistance in Leishmania and an enhanced risk of co-infection with HIV. Drug-resistance is usually associated with an increased expression of specific P-glycoproteins involved in membrane transport. The present review summarizes information which shows that drug-resistance is also associated with changes in physiological events such as parasite infectivity, incorporation of metabolites, xenobiotics conjugation and traffic, intracellular metabolism, host-parasite interaction, parasite cell shape and promastigote-amastigote differentiation. Furthermore, these events may change in a coordinated manner. An understanding of these physiological events may be helpful for designing chemotherapeutic approaches to multiple cellular targets, identifying strategies to circumvent Leishmania drug-resistance and succesfully treating leishmaniosis.</p>","PeriodicalId":17853,"journal":{"name":"Kinetoplastid Biology and Disease","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/1475-9292-2-14","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24072614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
BACKGROUND: This paper summarizes the main results obtained on Trypanosoma cruzi genetic diversity and population structure since this parasite became the theme of many genetic and molecular studies in the early seventies. RESULTS: T. cruzi exibits a paradigmatic pattern of long-term, clonal evolution, which has structured its natural populations into several discrete genetic subdivisions or "Discrete Typing Units" (DTU). Rare hybridization events are nevertheless detectable in natural populations and have been recently obtained in the laboratory. CONCLUSIONS: The DTUs and natural clones of T. cruzi constitute relevant units for molecular epidemiology and experimental evolution. Experimental mating opens the way to an in-depth knowledge of this parasite's formal genetics.
{"title":"Genetic subdivisions within Trypanosoma cruzi (Discrete Typing Units) and their relevance for molecular epidemiology and experimental evolution.","authors":"Michel Tibayrenc","doi":"10.1186/1475-9292-2-12","DOIUrl":"https://doi.org/10.1186/1475-9292-2-12","url":null,"abstract":"<p><p>BACKGROUND: This paper summarizes the main results obtained on Trypanosoma cruzi genetic diversity and population structure since this parasite became the theme of many genetic and molecular studies in the early seventies. RESULTS: T. cruzi exibits a paradigmatic pattern of long-term, clonal evolution, which has structured its natural populations into several discrete genetic subdivisions or \"Discrete Typing Units\" (DTU). Rare hybridization events are nevertheless detectable in natural populations and have been recently obtained in the laboratory. CONCLUSIONS: The DTUs and natural clones of T. cruzi constitute relevant units for molecular epidemiology and experimental evolution. Experimental mating opens the way to an in-depth knowledge of this parasite's formal genetics.</p>","PeriodicalId":17853,"journal":{"name":"Kinetoplastid Biology and Disease","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/1475-9292-2-12","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24072616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Célia M Marques De Brito, Marize Q Pires, Raquel S Pacheco
BACKGROUND: Recently new aspects of the immunopathology of Chagas disease have been described in patients infected with HIV and unusual clinical manifestations such as cutaneous lesions, involvement of central nervous system and/or serious cardiac lesions related to the reactivation of the parasite have been reported. Two uncloned Trypanosoma cruzi strains previously isolated from chronic chagasic patients with HIV co-infection were studied in order to evaluate the impact of the immunosuppression on the genetic diversity of the parasite. RESULTS: We have exploited an experimental model to determine whether genetically distinct populations appear after immunosuppression as a consequence of in vivo selection or in vitro propagation. The in vitro and in vivo conditions have allowed us to study the selected populations. The first strain was isolated from a case of reactivation of Chagas disease in a patient which presented four cerebral lesions. It was possible to demonstrate that the patient was infected with at least three distinct populations of T. cruzi. The population, recovered after immunosuppression, in mice was genetically divergent from the primary human isolate. The second strain, isolated from a hemophiliac/HIV positive patient presenting cardiac manifestation of Chagas disease showed no marked genetic difference after experimental immunosuppression. CONCLUSION: The immunological condition of the patient, associated or not to the reactivation of the infection, and also the strain of the parasite may have an important role during the course of the disease. The in vivo mechanism that generates parasite genetic variability or the participation of the selection under stress conditions will require further investigation.
背景:最近,在感染艾滋病毒的患者中发现了恰加斯病免疫病理的新方面,并报道了与寄生虫再活化有关的异常临床表现,如皮肤病变、中枢神经系统受累和/或严重的心脏病变。为了评估免疫抑制对寄生虫遗传多样性的影响,我们对之前从合并感染艾滋病毒的慢性南美锥虫病患者体内分离出的两株未克隆的克鲁斯锥虫菌株进行了研究。结果:我们利用一个实验模型来确定免疫抑制后是否会出现基因不同的种群,这是体内选择还是体外繁殖的结果。在体外和体内条件下,我们研究了被选择的种群。第一个菌株是从一个南美锥虫病再活化病例中分离出来的,该病例的患者有四个脑部病变。结果表明,该患者至少感染了三种不同的 T. cruzi 群体。在小鼠体内经过免疫抑制后恢复的群体在遗传学上与原发性人类分离株不同。第二个菌株是从一名血友病患者/艾滋病毒阳性患者身上分离出来的,该患者有恰加斯病的心脏表现,在实验性免疫抑制后没有发现明显的基因差异。结论:患者的免疫状况、是否与感染再活化有关以及寄生虫的菌株可能在疾病过程中起着重要作用。寄生虫基因变异的体内机制或应激条件下的选择参与还需要进一步研究。
{"title":"Chagas disease and HIV co-infection: genetic analyses of two Trypanosoma cruzi strains under experimental immunosuppression.","authors":"Célia M Marques De Brito, Marize Q Pires, Raquel S Pacheco","doi":"10.1186/1475-9292-2-17","DOIUrl":"10.1186/1475-9292-2-17","url":null,"abstract":"<p><p>BACKGROUND: Recently new aspects of the immunopathology of Chagas disease have been described in patients infected with HIV and unusual clinical manifestations such as cutaneous lesions, involvement of central nervous system and/or serious cardiac lesions related to the reactivation of the parasite have been reported. Two uncloned Trypanosoma cruzi strains previously isolated from chronic chagasic patients with HIV co-infection were studied in order to evaluate the impact of the immunosuppression on the genetic diversity of the parasite. RESULTS: We have exploited an experimental model to determine whether genetically distinct populations appear after immunosuppression as a consequence of in vivo selection or in vitro propagation. The in vitro and in vivo conditions have allowed us to study the selected populations. The first strain was isolated from a case of reactivation of Chagas disease in a patient which presented four cerebral lesions. It was possible to demonstrate that the patient was infected with at least three distinct populations of T. cruzi. The population, recovered after immunosuppression, in mice was genetically divergent from the primary human isolate. The second strain, isolated from a hemophiliac/HIV positive patient presenting cardiac manifestation of Chagas disease showed no marked genetic difference after experimental immunosuppression. CONCLUSION: The immunological condition of the patient, associated or not to the reactivation of the infection, and also the strain of the parasite may have an important role during the course of the disease. The in vivo mechanism that generates parasite genetic variability or the participation of the selection under stress conditions will require further investigation.</p>","PeriodicalId":17853,"journal":{"name":"Kinetoplastid Biology and Disease","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC270073/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24072611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}