What's new for 'Trypanosomatids' in PubMed

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Sent on Friday, 2011 Jan 14
Search kinetoplastids OR kinetoplastid OR Kinetoplastida OR "trypanosoma brucei" OR leishmania OR brucei OR leishmaniasis OR "African trypanosomiasis"
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PubMed Results

Items 1 - 10 of 10

1.	Cad Saude Publica. 2010 Aug;26(8):1495-1507. [Production of transmission foci for cutaneous leishmaniasis: the case of Pau da Fome, Rio de Janeiro, Brazil.] [Article in Portuguese] Kawa H, Sabroza PC, Oliveira RM, Barcellos C. Faculdade de Medicina, Universidade Federal Fluminense, Niterói, Brasil. Abstract This study analyzes the characteristics of one of the main foci for cutaneous leishmaniasis transmission in the city of Rio de Janeiro, Brazil, examining its territorial configuration and the relations with spatial organization processes. An analytical model was applied to the process of occupation and organization of urban space on a local scale, considering the new functions acquired by the spatial elements expressed by different work relations, land use, and land value. The study employed geoprocessing techniques and classification of images obtained by remote sensing, localization of households, and cases of cutaneous leishmaniasis, associated with qualitative data on the historical process of land occupation and use. The analysis detected areas with distinct conditions of vulnerability and showed that changes in these conditions allowed production of the epidemic in a given time period and its subsequent reduction. The study contributes to monitoring of the disease at the local level and application of effective measures for cutaneous leishmaniasis surveillance and control.
	PMID: 21229209 [PubMed - as supplied by publisher]
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2.	Trends Parasitol. 2011 Jan 10. [Epub ahead of print] Ticks as vectors of Leishmania parasites. Dantas-Torres F. Dipartimento di Sanità Pubblica e Zootecnia, Facoltà di Medicina Veterinaria, Università degli Studi di Bari, Str. Prov. per Casamassima km 3, 70010 Valenzano, Bari, Italy. Abstract Sand flies are the only accepted biological vectors of Leishmania parasites. However, secondary modes of transmission have been extensively discussed and speculated about in recent years. In particular, the hypothesis of ticks as vectors of Leishmania infantum was studied in the 20th century and today is being revisited using modern molecular biology techniques. Recent studies have shed new light on the discussion, but have also led to misleading conclusions on the role of ticks as Leishmania vectors. In this article, the role of brown dog ticks, Rhipicephalus sanguineus, as vectors of L. infantum is discussed, and the need for further research to better understand their participation in the epidemiology of leishmaniasis is advocated. Copyright © 2010 Elsevier Ltd. All rights reserved.
	PMID: 21227752 [PubMed - as supplied by publisher]
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3.	Lancet. 2011 Jan 10. [Epub ahead of print] Continuing challenge of infectious diseases in India. John TJ, Dandona L, Sharma VP, Kakkar M. Department of Clinical Microbiology and Department of Virology, Christian Medical College, Vellore, Tamil Nadu, India. Abstract In India, the range and burden of infectious diseases are enormous. The administrative responsibilities of the health system are shared between the central (federal) and state governments. Control of diseases and outbreaks is the responsibility of the central Ministry of Health, which lacks a formal public health department for this purpose. Tuberculosis, malaria, filariasis, visceral leishmaniasis, leprosy, HIV infection, and childhood cluster of vaccine-preventable diseases are given priority for control through centrally managed vertical programmes. Control of HIV infection and leprosy, but not of tuberculosis, seems to be on track. Early success of malaria control was not sustained, and visceral leishmaniasis prevalence has increased. Inadequate containment of the vector has resulted in recurrent outbreaks of dengue fever and re-emergence of Chikungunya virus disease and typhus fever. Other infectious diseases caused by faecally transmitted pathogens (enteric fevers, cholera, hepatitis A and E viruses) and zoonoses (rabies, leptospirosis, anthrax) are not in the process of being systematically controlled. Big gaps in the surveillance and response system for infectious diseases need to be addressed. Replication of the model of vertical single-disease control for all infectious diseases will not be efficient or viable. India needs to rethink and revise its health policy to broaden the agenda of disease control. A comprehensive review and redesign of the health system is needed urgently to ensure equity and quality in health care. We recommend the creation of a functional public health infrastructure that is shared between central and state governments, with professional leadership and a formally trained public health cadre of personnel who manage an integrated control mechanism of diseases in districts that includes infectious and non-infectious diseases, and injuries. Copyright © 2011 Elsevier Ltd. All rights reserved.
	PMID: 21227500 [PubMed - as supplied by publisher]
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4.	Parasite Immunol. 2011 Feb;33(2):132-6. doi: 10.1111/j.1365-3024.2010.01256.x. IL-17 and Regulatory Cytokines (IL-10 and IL-27) in L. braziliensis Infection. Novoa R, Bacellar O, Nascimento M, Cardoso TM, Ramasawmy R, Oliveira WN, Schriefer A, Carvalho EM. Serviço de Imunologia, Complexo Hospitalar Universitário Professor Edgard Santos, Universidade Federal da Bahia, Salvador, Bahia, Brazil Instituto Nacional de Ciência e Tecnologia de Doenças Tropicais (CNPq/MCT), Salvador, Brazil. Abstract Cutaneous leishmaniasis (CL) is characterized by high production of pro-inflammatory cytokines and development of pathology. Individuals with subclinical L. braziliensis infection (SC) have a positive skin test to leishmania, but do not develop disease. We evaluated whether the downregulation of inflammatory response in SC is mediated by IL-10 and IL-27 and whether IL-17 is associated with control of infection. Participants include SC individuals, patients with CL and healthy subjects. Cytokines protein and mRNA were detected by ELISA and real-time PCR. IFN-γ and TNF-α levels were higher in CL than in SC group. The IL-10 levels and mRNA for IL-10 were similar in both SC and CL. mRNA for IL-27 was increased in cells from SC after stimulation with L. braziliensis antigen. There was a tendency for increased levels of IL-17 in SC compared to CL. The weak type 1 immune response observed in SC L. braziliensis infection is not because of the regulatory effects of IL-10 and IL-27. The control of Leishmania infection may be mediated by innate immune response with participation of IL-17. The results from this pilot study warrant further larger studies to investigate the potential contributions of IL-17 and IL-27 to the control of L. braziliensis infection. © 2011 Blackwell Publishing Ltd.
	PMID: 21226726 [PubMed - in process]
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5.	Parasite Immunol. 2011 Feb;33(2):95-103. doi: 10.1111/j.1365-3024.2010.01253.x. Cocktail of gp63 and Hsp70 induces protection against Leishmania donovani in BALB/c mice. Kaur T, Sobti RC, Kaur S. Department of Zoology Department of Biotechnology, Panjab University, Chandigarh, India. Abstract The 63- kDa antigen of Leishmania donovani is a membrane-anchored matrix metalloprotease that has been shown to be involved in the infection process. We have shown that this antigen alone generates a Th1 type of protective response that is partial but when the animals are primed with the antigen along with the Hsp70, the level of protection is raised significantly, which is demonstrated by a considerable reduction in parasite load of immunized animals when compared to the infected controls. Delayed-type hypersensitivity responses to leishmanin were measured as an index of cell-mediated immune response and were found to be higher in immunized animals when compared to the infected controls, the maximum being in the animals immunized with cocktail of both the antigens. Maximum IgG2a and minimum IgG1 levels were observed in this group of animals. These animals also generated maximum levels of IFN-γ and IL-2 and minimum levels of IL-4 and IL-10 pointing towards the generation of a protective Th1 response and the suppression of the Th2 type of immune response. © 2011 Blackwell Publishing Ltd.
	PMID: 21226722 [PubMed - in process]
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6.	PLoS One. 2010 Aug 26;5(8):e12415. The bacterium endosymbiont of Crithidia deanei undergoes coordinated division with the host cell nucleus. Motta MC, Catta-Preta CM, Schenkman S, de Azevedo Martins AC, Miranda K, de Souza W, Elias MC. Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil. motta@biof.ufrj.br Abstract In trypanosomatids, cell division involves morphological changes and requires coordinated replication and segregation of the nucleus, kinetoplast and flagellum. In endosymbiont-containing trypanosomatids, like Crithidia deanei, this process is more complex, as each daughter cell contains only a single symbiotic bacterium, indicating that the prokaryote must replicate synchronically with the host protozoan. In this study, we used light and electron microscopy combined with three-dimensional reconstruction approaches to observe the endosymbiont shape and division during C. deanei cell cycle. We found that the bacterium replicates before the basal body and kinetoplast segregations and that the nucleus is the last organelle to divide, before cytokinesis. In addition, the endosymbiont is usually found close to the host cell nucleus, presenting different shapes during the protozoan cell cycle. Considering that the endosymbiosis in trypanosomatids is a mutualistic relationship, which resembles organelle acquisition during evolution, these findings establish an excellent model for the understanding of mechanisms related with the establishment of organelles in eukaryotic cells. PMCID: PMC2932560 Free PMC Article
	PMID: 20865129 [PubMed - indexed for MEDLINE]
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7.	Am Nat. 2010 Oct;176(4):424-39. Critical interplay between parasite differentiation, host immunity, and antigenic variation in trypanosome infections. Gjini E, Haydon DT, Barry JD, Cobbold CA. Department of Mathematics, University of Glasgow, University Gardens, United Kingdom. egjini@maths.gla.ac.uk Abstract Increasing availability of pathogen genomic data offers new opportunities to understand the fundamental mechanisms of immune evasion and pathogen population dynamics during chronic infection. Motivated by the growing knowledge on the antigenic variation system of the sleeping sickness parasite, the African trypanosome, we introduce a mechanistic framework for modeling within-host infection dynamics. Our analysis focuses first on a single parasitemia peak and then on the dynamics of multiple peaks that rely on stochastic switching between groups of parasite variants. A major feature of trypanosome infections is the interaction between variant-specific host immunity and density-dependent parasite differentiation to transmission life stages. In this study, we investigate how the interplay between these two types of control depends on the modular structure of the parasite antigenic archive. Our model shows that the degree of synchronization in stochastic variant emergence determines the relative dominance of general over specific control within a single peak. A requirement for multiple-peak dynamics is a critical switch rate between blocks of antigenic variants, which implies constraints on variant surface glycoprotein (VSG) archive genetic diversification. Our study illustrates the importance of quantifying the links between parasite genetics and within-host dynamics and provides insights into the evolution of trypanosomes.
	PMID: 20715972 [PubMed - indexed for MEDLINE]
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8.	J Clin Microbiol. 2010 Oct;48(10):3824-6. Epub 2010 Aug 4. Congenital Trypanosoma cruzi infection in neonates and infants from two regions of Chile where Chagas' disease is endemic. Jercic MI, Mercado R, Villarroel R.PMCID: PMC2953114 [Available on 2011/4/1]
	PMID: 20686091 [PubMed - indexed for MEDLINE]
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9.	Int J Parasitol. 2009 Dec;39(14):1603-10. Epub 2009 Jul 14. Genetically different isolates of Trypanosoma cruzi elic it different infection dynamics in raccoons (Procyon lotor) and Virginia opossums (Didelphis virginiana). Roellig DM, Ellis AE, Yabsley MJ. Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30606, USA. droellig@uga.edu Abstract Trypanosoma cruzi is a genetically and biologically diverse species. In the current study we determined T. cruzi infection dynamics in two common North American reservoirs, Virginia opossums (Didelphis virginiana) and raccoons (Procyon lotor). Based on previous molecular and culture data from naturally-exposed animals, we hypothesised that raccoons would have a longer patent period than opossums, and raccoons would be competent reservoirs for both genotypes T. cruzi I (TcI) and TcIIa, while opossums would only serve as hosts for TcI. Individuals (n=2 or 3) of each species were inoculated with 1x10(6) culture-derived T. cruzi trypomastigotes of TcIIa (North American (NA) - raccoon), TcI (NA - opossum), TcIIb (South American - human), or both TcI and TcIIa. Parasitemias in opossums gradually increased and declined rapidly, whereas parasitemias peaked sooner in raccoons and they maintained relatively high parasitemia for 5weeks. Raccoons became infected with all three T. cruzi strains, while opossums only became infected with TcI and TcIIb. Although opossums were susceptible to TcIIb, infection dynamics were dramatically different compared with TcI. Opossums inoculated with TcIIb seroconverted, but parasitemia duration was short and only detectable by PCR. In addition, raccoons seroconverted sooner (3-7days post inoculation) than opossums (10days post inoculation). These data suggest that infection dynamics of various T. cruzi strains can differ considerably in different wildlife hosts. PMCID: PMC2760633 Free PMC Article
	PMID: 19607833 [PubMed - indexed for MEDLINE]
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10.	Int J Parasitol. 2009 Nov;39(13):1455-64. Epub 2009 Jun 6. Enzymes of the antioxidant network as novel determiners of Trypanosoma cruzi virulence. Piacenza L, Zago MP, Peluffo G, Alvarez MN, Basombrio MA, Radi R. Departamento de Bioquímica and Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay. Abstract Virulence of Trypanosoma cruzi depends on a variety of genetic and biochemical factors. It has been proposed that components of the parasites' antioxidant system may play a key part in this process by pre-adapting the pathogen to the oxidative environment encountered during host cell invasion. Using several isolates (10 strains) belonging to the two major phylogenetic lineages (T. cruzi-I and T. cruzi-II), we investigated whether there was an association between virulence (ranging from highly aggressive to attenuated isolates at the parasitemia and histopathological level) and the antioxidant enzyme content. Antibodies raised against trypanothione synthetase (TcTS), ascorbate peroxidase (TcAPX), mitochondrial and cytosolic tryparedoxin peroxidases (TcMPX and TcCPX) and trypanothione reductase (TcTR) were used to evaluate the antioxidant enzyme levels in epimastigote and metacyclic trypomastigote forms in the T. cruzi strains. Levels of TcCPX, TcMPX and TcTS were shown to increase during differentiation from the non-infective epimastigote to the infective metacyclic trypomastigote stage in all parasite strains examined. Peroxiredoxins were found to be present at higher levels in the metacyclic infective forms of the virulent isolates compared with the attenuated strains. Additionally, an increased resistance of epimastigotes from virulent T. cruzi populations to hydrogen peroxide and peroxynitrite challenge was observed. In mouse infection models, a direct correlation was found between protein levels of TcCPX, TcMPX and TcTS, and the parasitemia elicited by the different isolates studied (Pearson's coefficient: 0.617, 0.771, 0.499; respectively, P<0.01). No correlation with parasitemia was found for TcAPX and TcTR proteins in any of the strains analyzed. Our data support that enzymes of the parasite antioxidant armamentarium at the onset of infection represent new virulence factors involved in the establishment of disease.
	PMID: 19505468 [PubMed - indexed for MEDLINE]
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