REPOSITÓRIO UFOP :: Navegando por Autor "Tafuri, Washington Luiz"

Navegando por Autor "Tafuri, Washington Luiz"

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Activity of the new triazole derivative albaconazole against Trypanosoma (Schizotrypanum) cruzi in dog hosts.
(2004) Guedes, Paulo Marcos da Matta; Urbina, Julio Alberto; Lana, Marta de; Afonso, Luís Carlos Crocco; Veloso, Vanja Maria; Tafuri, Washington Luiz; Coelho, George Luiz Lins Machado; Chiari, Egler; Bahia, Maria Terezinha
Albaconazole is an experimental triazole derivative with potent and broad-spectrum antifungal activity and a remarkably long half-life in dogs, monkeys, and humans. In the present work, we investigated the in vivo activity of this compound against two strains of the protozoan parasite Trypanosoma (Schizotrypanum) cruzi, the causative agent of Chagas’ disease, using dogs as hosts. The T. cruzi strains used in the study were previously characterized (murine model) as susceptible (strain Berenice-78) and partially resistant (strain Y) to the drugs currently in clinical use, nifurtimox and benznidazole. Our results demonstrated that albaconazole is very effective in suppressing the proliferation of the parasite and preventing the death of infected animals. Furthermore, the parasitological, PCR, serological, and proliferative assay results indicated parasitological cure indices of 25 and 100% among animals inoculated with T. cruzi strain Y when they were treated with albaconazole at 1.5 mg/kg of body weight/day for 60 and 90 days, respectively. On the other hand, although albaconazole given at 1.5 mg/kg/day was very effective in suppressing the proliferation of the parasite in animals infected with the Berenice-78 T. cruzi strain, no parasitological cure was observed among them, even when a longer treatment period (150 doses) was used. In conclusion, our results demonstrate that albaconazole has trypanocidal activity in vivo and is capable of inducing radical parasitological cure, although natural resistance to this compound was also indicated. Furthermore, the compound can be used in long-term treatment schemes (60 to 150 days) with minimal toxicity and thus represents a potentially useful candidate for the treatment of human Chagas’ disease.
American tegumentary leishmaniasis : effectiveness of an immunohistochemical protocol for the detection of leishmania in skin.
(2013) Alves, Cibele Fontes; Alves, Cíntia Fontes; Figueiredo, Maria Marta; Souza, Carolina Carvalho de; Coelho, George Luiz Lins Machado; Melo, Maria Norma; Tafuri, Washington Luiz; Raso, Pedro; Soares, Rodrigo Pedro Pinto; Tafuri, Wagner Luiz
Background: American tegumentary leishmaniasis (ATL) is endemic in Latin America, where Brazil has over 27 thousand cases per year. The aim of the present study was to develop an immunohistochemical method (IHC) for ATL diagnosis. For this purpose, we used serum from a dog naturally infected with Leishmania (L) infantum (canine hyperimmune serum) as the primary antibody, followed by a detection system with a secondary biotinylated antibody. Methodology: Skin samples were obtained from 73 patients in an endemic area of Caratinga, Minas Gerais (MG) State, Brazil all testing positive for ATL with the Montenegro skin test, microscopy, and PCR. Canine hyperimmune serum of a dog naturally infected with Leishmania (L.) infantum was employed as a primary antibody in an immunohistochemical diagnostic method using streptavidin-biotin peroxidase. To assess the specificity of this reaction, IHC assays employing two monoclonal antibodies were carried out. As the polymer-based technology is less time-consuming and labor intensive than the IHC labeled streptavidin-biotin peroxidase method, we compared the two methods for all samples. Results: The IHC method detected ATL in 67 of the 73 cases (91.8%). Immunolabeled parasites were primarily detected inside macrophages either in the superficial or the deep dermis. Detection was facilitated by the high contrast staining of amastigotes (dark brown) against the light blue background. A lower detection rate (71.2%) was observed with the both of the monoclonal Leishmania antibodies compared to the canine hyperimmune serum. This may have been due to a nonspecific background staining observed in all histological samples rendering positive detection more difficult. The higher efficacy of the canine hyperimmune serum in the IHC method was confirmed by the method using streptavidin-biotin peroxidase as well as that with the polymer-based technology (biotin-avidin-free system). Conclusions: The data are encouraging with regard to validating IHC as a standard alternative method for ATL diagnosis.
Cardiac plexus of dogs experimentally infected with Trypanosoma cruzi: inflammatory lesions and quantitative studies.
(1995) Caliari, Marcelo Vidigal; Lana, Marta de; Caliari, Estela Regina de Oliveira; Tafuri, Washington Luiz
Qualitative and quantitative aspects of the superficial and profound cardiac plexus of dogs experimentally infected with Be-62 and Be-78 strains of Trypanosoma cruzi were studied. Animals were autopsied in the acute phase o f infection. The inflammatory process, lesions and number of parasites were more intense and frequent in animals infected with the Be-78 strain than in those infected with Be-62. Despite this, no statistically significant differences could be found between the number of neuron bodies in the ganglia of infected and control dogs.
Chemotherapy with Benznidazole and Itraconazole for mice infected with different Trypanosoma cruzi clonal genotypes.
(2003) Toledo, Max Jean de Ornelas; Bahia, Maria Terezinha; Carneiro, Cláudia Martins; Martins Filho, Olindo Assis; Tibayrenc, Michel; Barnabé, Christian; Tafuri, Washington Luiz; Lana, Marta de
The benznidazole (BZ) and itraconazole (ITC) susceptibilities of a standard set of Trypanosoma cruzi natural stocks were evaluated during the acute phase and the chronic phase of experimental chagasic infection in BALB/c mice. Twenty laboratory-cloned stocks representative of the total phylogenetic diversity of T. cruzi, including genotypes 20 and 19 (T. cruzi I) and genotypes 39 and 32 (T. cruzi II), were analyzed. Our results demonstrate important differences among stocks that could be pointed out as markers of biological behavior. Members of the T. cruzi I group were highly resistant to both BZ and ITC, whereas members of the T. cruzi II group were partially resistant to both drugs, despite their susceptibilities to ITC during the chronic phase of infection. The resistance to BZ observed for T. cruzi I was mainly triggered by genotype 20 isolates, whereas resistance to ITC was due to both genotype 20 and 19 isolates. Two polar patterns of response to BZ observed for genotype 39 isolates had a major impact on the partial resistance pattern observed for members of the T. cruzi II group. Genotype 32 isolates showed a typical profile of susceptibility. The correlation between the response to treatment and phylogenetic classification of T. cruzi stocks was clearer for ITC than for BZ. In conclusion, the data presented show a correlation between phylogenetic divergence among T. cruzi stocks and their susceptibilities to chemotherapeutic agents in vivo. Our results warn of the necessity to take into account the lesser genetic subdivisions of T. cruzi stocks since the upper subdivisions (T. cruzi I and II) show a great deal of heterogeneity for in vivo drug susceptibility.
Comparison of Trypanosoma cruzi infection in dogs inoculated with blood or metacyclic trypomastigotes of Berenice-62 and Berenice-78 strains via intraperitoneal and conjunctival routes.
(2002) Bahia, Maria Terezinha; Tafuri, Washington Luiz; Caliari, Marcelo Vidigal; Veloso, Vanja Maria; Carneiro, Cláudia Martins; Coelho, George Luiz Lins Machado; Lana, Marta de
Neste trabalho foi avaliada a influência da fonte do inóculo (tripomastigota sangüíneo ou metacíclico) e da via de inoculação (intraperitoneal ou conjuntival) na evolução da infecção de cães pelas cepas Berenice- 62 e Berenice-78 do Trypanosoma cruzi. O índice de infectividade e os níveis de parasitaemia foram significativamente influenciados pelas condições de inoculação, tendo sido maiores nos animais inoculados pela via conjuntival, com tripomastigotas metacíclicos. Por outro lado, não foi observada relação entre as condições de inóculo e as lesões teciduais nos animais infectados com a cepa Berenice-78, pois todos apresentaram miocardite aguda severa. De forma inversa, nos animais infectados com a cepa Berenice-62, foi observada miocardite aguda intensa apenas nos cães inoculados com tripomastigotas metacíclicos, via intraperitoneal. Estes resultados sugerem que a taxa de infectividade e a evolução da infecção do hospedeiro vertebrado pelo T. cruzi podem ser marcadamente influenciadas pela fonte do inóculo e pela via de inoculação, mesmo quando a mesma cepa do parasita é utilizada.
Different infective forms trigger distinct immune response in experimental Chagas disease.
(2012) Vieira, Paula Melo de Abreu; Franscisco, Amanda Fortes; Machado, Evandro Marques de Menezes; Nogueira, Nívia Carolina; Fonseca, Kátia da Silva; Reis, Alexandre Barbosa; Carvalho, Andréa Teixeira de; Martins Filho, Olindo Assis; Tafuri, Washington Luiz; Carneiro, Cláudia Martins
Although metacyclic and blood trypomastigotes are completely functional in relation to parasite-host interaction and/or target cell invasion, they differ in the molecules present on the surface. Thus, aspects related to the variability that the forms of T. cruzi interacts with host cells may lead to fundamental implications on the immune response against this parasite and, consequently, the clinical evolution of Chagas disease. We have shown that BT infected mice presented higher levels of parasitemia during all the acute phase of infection. Moreover, the infection with either MT or BT forms resulted in increased levels of total leukocytes, monocytes and lymphocytes, specifically later for MT and earlier for BT. The infection with BT forms presented earlier production of proinflammatory cytokine TNF-a and later of IFN-c by both T cells subpopulations. This event was accompanied by an early cardiac inflammation with an exacerbation of this process at the end of the acute phase. On the other hand, infection with MT forms result in an early production of IFN-c, with subsequent control in the production of this cytokine by IL-10, which provided to these animals an immunomodulatory profile in the end of the acute phase. These results are in agreement with what was found for cardiac inflammation where animals infected with MT forms showed intense cardiac inflammation later at infection, with a decrease in the same at the end of this phase. In summary, our findings emphasize the importance of taking into account the inoculums source of T. cruzi, since vectorial or transfusional routes of T. cruzi infection may trigger distinct parasite-host interactions during the acute phase that may influence relevant biological aspects of chronic Chagas disease.
Dogs infected with the blood trypomastigote form of Trypanosomacruzi display an increase expression of cytokines and chemokines plusan intense cardiac parasitism during acute infection.
(2014) Souza, Sheler Martins de; Vieira, Paula Melo de Abreu; Roatt, Bruno Mendes; Reis, Levi Eduardo Soares; Fonseca, Kátia da Silva; Nogueira, Nívia Carolina; Reis, Alexandre Barbosa; Tafuri, Washington Luiz; Carneiro, Cláudia Martins
The recent increase in immigration of people from areas endemic for Chagas disease (Trypanosoma cruzi)to the United States and Europe has raised concerns about the transmission via blood transfusion andorgan transplants in these countries. Infection by these pathways occurs through blood trypomastigotes(BT), and these forms of T. cruzi are completely distinct of metacyclic trypomastigotes (MT), releasedby triatomine vector, in relation to parasite–host interaction. Thus, research comparing infection withthese different infective forms is important for explaining the potential impacts on the disease course.Here, we investigated tissue parasitism and relative mRNA expression of cytokines, chemokines, andchemokine receptors in the heart during acute infection by MT or BT forms in dogs. BT-infected dogspresented a higher cardiac parasitism, increased relative mRNA expression of pro-inflammatory andimmunomodulatory cytokines and of the chemokines CCL3/MIP-1 _, CCL5/RANTES, and the chemokinereceptor CCR5 during the acute phase of infection, as compared to MT-infected dogs. These results suggestthat infection with BT forms may lead to an increased immune response, as revealed by the cytokinesratio, but this kind of immune response was not able to control the cardiac parasitism. Infection with theMT form presented an increase in the relative mRNA expression of IL-12p40 as compared to that of IL-10or TGF- _1. Correlation analysis showed increased relative mRNA expression of IFN- _ as well as IL-10,which may be an immunomodulatory response, as well as an increase in the correlation of CCL5/RANTESand its CCR5 receptor. Our findings revealed a difference between inoculum sources of T. cruzi, as vectorialor transfusional routes of T. cruzi infection may trigger distinct parasite–host interactions during the acutephase, which may influence immunopathological aspects of Chagas disease.
Effects of specific treatment on parasitological and histopathological parameters in mice infected with different Trypanosoma cruzi clonal genotypes.
(2004) Toledo, Max Jean de Ornelas; Bahia, Maria Terezinha; Veloso, Vanja Maria; Carneiro, Cláudia Martins; Coelho, George Luiz Lins Machado; Alves, Cíntia Fontes; Martins, Helen Rodrigues; Cruz, Ruth Elizabeth; Tafuri, Washington Luiz; Lana, Marta de
The goal of this study was to verify the effect of specific treatment on parasitological and histopathological parameters in mice experimentally infected with different Trypanosoma cruzi clonal genotypes. Twenty cloned stocks were selected, representative of the whole phylogenetic diversity of the protozoan and belonging to the clonal genotypes 19 and 20 (T. cruzi I) and 39 and 32 (T. cruzi II). The stocks were inoculated in 40 BALB/c mice divided into four groups: (i) treated with benznidazole, (ii) treated with itraconazole and (iii and iv) untreated control groups (NT) for each drug, respectively. Seven parameters related to parasitaemia curves and histopathological lesions were analysed. Four during the acute phase (AP) and three during both the AP and chronic phase (CP) of infection. Statistical comparison between benznidazole-treated and NT groups for the biological parameters showed significant differences for all genotypes. Benznidazole treatment led to lower patent period, maximum of parasitaemia, day of maximum parasitaemia and area under the parasitaemia curve for all genotypes analysed. Percentage of positive haemoculture during AP and CP was lower for genotypes 19 and 32. Tissue parasitism (TP) and inflammatory process (IP) during AP were lower for genotypes 19 and 32, respectively. In general, itraconazole treatment induced a smaller reduction in these same parameters between treated and NT animals in relation to benznidazole treatment. Our results indicate that phylogenetic divergence among T. cruzi clonal genotypes must be taken in account in chemotherapy and studies dealing with all aspects of the parasite and the disease.
Estudo quantitativo e qualitativo dos plexos de Auerbach e Neissner do esôfago de cães inoculados com o Trypanosoma cruzi.
(1996) Caliari, Estela Regina de Oliveira; Caliari, Marcelo Vidigal; Lana, Marta de; Tafuri, Washington Luiz
Andrade caracterizou bem a fase aguda e a forma indeterminada da cardiopatia chagásica no cão1. Lana inoculando a cepa Be78 em cães caracterizou muito bem a cardiopatia chagásica crônica fibrosame, com quadro clínico e eletrocardiográfico muito semelhante a forma cardíaca humana". Pelo que sabemos, até o momento, não se documentou claramente a forma digestiva (megaesôfago e megacólon) experimental. Também não se tem notícias de estudos sistematizados dos neurônios dos plexos de Auerbach e Meissner do esôfago na tripanosomía s e cruzi experimental. Por estas razões realizamos o presente trabalho , no pressuposto de encontrar prováveis lesões neuronais do esôfago na infecção chagásica experimental canina.
Experimental Chagas' disease in dogs.
(1992) Lana, Marta de; Chiari, Egler; Tafuri, Washington Luiz
Fase crônica cardíaca fibrosante da Tripanossomíase cruzi experimental no cão.
(1988) Lana, Marta de; Tafuri, Washington Luiz; Caliari, Marcelo Vidigal; Bambirra, Eduardo Alves; Chiari, Cléa de Andrade; Leite, Virginea Hora Rios; Barbosa, Alfredo José Afonso; Toledo, Max Jean de Ornelas; Chiari, Egler
De acordo com os trabalhos publicados ate o momento, o cão esta sendo considerado, com ressalvas, como modelo ideal para o estudo da fase aguda e crônica indeterminada da tripanossomiase cruz jl 2 3 4 5 6 7 14 15 18 19 20 21 24 Os requisitos para um modelo ideal, estabelecidos pelo Comite de Doenca de Chagas do Programa Especial de Treinamento e Pesquisa de Doenças Parasitarias da Organização Mundial de Saude25 podem ser assim discriminados: permitir o isolamento do parasito ao longo do curso da infecção; apresentar reações sorológicas positivas, indicativas da persistência da infecção; apresentar manifestações clinicas da doença de Chagas crônica; desenvolver miocardite, miosite e outras alterações patológicas que caracterizam a doença; induzir a resposta imune contra tecido do hospedeiro. Há mais de oito anos estamos a procura de um modelo que não somente preencha todos os requisitos acima citados mas, principalmente, que desenvolva a cardiopatia grave evolutiva fibrosante com todas alterações clinicas observadas na forma humana. Ate o momento, os resultados que encontramos parecem indicar que alcançamos tal objetivo no modelo cão. A partir destes resultados e dos de outros autores, tentaremos aplicar metodologia moderna no estudo dos vários fatores patogeneticos no pressuposto de que, assim, será possível chegar ao esclarecimento da patogenia e de fisiopatologia das diferentes formas anatomoclinicas da doença. Dentre os numerosos fatores patogeneticos ate agora aventados, a fibrose nos parece o mais importante na determinação da insuficiência cardíaca congestiva (ICC) e da aperistalse. Não existe qualquer outra cardiopatia e/ou mega com aspecto tão peculiar. No miocárdio bem como nos megas, a fibrose (fibrilopoese) e focal e difusa ao mesmo tempo23. O presente trabalho tem a finalidade de documentar a fase crônica da doença de Chagas em cães que recebem inóculos diversos das cepas Colombiana13 e Berenice-7817 de T. cruzi, destacando aqueles animais que desenvolveram a cardiopatia fibrosante, com sinais e sintomas clínicos de ICC.
Follow-up of experimental chronic Chagas’ disease in dogs : use of polymerase chain reaction (PCR) compared with parasitological and serological methods.
(2002) Araújo, Flávio Marcos Gomes de; Bahia, Maria Terezinha; Magalhães, Neuza Maria de; Martins Filho, Olindo Assis; Veloso, Vanja Maria; Carneiro, Cláudia Martins; Tafuri, Washington Luiz; Lana, Marta de
In this study, the polymerase chain reaction (PCR) was compared with parasitological and serological methods to detect the infection in dogs, 5–12 years after experimental infection with Trypanosoma cruzi. The ability of parasitological methods to identify a positive animal was 22 and 11% by hemoculture and xenodiagnosis/xenoculture, respectively. On the other hand, the serological tests, including conventional serology and anti-live trypomastigote antibodies (ALTA) were positive in all infected dogs. Despite its low sensitivity, if considering only one reaction, the PCR analysis showed 100% of positivity, demonstrating the presence of parasite kDNA in all infected dogs. To identify a positive dog required at least two blood samples and up to nine repeated reactions using the same sample. Serial blood sample collection, ranging from 1 to 9, revealed that the percentage of dogs with positive PCR ranged from 67 to 100%. These findings suggested that, although the PCR is useful to detect the parasite in infected hosts, it should not be used isolated for the diagnosis of Chagas’ disease and warn for the necessity of serial blood collection and re-tests. Moreover, these data validate once more the dog as a model for Chagas’ disease since they demonstrate the permanence of infection by PCR, parasitological and serological methods, reaching relevant requisites for an ideal model to study this disease.
Further genetic characterization of the two Trypanosoma cruzi Berenice strains (Be-62 and Be-78) isolated from the first human case of Chagas disease (Chagas, 1909).
(2006) Cruz, Ruth Elizabeth; Macedo, Andréa Mara; Barnabé, Christian; Freitas, Jorge Marcelo de; Chiari, Egler; Veloso, Vanja Maria; Carneiro, Cláudia Martins; Bahia, Maria Terezinha; Tafuri, Washington Luiz; Lana, Marta de
We describe here an extension of a previous genetic characterization of Trypanosoma cruzi strains (Be-62 and Be-78) isolated from the patient Berenice, the first human case of Chagas disease [Chagas, C., 1909. Nova Tripanom´ıase humana. Estudos sobre morfologia e o ciclo evolutivo do Schizotrypanum cruzi, n. gen., n. sp., agente etiol´ojico da nova entidade morbida do homem. Mem. Inst. Oswaldo Cruz 1, 159–218]. We wanted to verify the composition of T. cruzi populations originated from these two isolates. In the present work, 22 enzymatic loci (MLEE), nine RAPD primers and 7 microsatellite loci were analyzed. Clones from both strains were also characterized to verify whether these strains are mono or polyclonal. Be-62 and Be-78 strains were different in 3 out of 22 enzymatic systems, in 3 out of 9 RAPD primers tested and in all microsatellite loci investigated. However, our data suggests that both strains are phylogenetically closely related, belonging to genetic group 32 from Tibayrenc and Ayala [Tibayrenc, M., Ayala, F.J., 1988. Isoenzime variability in Trypanosoma cruzi, the agent of Chagas’ disease: genetical, taxonomical, and epidemiological significance. Evolution 42, 277–292], equivalent to zymodeme 2 and T. cruzi II major lineage which, in Brazil, comprises parasites from the domestic cycle of the disease. Microsatellite analyses showed differences betweenthe parental strains but suggested that both populations are monoclonal since each strain and their respective clones showed the same amplification products.
Heart autonomic innervation during the acute phase of the experimental American trypanosomiasis in the dog.
(1998) Machado, Conceição Ribeiro da Silva; Caliari, Marcelo Vidigal; Lana, Marta de; Tafuri, Washington Luiz
Heart autonomic innervation was studied in dogs during the acute phase of the experimental infection with the Berenice-78 strain of Trypanosoma cruzi. A glyoxylic acid–induced fluorescence method for catecholamines and a thiocholine method for demonstrating acetylcholinesterase activity showed the sympathetic and the parasympathetic nerve fibers, respectively. At day 34 of infection, moderate-to-intense rarefaction of both cholinergic and noradrenergic nerve fibers occurred in the atria of all animals coincident with moderate to intense myocarditis. In the ventricles, sympathetic denervation was clearly present only when the inflammatory processes were moderate to intense. Preliminary results on the chronic phase indicate that normal autonomic innervation coexists with an incipient chronic fibrosing myocarditis.
Histopathological features, parasite density and cell phenotype of the popliteal lymph node in canine visceral leishmaniasis.
(2008) Giunchetti, Rodolfo Cordeiro; Martins Filho, Olindo Assis; Carneiro, Cláudia Martins; Mayrink, Wilson; Marques, Marcos José; Tafuri, Washington Luiz; Oliveira, Rodrigo Corrêa de; Reis, Alexandre Barbosa
While enlargement of popliteal lymph nodes (LN) is frequently described in canine visceral leishmaniasis (CVL), there are few histopathologic studies of lymph nodes during this chronic immunopathological condition.Besides a detailed histopathologic analysis, we have characterized the parasite load andmajor immunophenotypic features of theLNin Leishmania (Leishmania) chagasi-infected dogs. Our major histopathological findings highlight that hypertrophy/hyperplasia of LN cortical and medullary zones was the principal characteristic observed in asymptomatic dogs (AD), whereas atrophy of LN cortical zone was predominant in symptomatic animals (SD). The LN parasite density detected by anti-Leishmania immunohistochemical assay or expressed as Leishman Donovan Units was also highly correlated with the skin parasitism, the most reliable parameter to decode the clinical status of CVL. The major LN immunophenotypic changes during ongoing CVL were an increased frequency of T-lymphocytes, particularly CD8+ T-cells, upregulation of MHC-II expression by lymphocytes and decreased levels of CD21+ B-cells. Our findings further demonstrated that changes in the LNB-lymphocyte compartment exhibited a negative correlation with the skin parasite load. Conversely, we also showed evidence for a positive association between skin parasitismandLNT-cell-mediated immunity, suggesting thatT-cells, especiallyCD8+ lymphocytes, may have a Type-2 immunological profile in this lymphoid tissue in response to CVL.
Host-parasite interactions in chagas disease : genetically unidentical isolates of a single Trypanosoma cruzi strain identified In vitro via LSSP-PCR.
(2015) Paiva, Nívia Carolina Nogueira de; Vieira, Paula Melo de Abreu; Oliveri, Larissa Maris Rezende; Fonseca, Kátia da Silva; Lana, Gwenaelle Elza Nathalie Pound; Oliveira, Maykon Tavares de; Veloso, Vanja Maria; Reis, Alexandre Barbosa; Tafuri, Washington Luiz; Carneiro, Cláudia Martins
The present study aims at establishing whether the diversity in pathogenesis within a genetically diverse host population infected with a single polyclonal strain of Trypanosoma cruzi is due to selection of specific subpopulations within the strain. For this purpose we infected Swiss mice, a genetically diverse population, with the polyclonal strain of Trypanosoma cruzi Berenice-78 and characterized via LSSP-PCR the kinetoplast DNA of subpopulations isolated from blood samples collected from the animals at various times after inoculation (3, 6 and 12 months after inoculation). We examined the biological behavior of the isolates in acellular medium and in vitro profiles of infectivity in Vero cell medium. We compared the characteristics of the isolates with the inoculating strain and with another strain, Berenice 62, isolated from the same patient 16 years earlier. We found that one of the isolates had intermediate behavior in comparison with Berenice-78 and Berenice-62 and a significantly different genetic profile by LSSP-PCR in comparison with the inoculating strain. We hereby demonstrate that genetically distinct Trypanosoma cruzi isolates may be obtained upon experimental murine infection with a single polyclonal Trypanosoma cruzi strain.
Humoral immune response in dogs experimentally infected with Trypanosoma cruzi.
(1991) Lana, Marta de; Vieira, Lauro Mello; Coelho, George Luiz Lins Machado; Chiari, Egler; Veloso, Vanja Maria; Tafuri, Washington Luiz
Immunohistochemical studies in acute and chronic canine chagasic cardiomyopathy.
(2002) Caliari, Marcelo Vidigal; Lana, Marta de; Cajá, Rosângela Aparecida França; Carneiro, Cláudia Martins; Bahia, Maria Terezinha; Santos, César Augusto Bueno dos; Magalhães, Gustavo Albergaria; Sampaio, Ivan Barbosa Machado; Tafuri, Washington Luiz
A major characteristic of Chagas’ disease is a myocarditis constituted primarily of mononuclear cells, both during the acute and chronic phases of the disease. Using monoclonal antibodies and image analyses we have quantified canine CD8+ T cells (caCD8+ T cells), canine CD4+ T cells (caCD4+ T cells) and neutrophils in canine chagasic myocardiopathy induced by two strains isolated from the first human clinical case of Chagas’ disease. We also evaluated the influence of tissue parasitism in the genesis of chronic myocarditis through immunohistochemistry. As in human myocarditis, there was a predominance of T lymphocytes in the inflammatory infiltrate in all animals studied. In the dogs inoculated with strain Berenice 78 (Be78) and necropsied during the acute phase of infection, we found 58% caCD8+ and 42% caCD4+ T cells. In chronically infected animals, 53% of T cells were represented by caCD8+ and 47% were caCD4+ T cells. Since normal canine lymphoid organs are constituted by 70–80% caCD4+ T cells and 20–30% caCD8+ T cells our results indicate a higher proliferation of caCD8+ T cells in dogs inoculated with the Be78 strain. In chronic myocarditis induced by the Berenice 62 (Be62) strain, caCD8+ cells constituted 33% of the T cells and 67% were caCD4+ T cells, a proportion similar to that found in normal canine lymphoid organs. Since the Be78 strain induces greater loss of myocardiocytes than strain Be62, we believe that the caCD8+ T cells, among other factors, can be important in the genesis of these lesions. Amastigote nests and immunohistochemically labelled Trypanosoma cruzi antigen were not found in dogs necropsied during the chronic phase. The absence of the parasite in the myocardium suggests the involvement of other
Influence of the long-term Trypanosoma cruzi infection in vertebrate host on the genetic and biological diversity of the parasite.
(2005) Veloso, Vanja Maria; Romanha, Alvaro José; Lana, Marta de; Murta, Silvane Maria Fonseca; Carneiro, Cláudia Martins; Alves, Cíntia Fontes; Borges, Erika Carime; Tafuri, Washington Luiz; Coelho, George Luiz Lins Machado; Chiari, Egler; Bahia, Maria Terezinha
The influence of the long-term Trypanosoma cruzi infection in vertebrate host on the biological and genetic properties of the parasite was evaluated. Four T. cruzi isolates obtained from different chronic chagasic dogs infected with Berenice-78 T. cruzi strain during 2 and 7 years were comparatively analyzed. The long-term T. cruzi infection has led to alterations in parasitemia, virulence and pathogenicity of Be-78 strain for mice. These biological parameters varied from low to high in realation to the parental strain. Randomly amplified polymorphic DNA and isoenzyme profiles detected two distinct genetic groups of parasites. The first group included the parental strain and two T. cruzi isolates, and the second group the two other isolates. Interestingly, the isolates of the second group showed a reversibility of the genetic profile to the parental strain after 25 passages in mice. No correlation between the genetic groups and biological properties of the isolates was observed. Our findings confirmed the population heterogeneity of the Be-78 strain, and showed how differently it responds to the long-term infection in the same vertebrate hosts.
Myenteric plexus is differentially affected by infection with distinct Trypanosoma cruzi strains in Beagle dogs.
(2014) Paiva, Nívia Carolina Nogueira de; Fonseca, Kátia da Silva; Vieira, Paula Melo de Abreu; Diniz, Lívia de Figueiredo; Caldas, Ivo Santana; Moura, Sandra Aparecida Lima de; Veloso, Vanja Maria; Guedes, Paulo Marcos da Matta; Tafuri, Washington Luiz; Bahia, Maria Terezinha; Carneiro, Cláudia Martins
Chagasic megaoesophagus and megacolon are characterised by motor abnormalities related to enteric nervous system lesions and their development seems to be related to geographic distribution of distinct Trypanosoma cruzi subpopulations. Beagle dogs were infected with Y or Berenice-78 (Be-78) T. cruzi strains and necropsied during the acute or chronic phase of experimental disease for post mortem histopathological evaluation of the oesophagus and colon. Both strains infected the oesophagus and colon and caused an inflammatory response during the acute phase. In the chronic phase, inflammatory process was observed exclusively in the Be-78 infected animals, possibly due to a parasitism persistent only in this group. Myenteric denervation occurred during the acute phase of infection for both strains, but persisted chronically only in Be-78 infected animals. Glial cell involvement occurred earlier in animals infected with the Y strain, while animals infected with the Be-78 strain showed reduced glial fibrillary acidic protein immunoreactive area of enteric glial cells in the chronic phase. These results suggest that although both strains cause lesions in the digestive tract, the Y strain is associated with early control of the lesion, while the Be-78 strain results in progressive gut lesions in this model.

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