Bacterial vaginosis: prevalence, risk profile and association with sexually transmitted infections / Vaginose bacteriana: prevalência, perfil de risco e associação com infecções sexualmente transmissíveis / Vaginosis bacteriana: prevalencia, perfil de riesgo y asociación con infecciones de transmisión sexual

Background and Objectives: Bacterial vaginosis (BV) is the most common cause of vaginal discharge in the world. The study aimed to estimate the prevalence and to identify risk factors associated with bacterial vaginosis. Methods: A cross-sectional study was conducted in Ouro Preto, Brazil, between February and December 2017. Three hundred and forty-one women aged 18 years or older, users of the Brazilian Unified Health System, participated in this study. Women who used oral or topical antibiotics in the four weeks prior to the sample collection and women who had undergone a total hysterectomy were excluded from the study. After signing the Informed Consent Form and filling out a questionnaire containing sociodemographic, behavioral and sexual data, the participants were directed to the collection room, where the nurse collected the samples for the preventive examination of the cervix and also two vaginal swabs. Vaginal swabs and cervical samples were analyzed for cytological abnormalities and BV using Gram staining and cytology. Pathogens causing sexually transmitted infections (STIs) were identified by Polymerase Chain Reaction (PCR). For the analysis of the data, statistical package STATA version 10.0 was used. This study was approved by the Research Ethics Committee of the Federal University of Ouro Preto (UFOP). Results: During the study, 341 women were evaluated. The prevalence of BV using Gram staining (32.5% [CI95% 27.7-37.7%]) and cytology (27.7% [CI95% 23.032.8%]) was similar, however, the sensitivity of cytology was lower (77.8%). Risk factors associated with BV were smoking (IRR 1.5 [CI95%: 1.1  2.1]), use of an intrauterine device (IRR 2.8 [CI95%: 1.2 - 6.5]), and past medical history of BV (IRR 1.5 [CI95%: 1.1 - 2.1]). Correlation between the presence of BV and Trichomonas vaginalis (TV) infection (r=0.24) was observed. Conclusion: The prevalence of BV was affected by life habits and was prevalent in women with TV. Thus, behavioral and social prevention approaches to women with diverse risk profiles may help mitigate TV/BV prevalence and recurrence of BV.(AU)

Contexte et objectifs: La vaginose bactérienne (VB) est la cause la plus fréquente de pertes vaginales dans le monde. Le but de cette étude était d'évaluer la prévalence et les facteurs associés à la vaginose bactérienne. Méthodes: Il s'agit d'une approche descriptive, transversale et quantitative réalisée à Ouro Preto, Minas Gerais, Brésil, entre février et décembre 2017. 341 femmes ont participé à cette étude, âgées de 18 ans ou plus, utilisatrices du Système de santé unifié. Les femmes ayant utilisé des antibiotiques oraux ou topiques dans les quatre semaines précédant le prélèvement et les femmes ayant subi une hystérectomie totale ont été exclues de l'étude. Après avoir signé le formulaire de consentement éclairé et rempli un questionnaire contenant des données sociodémographiques, comportementales et sexuelles, les participants ont été dirigés vers la salle de collecte, où l'infirmière a prélevé les échantillons pour l'examen préventif du col de l'utérus. et aussi deux écouvillons vaginaux. Les échantillons de frottis vaginaux et cervicaux ont été analysés pour les anomalies cytologiques et VB en utilisant la coloration de Gram et la cytologie. Les agents pathogènes causant des infections sexuellement transmissibles (IST) ont été identifiés par réaction en chaîne par polymérase. Pour l'analyse des données, le progiciel statistique STATA version 10.0 a été utilisé. Cette étude a été approuvée par le Comité d'éthique de la recherche de l'Université fédérale d'Ouro Preto (UFOP). Résultats: Au cours de l'étude, 341 femmes ont été évaluées. La prévalence de la VB avec coloration de Gram (32,5% [IC 95% 27,7 - 37,7%]) et de la cytologie (27,7% [IC 95% 23,0 - 32,8%]) était similaire, cependant la sensibilité cytologique était plus faible (77,8%). Les facteurs de risque associés à la VB étaient le tabagisme (IRR 1,5 [IC 95%: 1,1 - 2,1]), l'utilisation d'un dispositif intra-utérin (IRR 2,8 [IC 95%: 1,2 - 6,5] ) et antécédents médicaux de VB (IRR 1,5 [IC 95%: 1,1 - 2,1]). Il y avait une corrélation entre la présence d'une infection à VB et Trichomonas vaginalis (TV) (r = 0,24). Conclusion: La prévalence de la VB était affectée par le mode de vie et l'infection TV. Ainsi, les approches de prévention comportementale et sociale pour les femmes présentant des profils de risque différents peuvent aider à atténuer la prévalence de la TV / VB et la récurrence de la VB.(AU)

Justificativa e Objetivos: A vaginose bacteriana (VB) é a causa mais comum de corrimento vaginal no mundo. O objetivo desse estudo foi avaliar a prevalência e os fatores associados à vaginose bacteriana. Métodos: Trata-se de um descritivo, de forma transversal e abordagem quantitativa realizado em Ouro Preto, Minas Gerais, Brasil, entre fevereiro a dezembro de 2017. Participaram desse estudo 341 mulheres com idade igual ou superior a 18 anos, usuárias do Sistema Único de Saúde (SUS). Mulheres que usaram antibióticos orais ou tópicos nas quatro semanas anteriores à coleta e mulheres que haviam sido submetidas a uma histerectomia total foram excluídas do estudo. Após a assinatura do Termo de Consentimento Livre e Esclarecido e preenchimento de questionário contendo dados sócio-demográfico, comportamental e sexual, as participantes foram encaminhadas para a sala de coleta, onde a enfermeira realizou a coleta das amostras para o exame preventivo do colo do útero e também de dois swabs vaginais. As amostras de esfregaço vaginal e cervical foram analisadas quanto às anormalidades citológicas e VB usando coloração de Gram e citologia. Patógenos causadores de infecções sexualmente transmissíveis (ISTs) foram identificados por Reação em Cadeia da Polimerase (PCR). Para a análise dos dados foi utilizado o pacote estatístico STATA versão 10.0. O presente estudo foi aprovado pelo Comitê de Ética em Pesquisa da Universidade Federal de Ouro Preto (UFOP). Resultados: Durante o estudo, 341 mulheres foram avaliadas. A prevalência de VB com coloração de Gram (32,5% [IC95% 27,7 - 37,7%]) e citologia (27,7% [IC95% 23,0 - 32,8%]) foi semelhante, porém a sensibilidade da citologia foi menor (77,8%). Os fatores de risco associados ao VB foram tabagismo (IRR 1,5 [IC95%: 1,1 - 2,1]), uso de dispositivo intrauterino (IRR 2,8 [IC 95%: 1,2 - 6,5]) e história médica pregressa de VB (IRR 1,5 [IC95%: 1,1 - 2.1]). Observou-se correlação entre a presença de infecção por VB e Trichomonas vaginalis (TV) (r = 0,24). Conclusão: A prevalência de VB foi afetada por hábitos de vida e infecção por TV. Assim, abordagens de prevenção comportamental e social para mulheres com diversos perfis de risco podem ajudar a mitigar a prevalência de TV / VB e recorrência de VB.(AU)

High-sugar diet leads to obesity and metabolic diseases in ad libitum -fed rats irrespective of caloric intake

ABSTRACT Objective Provide a comprehensive view of the events surrounding the sugar consumption, under conditions of energy equivalence; through the analysis of behavioral aspects of intake, and of biochemical, metabolic and physiological parameters, as well as the effect of this nutrient on the plasticity of adipose tissue. Materials and methods Newly weaned male Wistar rats were classified in two groups and subjected to the following normocaloric diets: standard chow diet or to high-sugar diet (HSD) ad libitum for 18 weeks. Results The animals submitted to the HSD were associated with a lower caloric intake during the 18 weeks of experimentation. However, the HSD induced a significant increase in body weight, white adipose tissue weight, adiposity index, Lee index, and the levels of triglycerides and very low-density lipoprotein in the serum. In addition, it induced glucose intolerance, insulin resistance and compensatory increase of insulin secretion by pancreatic β-cells. Also increased heart rate and induced hyperplasia, and hypertrophy of retroperitoneal visceral adipose tissue. In the liver, the HSD was associated with increased hepatic lipid content (i.e., triglycerides and cholesterol) and hepatomegaly. Conclusion The post-weaning consumption of HSD induces an adaptive response in metabolism; however, such an event is not enough to reverse the homeostatic imbalance triggered by the chronic consumption of this macronutrient, leading to the development of metabolic syndrome, irrespective of caloric intake. These findings corroborate recent evidence indicating that sugar is a direct contributor to metabolic diseases independent of a positive energy balance. Arch Endocrinol Metab. 2020;64(1):71-81

Anti-serum validation for use in immunohistochemistry for Trypanosoma cruzi detection

Abstract INTRODUCTION: The detection of Trypanosoma cruzi in tissue samples is important in many situations, such as testing of the reactivation of the infection. The detection of T. cruzi nests in endomyocardial biopsies (EMB) may be useful to evaluate graft rejection. Given their scarcity, such nests are not routinely identified. To increase the diagnosis sensitivity, immunohistochemistry (IHC) may serve as a promising strategy. Here, we validate an antiserum for the detection of T. cruzi infection by IHC. METHODS: We used 1) positive controls (PCs) - 13 EMB, 12 skin biopsies, and 1 heart with T. cruzi nests as sections stained with hematoxylin and eosin (HE); 2) negative controls - a) 10 explant hearts and 10 EMB with no amastigote nests or clinical/laboratory signs of chagasic infection; and b) eight samples with leishmaniasis, toxoplasmosis, or histoplasmosis; and 3) Cases - 31 EMB of chagasic patients with no parasite nests in HE sections but detected positive for T. cruzi DNA by polymerase chain reaction. As a primary antibody, a hyperimmune serum from T. cruzi-infected rabbits was used. RESULTS: IHC results were positive for 21 of 26 PCs (80.8%) and one case of cutaneous leishmaniasis. In 4 of 31 cases, IHC revealed nests (12.9%), which were undetected by conventional histological examination. CONCLUSIONS: This study shows that IHC with the tested antiserum increases the sensitivity of the diagnosis and may be recommended for routine use in EMB analyses of cardiac transplant patients with Chagas disease.

Quality Indicators of Cervical Cytopathology Tests in the Public Service in Minas Gerais, Brazil / Indicadores de qualidade dos exames citopatológicos da rede pública em Minas Gerais, Brasil

Objective The objective of this study is to assess the performance of cytopathology laboratories providing services to the Brazilian Unified Health System (Sistema Único de Saúde - SUS) in the State of Minas Gerais, Brazil. Methods This descriptive study uses data obtained from the Cervical Cancer Information System from January to December 2012. Three quality indicators were analyzed to assess the quality of cervical cytopathology tests: positivity index, percentage of atypical squamous cells (ASCs) in abnormal tests, and percentage of tests compatiblewith high-grade squamous intraepithelial lesions (HSILs). Laboratories were classified according to their production scale in tests per year≤5,000; from 5,001 to 10,000; from 10,001 to 15,000; and 15,001. Based on the collection of variables and the classification of laboratories according to production scale, we created and analyzed a database using Microsoft Office Excel 97-2003. Results In the Brazilian state of Minas Gerais, 146 laboratories provided services to the SUS in 2012 by performing a total of 1,277,018 cervical cytopathology tests. Half of these laboratories had production scales≤5,000 tests/year and accounted for 13.1% of all tests performed in the entire state; in turn, 13.7% of these laboratories presented production scales of > 15,001 tests/year and accounted for 49.2% of the total of tests performed in the entire state. The positivity indexes of most laboratories providing services to the SUS in 2012, regardless of production scale, were below or well below recommended limits. Of the 20 laboratories that performed more than 15,001 tests per year, only three presented percentages of tests compatible with HSILs above the lower limit recommended by the Brazilian Ministry of Health. Conclusion The majority of laboratories providing services to the SUS in Minas Gerais presented quality indicators outside the range recommended by the Brazilian Ministry of Health.

Objetivo Avaliar o desempenho dos laboratórios de citopatologia prestadores de serviço para o Sistema Único de Saúde (SUS) no estado de Minas Gerais, Brasil. Métodos estudo descritivo combase nos dados obtidos do Sistema de Informação do Câncer do Colo do Útero no período de janeiro a dezembro de 2012. Para avaliação da qualidade dos exames citopatológicos do colo do útero, foram analisados três indicadores de qualidade: índice de positividade, percentual de ASC (células escamosas atípicas) entre os exames alterados e percentual de exames compatíveis com HSIL (Lesão intraepitelial escamosa de alto grau). Os laboratórios foram classificados conforme escala de produção em:≤5.000; entre 5.001 e 10.000; entre 10.001 e 15.000 e 15.001. Após a coleta das variáveis e classificação dos laboratórios conforme escala de produção foi elaborado um banco de dados, o qual foi analisado por meio do programa Microsoft Office Excel 97-2003. Resultados Em 2012, no estado de Minas Gerais, 146 laboratórios prestaram serviço para o SUS realizando um total de 1.277.018 exames citopatológicos do colo do útero. Metade desses laboratórios apresentou escala de produção≤5.000 exames/ano, e efetuaram 13,1% do total de exames do estado, por outro lado 13,7% dos laboratórios apresentaram escala de produção > 15.001 exames/ano e efetuaram 49,2% do total de exames do estado. O índice de positividade apresentado pela maioria dos laboratórios que prestaram serviço para o SUS no ano de 2012, independente de sua escala de produção, foi abaixo ou muito abaixo do recomendado. Dentre os 20 laboratórios que efetuaram mais de 15.001 exames por ano, somente três apresentaram o percentual de exames compatíveis com HSIL acima do recomendado pelo Ministério da Saúde. Conclusão Amaioria dos laboratórios prestadores de serviço para o SUS no estado de Minas Gerais apresentou indicadores de qualidade fora dos parâmetros recomendados pelo Ministério da Saúde.

Experimental benznidazole treatment of Trypanosoma cruzi II strains isolated from children of the Jequitinhonha Valley, Minas Gerais, Brazil, with Chagas disease

Trypanosoma cruzi strains from distinct geographic areas show differences in drug resistance and association between parasites genetic and treatment response has been observed. Considering that benznidazole (BZ) can reduce the parasite burden and tissues damage, even in not cured animals and individuals, the goal is to assess the drug response to BZ of T. cruzi II strains isolated from children of the Jequitinhonha Valley, state of Minas Gerais, Brazil, before treatment. Mice infected and treated with BZ in both phases of infection were compared with the untreated and evaluated by fresh blood examination, haemoculture, polymerase chain reaction, conventional (ELISA) and non-conventional (FC-ALTA) serologies. In mice treated in the acute phase, a significant decrease in parasitaemia was observed for all strains. Positive parasitological and/or serological tests in animals treated during the acute and chronic (95.1-100%) phases showed that most of the strains were BZ resistant. However, beneficial effect was demonstrated because significant reduction (p < 0.05%) and/or suppression of parasitaemia was observed in mice infected with all strains (acute phase), associated to reduction/elimination of inflammation and fibrosis for two/eight strains. BZ offered some benefit, even in not cured animals, what suggest that BZ use may be recommended at least for recent chronic infection of the studied region.

The TcI and TcII Trypanosoma cruzi experimental infections induce distinct immune responses and cardiac fibrosis in dogs

Trypanosoma cruzi infection may be caused by different strains with distinct discrete typing units (DTUs) that can result in variable clinical forms of chronic Chagas disease. The present study evaluates the immune response and cardiac lesions in dogs experimentally infected with different T. cruzi strains with distinct DTUs, namely, the Colombian (Col) and Y strains of TcI and TcII DTU, respectively. During infection with the Col strain, increased levels of alanine aminotransferase, erythrocytes, haematocrit and haemoglobin were observed. In addition, CD8+ T-lymphocytes isolated from the peripheral blood produced higher levels of interleukin (IL)-4. The latter suggests that during the acute phase, infection with the Col strain may remain unnoticed by circulating mononuclear cells. In the chronic phase, a significant increase in the number of inflammatory cells was detected in the right atrium. Conversely, infection with the Y strain led to leucopoenia, thrombopoenia, inversion of the ratio of CD4+/CD8+ T-lymphocytes and alterations in monocyte number. The Y strain stimulated the production of interferon-γ by CD4+ and CD8+ T-lymphocytes and IL-4 by CD8+ T-cells. In the chronic phase, significant heart inflammation and fibrosis were observed, demonstrating that strains of different DTUs interact differently with the host.

Assessment of acute toxicity of the ethanolic extract of Lychnophora pinaster (Brazilian arnica)

Species of the Lychnophora genus are plants native to Brazil, popularly known as "Brazilian arnica" and used in folk medicine as alcoholic and hydro-alcoholic preparations for the treatment of bruises, inflammation, pain, rheumatism and insect bites. The present study aimed to evaluate the safety of the use of Lychnophora pinaster Mart., Asteraceae. Acute toxicity of the crude ethanolic extract was evaluated by administration of the extract by oral route to male and female Swiss mice. A single extract dose of 125, 250 or 500 mg/kg was administered and the effects on spontaneous locomotor activity, exploratory behavior, muscle strength, body weight, food and water consumption, relative organ weight, histology, as well as hematological and biochemical parameters were evaluated. The three doses administered to the animals did not cause muscle tone alterations, but doses of 250 and 500 mg/kg induced a significant inhibition of the spontaneous locomotor activity and exploratory behavior of the animals in open-field test. There was no alteration to hematological parameters and consumption of water and food, body weight variation and organs relative weight. Changes were observed in AST and ALT during assessment of biochemical parameters. The histopathological evaluation showed that the extract provoked cellular alterations, such as vacuolar degeneration and inflammation in kidneys and liver at all doses. Liver morphometric analyses of male and female mice showed that the extract did not have dose-dependent effects. Although females showed a significant increase in inflammatory cells, the effect was not dose-dependent.

Myenteric plexus is differentially affected by infection with distinct Trypanosoma cruzi strains in Beagle dogs

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.

Profile of wound healing process induced by allantoin / Perfil do processo de cicatrização induzido pela alantoína

PURPOSE: To evaluate and characterize the wound healing process profile induced by allantoin incorporated in soft lotion oil/water emulsion using the planimetric and histological methods. METHODS: Female Wistar rats (n=60) were randomly assigned to 3 experimental groups: (C) control group-without treatment; (E) group treated with soft lotion O/W emulsion excipients; (EA) group treated with soft lotion O/W emulsion containing allantoin 5 percent. The emulsions either containing or not allantoin were topically administered for 14 days and the wound area was evaluated by planimetry and by qualitative and quantitative histological analysis of open wound model. RESULTS: The data which were obtained and analyzed innovate by demonstrating, qualitatively and quantitatively, by histological analysis, the profile of healing process induced by allantoin. The results suggest that the wound healing mechanism induced by allantoin occurs via the regulation of inflammatory response and stimulus to fibroblastic proliferation and extracellular matrix synthesis. CONCLUSION: This work show, for the first time, the histological wound healing profile induced by allantoin in rats and demonstrated that it is able to ameliorate and fasten the reestablishment of the normal skin.

OBJETIVO: Avaliar e caracterizar o perfil cicatricial induzido pela alantoína incorporada em uma emulsão óleo/água, sob os aspectos planimétrico e histológico. MÉTODOS: Ratos Wistar fêmeas (n=60) foram agrupados aleatoriamente em três grupos experimentais grupo controle - sem tratamento (C); grupo tratado com emulsão pura (E); grupo tratado com emulsão contendo 5 por cento de alantoína (EA). As emulsões contendo ou não alantoína foram administradas topicamente durante 14 dias e a área da ferida foi avaliada por planimetria e por análise histológica qualitativa e quantitativa em modelo de ferida aberta. RESULTADOS: Na análise planimétrica não foi observado diferenças significativas entre os grupos experimentais. Os resultados da análise histológica sugerem que o mecanismo de cicatrização induzido pela alantoína ocorre via controle da resposta inflamatória e estímulos à proliferação fibroblástica e síntese de matrix extracelular de maneira mais intensa e rapidamente em relação aos grupos controles. CONCLUSÃO: Este trabalho mostra pela primeira vez o perfil histológico de cicatrização induzido pela alantoína em ratos, demonstrando ser capaz de melhorar e acelerar o processo de reconstituição da pele.

Pteridium aquilinum: o que sabemos e o que ainda falta saber / Pteridium aquilinum: what we know and what is yet to be learnt

A samambaia Pteridium aquilinum encontra-se amplamente distribuída no planeta, sendo considerada um problema ambiental, além de representar perigo para a saúde tanto de animais quanto da espécie humana. A taxonomia do gênero Pteridium tem sido objeto de discussão e novas propostas de classificação elevam variedades à categoria de espécies ou subespécies. Ao longo da história muito já se aprendeu sobre suas características biológicas, o que permitiu a adoção de medidas de prevenção de sua habilidade invasora e de seus efeitos tóxicos. Não obstante, ainda há aspectos a serem esclarecidos sobre como tais efeitos são exercidos, sobre seu(s) princípio(s) ativo(s) e respectivo mecanismo de ação, com o ptaquilosídeo sendo o composto mais estudado. Importantes efeitos desta substância foram demonstrados no nível molecular. Estudos epidemiológicos realizados com consumidores do vegetal revelaram elevação do risco para câncer de esôfago e estômago em associação à sua ingestão.

Bracken fern (Pteridium aquilinum) is present in practically all parts of Earth's surface, being considered a serious environmental problem besides representing a hazard for both animals and human beings. The taxonomy of the genus Pteridium has been discussed and former varieties are now proposed to be considered as species or subspecies. Along history much has been learnt about its biological characteristics, what has allowed the adoption of preventive measures against its encroaching ability and its toxic effects. Nevertheless there are still aspects to be clarified about how these effects are exerted, about its active principle(s) and respective mechanism of action, with ptaquiloside being the most studied compound. Important effects of this substance have been demonstrated at the molecular level. Epidemiological studies performed with consumers of the plant revealed an increase of the risk for esophageal and stomach cancer associated with its ingestion

Leishmania braziliensis: partial control of experimental infection by interleukin-12 p40 deficient mice

Resistance to infection by Leishmania major has been associated with the development of a Th1 type response that is dependent on the presence of interleukin 12 (IL-12). In this work the involvement of this cytokine in the response to infection by L. braziliensis, a less virulent species in the mouse model, was evaluated. Our results show that while interferon (IFN-gamma) deficient (-/-) mice inoculated L. braziliensis develop severe uncontrolled lesions, chronic lesions that remained under control up to 12 weeks of infection were observed in IL-12p40 -/- mice. IL 12p40 -/- mice had fewer parasites in their lesions than IFN-gamma-/- mice. Lymph node cells from IL-12p40 -/- were capable of producing low but consistent levels of IFN-gamma suggestive of its involvement in parasite control. Furthermore, as opposed to previous reports on L. major-infected animals, no switch to a Th2 response was observed in IL-12p40 -/- infected with L. braziliensis.

Quantitative analysis of cardiac lesions in chronic canine chagasic cardiomyopathy

Lesions observed in chronic chagasic cardiopathy frequently produce electrocardiographic alterations and affect cardiac function. Through a computerized morphometrical analysis we quantified the areas occupied by cardiac muscle, connective and adipose tissues in the right atrium of dogs experimentally infected with Trypanosoma cruzi. All of the infected dogs showed chronic myocarditis with variable reduction levels of cardiac muscle, fibrosis and adipose tissue replacement. In the atrial myocardium of dogs infected with Be78 and Be62 cardiac muscle represented 34 and 50 percent, fibrosis 28 and 32 percent and adipose tissue 38 and 18 percent, respectively. The fibrosis observed was both diffuse and focal and mostly intrafascicular, either partially or completely interrupting the path of muscle bundles. Such histological alterations probably contributed to the appearance of electrocardiographic disturbances verified in 10 out 11 dogs which are also common in human chronic chagasic cardiopathy. Fibrosis was the most important microscopic occurrence found since it produces rearrangements of collagen fibers in relation to myocardiocytes which causes changes in anatomical physiognomy and mechanical behavior of the myocardium. These abnormalities can contribute to the appearance of cardiac malfunction, arrythmias and congestive cardiac insufficiency as observed in two of the analyzed dogs. Strain Be78 caused destruction of atrial cardiac muscle higher than that induced by strain Be62

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

This paper aimed to verify the influence of the inoculum source (blood or metacyclic trypomastigote) and the route of inoculation (intraperitoneal or conjunctival) on the course of T. cruzi infection in dogs, using comparatively the T. cruzi strains Berenice-62 and Berenice-78. All dogs inoculated intraperitoneally became infected independently of the T. cruzi strain and source of trypomastigotes used. High level of infectivity was also observed when metacyclic trypomastigotes of both strains were inoculated by conjunctival route. However, when blood trypomastigotes were inoculated by conjunctival route the percentages of infectivity were significantly lower in dogs inoculated with both strains. Parasitaemia was significantly higher in animals infected with metacyclic trypomastigotes via the conjunctival route independently of the T. cruzi strain used. All animals infected with Berenice-78 strain showed severe acute myocarditis. On the other hand, animals infected with Berenice-62 showed severe acute myocarditis only when infected with metacyclic trypomastigote, via the intraperitoneal route. The results suggest that the source of the inoculum and the route of inoculation remarkably influence the evolution of the infection for the T. cruzi in the vertebrate host even when the same strain of the parasite is used.