ABSTRACT Background: After decentralizing the actions of the Chagas Disease Control Program (CDCP) in Brazil, municipalities were now responsible for control measures against this endemic, supervised by the Regional Health Superintendencies (RHS). We aimed to evaluate the recent entomological surveillance of Chagas disease in the Regional Health Superintendence of Governador Valadares (RHS/GV) from 2014 to 2019. Methods: Triatomines captured by residents during entomological surveillance were sent to the reference laboratory, where the species and evolutionary stages were identified, place of capture, and presence of Trypanosoma cruzi. A database was created, and the following were calculated: the rate of infection by T. cruzi (overall rate and rate by species), monthly seasonality, spatial distribution of species, number of captures, and infected triatomines/health microregions. Results: We identified 1,708 insects; 1,506 (88.2%) were triatomines, most were adult instars (n=1,469), and few were nymphs (n=37). The identified species were Triatoma vitticeps, Panstrongylus megistus, Panstrongylus diasi, Rhodnius neglectus, and Panstrongylus geniculatus. The first three were most frequently captured and distributed throughout the study area. Most bugs were captured intradomicile (72.5%), mainly in the second semester, between September and November, with an average infection rate of 41.5% (predominantly T. vitticeps, 49.2%). All municipalities sent triatomines, especially in the microregions of Governador Valadares. Conclusions: These data reinforce the need and importance of improving Chagas disease control measures in the region to establish active and participatory entomological surveillance.

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.

Introduction Açucena Municipality, Rio Doce Valley, State of Minas Gerais, Brazil temporarily (2001-2005) interrupted epidemiological surveillance for Chagas disease. The objective of this work was to evaluate the Chagas Disease Control Program (CDCP) in Açucena and to offer suggestions for improving local epidemiological surveillance. Methods This study was conducted in three phases: I) a serological investigation of schoolchildren aged 5 to 15 years using an enzyme-linked immunosorbent assay (ELISA) test performed on blood collected on filter paper followed by ELISA, indirect immunofluorescence (IIF) and indirect hemaglutination (IHA) on venous blood for borderline cases and those in the gray zone of reactivity; II) vector evaluation using the data obtained by local health agents during 2006-2010; and III) examination by ELISA, IIF and IHA of serum samples from the inhabitants of houses where infected Triatoma vitticeps was found and evaluation of their knowledge about Chagas disease. Results Five individuals had inconclusive results in the ELISA screening but were seronegative for Chagas disease. The triatomine evaluation revealed the presence of three species: Triatoma vitticeps, Panstrongylus megistus and Panstrongylus diasi. Triatoma vitticeps was the most prevalent and widespread, with a higher (67%) index of Trypanosoma cruzi flagellates and evidence of colonization. Most of the inhabitants of the infested houses recognized triatomines and had basic knowledge about Chagas disease. Conclusions Although T. vitticeps is not clearly associated with Chagas disease transmission, these results highlight the importance of maintaining CDCP in endemic areas and the need for greater emphasis on epidemiological surveillance, especially in areas with important vectorial changes or that have been modified by human intervention.

The etiological treatment of Chagas disease is recommended for all patients with acute or recent chronic infection, but controversies remain regarding the benefit of chemotherapy and interpretations of the parasitological cure after etiological treatment. This study compares the laboratory and clinical evaluations of Chagas disease patients who were diagnosed 13 years earlier. Fifty-eight Chagas disease patients (29 treated with benznidazole and 29 untreated) were matched at the time of treatment based on several variables. Conventional serology revealed the absence of seroconversion in all patients. However, lower serological titres were verified in the treated group, primarily among patients who had the indeterminate form of the disease. Haemoculture performed 13 years after the intervention was positive for 6.9% and 27.6% of the treated and untreated patients, respectively. Polymerase chain reaction tests were positive for 44.8% and 13.8% of the treated and untreated patients, respectively. Patients who presented with the indeterminate form of the disease at the beginning of the study exhibited less clinical progression (17.4%) compared with the untreated group (56.5%). Therefore, this global analysis revealed that etiological treatment with benznidazole may benefit patients with respect to the clinical progression of Chagas disease and the prognosis, particularly when administered to patients with the indeterminate form of the disease.

INTRODUÇÃO: O objetivo foi desenvolver um método sorológico in-house de alta especificidade e sensibilidade para diagnosticar e monitorar a morbidade da doença de Chagas. MÉTODOS: Para tal, a reatividade sorológica de IgG e subclasses foi testada em soros de pacientes chagásicos de Berilo, Vale do Jequitinhonha/MG/Brasil. A reatividade sorológica foi também avaliada em amostras de pacientes com outras doenças infecto-contagiosas relevantes, incluindo o HIV, vírus da hepatite C (VHC), sífilis (SYP), leishmaniose visceral (LV), leishmaniose tegumentar americana (LTA) e controles não infectados (NI) para verificar o desempenho do método. Outras análises foram feitas para avaliar a aplicabilidade desta metodologia no monitoramento da morbidade da doença de Chagas. Com este propósito os pacientes com doença de Chagas foram anteriormente classificados em três grupos: indeterminados (IND), cardíacos (CARD) e digestivos/mistos (DIG/Mis) conforme seu estado clínico. RESULTADOS: A análise da reatividade sorológica de IgG total na diluição 1:40 mostrou ser uma abordagem importante no diagnóstico da doença de Chagas (100% de sensibilidade e especificidade e ausência de reação cruzada com as demais infecções). A análise das subclasses de IgG mostrou reação cruzada principalmente com NI, LV e LTA em todas as diluições. O grupo IND apresentou a maior reatividade para IgG3 e o grupo DIG/Mis apresentou nível mais elevado de IgG se comparados aos grupos IND e CARD. CONCLUSÕES: Estes achados demonstram que o método de ELISA in-house apresenta uma promissora aplicabilidade no diagnóstico diferencial e na avaliação da morbidade da doença de Chagas.

INTRODUCTION: The goal was to develop an in-house serological method with high specificity and sensitivity for diagnosis and monitoring of Chagas disease morbidity. METHODS: With this purpose, the reactivities of anti-T. cruzi IgG and subclasses were tested in successive serum dilutions of patients from Berilo municipality, Jequitinhonha Valley, Minas Gerais, Brazil. The performance of the in-house ELISA was also evaluated in samples from other relevant infectious diseases, including HIV, hepatitis C (HCV), syphilis (SYP), visceral leishmaniasis (VL), and American tegumentary leishmaniasis (ATL), and noninfected controls (NI). Further analysis was performed to evaluate the applicability of this in-house methodology for monitoring Chagas disease morbidity into three groups of patients: indeterminate (IND), cardiac (CARD), and digestive/mixed (DIG/Mix), based on their clinical status. RESULTS: The analysis of total IgG reactivity at serum dilution 1:40 was an excellent approach to Chagas disease diagnosis (100% sensitivity and specificity). The analysis of IgG subclasses showed cross-reactivity, mainly with NI, VL, and ATL, at all selected serum dilutions. Based on the data analysis, the IND group displayed higher IgG3 levels and the DIG/Mix group presented higher levels of total IgG as compared with the IND and CARD groups. CONCLUSIONS: These findings demonstrated that methodology presents promising applicability in the analysis of anti-T. cruzi IgG reactivity for the differential diagnosis and evaluation of Chagas disease morbidity.

O objetivo deste estudo foi avaliar o Programa de Controle de doença de Chagas instalado desde 1982 no município de Berilo, Vale do Jequitinhonha, MG, Brasil, baseado na avaliação de 5.242 unidades domiciliares e 7.807 anexos após oito anos de implantação da vigilância epidemiológica que ocorreu em 1997. Um total de 391 triatomíneos (280 Panstrongylus megistus e 111 Triatoma pseudomaculata) foram capturados, indicando o contínuo predomínio da primeira espécie. No entanto, Triatoma pseudomaculata está claramente se tornando mais importante nesta região, com colônias intradomiciliares sendo detectadas recentemente. Parâmetros entomológicos, como os índices de dispersão (17%) e infestação intradomiciliar (0,15%), são compatíveis com a fase de vigilância epidemiológica. A maioria das UDs apresenta padrão de construção tipo A (tijolo com reboco) e C (adobe com reboco). Dentre os habitantes das unidades domiciliares infestadas por triatomíneos, 25% apresentavam testes reativos na ELISA, HAI e IFI para antígenos de Trypanosoma cruzi.

This study aimed to evaluate the Chagas Disease Control Program which has operated since 1982 in the municipality of Berilo in the Jequitinhonha Valley, Minas Gerais, Brazil, based on evaluation of 5,242 domiciliary units (DUs) and 7,807 outbuildings over an eight-year period of epidemiological surveillance implanted in 1997. A total of 391 triatomines (280 Panstrongylus megistus and 111 Triatoma pseudomaculata) were captured, indicating the continued predominance of the former species. However, Triatoma pseudomaculata is clearly becoming more important in this region, with intradomiciliary colonies being detected in recent years. Entomological parameters, such as dispersion (17%) and intradomiciliary infestation (0.15%) indices, are compatible with the results of the epidemiological surveillance. The majority of DUs were of construction type A (plaster over bricks) or C (plaster over adobe). Twenty-five percent of the inhabitants of the DUs infested by triatomines were reactive in ELISA, IHA and IIF tests for Trypanosoma cruzi antigens.

Twenty-eight Chagas disease patients (CD), 22 with the indeterminate clinical form (IND) and six with the cardiac or digestive form (CARD/DIG), were treated with benznidazole and underwent clinical and laboratorial analysis before (IND and CARD/DIG) and nine years after [patients after treatment (CDt), patients with the indeterminate clinical form at treatment onset (INDt) and with the cardiac or digestive form at treatment onset (CARD/DIGt)] treatment. The data demonstrate that 82.1% of CDt patients (23/28) remained clinically stable and 95.4% of the INDt (21/22) and 33.3% of the CARD/DIGt (2/6) patients showed unaltered physical and laboratorial examinations. The clinical evolution rate was 2%/year and was especially low in INDt patients (0.5%/year) relative to CARD/DIGt patients (7.4%/year). Positive haemoculture in treated patients was observed in 7.1% of the cases. None of the INDt (0/21) and 33.3% of the CARD/DIGt (2/6) patients displayed positive cultures. The PCR presented a positive rate significantly higher (85.2%, 23/27) than haemoculture and two samples from the same patient revealed the same result 57.7% of the patients. Conventional serology-ELISA on 16 paired samples remained positive in all individuals. Semi-quantitative ELISA highlighted significant decreases in reactivity, particularly in INDt relative to IND. Non-conventional serology-FC-ALTA-IgG, after treatment, showed positive results in all sera and 22 paired samples examined at seven and nine years after treatment, demonstrated significantly lower reactivity, particularly in INDt patients. This study was retrospective in nature, had a low number of samples and lacked an intrinsic control group, but the data corroborate other results found in the literature. The data also demonstrate that, even though a cure has not been detected in the none-treated patients, the benefits for clinical evolution were selectively observed in the group of INDt patients and did not occur for CARD/DIGt patients.

The goals of the present study were to evaluate the kinetics of blood parasitism by examination of fresh blood, blood culture (BC) and PCR assays and their correlation with heart parasitism during two years of infection in Beagle dogs inoculated with the Be-78, Y and ABC Trypanosoma cruzi strains. Our results showed that the parasite or its kDNA is easily detected during the acute phase in all infected animals. On the other hand, a reduced number of positive tests were verified during the chronic phase of the infection. The frequency of positive tests was correlated with T. cruzi strain. The percentage of positive BC and blood PCR performed in samples from animals inoculated with Be-78 and ABC strains were similar and significantly larger in relation to animals infected with the Y strain.Comparison of the positivity of PCR tests performed using blood and heart tissue samples obtained two years after infection showed two different patterns associated with the inoculated T. cruzi strain: (1) high PCR positivity for both blood and tissue was observed in animals infected with Be-78 or ABC strains; (2) lower and higher PCR positivity for the blood and tissue, respectively, was detected in animals infected with Y strains. These data suggest that the sensitivity of BC and blood PCR was T. cruzi strain dependent and, in contrast, the heart tissue PCR revealed higher sensitivity regardless of the parasite stock.

Oito anos após a implantação da vigilância epidemiológica para doença de Chagas em Berilo, Vale do Jequitinhonha, MG, Brasil, foi realizada uma pesquisa para verificar o impacto do Programa de Controle Vetorial. Neste trabalho, 5. 242 (96%) unidades domiciliares foram vistoriadas. Dez estavam infestadas por Triatoma pseudomaculata. Em nove delas os insetos estavam infestando o peridomicílio e em uma casa foi constatado um foco intradomiciliar associado a morcegos. Foram capturados 111 insetos da espécie Triatoma pseudomaculata e nenhum exemplar estava infectado por Trypanosoma cruzi. Na casa infestada e em torno dela foram instaladas respectivamente 8 e 100 armadilhas de Noireau et al16 e nenhum triatomíneo foi capturado. Oitenta morcegos capturados e examinados também estavam negativos para Trypanosoma cruzi bem como três gambás (Didelphis albiventris) e um roedor, todos capturados no peridomicílio. Um porcentual de 24% dos moradores das casas infestadas por Triatoma pseudomaculata foi sororeativo (ELISA, HAI e IFI) para Tripanosoma cruzi.

Impact of the vector control program was evaluated eight years after implantation of epidemiological surveillance for Chagas’ disease in Berilo, a municipality in the Jequitinhonha Valley of the Brazilian State of Minas Gerais. In all 5,242 domiciliary units (96% of the total) were inspected and 10 found to be infested by the triatomine bug Triatoma pseudomaculata. Triatomines were found associated with bats inside one house and in the peridomiciles of the other nine. None of the 111 Triatoma pseudomaculata captured was infected with Trypanosoma cruzi. Noireau et al16 traps were installed in (n=8) and around (n=100) the infested house but no Trypanpsoma cruzi-infected triatomines were found. None bat, opossums (Didelphis albiventris) and rat captured in the peridomicile were infected with Trypanosoma cruzi although 24% of the inhabitants of the house infested by Triatoma pseudomaculata were seropositive for the parasite, based on ELISA, IHA and IIF.

Trypanosoma cruzi is a hemoflagelate parasite associated with heart dysfunctions causing serious problems in Central and South America. Beagle dogs develop the symptoms of Chagas disease in humans, and could be an important experimental model for better understanding the immunopathogenic mechanisms involved in the chagasic infection. In the present study we investigated the relation among biological factors inherent to the parasite (trypomastigote polymorphism and in vitro infectivity) and immunoglobulin production, inflammation, and fibrosis in the heart of Beagle dogs infected with either T. cruzi Y or Berenice-78 strains. In vitro infectivity of Vero cells as well as the extension of cardiac lesions in infected Beagle was higher for Y strain when compared to Berenice-78 strain. These data suggested that in vitro infectivity assays may correlate with pathogenicity in vivo. In fact, animals infected with Y strain, which shows prevalence of slender forms and high infectivity in vitro, presented cardiomegaly, inflammation, and fibrosis in heart area. Concerning the immunoglobulin production, no statistically significant difference was observed for IgA, IgM or IgG levels among T. cruzi infected animals. However, IgA together IgM levels have shown to be a good marker for the acute phase of Chagas disease.

Seis anos após o início da vigilância epidemiológica para doença de Chagas em Berilo e José Gonçalves de Minas, Vale do Jequitinhonha, MG, Brasil, foi realizado um inquérito sorológico para verificar se a transmissão desta endemia estava ocorrendo naquela área. Uma amostra aleatória de 1.412 crianças, de 7 a 14 anos, foi avaliada. Foram encontradas seis crianças positivas assintomáticas, totalizando uma prevalência de 0,4%. Hemocultura confirmou a infecção em cinco dos seis casos positivos. Uma investigação epidemiológica adicional, revelou importantes antecedentes, tais como: casos da doença em parentes e condições de moradia e ecológicas predisponentes. Nossos resultados demonstram uma soroprevalência similar (0,4%) em escolares de 7 a 14 anos àquela observada há seis anos (0,2%) em crianças de 0-9 anos. Dessa forma, considerando a presença constante de Panstrogylus megistus estes achados reforçam a necessidade de uma vigilância epidemiológica contínua e aperfeiçoada para Doença de Chagas naquela região.

Six years after the beginning of the epidemiological surveillance of Chagas disease in Berilo and José Gonçalves de Minas, Jequitinhonha Valley, MG, Brazil, a serological inquiry was performed to observe whether the transmission of this endemy was occurring in this area. A randomized sample of 1,412 children seven to 14 years old, was screened. Six asymptomatic children were found to be positive, leading to 0.4% of prevalence. Hemoculture confirmed infection in five out of the six positive cases. Additional epidemiological investigation revealed important antecedents, such as disease reports in relatives and predisposing ecological and housing conditions. Our results demonstrated similar seroprevalence (0.4%) in schoolchildren, ranging from seven to 14 years old, and that were observed six years ago (0.2%) for children 0-9 year-old. Thus, considering the constant presence of Panstrogylus megistus in the peridomicile these findings emphasize the need of continuous improved epidemiological surveillance of Chagas disease in this region.

As lesões observadas na cardiopatia chagásica crônica frequentemente produzem alterações eletrocardiográficas e afetam a função cardíaca. Através de uma análise morfométrica computadorizada nós quantificamos as áreas ocupadas por músculo cardíaco, tecido conjuntivo fibroso e tecido adiposo no átrio direito de cães experimentalmente infectados pelo Trypanosoma cruzi. Todos os cães infectados apresentaram miocardite crônica fibrosante com graus variáveis de redução de músculo cardíaco, fibrose e substituição por tecido adiposo. No miocárdio atrial dos cães infectados pelas cepas Be78 e Be62 foram observados 34 e 50% de músculo cardíaco, 28 e 32% de fibrose e, 38 e 18% de tecido adiposo, respectivamente. A fibrose observada era tanto difusa quanto focal e, principalmente intrafascicular interrompendo total ou parcialmente o percurso dos feixes musculares. Tais alterações histológicas provavelmente contribuiram para o surgimento dos distúrbios eletrocardiográficos verificados em 10 dos 11 cães estudados e que são comuns na cardiopatia chagásica crônica humana. De todos os achados microscópicos encontrados, a fibrose foi a mais importante por produzir rearranjos na fibras colágenas em relação aos miocardiócitos, modificando a fisionomia anatômica e o comportamento mecânico do miocárdio. Tais anormalidades estruturais podem contribuir para o surgimento à disfunção cardíaca, arritmias e à insuficiência cardíaca congestiva como verificado em dois cães analisados. A cepa Be78 produziu uma destruição de músculo cardíaco atrial estatisticamente superior à induzida pela cepa Be62.

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%, fibrosis 28 and 32% and adipose tissue 38 and 18%, 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.

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.

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.

Foi realizado um estudo quantitativo e qualitativo dos plexos de Auerbach e Meissner do esôfago de quatro cães chagásicos sacrificados na fase aguda da infecção. As ganglionites e periganglionites do plexo de Auerbach variaram de discretas a moderadas, induzindo lesões neuronais significativas, principalmente em dois animais. Os gânglios do plexo de Meissner foram observados em pequeno número, impossibilitando qualquer análise. Miosite discreta ou moderada foi observada principalmente no terço inferior do esôfago, raramente associada a ninhos de amastigotas. A contagem de gânglios e neurônios não demonstrou desnervação. Apesar de em nenhum dos cães ter sido induzida a formação de megaesôfago, relatamos lesões do plexo de Auerbach e de miocélulas do esôfago de animais na fase aguda da infecção chagásica. Este parece ser o primeiro estudo quantitativo e qualitativo sistemático dos plexos de Auerbach e Meissner do esôfago na tripanosomíase cruzi experimental.

A quantitative and qualitative study was conducted on the Auerbach and Meissner plexuses of the esophagus of four chagasic dogs sacrificed during the acute pbase of infection. Ganglionitis and periganglionitis of the Auerbach plexus ranged from mild to moderate and induced significant neuronal lesions, especially in two animals. The ganglions of the Meissner plexus were obsenvd in small number which did not permit any analysís. Mild or moderate myositis iras obsewed mainly in the lower third of the esophagus and was rarely associated with amastigote nests. Ganglion and neuron connts did not demonstrate denervation. Although the formation of megaesophagus was not induced in any dog, lesions of the Auerbach plexus and myocells of the esophagus were observed during the acute phase of chagasic infection. To our knowledge, this is the first systematic quantitative and qualitative study of the Auerbach and Meissner plexuses of the esophagus in experimental trypanosomiasis cruzi.

Foi realizado estudo qualitativo e quantitativo dos plexos cardíacos superficiais e profundos em cães inoculados com o Trypanosoma cruzi das cepas Be-62 e Be-78 e sacrificados na fase aguda. O processo inflamatório, as lesões e o parasitismo dos plexos foram mais intensos e frequentes nos animais inoculados com a cepa Be-78 do que naqueles inoculados com a cepa Be- 62. Apesar deste fato, não foi verificada diferença estatisticamente significativa entre o número de corpos de neurônio por gânglio dos animais chagásicos e os controles.

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 of 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.