Socioenvironmental and nutritional factors associated with Schistosoma mansoni infection among schoolchildren in a public-school at south of Espírito Santo, Brazil / Factores socioambientais e nutricionais associados à infecção por Schistosoma mansoni entre crianças em idade escolar numa escola pública do sul do Espírito Santo, Brasil

Introduction: Schistosomiasis mansoni is a neglected tropical disease that still needs adequate efforts for its control. This study investigated the factors that may been corroborating to Schistosoma mansoni infection amongst scholar children living in Alegre, Brazil. Methods: A school-based transversal study was conducted with 55 schoolchildren aged 6-10 years enrolled in one full-time municipal school at Alegre-ES. All participants were evaluated by food quality consumed classified according to School Child Diet Index - Ales Index and by anthropometric parameters of nutritional status. A parasitological survey was performed in stool samples from children that accepted to bring them to the school. Results: Ales Index revealed 70.91% (39/55) low-quality feeding, 10.91% (06/55) intermediate-quality feeding and 18.18% (10/55) good-quality feeding. An overall of 3.64% (02/55) malnutrition, 3.64% (02/55) obesity, 9.09% (05/55) overweight and 83.64% (46/55) normal weight were verified by body mass index (BMI)/age. Height/age revealed 5.45% (03/55) short stature-for-age and 94.55% (52/55) adequate stature-for-age. Parasitological survey showed 4.0% (01/25) of children infected with both S. mansoni and Ancylostoma duodenale and another child (01/25) positive only to A. duodenale. There were associations between BMI/age and food quality (P < 0.05); intestinal polyparasitism and schistosomiasis mansoni (P < 0.05) and between the absence of sewage network with the occurrence of S. mansoni infection (P < 0.05). Conclusion: S. mansoni infection still needs to be controlled by efforts that improve environmental safety and may include the access to good-quality feeding and adequate hygienic sanitary conditions, even in areas considered as low endemicity to schistosomiasis mansoni in Brazil. 

Evolução da cardiopatia chagásica em cães tratados com Benznidazol na fase crônica da infecção experimental pelo Trypanosoma cruzi.

A eficácia do tratamento com Benznidazol (Bz) na fase crônica da infecção e conseqüente prognóstico da cardiopatia chagásica permanece controversa. Neste estudo foram avaliados os efeitos do tratamento com Bz na evolução da cardiopatia chagásica crônica, utilizando cães infectados com a cepa Berenice-78 como modelo experimental. Os animais infectados foram divididos em dois grupos experimentais: (i) 12 cães tratados na fase crônica com 7,0 mg de Bz/kg, divididos em duas doses diárias, durante 60 dias; (ii) 12 cães mantidos como controles não tratados. Outros 8 animais constituíram o grupo controle não-infectado. A parasitemia foi monitorada pela PCR realizada em amostras de sangue e tecido muscular cardíaco coletados no 1o e 12o mês após o tratamento (MAT). A potente supressão da parasitemia, induzida pelo tratamento com Bz, foi observada pelos resultados negativos em 81,9% (9 de 11) dos animais tratados em relação a 36,3% (4 de 11) nos animais não tratados quando realizada a PCR no sangue coletado no 1o MAT. Resultados semelhantes foram observados na PCR do tecido muscular cardíaco, realizada no mesmo período, quando o kDNA do parasito foi detectado somente em 33%,3 (2 de 6) dos animais tratados e em 100% dos animais não tratados. Um aumento dos resultados positivos na PCR do sangue e tecido foi detectado 12 MAT. Este resultado foi verificado em 60% (3 de 5) no sangue e 80% (4 de 5) no tecido muscular cardíaco dos animais tratados. Para avaliação da cardiomegalia e função sistólica ou diastólica os animais foram examinados por ecocardiograma no 1o e 12o MAT. Foram mensurados os parâmetros fração de encurtamento, volume do Átrio Esquerdo (AE), fração de ejeção, volume diastólico e diâmetro sistólico do Ventrículo Esquerdo (VE). Após essa avaliação, metade dos animais foi eutanaziada para realização das análises histopatológicas no coração. O tratamento induziu uma redução de 20% a 36% de células inflamatórias e deposição intrafascicular de colágeno no 1o MAT. Nesta fase da infecção, não houve diferença significativa nos parâmetros ecocardiográficos mensurados entre os grupos de animais infectados (tratados ou não) e não infectados. Diferentemente, 12 MAT, as lesões cardíacas foram semelhantes entre os animais infectados (tratados ou não) e significativamente maiores que naqueles não infectados. Variáveis ecocardiográficas relacionadas com cardiomegalia e disfunção diastólica também foram semelhantes entre os animais infectados (tratados ou não) e significativamente maiores que nos animais não infectados. De modo interessante, o tratamento preveniu alterações na função sistólica, uma vez que não ocorreram diferenças na fração de ejeção e fração de encurtamento entre os animais tratados e não infectados. Esses resultados demonstram que o tratamento com Bz na fase crônica da infecção de cães é eficiente em prevenir as lesões cardíacas imediatamente após o tratamento e a função sistólica um longo tempo após o término do tratamento.The analysis of available information reveals that the efficacy of benznidazole treatment in chronic chagasic infection is doubtful. In this study we evaluated the effect of Bz-treatment on the cardiac alterations using dogs infected with Berenice-78 strain as experimental model. The infected animals were divided in two experimental groups: (i) 12 dogs were Bz-treated at 7.0 mg/kg bid (Q12) for 60 days during the chronic phase; (ii) 12 dogs were maintained as non-treated control. Another 8 animals were maintained as non-infected control group. After the benznidazole-treatment the parasite load was monitored by blood and heart tissue PCR performed in the 1 st and 12 th months post-treatment (MPT). The potent suppression of parasitemia induced by Bz-treatment was associated with negative results of blood PCR performed in the 1 st MPT in 81.8% (9 of 11) of treated animals in relation to 36,3% (4 of 11) in those infected and non-treated animals. Similar results were observed in heart tissue PCR in the same period, when the parasite kDNA was detected only in 33,3% (2 of 6) of the treated animals. In contrast, 100% of infected and non-treated animals showed positive tissue PCR tests. An increase of positive results in blood and tissue PCR was detected 12 MPT. This result was verified in 60% (3 of 5) of blood and 80% (4 of 5) of tissue samples obtained of Bz-treated animals. For cardiomegaly and systolic or diastolic function evaluation the animals were examined by echocardiography in the 1 st and 12 th MPT. The parameters fractional shortening, Left Atrium (LA) volume, Left-ventricle (LV) ejection fraction, diastolic volume and systolic diameter were measured. After this evaluation a half of animals were euthanized in the same period for histopathological analysis of heart tissue. Bz-treatment led to a reduction of around 20% to 36% of inflammatory cells and intrafascicular collagen deposition when compared to non-treated animals in the first MPT. Additionally, all animals evaluated showed echocardiographic parameters similar to non-infected animals. M Differently, 12 MPT the intensity of cardiac lesions were similar to treated and non-treated animals and significantly larger than those detected in non-infected animals. Also, the echocardiographic parameters, related with cardiomegaly (LV and LA volume, LV systolic diameter) and diastolic function (LA volume), were similar among treated and non-treated animals and significantly higher than those observed in non-infected animals. Interestingly, the Bz-treatment was able to prevent alterations related to cardiac systolic functions (LV ejection and shortening fraction) such these parameters were similar to treated and non-infected animals. Taken together, the results indicate that Bz-treatment performance during the chronic phase of the dogs' infection is efficient in preventing cardiac lesions immediately after the treatment and systolic cardiac function long-time post-treatment

Avaliação da susceptibilidade/resistência ao benznidazol em populações de Trypanosoma cruzi submetidas a diferentes formas de manutenção no laboratório.

O objetivo deste estudo foi avaliar a possibilidade de indução de resistência ao benznidazol de populações do Trypanosoma cruzi consideradas 100% sensíveis ao fármaco. Para isto, foram utilizados camundongos Swiss infectados com cinco (Be-62A, Be-62B, Be-78C, Be-78D e Be-78E) populações do T. cruzi, obtidas de diferentes cães chagásicos crônicos infectados com as cepas do T. cruzi Be-62 e Be-78, ambas 100% sensíveis ao benznidazol. Quatro diferentes populações resistentes do T. cruzi foram selecionadas após dois a 11 ciclos sucessivos de tratamento com benznidazol. Para avaliar a estabilidade do fenótipo de resistência ao benznidazol as populações do T. cruzi foram mantidas durante seis a 12 meses sem a pressão do fármaco: (1) através de passagens sangüíneas sucessivas em camundongos não tratados, e (2) em meio de cultura acelular, meio LIT. Novas alterações do nível de resistência ao benznidazol foram detectadas após a manutenção do parasito sem a pressão do fármaco. Todas as populações do T. cruzi benznidazol-resistentes mantidas através de passagens sangüíneas sucessivas em camundongos continuaram a apresentar 100% de resistência ao fármaco. Entretanto, a maior dificuldade encontrada na detecção da falha terapêutica indica o aumento de subpopulações do T. cruzi sensíveis ao benznidazol dentro de cada isolado. Por outro lado, os isolados Be-78C e E (100% resistentes), passaram a apresentar 50% e 20% de susceptibilidade ao benznidazol após serem mantidos por um ano e seis meses em meio de fenótipo de resistência , respectivamente. Estes resultados colaboram com a hipótese de que a forma de manipulação do T. cruzi pode influenciar o fenótipo de resistência ao benznidazolThe aim of this study was to induce the resistance in vivo to benznidazole using Trypanosoma cruzi populations sensitive to the drug. To do so, Swiss mice were infected with five (Be-62A and B, and Be-78C, D and E) T. cruzi isolates obtained from different chronic Chagasic dogs infected with Be-62 and Be-78 T. cruzi strains, both 100% sensitive to benznidazole. Four benznidazole-resistant T. cruzi population was selected after 2 to 11 successive cycles of treatment with benznidazole. After the stability in the resistance phenotype T. cruzi populations were maintained for six to 12 months without drug pressure: (1) through successive blood passage in not-treated mice, and (2) in acellular culture, LIT medium. New changes in benznidazole resistance level were showed after maintenance of the parasite without drug pressure. All benznidazoleresistant T. cruzi populations maintained through successive blood passages in mice continued to present 100% of benznidazole resistance. However, a greater difficulty was observed in detecting the therapeutics failure, indicating an increase of benznidazole parasite sensitive subpopulations in each benznidazole resistant T. cruzi isolated. On the other hand, the 100% benznidazole resistant Be-78C and E started to present 50% and 20% of susceptibility after the maintenance for one year and six months in culture medium, respectively. Theses results corroborate the hypothesis that the manipulation of the T. cruzi may influence the susceptibility phenotype of benznidazole in T. cruzi. This work demonstrates the in vivo resistance induction to benznidazole in T. cruzi strains 100% sensitive to the benznidazole (Be-62 and Be-78) for the first time, and makes an experimental model available for the study of mechanisms of drug resistance in T. cruzi

Evolução da cardiopatia chagásica em cães tratados com Benznidazol na fase crônica da infecção experimental pelo Trypanosoma cruzi.

A eficácia do tratamento com Benznidazol (Bz) na fase crônica da infecção e conseqüente prognóstico da cardiopatia chagásica permanece controversa. Neste estudo foram avaliados os efeitos do tratamento com Bz na evolução da cardiopatia chagásica crônica, utilizando cães infectados com a cepa Berenice-78 como modelo experimental. Os animais infectados foram divididos em dois grupos experimentais: (i) 12 cães tratados na fase crônica com 7,0 mg de Bz/kg, divididos em duas doses diárias, durante 60 dias; (ii) 12 cães mantidos como controles não tratados. Outros 8 animais constituíram o grupo controle não-infectado. A parasitemia foi monitorada pela PCR realizada em amostras de sangue e tecido muscular cardíaco coletados no 1o e 12o mês após o tratamento (MAT). A potente supressão da parasitemia, induzida pelo tratamento com Bz, foi observada pelos resultados negativos em 81,9% (9 de 11) dos animais tratados em relação a 36,3% (4 de 11) nos animais não tratados quando realizada a PCR no sangue coletado no 1o MAT. Resultados semelhantes foram observados na PCR do tecido muscular cardíaco, realizada no mesmo período, quando o kDNA do parasito foi detectado somente em 33%,3 (2 de 6) dos animais tratados e em 100% dos animais não tratados. Um aumento dos resultados positivos na PCR do sangue e tecido foi detectado 12 MAT. Este resultado foi verificado em 60% (3 de 5) no sangue e 80% (4 de 5) no tecido muscular cardíaco dos animais tratados. Para avaliação da cardiomegalia e função sistólica ou diastólica os animais foram examinados por ecocardiograma no 1o e 12o MAT. Foram mensurados os parâmetros fração de encurtamento, volume do Átrio Esquerdo (AE), fração de ejeção, volume diastólico e diâmetro sistólico do Ventrículo Esquerdo (VE). Após essa avaliação, metade dos animais foi eutanaziada para realização das análises histopatológicas no coração. O tratamento induziu uma redução de 20% a 36% de células inflamatórias e deposição intrafascicular de colágeno no 1o MAT. Nesta fase da infecção, não houve diferença significativa nos parâmetros ecocardiográficos mensurados entre os grupos de animais infectados (tratados ou não) e não infectados. Diferentemente, 12 MAT, as lesões cardíacas foram semelhantes entre os animais infectados (tratados ou não) e significativamente maiores que naqueles não infectados. Variáveis ecocardiográficas relacionadas com cardiomegalia e disfunção diastólica também foram semelhantes entre os animais infectados (tratados ou não) e significativamente maiores que nos animais não infectados. De modo interessante, o tratamento preveniu alterações na função sistólica, uma vez que não ocorreram diferenças na fração de ejeção e fração de encurtamento entre os animais tratados e não infectados. Esses resultados demonstram que o tratamento com Bz na fase crônica da infecção de cães é eficiente em prevenir as lesões cardíacas imediatamente após o tratamento e a função sistólica um longo tempo após o término do tratamento.The analysis of available information reveals that the efficacy of benznidazole treatment in chronic chagasic infection is doubtful. In this study we evaluated the effect of Bz-treatment on the cardiac alterations using dogs infected with Berenice-78 strain as experimental model. The infected animals were divided in two experimental groups: (i) 12 dogs were Bz-treated at 7.0 mg/kg bid (Q12) for 60 days during the chronic phase; (ii) 12 dogs were maintained as non-treated control. Another 8 animals were maintained as non-infected control group. After the benznidazole-treatment the parasite load was monitored by blood and heart tissue PCR performed in the 1 st and 12 th months post-treatment (MPT). The potent suppression of parasitemia induced by Bz-treatment was associated with negative results of blood PCR performed in the 1 st MPT in 81.8% (9 of 11) of treated animals in relation to 36,3% (4 of 11) in those infected and non-treated animals. Similar results were observed in heart tissue PCR in the same period, when the parasite kDNA was detected only in 33,3% (2 of 6) of the treated animals. In contrast, 100% of infected and non-treated animals showed positive tissue PCR tests. An increase of positive results in blood and tissue PCR was detected 12 MPT. This result was verified in 60% (3 of 5) of blood and 80% (4 of 5) of tissue samples obtained of Bz-treated animals. For cardiomegaly and systolic or diastolic function evaluation the animals were examined by echocardiography in the 1 st and 12 th MPT. The parameters fractional shortening, Left Atrium (LA) volume, Left-ventricle (LV) ejection fraction, diastolic volume and systolic diameter were measured. After this evaluation a half of animals were euthanized in the same period for histopathological analysis of heart tissue. Bz-treatment led to a reduction of around 20% to 36% of inflammatory cells and intrafascicular collagen deposition when compared to non-treated animals in the first MPT. Additionally, all animals evaluated showed echocardiographic parameters similar to non-infected animals. M Differently, 12 MPT the intensity of cardiac lesions were similar to treated and non-treated animals and significantly larger than those detected in non-infected animals. Also, the echocardiographic parameters, related with cardiomegaly (LV and LA volume, LV systolic diameter) and diastolic function (LA volume), were similar among treated and non-treated animals and significantly higher than those observed in non-infected animals. Interestingly, the Bz-treatment was able to prevent alterations related to cardiac systolic functions (LV ejection and shortening fraction) such these parameters were similar to treated and non-infected animals. Taken together, the results indicate that Bz-treatment performance during the chronic phase of the dogs' infection is efficient in preventing cardiac lesions immediately after the treatment and systolic cardiac function long-time post-treatment

Chagas cardiomyopathy : the potential effect of benznidazole treatment on diastolic dysfunction and cardiac damage in dogschronically infected with Trypanosoma cruzi.

Cardiac involvement represents the main cause of mortality among patients with Chagas disease, and therelevance of trypanocidal treatment to improving diastolic dysfunction is still doubtful. In the presentstudy, we used a canine model infected with the benznidazole-sensitive Berenice-78 Trypanosoma cruzistrain to verify the efficacy of an etiologic treatment in reducing the parasite load and ameliorating cardiacmuscle tissue damage and left ventricular diastolic dysfunction in the chronic phase of the infection. Theeffect of the treatment on reducing the parasite load was monitored by blood PCR and blood cultureassays, and the effect of the treatment on the outcome of heart tissue damage and on diastolic function wasevaluated by histopathology and echo Doppler cardiogram. The benefit of the benznidazole-treatmentin reducing the parasite burden was demonstrated by a marked decrease in positive blood culture andPCR assay results until 30 days post-treatment. At this time, the PCR and blood culture assays yieldednegative results for 82% of the treated animals, compared with only 36% of the untreated dogs. However,a progressive increase in the parasite load could be detected in the peripheral blood for one year post-treatment, as evidenced by a progressive increase in positive results for both the PCR and the bloodculture assays at follow-up. The parasite load reduction induced by treatment was compatible with thelower degree of tissue damage among animals euthanized in the first month after treatment and withthe increased cardiac damage after this period, reaching levels similar to those in untreated animals atthe one-year follow-up. The two infected groups also presented similar, significantly smaller values forearly tissue septal velocity (E’ SIV) than the non-infected dogs did at this later time. Moreover, in thetreated animals, an increase in the E/E’ septal tissue filling pressure ratio was observed when comparedwith basal values as well as with values in non-infected dogs. These findings strongly suggest that thetemporary reduction in the parasite load that was induced by benznidazole treatment was not able toprevent myocardial lesions and diastolic dysfunction for long after treatment

Trypanosoma cruzi : acute and long-term infection in the vertebrate host can modify the response to benznidazole.

We analyzed the influence of Trypanosoma cruzi maintenance in different hosts (dog and mouse) on its susceptibility to benznidazole treatment. Five T. cruzi stocks were isolated from dogs inoculated with Be-62 or Be-78 strain (both sensitive to benznidazole) 2–10 years ago, and the benznidazole sensitivity was then determined using the mouse as experimental model. The different T. cruzi stocks obtained from long-term infected dogs showed 50–90% drug resistance right after isolation. However, maintenance of these T. cruzi stocks in mice, by successive blood passages (2.5 years), led to either a decrease or stability of the drug resistance pattern and an increase in parasite virulence. We also demonstrated the effectiveness of the induction of parasitemia reactivation by cyclophosphamide immunosuppression in the evaluation of the response to the specific drug treatment

Cardiomyopathy prognosis after benznidazole treatment in chronic canine Chagas' disease.

Objectives: To evaluate the effects of benznidazole on Chagas’ disease cardiac prognosis using an experimental dog model of infection. Methods: A total of 28 dogs were divided into three groups: 10 were infected with Trypanosoma cruzi and treated benznidazole during the chronic phase, 10 were infected but untreated, and 8 were non-infected/ healthy. The trypanocidal efficacy was measured by parasite kDNA detection in blood and cardiac tissue samples. The effects of benznidazole in ameliorating the cardiac systolic function were evaluated by echodopplercardiogram. Results: The benznidazole initially induced a potent suppression of parasitaemia in treated animals. However, 12 months post-treatment, the parasite kDNA detections were similar between infected groups. In the baseline echocardiographic parameters there was no variation among all animals. Similarly, 1 month post-treatment there was no significant difference among healthy and infected animals with regard to systolic function. At 12 months post-treatment, an increase in cardiac chamber size related to cardiomegaly was detected among treated and untreated animals, but not in the healthy controls. Interestingly, in spite of both groups of infected animals developing a decrease in their systolic cardiac function, this decline was slightly less in the treated animals. We also evaluated levels of tumour necrosis factor-a and interleukin-10 in peripheral blood mononuclear cell culture supernatant. Cytokine profiles were similar between infected animal groups and correlated with alterations in cardiac function. Conclusions: The temporary suppression of the T. cruzi infection induced by benznidazole treatment was efficient in reducing systolic cardiac function alterations, but not in preventing the development of cardiomyopathy

Trypanosoma cruzi : induction of benznidazole resistance in vivo and its modulation by in vitro culturing and mice infection.

Through a continuous in vivo drug pressure protocol, using mice as experimental model, we induced benznidazole resistance in Trypanosoma cruzi stocks. Full resistance was obtained for four out of five T. cruzi stocks analyzed. However, the number of benznidazole doses (40–180), as well as the time (4–18 months) necessary to induce resistance varied among the different T. cruzi stocks. The resistance phenotype remained stable after T. cruzi stocks has been maintained by 12 passages in mice (six months) and in acellular culture for the same time. However, the maintenance of resistant parasite for 12 months in acellular culture induces a reduction in its level of benznidazole resistance, while no alteration was detected in parasite maintained for the same time in mice. The data showed the stability of the resistance acquired by drug pressure, but suggest the possibility of reversible changes in the resistance levels after maintenance for long time in acellular culture

Protein deficiency alters CX3CL1 and endothelin-1 in experimental Trypanosoma cruzi-induced cardiomyopathy.

objective Chagas heart disease is developed as a result of the infection with Trypanosoma cruzi. Protein malnutrition contributes to secondary immunodeficiency. The aim of this study was to investigate the role of a low protein diet on the production of endothelin-1 and CX3CL1 in blood and cardiac tissue samples in an experimental model with T. cruzi infection. methods Fisher rats were submitted to low protein (6%) and normal protein (15%) diets and then infected with the Y strain of T. cruzi. At days 15 and 120, parasites and immune cells were evaluated. results The low protein diet reduced body weight and circulating serum proteins, but promoted elevation of CX3CL1 and endothelin-1 levels in infected animals, which were unable to control blood parasitemia replication. In heart tissue, the low protein diet reduced cardiac CX3CL1, endothelin-1 and leucocyte infiltration in the acute phase, in particular CD68 and CD163 macrophage phenotypes. conclusion Together, these results highlight the participation of endothelin-1 and CX3CL1 in the inflammatory process of Chagas diesease, both being mediators partially controlled by the host nutritional status

Myocardial scars correlate with eletrocardiographic changes in chronic Trypanosoma cruzi infection for dogs treated with Benznidazole.

objectives The cardiac form of Chagas disease is evidenced by a progressive cardiac inflammation that leads to myocarditis, fibrosis and electrocardiographic (ECG) conduction abnormalities. Considering these characteristics, the aim of this study was to prospectively evaluate the early ECG changes in dogs that were experimentally inoculated with Benznidazole (Bz)-susceptibly (Berenice-78) and Bz-resistant (VL-10, and AAS) Trypanosoma cruzi strains and, later, evaluate the efficacy of Bz treatment for preventing these ECG alterations. methods Electrocardiographic changes of treated and untreated animals were prospectively evaluated for up to 270 days after infection, at which point collagen (right atrium) quantification was performed. results All infected dogs had a high intensity of heart fibrosis (4616.00 ± 1715.82 collagen ⁄ 74931 lm2 in dogs infected with Berenice-78 strain, 5839.2 ± 1423.49 collagen ⁄ 74931 lm2 in infected by AAS and 6294.40 ± 896.04 collagen ⁄ 74931 lm2 in animals infected with VL-10 strain), while 78.57% of all infected dogs showed ECG alterations. Bz Therapy reduced or prevented fibrosis in Bz-susceptible Berenice-78 (2813.00 ± 607.13 collagen ⁄ 74931 lm2) and Bz-resistant AAS strains (4024 ± 1272.44 collagen ⁄ 74931 lm2), coincident with only 10% de ECG alterations at 270 days. However, in those animals infected with a Bz-resistant VL-10 strain, specific treatment did not alter collagen deposition (6749.5 ± 1596.35 collagen ⁄ 74931 lm2) and there was first atrioventricular block and chamber overload at 120 and 270 days after infection, with 75% abnormal ECG exams. conclusions These findings indicate that an effective antiparasitic treatment in the early stage of Chagas disease can lead to a significant reduction in the frequency and severity of the parasite-induced cardiac disease, even if parasites are not completely eliminated