Search

OBJECTIVE To analyze the impact of the covid-19 pandemic on the use of primary health care services to follow-up the child growth and development in Brazil. METHOD A total of 7.9 million consultations of children (0–2 years old) across Brazil between March 2017 and May 2020 were studied. Differences between medians were analyzed using non-parametric tests, the Global Moran Index (IGM) and the Local Indicators of Spatial Association. RESULTS During the initial period of the pandemic, the median number of consultations was significantly lower than the same period in previous years, reducing more than 50%. The drop in 2020, compared to 2019, ranged from 49% to 62.2% across all regions of the country, except the South. The percentage reduction registered in 2019–2020 showed significant spatial autocorrelation (IGM = 0.20; p = 0.04), with the presence of low-low (states with reduction between 29% and 51%) and high-high (states with reduction between 55% and 69%) spatial clusters. CONCLUSION The covid-19 pandemic impacted the follow-up of child growth and development in primary health care services in Brazil, with a geographically uneven reduction.

Background Albendazole (ALB) is administered annually to millions of children through global deworming programs targeting soil-transmitted helminths (STHs: Ascaris lumbricoides, Trichuris trichiura and hookworms, Necator americanus and Ancylostoma duodenale). However, due to the lack of large individual patient datasets collected using standardized protocols and the application of population-based statistical methods, little is known about factors that may affect individual responses to treatment. Methodology/Principal findings We re-analyzed 645 individual patient data from three standardized clinical trials designed to assess the efficacy of a single 400 mg oral dose of ALB against STHs in schoolchildren from different study sites, each with varying history of drug pressure based on duration of mass drug administration programs: Ethiopia, low; Lao People’s Democratic Republic (PDR), moderate; Pemba Island (Tanzania), high. Using a Bayesian statistical modelling approach to estimate individual responses (individual egg reduction rates, ERRi), we found that efficacy was lower in Pemba Island, particularly for T. trichiura. For this STH, the proportion of participants with a satisfactory response (ERRi ≥50%), was 65% in Ethiopia, 61% in Lao PDR but only 29% in Pemba Island. There was a significant correlation between ERRi and infection intensity prior to drug administration (ERRi decreasing as a function of increasing infection intensity). Individual age and sex also affected the drug response, but these were of negligible clinical significance and not consistent across STHs and study sites. Conclusions/Significance We found decreased efficacy of ALB against all the STHs analyzed in Pemba Island (Tanzania), an area with high drug pressure. This does not indicate causality, as this association may also be partially explained by differences in infection intensity prior to drug administration. Notwithstanding, our results indicate that without alternative treatment regimens, program targets will not be achievable on Pemba Island because of inadequate efficacy of ALB. Trial registration The study was registered on Clinicaltrials.gov (ID: NCT03465488) on March 7, 2018., Author summary More than 500 million children worldwide receive a single oral dose of albendazole or mebendazole annually to reduce disease caused by intestinal worms (roundworm, whipworm and hookworm). However, it is unclear whether individuals respond differently to treatment. We re-analyzed 645 individual patient data from three standardized clinical trials with albendazole using a statistical method and explored how drug responses among individuals from study sites with different prior rounds of drug distribution. We found that individuals’ responses were worse when drug pressure and infection intensity were greater. Individual age and sex also affected the response, but these were often of negligible clinical significance and not consistent across worm species and study sites. We confirmed that albendazole is ineffective against whipworm on Pemba Island, but given the high intensity of infection at this study side, it remains unclear whether this treatment failure is explained by high drug pressure (and emerging anthelmintic resistance) or high infection intensity. Nevertheless, our results indicate that alternative treatment regimens are required to control intestinal worms in Pemba Island.

To estimate the prevalence of high cardiovascular risk (CVR), the proportion of people with high CVR who receive treatment and counseling, and to investigate the sociodemographic factors associated with this outcome, in Brazil.This was a cross-sectional study, using subsample data from the National Health Survey, collected via biochemical tests, in 2014-2015. Poisson regression was used.The proportion of high CVR in men was 11.2% (95%CI 9.6;12.9), and 10.4% (95%CI 9.2;11.8%) in women. In the group with high CVR, 68.8% (95%CI 63.7;73.4%) received counseling, 59.3% (95%CI 54.2;64.3%) received medication, and 55.6% (95%CI 50.4;60.7%) received both. In the multivariate analysis, receiving treatment and counseling was associated with being aged 50 years and over, and poor/very poor self-rated health (PR=1.26 - 95%CI 1.06;1.51).The proportion of people with high CVR who had received treatment and counseling was over 50%.Estimar a prevalência de risco cardiovascular (RCV) elevado, a proporção de pessoas com RCV elevado que recebem tratamento e aconselhamento, e investigar os fatores sociodemográficos associados ao desfecho, no Brasil.Estudo transversal, com dados de subamostra da Pesquisa Nacional de Saúde, coletados por exames bioquímicos, em 2014-2015. Empregou-se regressão de Poisson.A proporção de RCV elevado em homens foi de 11,2% (IC95% 9,6;12,9), e em mulheres, de 10,4% (IC95% 9,2;11,8%). No grupo com RCV elevado, 68,8% (IC95% 63,7;73,4%) receberam aconselhamento; 59,3% (IC95% 54,2;64,3%), medicamento; e 55,6% (IC95% 50,4;60,7%), ambos. Na análise multivariável, receber tratamento e aconselhamento mostrou associação com a idade de 50 anos e mais, e com autoavaliação de saúde ruim/muito ruim (RP=1,26 - IC95% 1,06;1,51).A proporção de pessoas com RCV elevado que receberam tratamento e aconselhamento foi superior a 50%.Estimar la prevalência de riesgo cardiovascular (RCV) elevado, la proporción de personas con RCV elevado que reciben tratamiento y asesoramiento, e investigar los factores sociodemográficos asociados al resultado, en Brasil.Estudio transversal, con datos de la submuestra de la Investigación Nacional de Salud, recolectados por exámenes bioquímicos, en 2014-2015. Se usó la regresión de Poisson.La proporción de RCV elevado en hombres fue del 11,2% (IC95% 9,6; 12,9) y en mujeres del 10,4% (IC95% 9,2;11,8%). En el grupo con RCV elevado, 68,8% (IC95% 63,7; 73,4%) recibió asesoramiento, 59,3% (IC95% 54,2;64,3%) medicamento y 55,6% (IC95% 50,4;60,7%) ambos. En el análisis multivariable, recebir tratamiento y asesoramiento se mostró asociado a la edad de 50 años y más, y a autoevaluación de salud mala/muy mala (RP=1,26 - IC95% 1,06;1,51).La proporción de personas con RCV elevado que recibió tratamiento y asesoramiento fue superior a 50%.

Background Efforts to control soil-transmitted helminth (STH) infections have intensified over the past decade. Field-survey data on STH prevalence, infection intensity and drug efficacy is necessary to guide the implementation of control programs and should be of the best possible quality. Methodology During four clinical trials designed to evaluate the efficacy of albendazole against STHs in Brazil, Ethiopia, Lao PDR and Tanzania, quality control (QC) was performed on the duplicate Kato-Katz thick smears and the data entry. We analyzed datasets following QC on both fecal egg counts (FECs) and data entry, and compared the prevalence of any STH infection and moderate-to-heavy intensity (MHI) infections and the drug efficacy against STH infections. Results Across the four study sites, a total of 450 out of 4,830 (9.3%) Kato-Katz thick smears were re-examined. Discrepancies in FECs varied from ~3% (hookworms) to ~6.5% (Ascaris lumbricoides and Trichuris trichiura). The difference in STH prevalence and prevalence of MHI infections using the datasets with and without QC of the FECs did not exceed 0.3%, except for hookworm infections in Tanzania, where we noted a 2.2 percentage point increase in MHI infections (pre-QC: 1.6% vs. post-QC: 3.8%). There was a 100% agreement in the classification of drug efficacy of albendazole against STH between the two datasets. In total, 201 of the 28,980 (0.65%) data entries that were made to digitize the FECs were different between both data-entry clerks. Nevertheless, the overall prevalence of STH, the prevalence of MHI infections and the classification of drug efficacy remained largely unaffected. Conclusion/significance In these trials, where staff was informed that QC would take place, minimal changes in study outcomes were reported following QC on FECs or data entry. Nevertheless, imposing QC did reduce the number of errors. Therefore, application of QC together with proper training of the personnel and the availability of clear standard operating procedures is expected to support higher data quality., Author summary Over the past ten years, there has been a worldwide intensification of large-scale deworming programs aimed at controlling the morbidity of intestinal worms (roundworms, whipworms and hookworms). In order to make well-founded decisions, it is of utmost importance that the program managers have access to high quality data on the prevalence and intensity of these infections, and the therapeutic efficacy of the administered drugs. In the present study, we report the results of the quality control (QC) that was performed on the diagnosis and the data entry. We analyze and discuss how QC affected the study outcomes of four clinical trials designed to assess the therapeutic efficacy of a standard deworming treatment in Brazil, Ethiopia, Lao PDR and Tanzania. Our results indicate that, when staff is aware that QC will be performed, study outcomes were not significantly affected by performing QC on both the diagnosis or the data entry. Nevertheless, it is important to highlight that training, adherence to good standard operating procedures and performing QC does improve the overall quality of the data.

The World Health Organization (WHO) has defined moderate-to-heavy intensity (M&HI) infections with soil-transmitted helminths (Ascaris lumbricoides, Trichuris trichiura and the two hookworms, Ancylostoma duodenale and Necator americanus) based on specific values of eggs per gram of stool, as measured by the Kato-Katz method. There are a variety of novel microscopy and DNA-based methods but it remains unclear whether applying current WHO thresholds on to these methods allows for a reliable classification of M&HI infections. We evaluated both WHO and method-specific thresholds for classifying the M&HI infections for novel microscopic (FECPAKG2, McMaster and Mini-FLOTAC) and DNA-based (qPCR) diagnostic methods. For this, we determined method-specific thresholds that best classified M&HI infections (defined by Kato-Katz and WHO thresholds; reference method) in two multi-country drug efficacy studies. Subsequently, we verified whether applying these method-specific thresholds improved the agreement in classifying M&HI infections compared to the reference method. When we applied the WHO thresholds, the new microscopic methods mainly misclassified M&HI as low intensity, and to a lesser extent low intensity infection as M&HI. For FECPAKG2, applying the method-specific thresholds significantly improved the agreement for Ascaris (moderate → substantial), Trichuris and hookworms (fair → moderate). For Mini-FLOTAC, a significantly improved agreement was observed for hookworms only (fair → moderate). For the other STHs, the agreement was almost perfect and remained unchanged. For McMaster, the method-specific thresholds revealed a fair to a substantial agreement but did not significantly improve the agreement. For qPCR, the method-specific thresholds based on genome equivalents per ml of DNA moderately agreed with the reference method for hookworm and Trichuris infections. For Ascaris, there was a substantial agreement. We defined method-specific thresholds that improved the classification of M&HI infections. Validation studies are required before they can be recommended for general use in assessing M&HI infections in programmatic settings., Author summary The prevalence of moderate-to-heavy intensity (M&HI) infections is a key indicator for measuring the success of large-scale deworming programs for intestinal worms because they account for the majority of the worm-attributable morbidity. Currently, intestinal worm infections are classified as M&HI when the number of worm eggs that are microscopically detected in stool using a standard diagnostic method exceeds a threshold set by the World Health Organization. Over the years, a variety of new promising diagnostic methods have been introduced for the diagnosis of intestinal worms. Although they have some important advantages over the current standard method, it is not clear whether they can reliably classify M&HI infections. This is because their test results either systematically indicate lower egg counts or are expressed in a unit other than eggs per gram of stool (e.g, concentration of worm DNA), warranting the need for method-specific thresholds. We defined method-specific thresholds and verified whether they increased the correct classification of M&HI infections. Overall, our results indicate that method-specific thresholds improved the classification of M&HI infections, but that further validation is required before they can be recommended for evaluating the occurrence M&HI infections in large-scale deworming programs.

Objective: to evaluate anthropometric and demographic indicators associated with high blood pressure in children aged 6 to 10 years in urban and rural areas of Minas Gerais. Method: this is a cross-sectional study with 335 children. Anthropometric, demographic and blood pressure data were collected. The statistics analyzes were performed using the chi-square, t-student, Mann-Whitney and logistic regression tests, and the odds ratio was the association measure. Results: the prevalence of high blood pressure was significantly higher among rural children. In the urban area, the chance of high blood pressure was higher in children who had a high body mass index (2.97 [1.13-7.67]) and in the rural area, in those who had increased waist circumference (35.4 [3.0-406.2]) and the age range of 9-10 years (4.29 [1.46-12.6]). Conclusion: elevated body mass index and waist circumference were important anthropometric indicators for high blood pressure, as well as age in children living in rural area. The evaluation of body mass index and waist circumference, in addition to nutritional assessments, represents an important action for the screening of high blood pressure in children from different territorial contexts. Objetivo: evaluar los indicadores antropométricos y demográficos asociados a la presión arterial elevada de niños entre 6 y 10 años de edad en zonas urbana y rurale de Minas Gerais. Método: se trata de un estudio transversal realizado entre 335 niños. Se recopilaron datos antropométricos, demográficos y de presión arterial. Los análisis se realizaron con las pruebas de Chi-cuadrado, t de Student, Mann-Whitney y regresión logística, considerando el odds ratio como medida de asociación. Resultados: la prevalencia de la presión arterial elevada era significativamente más alta entre los niños de las zonas rurales. En la zona urbana, la probabilidad era mayor en los niños con índice alto de masa corporal [2,97(1,13-7,67)] y en la zona rural, en los que tenían más perímetro de cintura [35,4(3,0-406,2)] y grupo de edad de 9-10 años [4,29(1,46-12,6)]. Conclusión: el índice de masa corporal y la circunferencia de la cintura altos fueron indicadores antropométricos importantes para la presión arterial elevada, así como la edad en niños residentes de la zona rural. La evaluación del índice de masa corporal y del perímetro de la cintura, además de las evaluaciones nutricionales, son factores importantes para el sondeo de la hipertensión arterial en niños de diferentes contextos territoriales. Objetivo: avaliar indicadores antropométricos e demográficos associados à pressão arterial elevada em crianças de 6 a 10 anos de idade de áreas urbana e rural de Minas Gerais. Método: estudo transversal realizado com 335 crianças. Foram coletados dados antropométricos, demográficos e de pressão arterial. As análises foram realizadas por meio dos testes Qui-quadrado, t student, Mann-Whitney e regressão logística, com cálculo do odds ratio como medida de associação. Resultados: a prevalência de pressão arterial elevada foi significativamente maior entre as crianças da área rural. Na área urbana, a chance de pressão arterial elevada foi maior nas crianças que possuíam o índice de massa corporal elevado (2,97 [1,13-7,67]) e, na área rural, naquelas que possuíam a circunferência da cintura aumentada (35,4 [3,0-406,2]) e faixa etária de 9-10 anos (4,29 [1,46-12,6]). Conclusão: o índice de massa corporal e a circunferência da cintura elevados foram importantes indicadores antropométricos para a pressão arterial elevada, assim como a idade em crianças residentes na área rural. A avaliação do índice de massa corporal e da circunferência da cintura, para além das avaliações nutricionais, representa importante ação para o rastreio de pressão arterial elevada em crianças de diferentes contextos territoriais.

Objective To evaluate the effectiveness of two teaching strategies, both guided by the concept of dialogicity, on adolescents’ knowledge about schistosomiasis and adherence to diagnostic fecal testing. Methods Two teaching strategies related to schistosomiasis were developed, an educational video and group conversation, which were tested in two groups of students aged 10–15 years old. Before and after the intervention, a questionnaire was applied to assess participants' knowledge about schistosomiasis and, after the intervention, two fecal samples were requested from each participant. Comparisons were performed by paired t- and McNemar tests. Results Both strategies resulted in statistically significant improvements in knowledge between the pre- and post-tests. Students who watched the video had a higher return rate of fecal samples and percentage of correct questionnaire answers, mainly on questions about schistosomiasis infection. Conclusion Teaching strategies based on dialogue favored the construction of concepts about schistosomiasis that can influence the adoption of positives attitudes related to health. Practical implications Using teaching strategies based on the concept of dialogicity can favor the increase of knowledge of school age children about schistosomiasis and can influence behavioral change related to health.

to evaluate anthropometric and demographic indicators associated with high blood pressure in children aged 6 to 10 years in urban and rural areas of Minas Gerais.this is a cross-sectional study with 335 children. Anthropometric, demographic and blood pressure data were collected. The statistics analyzes were performed using the chi-square, t-student, Mann-Whitney and logistic regression tests, and the odds ratio was the association measure.the prevalence of high blood pressure was significantly higher among rural children. In the urban area, the chance of high blood pressure was higher in children who had a high body mass index (2.97 [1.13-7.67]) and in the rural area, in those who had increased waist circumference (35.4 [3.0-406.2]) and the age range of 9-10 years (4.29 [1.46-12.6]).elevated body mass index and waist circumference were important anthropometric indicators for high blood pressure, as well as age in children living in rural area. The evaluation of body mass index and waist circumference, in addition to nutritional assessments, represents an important action for the screening of high blood pressure in children from different territorial contexts.avaliar indicadores antropométricos e demográficos associados à pressão arterial elevada em crianças de 6 a 10 anos de idade de áreas urbana e rural de Minas Gerais.estudo transversal realizado com 335 crianças. Foram coletados dados antropométricos, demográficos e de pressão arterial. As análises foram realizadas por meio dos testes Qui-quadrado, t student, Mann-Whitney e regressão logística, com cálculo do odds ratio como medida de associação.a prevalência de pressão arterial elevada foi significativamente maior entre as crianças da área rural. Na área urbana, a chance de pressão arterial elevada foi maior nas crianças que possuíam o índice de massa corporal elevado (2,97 [1,13-7,67]) e, na área rural, naquelas que possuíam a circunferência da cintura aumentada (35,4 [3,0-406,2]) e faixa etária de 9-10 anos (4,29 [1,46-12,6]).o índice de massa corporal e a circunferência da cintura elevados foram importantes indicadores antropométricos para a pressão arterial elevada, assim como a idade em crianças residentes na área rural. A avaliação do índice de massa corporal e da circunferência da cintura, para além das avaliações nutricionais, representa importante ação para o rastreio de pressão arterial elevada em crianças de diferentes contextos territoriais.evaluar los indicadores antropométricos y demográficos asociados a la presión arterial elevada de niños entre 6 y 10 años de edad en zonas urbana y rurale de Minas Gerais.se trata de un estudio transversal realizado entre 335 niños. Se recopilaron datos antropométricos, demográficos y de presión arterial. Los análisis se realizaron con las pruebas de Chi-cuadrado, t de Student, Mann-Whitney y regresión logística, considerando el odds ratio como medida de asociación.la prevalencia de la presión arterial elevada era significativamente más alta entre los niños de las zonas rurales. En la zona urbana, la probabilidad era mayor en los niños con índice alto de masa corporal [2,97(1,13-7,67)] y en la zona rural, en los que tenían más perímetro de cintura [35,4(3,0-406,2)] y grupo de edad de 9-10 años [4,29(1,46-12,6)].el índice de masa corporal y la circunferencia de la cintura altos fueron indicadores antropométricos importantes para la presión arterial elevada, así como la edad en niños residentes de la zona rural. La evaluación del índice de masa corporal y del perímetro de la cintura, además de las evaluaciones nutricionales, son factores importantes para el sondeo de la hipertensión arterial en niños de diferentes contextos territoriales.

Praziquantel (PZQ) is an effective chemotherapy for schistosomiasis mansoni and a mainstay for its control and potential elimination. However, it does not prevent against reinfection, which can occur rapidly in areas with active transmission. A guide to ranking the risk factors for Schistosoma mansoni reinfection would greatly contribute to prioritizing resources and focusing prevention and control measures to prevent rapid reinfection. The objective of the current study was to explore the relationship among the socioeconomic, demographic, and epidemiological factors that can influence reinfection by S. mansoni one year after successful treatment with PZQ in school-aged children in Northeastern Minas Gerais state Brazil. Parasitological, socioeconomic, demographic, and water contact information were surveyed in 506 S. mansoni-infected individuals, aged 6 to 15 years, resident in these endemic areas. Eligible individuals were treated with PZQ until they were determined to be negative by the absence of S. mansoni eggs in the feces on two consecutive days of Kato-Katz fecal thick smear. These individuals were surveyed again 12 months from the date of successful treatment with PZQ. A classification and regression tree modeling (CART) was then used to explore the relationship between socioeconomic, demographic, and epidemiological variables and their reinfection status. The most important risk factor identified for S. mansoni reinfection was their “heavy” infection at baseline. Additional analyses, excluding heavy infection status, showed that lower socioeconomic status and a lower level of education of the household head were also most important risk factors for S. mansoni reinfection. Our results provide an important contribution toward the control and possible elimination of schistosomiasis by identifying three major risk factors that can be used for targeted treatment and monitoring of reinfection. We suggest that control measures that target heavily infected children in the most economically disadvantaged households would be most beneficial to maintain the success of mass chemotherapy campaigns.

Background Preventive chemotherapy (PC) with benzimidazole drugs is the backbone of soil-transmitted helminth (STH) control programs. Over the past decade, drug coverage has increased and with it, the possibility of developing anthelmintic resistance. It is therefore of utmost importance to monitor drug efficacy. Currently, a variety of novel diagnostic methods are available, but it remains unclear whether they can be used to monitor drug efficacy. In this study, we compared the efficacy of albendazole (ALB) measured by different diagnostic methods in a head-to-head comparison to the recommended single Kato-Katz. Methods An ALB efficacy trial was performed in 3 different STH-endemic countries (Ethiopia, Lao PDR and Tanzania), each with a different PC-history. During these trials, stool samples were evaluated with Kato-Katz (single and duplicate), Mini-FLOTAC, FECPAKG2, and qPCR. The reduction rate in mean eggs per gram of stool (ERR) and mean genome equivalents / ml of DNA extract (GERR) were calculated to estimate drug efficacy. Principal findings and conclusions The results of the efficacy trials showed that none of the evaluated diagnostic methods could provide reduction rates that were equivalent to a single Kato-Katz for all STH. However, despite differences in clinical sensitivity and egg counts, they agreed in classifying efficacy according to World Health Organization (WHO) guidelines. This demonstrates that diagnostic methods for assessing drug efficacy should be validated with their intended-use in mind and that other factors like user-friendliness and costs will likely be important factors in driving the choice of diagnostics. In addition, ALB efficacy against STH infections was lower in sites with a longer history of PC. Yet, further research is needed to identify factors that contribute to this finding and to verify whether reduced efficacy can be associated with mutations in the β-tubulin gene that have previously been linked to anthelmintic resistance. Trial registration ClinicalTrials.gov NCT03465488., Author summary During the last decade, the scale of deworming programs that aim to eliminate the morbidity caused by intestinal worms has increased to a level that is unprecedented in history. It is therefore of utmost importance to monitor any change in therapeutic efficacy that may arise from emerging drug resistance. Currently, a variety of novel methods have been described, but it remains unclear whether they can be used for monitoring drug efficacy. We applied different diagnostic methods to measure the efficacy of a commonly administered drug in deworming programs in 3 countries with different historical exposure to deworming programs. Compared to the standard diagnostic method, all diagnostic methods revealed good agreement in classifying the therapeutic efficacy according to World Health Organization guidelines, despite clear differences in diagnostic performance. We also noticed that the drug efficacy was lower in countries where drug pressure has been high. However, more research is necessary to identify factors that explain this variation in drug efficacy, including but not limited to the frequency in mutations in genes that are known to be linked with anthelmintic resistance.

Background Because the success of deworming programs targeting soil-transmitted helminths (STHs) is evaluated through the periodically assessment of prevalence and infection intensities, the use of the correct diagnostic method is of utmost importance. The STH community has recently published for each phase of a deworming program the minimal criteria that a potential diagnostic method needs to meet, the so-called target product profiles (TPPs). Methodology We compared the diagnostic performance of a single Kato-Katz (reference method) with that of other microscopy-based methods (duplicate Kato-Katz, Mini-FLOTAC and FECPAKG2) and one DNA-based method (qPCR) for the detection and quantification of STH infections in three drug efficacy trials in Ethiopia, Lao PDR, and Tanzania. Furthermore, we evaluated a selection of minimal diagnostic criteria of the TPPs. Principal findings All diagnostic methods showed a clinical sensitivity of ≥90% for all STH infections of moderate-to-heavy intensities. For infections of very low intensity, only qPCR resulted in a sensitivity that was superior to a single Kato-Katz for all STHs. Compared to the reference method, both Mini-FLOTAC and FECPAKG2 resulted in significantly lower fecal egg counts for some STHs, leading to a substantial underestimation of the infection intensity. For qPCR, there was a positive significant correlation between the egg counts of a single Kato-Katz and the DNA concentration. Conclusions/Significance Our results indicate that the diagnostic performance of a single Kato-Katz is underestimated by the community and that diagnostic specific thresholds to classify intensity of infection are warranted for Mini-FLOTAC, FECPAKG2 and qPCR. When we strictly apply the TPPs, Kato-Katz is the only microscopy-based method that meets the minimal diagnostic criteria for application in the planning, monitoring and evaluation phase of an STH program. qPCR is the only method that could be considered in the phase that aims to seek confirmation for cessation of program. Trial registration ClinicalTrials.gov NCT03465488, Author summary To control the burden caused by intestinal worms, the World Health Organization recommends large-scale deworming programs where anti-worm drugs are administered to at-risk populations. The decision to scale down drug distribution is based on the periodically assessment of prevalence and intensity of infections using a standard diagnostic method. Today, the scientific community strongly doubts whether this method can be used throughout the program. This is in particular when it fails to detect infections of low intensity, and hence may result in prematurely stopping the distribution of drugs. We compared the diagnostic performance of alternative diagnostic methods in three drug efficacy trials in two African and one Asian country. The diagnostic methods were based on demonstration of worm eggs or worm DNA in stool. We also checked the results with minimal diagnostic criteria which have been recently been proposed by the scientific community. Our results indicate that of all diagnostic methods based on demonstration of worm eggs, only the current standard method fulfills the diagnostic criteria for planning, monitoring and evaluation phases of deworming program. Furthermore, we showed that DNA-based methods could be considered in the phase that aims to seek confirmation for cessation of the deworming program.

In this work were investigated the relationship between Hookworm/Schistosoma mansoni infections and allergy related risk factors in two endemic areas with distinct prevalence of infections and co-infection. The intensity of infections, eosinophilia, allergy risk factors, infections status and anti-Der p1 IgE levels before and 2 years (population 1) and 3 years (population 2) after anthelmintic treatment, were evaluated. It was observed that the population with lower prevalence and intensity of infection (population 2) had lower eosinophils counts (>600/mm3) and higher animal contact than the population with higher parasites intensity (population 1). After anthelmintic treatment the intensity of S. mansoni single infection decreased, but no changes were observed in Hookworm and co-infected individuals. The anthelmintic treatment also enhanced anti-Der p1 IgE optical density in ELISA on the subgroups that became negative for helminth infection regardless of their previous infection condition in population 1. Facing that, we evaluated the anti-Der p1 IgE reactivity index, and the ratio (after/before treatment) was significantly higher in patients co-infected before treatment. On the other hand, no association between anti-Der p1 IgE reactivity index and the intensity of infections were observed. In conclusion, effective anthelmintic therapy of subjects from endemic areas with high prevalence of Hookworm and S. mansoni infections enhances anti-Der p1 IgE levels.

Background Immunoepidemiologic studies have shown a relationship between IgE and IgG4 antibodies with age and with resistance and susceptibility to infection. It is believed that the IgE and IgG4 responses to soluble egg antigen (SEA) can be used for serological analysis of infection and post-treatment status. This study aimed to evaluate the association between Schistosoma mansoni infection and anti-SEA IgG4 and IgE reactivities, and determine whether these reactivities could be used as biomarkers of infection. Methods Between 2001 and 2009, a longitudinal study was performed in which parasitologic and blood specimens and socioeconomic and water-contact information were collected from 127 individuals. All patients positive for S. mansoni infection were treated. Results Schistosomiasis prevalence and the geometric mean of the egg count in 2001 were 59% and 61.05, respectively, decreasing to 26.8% and 8.78 in 2009. IgG4 anti-SEA reactivity in infected individuals was significantly higher than that in uninfected individuals at all time points. Analysis of receiver-operating characteristic (ROC) area showed that the IgG4 anti-SEA antibodies were able to predict infection by S. mansoni at each time point. Conclusion IgG4 anti-SEA reactivity can be used as a biomarker for immune monitoring of the presence of infection with S. mansoni in endemic areas.

RESUMO: Estudo observacional que analisa a qualidade das ações de diagnóstico, tratamento e controle da esquistossomose na Estratégia Saúde da Família (ESF) em área endêmica. Foram utilizados questionários estruturados em 97 profissionais de saúde da ESF e em secretários municipais de saúde de 25 municípios pertencentes à Gerência Regional de Saúde de Pedra Azul, Minas Gerais. Foram utilizados os Modelos de Variáveis Latentes para definir um escore a fim de avaliar a qualidade da proposta. Os resultados mostraram que 57,8% das equipes da ESF realizam suas ações de maneira insatisfatória ou crítica. Os profissionais não realizam ações efetivas para controle da infecção e 8,1% não utilizam o método diagnóstico preconizado pelo governo. As estratégias de vigilância e controle ainda são incipientes. Da mesma forma, os profissionais não receberam treinamento adequado para o desenvolvimento das ações de prevenção e controle da esquistossomose. Falta material educativo para o desempenho das atividades de educação em saúde, sendo que as equipes da ESF realizam atividades educativas nas escolas em 48% dos municípios. Menos da metade dos profissionais entrevistados conhecia o Programa de Controle da Esquistossomose (PCE). É necessário integrar as práticas do PCE à ESF, além de buscar um adequado suporte da gestão municipal por meio de pactuações e do controle social. ABSTRACT: Observational study that examined the quality of the preventive actions for schistosomiasis control in the Brazilian Family Health Strategy (FHS) in an endemic area. Structured questionnaires were used to interview 97 health professionals of the FHS and the Secretary of Health of 25 municipalities belonging to the State Health Department of Pedra Azul, Minas Gerais, Brazil. Models of latent variables were used to define a score to evaluate the quality of the process. The results showed that 57.8% of the FHS teams' actions were unsatisfactory or critical. The professionals did not perform effective activities for the control of the infection and 8.1% did not use the diagnostic methods required by the government. Similarly, the professionals did not receive adequate training for the development of schistosomiasis prevention and control. There was a lack of educational materials to carry out health education activities, and the FHS teams conducted educational activities in only 48% of the schools of municipalities. Less than half of the professionals interviewed knew about the Schistosomiasis Control Program. We concluded that it is necessary to integrate this Program's practices to the FHS, and seek a suitable support of municipal management through pacts and social control.

The objective of the present paper was to compare accessibility and utilisation of schistosomiasis diagnostic and treatment services in a small village and the surrounding rural area in northern part of the state of Minas Gerais Brazil. The study included 1,228 individuals: 935 central village residents and 293 rural residents of Sao Pedro do Jequitinhonha. Schistosoma mansoni infection rates were significantly higher in the central village than in the rural area during a survey in 2007 (44.3% and 23.5%, respectively) and during the 2002 schistosomiasis case-finding campaign (33.1% and 26.5%, respectively) (p < 0.001). However, during the 2002-2006 period, only 23.7% of the villagers and 27% of the rural residents obtained tests on their own from health centres, hospitals and private clinics in various nearby towns. In 2007, 63% of the villagers and 70.5% of the rural residents reported never having received treatment for schistosomiasis. This paper reveals considerable variation in the accessibility and utilisation of schistosomiasis-related health services between the central village and the rural area. A combination of low utilisation rates between 2002-2006 and persistently high S. mansoni infection rates suggest that the schistosomiasis control program must be more rapidly incorporated into the primary health services.

We have been investigating whether human eosinophils play an important role in schistosomiasis mansoni morbidity. Our main focus has been on the activation-related cell surface markers (CD23/CD69/CD25/HLA-DR/CD28/CD80) and the detection of TNF-alpha, IL-4 and IL-5 in peripheral blood eosinophils from chronic Schistosoma mansoni-infected patients. Our studies compare both, intestinal (INT) and individuals with periportal fibrosis (FIB). Our major findings, point to distinct profile of activation-related surface markers on eosinophils as the hallmark of disease morbidity during chronic S. mansoni infection. Up-regulation of several activation-related markers was observed on eosinophils from FIB group, but not INT, which include early activation markers, such as CD69 and CD23. INT displayed a distinct profile, with up-regulation of molecules related to the late activation (CD25, HLA-DR, CD28 and CD80). These results suggest that some immunoregulatory events may take place controlling the early eosinophil activation in the INT group. Higher levels of eosinophil-derived cytokines were observed in FIB, regardless the antigen stimulation in vitro. A mixed cytokine pattern, characterized by positive correlation between TNF-alpha, IL-4 and IL-5 was observed in both INT and FIB. However, lack of correlation between the cytokine expression and the eosinophil activation status points out that even those FIB patients presenting minor increment on eosinophil activation displayed higher levels of cytokine-positive eosinophils. Indeed, the positive association between lymphocyte-derived IL-10 and the eosinophils cytokine profile was observed exclusively in INT further emphasize our hypothesis that immunoregulatory events take place controlling disease morbidity in human schistosomiasis. The impaired IL-10-driven immunoregulatory function may play an important role on the establishment of pathology in patients bearing periportal fibrosis.

Observational study that examined the quality of the preventive actions for schistosomiasis control in the Brazilian Family Health Strategy (FHS) in an endemic area. Structured questionnaires were used to interview 97 health professionals of the FHS and the Secretary of Health of 25 municipalities belonging to the State Health Department of Pedra Azul, Minas Gerais, Brazil. Models of latent variables were used to define a score to evaluate the quality of the process. The results showed that 57.8% of the FHS teams' actions were unsatisfactory or critical. The professionals did not perform effective activities for the control of the infection and 8.1% did not use the diagnostic methods required by the government. Similarly, the professionals did not receive adequate training for the development of schistosomiasis prevention and control. There was a lack of educational materials to carry out health education activities, and the FHS teams conducted educational activities in only 48% of the schools of municipalities. Less than half of the professionals interviewed knew about the Schistosomiasis Control Program. We concluded that it is necessary to integrate this Program's practices to the FHS, and seek a suitable support of municipal management through pacts and social control.

Este estudo teve como objetivo avaliar a relação entre a infecção e a reinfecção pelo Schistosoma mansoni e os fatores demográficos, socioeconômicos, imunológicos e de contato com água, em 127 indivíduos residentes em Virgem das Graças, área rural endêmica domunicípio de Ponto dos Volantes, Minas Gerais. Foram coletados dados socioeconômicos, demográficos e de contato com água além de fezes e sangue para análises parasitológicas e sorológicas de todos os indivíduos participantes do estudo no período entre 2001 e 2009. Osoro foi utilizado para avaliação da reatividade dos anticorpos IgE e IgG4 específicos contra antígenos do ovo (SEA) e do verme adulto (SWAP). A prevalência da endemia no inicio do estudo (2001) foi 59% (IC 95%= 50,38- 67,72) e a média geométrica de ovos por grama de fezes (OPG) de 61,05 (IC95%= 58,70 63,40). Um ano após o tratamento de todos os indivíduos (2002), a prevalência e a carga parasitária reduziram significativamente para 16,5% (IC 95%= 9,98 23,08) e 40,6 opg (IC 95%= 37,80 43,42), respectivamente. Em 2005, a prevalência aumentou para 27,6% (IC 95%= 19,68 35,43), mas a carga parasitáriamanteve-se semelhante à de 2002 sendo de 39,81 opg (IC95%= 37,27 42,35). No último ano avaliado (2009) a prevalência permaneceu em 26,8% (IC 95%= 18,96 34,57), mas a carga parasitária reduziu significativamente para 8,78 opg (IC 95%= 6,45 11,11) quandocomparada aos anos anteriores. A análise multivariada mostrou que a idade, o contato com água e as características imunológicas foram associadas à infecção pelo S. mansoni. Um maior risco de infecção foi observado nos indivíduos mais jovens (6-14 e 15-29 anos) e naqueles que realizavam atividades de pescar e atravessar o córrego. Foi evidenciado também que o aumento na reatividade de IgG4 anti-SEA e SWAP e da razão entre IgG4/IgE contra esses antígenos relacionaram-se ao risco de infecção pelo parasito, deixando os indivíduos mais susceptíveis. A análise da reatividade de IgE anti-SEA e SWAP mostrou um aumento ao longo do tempo tanto para os indivíduos infectados quanto para os não infectados e quando estratificados por idade, foi mais expressivo a partir de 2005. Em relação ao anticorpo IgG4, foram observadas reatividades significativamente mais elevadas deste anticorpo contra o antígeno SEA nos indivíduos infectados em todos os períodos investigados. A reatividade dos anticorpos IgG4 anti-SEA por idade mostrou uma redução progressiva e significativa aolongo do tempo, exceto para os indivíduos mais jovens (6-14 anos). Na reinfecção, houve um aumento progressivo e significativos da reatividade de IgE anti-SEA e SWAP ao longo do tempo tanto no grupo do indivíduos que reinfectaram quanto naqueles que não reinfectaramsendo a distribuição da reatividade similar entre os grupos. A análise da área da curva ROC mostrou que os anticorpos IgG4 anti-SEA tiveram um poder significativo de predizer a infecção pelo S. mansoni em todos os anos investigados. Os anticorpos IgG4 anti-SEA e razão entre IgG4/IgE anti-SEA apresentaram uma baixa capacidade de predizer a reinfecção, com a área da curva em torno de 66%. Conclui-se que o fator imunológico não é o único que explica o fato do indivíduo estar ou não infectado pelo S. mansoni e que somente a reatividade de anticorpos IgG4 anti-SEA podem ser utilizados como biomarcadores imunológicos de monitoramento para predizer a presença da infecção pelo S. mansoni em áreas endêmicas. This study aimed to evaluate the relationship between S. mansoni infection and reinfection using demographic, socioeconomic, immunological and water contact factors, in 127 individuals in Virgem das Graças, an endemic area in municipality of Ponto dos Volantes,Minas Gerais. Demographic, socioeconomic and water contact behavioral data were collected, as well as feces and blood for parasitological and serological analysis, of all individuals participating in the study between 2001 and 2009. Serum was used to evaluate specific IgE and IgG4 antibody reactivity against soluble egg (SEA) and adult worm (SWAP) antigens. The prevalence for S. mansoni infection before treatment (2001) was 59% (CI 95%= 50.38-67.72) with the geometric mean egg count (epg) of 61.05 (CI95%= 58.70 63.40). One yearafter treatment (2002), prevalence and intensity of infection reduced significantly to 16.5% (CI 95%= 9.98 23.08) and 40.6 epg (CI 95%= 37.80 43.42), respectively. In 2005, the prevalence increased to 27.6% (CI 95% = 19.68 to 35.43), but the intensity of infection remained similar to that of 2002 with 39.81 epg (CI 95% = 37.27 - 42.35). In the last year ofevaluation (2009), the prevalence remained at 26.8% (CI 95% = 18.96 to 34.57) but the intensity of infection reduced significantly to 8.78 epg (CI 95% = 6.45 to 11.11) when compared to previous years. Multivariate analysis showed that age, water contact and immunological characteristics were associated with S. mansoni infection. A higher risk of infection was observed in younger individuals (6-14 and 15-29 years) as well as in those who performed activities of fishing and crossing stream. It was shown that the increase in IgG4 anti-SEA and SWAP reactivity and the IgG4/IgE ratio against these antigens were related torisk of infection, with individuals being more susceptible to infection. Analysis of IgE anti-SEA and SWAP reactivity showed an increase over time for both infected and uninfected individuals and when stratified by age, being more significant in 2005. In regard to IgG4 anti- SEA antibodies, there was a significantly higher level of antibody reactivity in the infected individuals in all investigated years. The reactivity of IgG4 anti-SEA antibodies by age, showed a significant progressive reduction over time, except for the younger individuals (6-14 years). In relation to reinfection, we also observed a significant progressive increase in IgEanti- SEA and anti-SWAP levels over time in the group of individuals who were reinfected when compared with those who did not reinfect, and the distribution of these antibody reactivities very similar between groups. The ROC analysis showed that the IgG4anti-SEA antibody had significant power to predict infection by S. mansoni in every study points. IgG4 anti-SEA antibodies and IgG4/IgE anti-SEA ratio showed a low ability to predict reinfection, with a curve area around 66%. Our results showed that the prevalence of S. mansoni infection can not be attributed only to immunological factors. We conclude that the IgG4 anti-SEA antibody can be used as immunological monitoring biomarker to predict S.mansoni infection in endemic areas.

Background Obtaining informed consent for clinical trials is especially challenging when working in rural, resource-limited areas, where there are often high levels of illiteracy and lack of experience with clinical research. Such an area, a remote field site in the northeastern part of the state of Minas Gerais, Brazil, is currently being prepared for clinical trials of experimental hookworm vaccines. This study was conducted to assess whether special educational tools can be developed to increase the knowledge and comprehension of potential clinical trial participants and thereby enable them to make truly informed decisions to participate in such research. Methodology/Principal Findings An informational video was produced to explain the work of the research team and the first planned hookworm vaccine trial, using a pedagogical method based on analogies. Seventy-two adults living in a rural community of Minas Gerais were administered a structured questionnaire that assessed their knowledge of hookworm, of research and of the planned hookworm vaccine trial, as well as their attitudes and perceptions about the researchers and participation in future vaccine trials. The questionnaire was administered before being shown the educational video and two months after and the results compared. After viewing the video, significant improvements in knowledge related to hookworm infection and its health impact were observed: using a composite score combining related questions for which correct answers were assigned a value of 1 and incorrect answers a value of 0, participants had a mean score of 0.76 post-video compared to 0.68 pre-video (p = 0.0001). Similar improvements were seen in understanding the purpose of vaccination and the possible adverse effects of an experimental vaccine. Although 100% of participants expressed a positive opinion of the researchers even before viewing the film and over 90% said that they would participate in a hookworm vaccine trial, an increase in the number who expressed fear of being vaccinated with a novel vaccine was seen after viewing the video (51.4% post-video versus 29.2% pre-video). Increases were also seen in the proportion who thought that participation in a vaccine trial would be inconvenient or disrupt their daily activities. Conclusions/Significance Even in rural, resource-limited populations, educational tools can be specially designed that significantly improve understanding and therefore the likelihood of obtaining truly informed consent for participation in clinical research. The observed changes in the knowledge and perceptions of the research participants about hookworm infection and the experimental hookworm vaccine demonstrate that the video intervention was successful in increasing understanding and that the subjects acquired knowledge pertinent to the planned research., Author Summary Conducting clinical trials of new vaccines in rural, resource-limited areas can be challenging since the people living in these areas often have high levels of illiteracy, little experience with clinical research, and limited access to routine health care. Especially difficult is obtaining informed consent for participation in this type of research and ensuring that potential participants adequately understand the potential risks and benefits of participation. The researchers have been preparing a remote field site in the northeastern part of the state of Minas Gerais, Brazil, for clinical trials of experimental hookworm vaccines. A special educational video was designed based on the method of analogies to introduce new scientific concepts related to the researchers' work and to improve knowledge of hookworm, a disease that is highly prevalent in their community. A questionnaire was administered both before and after the video was shown to a group of adults at the field site, which demonstrated the effectiveness of the video in disseminating knowledge about hookworm infection and about the vaccine being developed. Therefore, even in a rural, resource-limited area, educational tools can be specially designed that significantly improve understanding and therefore the likelihood of obtaining truly informed consent for participation in clinical research.

This study examines the relative contribution of age-specific total IgE levels, eosinophils and water contact behavior to the prevalence and intensity (geometric mean egg counts) of Schistosoma mansoni infection in the poor rural population of Virgem das Graças in northern Minas Gerais State. In bivariate analysis, age was strongly correlated with both prevalence and intensity of infection, while eosinophil levels with prevalence only (p

Este estudo teve como objetivo avaliar a relação entre os fatores socioeconômicos, demográficos, de contato com água e reinfeção pelo S. mansoni com os níveis de IgE total, em 340 indivíduos residentes em área endêmica, do município de Ponto dos Volantes, Minas Gerais. Os dados socioeconômicos, demográficos e de contato com água foram coletados utilizando questionários desenvolvidos pelo nosso grupo. Foram coletadas 3 amostras de fezes e examinado pelo método Kato-Katz. Soro também foi coletado dos participantes do estudo para avaliação dos níveis de IgE total pela técnica de ELISA. A prevalência da endemia antes do tratamento foi de 65% (IC95%= 58,72 71,28) e a média geométrica do número de ovos por grama de fezes de 59,27 (IC95%= 54,93 63,61). Um ano após o tratamento a prevalência foi reduzida para 13,8% (IC95%= 6,01 21,5) e média geométrica do número de ovos para 24,33 (IC95%= 17,70 30,96), sendo esta diferença estatisticamente significativa. Antes do tratamento a maior intensidade de infecção ocorreu na faixa etária de 15-29 anos e a maior prevalência foi observada na faixa etária de 30-49 anos. Após tratamento a prevalência, intensidade de infecção e a reinfecção foram maiores na faixa etária de 6-14 anos. Os níveis de IgE total (mg/mL) antes do tratamento foram de 7,8 (IC95%= 6,6 9,6) e após tratamento, de 3,8 (IC 95%= 3,2 4,3) com p0.01. Total IgE (mg/mL) levels increased with the age and were higher in male individuals. The lowest median total IgE levels were observed among schistosomiais negative individuals then reinfected and not reinfected individuals, this difference was statistically significant. Linear Regression Model was used to examine the data both on individual and household levels and to evaluate the correlation between all independent variables and total levels IgE (mg/mL) after treatment. The multivariate analysis showed that crossing stream was related to age, sex, having shower, total TBM and schistosomiasis were correlated and statistically significant with total levels IgE after treatment. Theses results showed that these variables have an important effect on total IgE levels after treatment and that higher total IgE levels after treatment seems to be a predictive factor of reinfection by S. mansoni.

Hookworm infection is considered one of the most important poverty-promoting neglected tropical diseases, infecting 576 to 740 million people worldwide, especially in the tropics and subtropics. These blood-feeding nematodes have a remarkable ability to downmodulate the host immune response, protecting themselves from elimination and minimizing severe host pathology. While several mechanisms may be involved in the immunomodulation by parasitic infection, experimental evidences have pointed toward the possible involvement of regulatory T cells (Tregs) in downregulating effector T-cell responses upon chronic infection. However, the role of Tregs cells in human hookworm infection is still poorly understood and has not been addressed yet. In the current study we observed an augmentation of circulating CD4+CD25+FOXP3+ regulatory T cells in hookworm-infected individuals compared with healthy non-infected donors. We have also demonstrated that infected individuals present higher levels of circulating Treg cells expressing CTLA-4, GITR, IL-10, TGF-β and IL-17. Moreover, we showed that hookworm crude antigen stimulation reduces the number of CD4+CD25+FOXP3+ T regulatory cells co-expressing IL-17 in infected individuals. Finally, PBMCs from infected individuals pulsed with excreted/secreted products or hookworm crude antigens presented an impaired cellular proliferation, which was partially augmented by the depletion of Treg cells. Our results suggest that Treg cells may play an important role in hookworm-induced immunosuppression, contributing to the longevity of hookworm survival in infected people., Author Summary The hookworm infection is characterized by the long-term survival of the parasite and the concomitant modulation of the host immunity. Among several mechanisms that may account for the suppression of T cell response, we here described the presence and role of T regulatory cells (also known as Tregs) in the human hookworm infection. Tregs are a minor subpopulation of CD4+ T-cells, which also express specific cell markers that allow its further identification (CD25 and FOXP3). Our results showed that hookworm infection induce an augmentation of Tregs in the peripheral blood, followed by the higher levels of circulating Treg cells expressing several markers and cytokines associated with cell regulation (CTLA-4, GITR, IL-10, TGF-β and IL-17). We also demonstrated that in vitro depletion of Tregs partially enhanced the naturally impaired cellular proliferation of lymphocytes from infected individuals after antigenic stimulation. Our results suggest that Treg cells may play an important role in hookworm-induced immunosuppression, contributing to the longevity of hookworm survival in infected people.

A esquistossomose é uma das parasitoses mais prevalentes no mundo e é um grande problema de saúde pública, principalmente nos países em desenvolvimento. Atualmente a medida mais utilizada para o controle da doença é a quimioterapia. Entretanto, sabe-se que mesmo após o tratamento os indivíduos se reinfectam. Sabe-se também que há uma estreita relação entre os fatores demográficos, socioeconômicos e comportamentais na dinâmica da transmissão da esquistossomose. Diante disso, a realização deste estudo teve como objetivo analisar a reinfecção pelo Schistosoma mansoni entre escolares com idade de 5 a 15 anos. Os participantes foram 407 crianças e adolescentes infectados pelo S. mansoni e residentes no município de Ponto dos Volantes, nas comunidades de Palha, Astraluta, Caju (Jequitinhonha) e Córrego São João (Itaobim), sendo todas essas áreas consideradas endêmicas para a esquistossomose. No início do estudo, todos os voluntários foram tratados com Praziquantel e responderam aos questionários socioeconômico e de contato com a água. Foram coletadas, também, as coordenadas geográficas das suas residências. Um ano após o tratamento foram realizados exames parasitológicos de fezes de todos os escolares para avaliar a reinfecção tendo sido encontrada uma taxa de 21,6 %. O modelo multivariado mostrou que a carga parasitária pré-tratamento (p < 0,001) e a falta de fornecimento de água tratada (p = 0,010) mantiveram-se associadas à reinfecção. Aqueles que reinfectaram tiveram um maior contato com água potencialmente contaminada apesar da diferença não ter sido significativa. A análise espacial apontou que, em todas as áreas estudadas, a reinfecção ocorreu de forma heterogênea. Concluiu-se que a taxa de reinfecção pelo S. mansoni é preocupante e que possuir uma alta carga parasitária antes do tratamento e residir em local onde não há água tratada foram os principais fatores de risco para a reinfecção pelo S. mansoni. Schistosomiasis is one of the most prevalent parasitic diseases in the world and is a major public health problem, particularly in developing countries. Currently the most commonly used measure for controlling the condition is chemotherapy. However, after the treatment, the individuals become infected again. It is well known that there is a close relationship between demographic, socioeconomic and behavioral factors in the dynamics of schistosomias is transmission. Therefore, this study aimed to analyze reinfection by Schistosoma mansoni in school children aged 5-15 years. Participants were 407 children and adolescents infected with S. mansoni and residents in the municipality of Ponto dos Volantes, and the communities of Palha, Astraluta, Caju and Córrego São João, all of which are endemic areas for schistosomiasis. At baseline, all subjects were treated with Praziquantel, responded to socioeconomic and water contact questionnaires. The geographical coordinates of all houses were collected. One year after the treatment another faecal exam was performed to evaluate reinfection rates. The results showed a reinfection rate of 21.6%. The multivariate model showed that parasite load before treatment (p < 0.001) and lack of treated water supply (p = 0.010) remained associated to reinfection. Spatial analys is showed that in all areas studied reinfection occurred heterogeneously. It is concluded that the reinfection rate is worrisome and having high intensity of infection before treatment and leaving in areas with no treated water were considered the main risk factors to re-infection with S. mansoni.