Abstract Objective To describe and compare the health status between vulnerable population participating in a program to tackle energy poverty (Energía, la justa) and the non-energy poor Barcelona (Spain) population and to analyse among participants the effect of energy poverty intensity on health. Method Cross-sectional study based on data from program participants obtained before the intervention. Participants (1799 women and 671 men) were compared to non-energy poor population of Barcelona (1393 women and 1215 men) sampled from the Barcelona Public Health Survey (2016). Standardized prevalence and prevalence ratios of self-perceived poor health, asthma, chronic bronchitis, and depression and/or anxiety were estimated, and among participants the association between health status and energy poverty intensity was estimated with multivariate models. Results The probability of poor self-perceived physical and mental health ranged from 2.2 to 5.3 times greater in the program participants than non-energy poor Barcelona population. Among program participants, those most affected were found to be the most likely to report poor health outcomes, regardless of other sociodemographic factors. Conclusions The prevalence of poor physical and mental health was considerably higher among women and men participating in the programme compared to the non-energy poor population and was even worse among those who were more severely affected. Public policies that tackle energy poverty and its consequences are urgently needed in Spain.

RESUMEN Objetivo Describir y comparar el estado de salud entre la población vulnerable que participa en un programa de lucha contra la pobreza energética (Energía, la justa) y la población sin pobreza energética de Barcelona (España), y analizar entre las personas participantes el efecto de la intensidad de la pobreza energética en la salud. Método Estudio transversal basado en datos de los/las participantes en el programa obtenidos antes de la intervención. Se compararon los/las participantes (1799 mujeres y 671 hombres) con población sin pobreza energética de Barcelona (1393 mujeres y 1215 hombres) seleccionada de la Encuesta de Salud Pública de Barcelona (2016). Se estimaron la prevalencia estandarizada y las razones de prevalencia de mala salud, asma, bronquitis crónica y depresión o ansiedad autopercibida. Entre los/las participantes se estimó la asociación entre el estado de salud y la intensidad de la pobreza energética con modelos multivariantes. Resultados Los/las participantes presentaron entre 2,2 y 5,3 veces peores resultados en salud que la población sin pobreza energética. Entre los/las participantes se encontró que las personas más afectadas eran las que tenían más probabilidades de reportar peores resultados de salud, independientemente de otros factores sociodemográficos. Conclusiones La prevalencia de mala salud física y mental era considerablemente mayor en las mujeres y los hombres que participaron en el programa en comparación con la población sin pobreza energética, y era aún peor entre los/las más severamente afectados. En España se necesitan con urgencia políticas públicas que aborden la pobreza energética y sus consecuencias.

Abstract Objective To describe and compare the health status between vulnerable population participating in a program to tackle energy poverty (Energía, la justa) and the non-energy poor Barcelona (Spain) population and to analyse among participants the effect of energy poverty intensity on health. Method Cross-sectional study based on data from program participants obtained before the intervention. Participants (1799 women and 671 men) were compared to non-energy poor population of Barcelona (1393 women and 1215 men) sampled from the Barcelona Public Health Survey (2016). Standardized prevalence and prevalence ratios of self-perceived poor health, asthma, chronic bronchitis, and depression and/or anxiety were estimated, and among participants the association between health status and energy poverty intensity was estimated with multivariate models. Results The probability of poor self-perceived physical and mental health ranged from 2.2 to 5.3 times greater in the program participants than non-energy poor Barcelona population. Among program participants, those most affected were found to be the most likely to report poor health outcomes, regardless of other sociodemographic factors. Conclusions The prevalence of poor physical and mental health was considerably higher among women and men participating in the programme compared to the non-energy poor population and was even worse among those who were more severely affected. Public policies that tackle energy poverty and its consequences are urgently needed in Spain.

RESUMEN Objetivo Describir y comparar el estado de salud entre la población vulnerable que participa en un programa de lucha contra la pobreza energética (Energía, la justa) y la población sin pobreza energética de Barcelona (España), y analizar entre las personas participantes el efecto de la intensidad de la pobreza energética en la salud. Método Estudio transversal basado en datos de los/las participantes en el programa obtenidos antes de la intervención. Se compararon los/las participantes (1799 mujeres y 671 hombres) con población sin pobreza energética de Barcelona (1393 mujeres y 1215 hombres) seleccionada de la Encuesta de Salud Pública de Barcelona (2016). Se estimaron la prevalencia estandarizada y las razones de prevalencia de mala salud, asma, bronquitis crónica y depresión o ansiedad autopercibida. Entre los/las participantes se estimó la asociación entre el estado de salud y la intensidad de la pobreza energética con modelos multivariantes. Resultados Los/las participantes presentaron entre 2,2 y 5,3 veces peores resultados en salud que la población sin pobreza energética. Entre los/las participantes se encontró que las personas más afectadas eran las que tenían más probabilidades de reportar peores resultados de salud, independientemente de otros factores sociodemográficos. Conclusiones La prevalencia de mala salud física y mental era considerablemente mayor en las mujeres y los hombres que participaron en el programa en comparación con la población sin pobreza energética, y era aún peor entre los/las más severamente afectados. En España se necesitan con urgencia políticas públicas que aborden la pobreza energética y sus consecuencias.

ABSTRACT Soils for livestock production have a high heterogeneity that causes variability in forage production. The aims of this study were (i) to assess the relationship between ECa and soil properties and then use this information to determine potential management zones (PMZ) and (ii) evaluate if these PMZ are related to forage yield of tall fescue during different regrowth periods under contrasting levels of N availability. The ECa was measured in a 5.75 ha paddock that sustained a permanent pasture dominated by tall fescue. A 30 m by 30 m grid cell size was chosen and 43 sampling areas (SA) each 4 m2 in size, were geo-referenced. In each SA soil samples were collected and analyzed for soil physicochemical properties such as pH, texture, organic matter, gravimetric soil water content (%) at 33 and 1500 kPa, salinity, soluble sodium, calcium and magnesium and sodium adsorption ratio . In addition, SA were divided into two experimental units of 1 m by 2 m, one of which was fertilised with 250 kg N ha-1 (N250) at the beginning of four regrowth periods (spring 2015, spring 2016, autumn 2016 and autumn 2017) and the other was not fertilised with N (N0). At the end of each regrowth period, the accumulated biomass (AB) was estimated. ECa was associated with salinity and sand percentage (R2 = 0,67). Two PMZ were delimited and the differences in AB were compared through analysis of variance. In spring, the average AB showed a significant PMZ x N interaction (P = 0.02). By contrast, the effects of PMZ on forage yield were not statistically significant in autumn (P > 0.05). In conclusion, in spring, the production of tall fescue can be managed by PMZs delimited by ECa. However, the delimitation of PMZs was not possible during autumn.

RESUMEN Los suelos ganaderos presentan una elevada heterogeneidad que provoca variabilidad en la producción de forraje. Por lo tanto, los objetivos de este trabajo fueron (a) determinar, a escala de lote, si la relación entre la conductividad eléctrica aparente (CEa) y propiedades edáficas, permite delimitar zonas de manejo potenciales (ZMP) y (b) evaluar si estas ZMP se relacionan, en primavera y otoño, con la variación espacial de la producción de forraje de una pastura de festuca alta creciendo con y sin limitantes de nitrógeno (N). En un lote de 5,75 ha que tenía implantada una pastura de festuca alta, se midió la CEa y en una grilla de 30 x 30 m se georreferenciaron 43 áreas de muestreo (AM) donde se determinaron propiedades edáficas (pH, textura, matéria orgânica, humedad gravimétrica (%) a 33 y 1500 kPa, salinidad, sodio, calcio, magnesio solubles y relación de absorción de sodio). Además, en cuatro rebrotes: primavera 2015, primavera 2016, otoño 2016 y otoño 2017 se marcaron dos parcelas en cada AM y se aplicaron dos tratamientos: N0 (sin aplicación de N) y N250 (250 kg ha-1 de N) para determinar la biomasa seca acumulada (BA). La salinidad y el porcentaje de arena fueron las variables que más explicaron la variabilidad de la CEa (R2 = 0,67). Para el lote bajo estudio se delimitaron dos ZMP hallándose, en la BA promedio de primavera, interacción entre los factores de tratamiento ZMP y N (P = 0,02). Sin embargo, este comportamiento no se manifestó en la BA promedio de otoño (P > 0,05). En conclusión, mediante la CEa podrían delimitarse ZMP en primavera lo que facilitaría el manejo de pasturas de festuca alta. En cambio, no sería posible delimitar ambientes en otoño.

Abstract Pinus pseudostrobus var. oaxacana, an important species of Oaxaca State from its wood quality; even though it is preferred for reforestation and plantations, the seed production capacity of this species is unknown. The aim of the actual study was to evaluate the morphological variation, reproductive characteristics and their relationship with environmental factors of cones and seeds of selected P. pseudostrobus var. oaxacana trees as seed trees from five provenances of the state. From November to December 2017, 1 058 cones were collected from 42 selected trees, to which the following characteristics were assessed: length, diameter, dry weight, number of scales, number and of weight of fully developed seeds, average weight per seed, reproductive efficiency and inbreeding index. Trees and provenances were differentiated by analysis of variance and mean tests (Duncan, 0.05). Reproductive characteristics were correlated with environmental variables (collection sites) and morphological characteristics. Selected trees were 51.7±8.0 years old, 36.4±4.6 m high and 54.5±8.2 cm diameter at breast height. The average values per cone were: 101.3 mm long; 56 mm diameter, 97.9 g dry weight; 133 scales; 107 developed seeds per cone; 2.35 g weight of developed seeds per cone; 0.021 g average weight per seed; reproductive efficiency of 13.09 mg per gram of strobilus; inbreeding index (II = 0.50) indicates a high level of self-fertilization. Of the evaluated characteristics, reproductive efficiency and II did not show significant differences.

Resumen Pinus pseudostrobus var. oaxacana es un taxon importante en Oaxaca por la calidad de su madera; aunque, también es preferida para la reforestación y plantaciones, pero se desconoce su capacidad para la producción de semilla. Los objetivos de la presente investigación consistieron en evaluar la variación morfológica, conocer las características reproductivas de conos y semillas y su relación con factores ambientales de árboles semilleros de la especie de interés seleccionados en cinco procedencias del estado. Durante noviembre y diciembre de 2017, se recolectaron 1 058 conos de 42 individuos a los que se les midieron variables morfológicas, y determinaron la eficiencia reproductiva e índice de endogamia; los árboles y procedencias se diferenciaron mediante análisis de varianza y pruebas de medias de Duncan. Las características reproductivas se correlacionaron con variables ambientales (sitios de recolecta) y dasométricas de los progenitores. Los datos registrados fueron 51.7±8.0 años de edad, altura de 36.4±4.6 m y diámetro normal de 54.5±8.2 cm. Los valores medios obtenidos por cono fueron: longitud 101.3 mm, diámetro 56 mm, peso seco 97.9 g, 133 escamas, 107 semillas desarrolladas por cono; las semillas desarrolladas por cono pesaron 2.35 g, peso promedio por semilla 0.021 g; eficiencia reproductiva 13.09 mg por gramo de estróbilo; IE = 0.50 (índice de endogamia), que indica un alto nivel de autofecundación; el IE decrece con la altitud y aumenta con la cantidad de recolecta. De las características evaluadas, la eficiencia reproductiva e IE no mostraron diferencias significativas entre poblaciones.

Abstract Non-nutritive sweeteners (NNS) are food additives that have been used as a possible tool to reduce energy and sugar intake. There is a scientific debate around the real benefits of their use. NNS are substances widely evaluated in the scientific literature. Their safety is reviewed by international regulatory health agencies. Health professionals and consumers often lack education and objective information about food additives based on the best scientific evidence. NNS have been used as a substitute for sucrose, especially by people with diabetes mellitus and obesity. However, concerns related to their possible association with preterm birth have been raised, and also with their use during pregnancy and lactation because of the possibility of metabolic or other consequences in both the mother and offspring. This analysis of the evidence in gynecology and obstetrics presents a review of the most commonly asked questions regarding this matter by health professionals and their patients. This document evaluates a diversity of scientific publications under the sieve of evidence-based medicine and the regulatory framework for food additives to elucidate whether the use of NNS in women in these critical stages of pregnancy and breastfeeding represents a potential risk.

Resumen Los edulcorantes no calóricos (ENC) son aditivos de alimentos que se utilizan para sustituir azúcares y potencialmente para reducir la ingesta energética. Existe un debate científico en torno a los beneficios reales de su uso. Los ENC son sustancias ampliamente evaluadas en la literatura científica. Su seguridad es revisada por las agencias regulatorias internacionales del campo de la salud. Los profesionales de la salud y los consumidores con frecuencia carecen de educación e información rigurosa, objetiva y sustentada en la evidencia científica y el juicio clínico sobre el uso de aditivos en los alimentos. Los ENC se han empleado como sustitutos de la sacarosa, en especial por las personas con diabetes mellitus y obesidad. Sin embargo, se han planteado inquietudes relacionadas con su posible asociación con el parto pretérmino y con su uso durante el embarazo y la lactancia, ante la posibilidad de consecuencias metabólicas o de otra índole en la madre o en el neonato. Este análisis de la evidencia en ginecología y obstetricia presenta una revisión que intenta responder a preguntas que habitualmente se hacen al respecto los profesionales de la salud y sus pacientes. En este documento se evalúan diversas publicaciones científicas bajo el tamiz de la medicina basada en la evidencia y del marco regulatorio para aditivos de alimentos con el fin dilucidar si el uso de ENC en las mujeres durante las etapas críticas del embarazo y la lactancia supone o no un posible riesgo.

Soil erosion is a relevant factor in land degradation, causing several negative impacts to different levels in the environment, agriculture, etc. The tobacco plantations in the western part of the country have been negatively affected by the water erosion due to natural and human factors. For the implementation of a strategy for sustainable land management a key element is to quantify the soil losses in order to establish policies for soil conservation. The nuclear techniques have advantages in comparison with the traditional methods to assess soil erosion and have been applied in different agricultural settings worldwide. The tobacco cultivation in Pinar del Río is placed on soils with high erosion levels, therefore is important to apply techniques which support the soil erosion rate quantification. This work shows the use of 137Cs technique to characterize the soil erosion status in two sectors in a farm with tobacco plantations located in the south-western plain of Pinar del Rio province. The sampling strategy included the evaluation of selected transects in the slope direction for the studied site. The soil samples were collected in order to incorporate the whole 137Cs profile. Different conversion models were applied and the Mass Balance Model II provided the more representative results, estimating the soil erosion rate from –18,28 to 8,15 t ha-1año-1

La erosión del suelo es un elemento importante en la degradación de tierras, provocando impactos negativos a varios niveles (parcela, finca, cuenca, etc). El cultivo del tabaco en el occidente del país se ha visto negativamente afectado por la erosión hídrica asociado a factores naturales y antrópicos. Un elemento fundamental para implementar una estrategia de manejo sostenible de tierras es la cuantificación de las pérdidas de suelo, ya que permiten establecer políticas de conservación de suelos. Las técnicas nucleares en la evaluación de la erosión, poseen ventajas en comparación con los métodos tradicionales y han sido aplicadas en diferentes agrosistemas a nivel mundial. En la provincia Pinar del Río, los suelos dedicados al cultivo del tabaco, presentan elevados niveles erosivos, por lo que es importante utilizar técnicas que permitan la cuantificación de las tasas de erosión de suelos. El trabajo muestra el uso de la técnica del 137Cs para caracterizar el estado de la erosión de suelos en dos sectores de una granja con plantaciones de tabaco, ubicadas en la Llanura Suroccidental de la provincia de Pinar del Río. La estrategia de muestreo incorporó la evaluación de transectas seleccionadas en dirección de la pendiente, siendo tomadas muestras de suelos que incluyeron todo el 137Cs del perfil. Se emplearon varios modelos de conversión; el Modelo de Balance de Masa II proporcionó los mejores resultados, obteniéndose una tasa de redistribución de suelos con valores de -18,28 a 8,15 t ha-1año-1

During the last century, soil maps were developed in the province of Buenos Aires on a scale of 1:50000. Generally, fields in t Southeastern pampas contain more than one mapping unit composed of different soil series with several agricultural aptitudes. In the 1:50000 scale maps, the precise location of these soil series are not always successfully identified. The effective depth of the soil profile is an indicator of soil series. The objectives of this study were to: (l) examine the spatial structure of apparent electrical conductivity (ECa), (ll) evaluate the spatial relationship of soil ECa between different sensors (Geoids EM38-mk2 y veris 3100); and (lll) to evaluate the spatial relationship of ECa and soil depth, as an indicator of soil series. Sampling was carried out in a field of 16 ha, located in the EEA Balcarce. The measurement of ECa was performed using a non-contact sensor (Geonics EM38-MK2) in a vertical dipole orientation (0-150 cm depth) and a contact sensor (Veris 3100) (0-30 and 0-90 cm depth). Soil depth was measured at an average distance between sampling points of 25 m with a Giddings hydraulic sampler. The highest spatial correlations (r= -0.77) were achieved with data collected with the EM38-mk2 (0-150 cm depth) and Veris 3100 (0-90 cm depth)). Soil depth was mainly associated with surface ECa (0-30 cm) measured by Veris 3100 (r= -0.58). Therefore, ECa can be used as an indicator of the soil series in fields with depth variability.

Durante el siglo pasado, se elaboraron mapas de suelo en la provincia de Buenos Aires a una escala de 1:50000. Por lo general, los lotes de producción del Sudeste Bonaerense contienen más de una unidad cartográfica con distintas series de suelo con diferentes aptitudes agrícolas. En los mapas a escala 1:50000, la ubicación precisa de estas series de suelo no siempre se logra identificar. La profundidad efectiva del perfil del suelo es un indicador de las series de suelo. El objetivo del presente trabajo fue: (l) examinar la estructura espacial de la CEa (ll) evaluar la relación espacial de la Conductividad Eléctrica Aparente del suelo entre diferentes sensores (Geonics EM38-mk2 y veris 3100); y (lll) evaluar la relación espacial de la CEa y la profundidad del suelo, como un indicador de la serie de suelo. Los muestreos se efectuaron en un lote de 16 ha ubicado en la EEA Balcarce. La medición de la CEa fue realizada con un sensor de no-contacto (Geonics EM38-mk2) en la orientación dipolo vertical (0-150 cm de profundidad) midiendo la CEa por inducción electromagnética, y un sensor de contacto (Veris 3100) (0-30 y 0-90 cm de profundidad). La profundidad del suelo fue medida a una distancia promedio entre puntos de muestreo de 25 m con un muestreador hidráulico (Giddings). Los datos colectados con el EM38-mk2 en la orientación dipolo vertical (0-150 cm de profundidad) y Veris 3100 (0-90 cm de profundidad) presentaron las mayores correlaciones espaciales (r= 0, 77) La profundidad del suelo estuvo principalmente asociada a la CEa superficial (0-30 cm) medida por el Veris 3100 (r= -0,58). La CEa puede usarse como indicador de la serie de suelo en lotes que presenten variabilidad en su profundidad efectiva.

Genital infection by Schistosoma mansoni is usually misdiagnosed in individuals who reside in, or travel to endemic areas. We describe two cases of genital tumor associated with S. mansoni infection manifested by methrorragy. Surgical specimens revealed leiomyomas in both cases associated with S. mansoni. In one of them, granulomas were found in the ovary and in the other they were found in the uterine tube. Although none presented intestinal/hepatic disease, fecal egg excretion was detected in one. Both had elevated pretreatment antibody reactivity to S. mansoni antigen, but follow-up showed different outcomes. Schistosomiasis should be considered as a diagnosis in individuals with methrorragy residing in or having traveled to endemic areas. Since diagnosis follows genital amputation, and cure control is troublesome, improvement of diagnostic tools and follow-up markers are important priorities to decrease schistosomiasis morbidity.

Meningite e encefalite são complicações da infecção pelo vírus do Oeste do Nilo (VON). Embora o VON seja endêmico na América do Norte, recentemente o vírus foi descrito na Colômbia e Argentina. Sua pesquisa no Brasil é importante uma vez que o vírus nunca fora estudado antes em nosso país. OBJETIVO: Investigar a presença do VON em casos de meningite e encefalite viral de etiologia desconhecida, na cidade no Rio de Janeiro, Brasil. MéTODO: Trinta e sete adultos com quadro de meningite/encefalite tiveram seu LCR e soro testados para anticorpos anti-VON, pelo método ELISA. RESULTADOS: Apenas um caso obteve sorologia positiva para VON, mas a sorologia para dengue também fora positiva. O teste da neutralização por redução de placa foi utilizado para distinção entre as infecções, sendo negativo para VON. CONCLUSÃO: A infecção por VON pode ser confundida com a infecção pelo vírus da dengue, seus sintomas e quadro neurológico são similares. Nós não encontramos o VON em pacientes com meningite/ encefalite na cidade do Rio de Janeiro. Até o momento ele ainda não foi identificado no Brasil

Meningitis and encephalitis are complications of West Nile virus (WNV) infection. Although WNV is endemic in North America, the virus has recently been reported in Colombia and Argentina. Investigation of WNV in Brazil is important since this virus has never been studied previously in this country. OBJECTIVE: To investigate the presence of WNV infection in viral encephalitis/meningitis cases of unknown etiology in the city of Rio de Janeiro, Brazil. METHOD: Thirty-seven adults with viral meningitis/encephalitis had their serum and CSF tested for WNV antibodies using the ELISA method. RESULTS: Only one case was WNV-positive, but this case was also positive for dengue. The plaque reduction neutralization test distinguished infections, and was negative for WNV. CONCLUSION: WNV can be confused with dengue infection. Their symptoms and neurological picture are similar. We did not find WNV in any patients with encephalitis and meningitis in the city of Rio de Janeiro. Up to now, it has not been detected in Brazil

The kinetic constants of an aerobic biodegradation mechanism of dairy wastewaters were estimated using techniques of simulation, estimation of parameters and sensitivity analysis, available in the software Aquasim v 2.1b. A discontinuous, agitated reactor, of 4 liters capacity with a permanent air injection was used. Two kinetic models, Monod and first order were considered to represent substrate consumption as a function of time. Due to a high value of Monod's constant, K S, the data analysis was restricted to the first kinetic proposed. The values obtained for the parameters of endogenous breathing k d and cellular synthesis Y, were similar, whereas the sensitivity analysis revealed non-identifying Monod parameters. The importance of this software to carry out the analysis shown above and the validation of the first order kinetic for representing the substrate consumption are two of the most important conclusions of this work.

Se estimaron parámetros cinéticos del mecanismo de biodegradación aeróbica de efluentes lácteos, empleando técnicas de simulación, estimación de parámetros y análisis sensitivo, disponibles en el software Aquasim v 2.1b. Se utilizó un reactor tanque agitado discontinuo de 4 litros de capacidad con inyección de aire permanente. El consumo de sustrato se representó considerando cinética de primer orden en un caso y del tipo de Monod en el otro. Se obtuvo un elevado valor de la constante de Monod, K S, lo cual limitó el análisis a la primera alternativa. Los valores hallados de los parámetros de respiración endógena k d y síntesis celular Y, fueron similares en ambos casos, mientras que el análisis sensitivo determinó parámetros de Monod no identificables. Se concluye que para este caso resulta válida una cinética de primer orden para representar el consumo de sustrato y se destaca la importancia de esta herramienta para efectuar el análisis.

a comparative analysis of three kinetic models (Monod, exponential and n-order kinetic) representative of substrate degradation of effluents from a dairy factory is presented. Estimation of model parameters and sensitivity analysis were done through data analysis and computational simulation using the software Aquasim v. 2.1.b. Experimental data from a pilot plant were used, estimating the kinetic parameters and performing sensitivity analysis for each case. The n-order kinetic model (μ=kSn) showed to be the best option to represent the degradation of the treated wastewater. With this model, besides achieving acceptable fitting of the experimental data, its parameters k and n are clearly identified. The Monod model, however, although gives lower error, contains parameters with no physical meaning.

Se realizó un análisis comparativo de tres modelos cinéticos (Monod, exponencial y cinética de orden-n) representativos del consumo de substrato de los efluentes de una empresa láctea. Se empleó técnicas de simulación y de análisis de datos disponibles en el programa Aquasim v. 2.1.b. Para ello se correlacionaron datos experimentales obtenidos a nivel piloto, efectuándose en cada caso la estimación de los parámetros cinéticos y el análisis de sensibilidad. Se determinó que el modelo cinético de orden-n (μ=kSn), resulta la opción más adecuada para representar la degradación del substrato de los efluentes. Con este modelo, además de lograr un ajuste aceptable de los datos experimentales sus parámetros k y n son claramente identificables. El modelo de Monod, sin embargo, aún cuando genera un menor error, contiene parámetros no identificables.

Small mammals are found naturally infected by Schistosoma mansoni, becoming a confounding factor for control programs of schistosomiasis in endemic areas. The aims of this study were: to investigate the infection rates by S. mansoni on the water-rat Nectomys squamipes during four years in endemic areas of Sumidouro, state of Rio de Janeiro, using mark-recapture technique; to compare two diagnostic methods for schistosomiasis; and to evaluate the effects of the chemotherapy in the human infected population on the rodent infection rates. The rodent infection rates of S. mansoni increased when rodent population sizes were lower. Coprology and serology results presented the same trends along time and were correlated. Serology could detect recent infection, including the false negatives in the coprology. The chemotherapy in the humans could not interrupt the rodent infection. Rodents can increase the schistosomiaisis transmission where it already exists, they probably maintain the transmission cycle in the nature and can be considered as biological indicators of the transmission sites of this parasite since they are highly susceptible to infection. The water-rats may present different levels of importance in the transmission dynamics of S. mansoni infection cycle for each area, and can be considered important wild-reservoirs of this human disease.