Intestinal parasite infestation in indigenous Mbyá-Guaraní communities in Misiones, Argentina, was IntroducciónLas parasitosis intestinales y la contaminación fecal representan un importante problema que enfrenta la salud pública y ambiental en los países en vías de desarrollo 1,2 . Estas infecciones son generalmente subestimadas por ser asintomáticas, pero sus efectos pueden contribuir a la morbilidad cuando están asociados a la malnutrición 1 . En la mayoría de los casos se cuenta con datos de prevalencia fragmentarios, procedentes de niños en edad escolar o de hospitales, que no son representativos del total de la población en un área determinada 2 . Si bien existen estudios de campo desarrollados en diferentes poblaciones, no han sido utilizados en la elaboración de medidas preventivas, ni han sido devueltos a las poblaciones involucradas, de manera que participen en la búsqueda de alternativas para la protección de la salud 1,2 .El efecto del cambio cultural y la degradación ambiental en la prevalencia de infecciones parasitarias ha sido estudiado en poblaciones indígenas americanas 3,4 . Fitton 4 sostuvo que los procesos de colonización y de explotación de los recursos naturales han contribuido a la progresiva aculturación de poblaciones indíge-nas de Ecuador. Esta situación, unida al sedentarismo y la deficiente atención de la salud, favoreció la transmisión de infecciones parasitarias en esas poblaciones 3,4 . Por otra parte, también las infecciones parasitarias causan o agra-

Indigenous communities in Argentina represent socially and economically neglected populations. They are living in extreme poverty and environmental degradation conditions. New information about health status and socio-environmental features is urgently needed to be applied in future sanitary policies. Present study describes the nutritional status, body composition, and intestinal parasitism among Mbyá-Guaraní children from three communities in the Misiones Province. Anthropometric parameters were analyzed for 178 individuals (aged 1-14). Data were transformed to z-scores using NHANES I and II. Stunting showed the greatest prevalence (44.9%). Children were found to have low arm circumference and low arm muscle area, although with tricipital skinfold value near to the reference. They also tend to have shorter than normal lower limbs. Fecal samples and anal brushes (for Enterobius vermicularis) were collected in 45 children (aged 1-13). Ritchie's sedimentation and Willis' flotation techniques were used to determine parasitoses. Ninety five percent of children were infected with at least one species and 81.4% were polyparasitized. The higher prevalences corresponded to Blastocystis hominis, hookworms (Ancylostoma duodenale/Necator americanus), and Entamoeba coli. Associations occurred between hookworms with B. hominis/E. coli and B. hominis with nonpathogenic amoebas. Thirty nine percent of the children with stunting presented B. hominis, Strongyloides, and hookworms. Our results indicate that this indigenous population is subjected to extreme poverty conditions and is one of the most marginalized in this country. Severe growth stunting and parasitic infection are still quite common among Mbyá children affecting about half of them along with significant changes in body composition and proportions.

Environmental perturbations of many kinds influence growth and development. Little is known, however, about the influence of environmental factors on the patterns of phenotypic integration observed in complex morphological traits. We analyze the changes in phenotypic variance-covariance structure of the rat skull throughout the early postnatal ontogeny (from birth to weaning) and evaluate the effect of intrauterine growth retardation (IUGR) on this structure. Using 2D coordinates taken from lateral radiographs obtained every 4 days, from birth to 21 days old, we show that the pattern of covariance is temporally dynamic from birth to 21 days. The environmental perturbation provoked during pregnancy altered the skull growth, and reduced the mean size of the IUGR group. These environmental effects persisted throughout lactancy, when the mothers of both groups received a standard diet. More strikingly, the effect grew larger beyond this point. Altering environmental conditions did not affect all traits equally, as revealed by the low correlations between covariance matrices of treatments at the same age. Finally, we found that the IUGR treatment increased morphological integration as measured by the scaled variance of eigenvalues. This increase coincided and is likely related to an increase in morphological variance in this group. This result is expected if somatic growth is a major determinant of covariance structure of the skull. In summary, our findings suggest that environmental perturbations experienced in early ontogeny alter fundamental developmental processes and are an important factor in shaping the variance-covariance structure of complex phenotypic traits.

Integration and modularity are fundamental determinants of how natural selection effects evolutionary change in complex multivariate traits. Interest in the study of the specific developmental basis of integration through experimental approaches is fairly recent and it has mainly focused on its genetic determinants. Here we present evidence that postnatal environmental perturbations can modify the covariance structure by influencing the variance of some developmental processes relative to the variances of other processes that contribute to such structure. We analyzed the effects of the reduction of nutrient supply in different ontogenetic stages (i.e., before and after weaning, and from birth to adulthood) in Rattus norvegicus. Our results show that this environmental perturbation alters the phenotypic variation/covariation structure of the principal modules of the skull (base, vault and face). The covariance matrices of different treatment groups exhibit low correlations and are significantly different, indicating that the treatments influence covariance structure. Postnatal nutrient restriction also increases the variance of somatic growth. This increased variance drives an increase in overall integration of cranial morphology through the correlated allometric effects of size variation. The extent of this increase in integration depends on the time and duration of the nutritional restriction. These results support the conclusion that environmental perturbations can influence integration and thus covariance structure via developmental plasticity.

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and educational use, including for instruction at the author's institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. We also analyzed samples of soil, water, and canine feces and surveyed other domestic and environmental data using structured questionnaires to each child's parents. To associate the parasitological, anthropometric and socio-environmental data, a categorical analysis of principal components (catPCA) was conducted. In the first axis of catPCA, the correlations among socio-environmental variables showed a gradient of "relative welfare". The eigenvectors showed the most influential variables in the analysis were promiscuity (0.0765), father's education (−0.741), crowding (0.727), wastewater disposal (−0.658), mother's education (−0.574), and flooding (−0.409). The 85% of children were parasitized and 79.6% polyparasitized. The 27.7% of children had deficit in some nutritional status indicator, being the stunting the most prevalent deficit (16.8%). There also found parasites in 42% of the dog feces, 53% of the soil samples, and non-pathogenic amoebae in the water samples. The SEV was mainly associated with geohelminths and stunting, especially among the poorest children. The study evidences that living conditions are variable within this population. Part of these variations could be linked to the differences in the extent to which parents are able to use their scant resources to influence their children's morbidity. Further studies need to be done from a qualitative approach.

Parasitosis intestinales en niños de edad preescolar y escolar: situación actual en poblaciones urbanas, periurbanas y rurales en Brandsen,

Objetivos. Evaluar el estado nutricional y la composición corporal, como indicadores de la calidad de vida, en niños pobres que concurren a comedores comunitarios de La Conclusiones. En las comunidades infantiles estudiadas coexisten la desnutrición y el sobrepeso. La elevada prevalencia de retraso en el crecimiento (talla baja para la edad) y desnutrición global (peso bajo para la edad) y la grave reducción de la masa muscular, aun en niños con sobrepeso u obesidad, parecen ser consecuencias de un proceso adaptativo inevitable frente a las condiciones adversas de vida.Estado nutricional, composición corporal, infante, niño, trastornos de la nutrición del niño, Argentina. RESUMENHasta mediados de la década de 1970, la pobreza, definida en términos de ingresos, era una cuestión marginal en Argentina. En 1974, solamente 3,8% de los hogares del país se encontraban por debajo de la línea de pobreza, es decir, sus ingresos mensuales estaban Palabras clave

We analyzed the nutritional status of urban and rural schoolchildren from Mendoza (Argentina), but avoided rural and urban categorization by generating subpopulations as a function of their socioenvironmental characteristics. We transformed weight and height data into z-scores using the CDC/NCHS growth charts; defined underweight, stunting, and wasting by z-scores of less than -2 SD; and calculated overweight and obesity, according to the cutoff proposed by the International Obesity Task Force. Socioenvironmental characteristics included housing, public services, parental resources, and farming practices; we processed these variables by categorical principal-component analysis. The two first axes defined four subgroups of schoolchildren: three of these were associated with urban characteristics, while the remaining subgroup was considered rural. Nutritional status differed across groups, whereas overweight was similar among the groups and obesity higher in urban middle-income children. Urban differences were manifested mainly as underweight, but rural children exhibited the greatest stunting and wasting. Thus, the negative effects of environment on nutritional status in children are not restricted to poor periurban and rural areas, though these are indeed unfavorable environments for growth: some urban families provide children with sufficient quantity and diversity of foods to expose them to obesity. By contrast, the more affluent urban families would appear to have greater possibilities for allowing their children to adopt a healthy life-style. Although the causes of differences in nutritional status between middle- and high-income urban groups are not clear, these determinants probably involve economic as well as educational influences.