Desarrollo de una metodología para la detección de cuerpos de agua mediante el análisis de imágenes SAR COSMO SkyMed y DEMs

En esta tesis se integran índices hidrológicos relativos a la acumulación de agua del terreno con datos radar de la constelación COSMO-SkyMed en una metodología de detección de cuerpos de agua continentales y zonas anegables, apropiada para aplicaciones de tipo operativo de monitoreo; que potencialmente puede ser usada en prevención y respuesta, tanto a inundaciones como a brotes de enfermedades transmitidas por vectores. Se definió un procedimiento de cálculo de índice topográfico de humedad a partir de un modelo de elevación digital y se consideró el efecto de la cobertura de vegetación en este patrón de acumulación de humedad. Se generó un sistema de clasificación de imágenes COSMO-SkyMed, basado en novedosas variables de textura y entrenado automáticamente. Todos los algoritmos desarrollados en esta tesis fueron implementados en el lenguaje de programación IDL

Interaction between spatial and temporal scales for entomological field data: Analysis of Aedes Aegypti oviposition series

Background In Argentina, Aedes aegypti represents an important public health threat, since it is the vector responsible for the transmission of dengue, chikungunya, zika and yellow fever. Mundo Sano Foundation has been carrying out periodic surveys of immature vector stages in several cities of northern Argentina. The main tool to mitigate their spread is through vector control. The identification of vector "hot spots" is an important key to design preventive program tools. Geostatistical techniques such as spatial autocorrelation (SAC) and kriging interpolation can be used to predict vector abundance in unsampled areas using data obtained from monitored sites. The knowledge of the spatial autocorrelation of vector abundance is fundamental and it can also be used to design disease surveillance strategies: To determine the characteristics of chemical control; to select ovitrap placement (distance between samples); and to determine the optimum sample size, among others. It is important to analyze the effect of the variation of the scale in the observed phenomenon. Methods This paper analyzes a two years series of weekly oviposition data from 25 ovitraps distributed in the urban area of a small city (104 measurements were collected for each ovitrap). We aim to understand how the relationship between sites measurements varies considering its relative location in the city, for different temporal sampling frequency or temporal resolution (TR). Different similarity measures between curves and graphic representations of these relationships, are explored. Among these, an innovative use of polar graphs -a tool commonly used to detect changes in satellite images- is examined. We evaluate variograms and SAC for multitemporal data (oviposition curves) at each TR. Results Similarity between curves does not show spatial continuity in relation to the spatial arrangement of ovitraps, may be due to the effect of processes that are only observable at the microhabitat scale or due to sociodemographic factors. As the temporal resolution is greater in a given area, a greater number of ovitraps are needed to capture the spatial heterogeneity of the abundance of the vector. At the maximum TR analyzed, the minimum distance of spatial correlations was set at 1000 m. This has implications on the quantity of ovitraps per area unit required in the field in order to obtain a good description of the population dynamics of Ae. aegypti at the peridomestic level. Conclusion The results would indicate that when varying the time scale of analysis, the spatial scale should be modified accordingly to adapt to the new data structure. The ability to predict ecological phenomena depends on the relationships between spatial and temporal scales. The approach and innovative statistical tools described in this study, based on empirical data from a field study, may be used by different Ae. aegypti monitoring and control programs in order to design and implement tailor-made interventions. It would allows to support not only the selection of field samples, and to obtain data interpolation parameters, but also to contribute to the development of vector abundance models.Fil: Lanfri, Sofía. Comision Nacional de Actividades Espaciales. Instituto de Altos Estudios Espaciales "Mario Gulich"; Argentina. Fundación Mundo Sano; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Espinosa, Manuel. Fundación Mundo Sano; ArgentinaFil: Lanfri, Mario. Comision Nacional de Actividades Espaciales. Instituto de Altos Estudios Espaciales "Mario Gulich"; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Periago, Maria Victoria. Fundación Mundo Sano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Abril, Marcelo. Fundación Mundo Sano; ArgentinaFil: Scavuzzo, Carlos Marcelo. Comision Nacional de Actividades Espaciales. Instituto de Altos Estudios Espaciales "Mario Gulich"; Argentina. Universidad Nacional de Córdoba; Argentin

Algoritmos para el alerta temprana de dengue en un ambiente geomático

En el marco de un convenio CONAE-Ministerio de Salud de la Nación se está desarrollando un proyecto para implementar un sistema informático de Alerta Temprana de Dengue. Mientras que el sistema y sus subsistemas son descriptos brevemente, en este trabajo se explica detalladamente la unidad Environmental Risk del subsistema Algorithm Executor encargada del proceso que calcula el riesgo ambiental de Dengue a nivel de localidades de la República Argentina. El cálculo de riesgo implica la suma de dos componentes: a) una estática relacionada con las condiciones ambientales históricas que determinan la probabilidad de que el vector se desarrolle en el lugar y b) una componente dinámica relacionada con las condiciones actuales que posibiliten la transmisión viral. La primera componente se estima mediante una combinación de los métodos de Máxima Entropía y de Regresión Logística, mientras que la segunda componente es calculada por un algoritmo que contabiliza la cantidad de períodos de incubación extrínseca que pueden ser completados en cada localidad de acuerdo a la temperatura media diaria, estimada desde un satélite. Se muestra como resultado la estratificación de las localidades de Argentina en función de su riesgo ambiental de Dengue.Sociedad Argentina de Informática e Investigación Operativ

An operative dengue risk stratification system in Argentina based on geospatial technology

Based on an agreement between the Ministry of Health and the National Space Activities Commission in Argentina, an integrated informatics platform for dengue risk using geospatial technology for the surveillance and prediction of risk areas for dengue fever has been designed. The task was focused on developing stratification based on environmental (historical and current), viral, social and entomological situation for >3,000 cities as part of a system. The platform, developed with open-source software with pattern design, following the European Space Agency standards for space informatics, delivers two products: a national risk map consisting of point vectors for each city/town/locality and an approximate 50 m resolution urban risk map modelling the risk inside selected high-risk cities. The operative system, architecture and tools used in the development are described, including a detailed list of end users’ requirements. Additionally, an algorithm based on bibliography and landscape epidemiology concepts is presented and discussed. The system, in operation since September 2011, is capable of continuously improving the algorithms producing improved risk stratifications without a complete set of inputs. The platform was specifically developed for surveillance of dengue fever as this disease has reemerged in Argentina but the aim is to widen the scope to include also other relevant vector-borne diseases such as chagas, malaria and leishmaniasis as well as other countries belonging to south region of Latin America

Environmental characteristics around the household and their association with hookworm infection in rural communities from Bahir Dar, Amhara Region, Ethiopia

Soil-Transmitted Helminths (STH) are highly prevalent Neglected Tropical Disease in Ethiopia, an estimated 26 million are infected. Geographic Information Systems and Remote Sensing (RS) technologies assist data mapping and analysis, and the prediction of the spatial distribution of infection in relation to environmental variables. The influence of socioeconomic, environmental and soil characteristics on hookworm infection at the individual and household level is explored in order to identify spatial patterns of infection in rural villages from Zenzelema (Amhara region). Inhabitants greater than 5 years old were recruited in order to assess the presence of STH. Socioeconomic and hookworm infection variables at the household level and environmental variables and soil characteristics using RS were obtained. The dominant STH found was hookworm. Individuals which practiced open defecation and those without electricity had a significant higher number of hookworm eggs in their stool. Additionally, adults showed statistically higher hookworm egg counts than children. Nonetheless, the probability of hookworm infection was not determined by socioeconomic conditions but by environmental characteristics surrounding the households, including a combination of vigorous vegetation and bare soil, high temperatures, and compacted soils (high bulk density) with more acidic pH, given a pH of 6.0 is optimal for hatching of hookworm eggs. The identification of high-risk environmental areas provides a useful tool for planning, targeting and monitoring of control measures, including not only children but also adults when hookworm is concerned.Fil: Anegagrie, Melaku. Fundación Mundo Sano; España. Instituto de Salud Carlos III; EspañaFil: Lanfri, Sofía. Fundación Mundo Sano; Argentina. Comisión Nacional de Actividades Espaciales. Instituto de Altos Estudios Espaciales "Mario Gulich"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Aramendia, Aranzazu Amor. Fundación Mundo Sano; España. Instituto de Salud Carlos III; EspañaFil: Scavuzzo, Carlos Matias. Fundación Mundo Sano; Argentina. Comision Nacional de Actividades Espaciales. Instituto de Altos Estudios Espaciales "Mario Gulich"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Herrador, Zaida. Instituto de Salud Carlos III; EspañaFil: Benito, Agustín. Instituto de Salud Carlos III; EspañaFil: Periago, Maria Victoria. Fundación Mundo Sano; Argentin