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

Analytic hierarchy process applied to landslide susceptibility mapping of the North Branch of Argentino Lake, Argentina

In the present study, we achieved the susceptibility mapping to slope instability processes by the implementation of Analytic Hierarchy Process and Weighted Linear Combination methods, in the North Branch of Argentino Lake, Southern Patagonian Icefield. The strong retraction of the glaciers in the area has triggered paraglacial readjustments, producing instability processes that favor the generation of mass removal processes. The results obtained from optical satellite images show that the highest degrees of susceptibility (4 and 5) are located on the western slopes of the Upsala Channel, Bertacchi and Cono Tributary Glaciers, and the Moyano and Norte Valleys, respectively. These slopes coincide with the geographic location of previous events surveyed by the inventory of unstable areas of the zone. Low degrees of susceptibility are found on the downhill valleys, outcrops rock and glaciers. The Consistency Ratio was 0.069, indicating that being less than 0.1 the study is reliable. The study sheds light on the knowledge of slopes and valleys that are more susceptible to processes of instability in mountainous areas, which would make it possible to prevent possible hazards associated with these events.Fil: Moragues, Silvana Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Lenzano, María Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Lanfri, Mario. Comision Nacional de Actividades Espaciales. Gerencia de Coordinacion.; ArgentinaFil: Moreiras, Stella Maris. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Lenzano, Luis Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentin

Operational satellite-based temporal modelling of Aedes population in Argentina

Aedes aegypti is a vector for Chikungunya, Dengue and Zika viruses in Latin America and is therefore a large public health problem for the region. For this reason, several inter-institutional and multidisciplinary efforts have been made to support vector control actions through the use of geospatial technologies. This study presents the development of an operational system for the application of free access to remotely sensed products capable of assessing the oviposition activity of Ae. aegypti in all of Argentina?s northern region with the specific aim to improve the current Argentine National Dengue risk system. Temporal modelling implemented includes remotely sensed variables like the normalized difference vegetation index, the normalized difference water index, day and night land surface temperature and precipitation data available from NASA?s tropical rainfall measuring mission and global precipitation measurement. As a training data set, four years of weekly mosquito oviposition data from four different cities in Argentina were used. A series of satellite-generated variables was built, downloading and resampling the these products both spatially and temporally. From an initial set of 41 variables chosen based on the correlation between these products and the oviposition series, a subset of 11 variables were preserved to develop temporal forecasting models of oviposition using a lineal multivariate method in the four cities. Subsequently, a general model was generated using data from the cities. Finally, in order to obtain a model that could be broadly used, an extrapolation method using the concept of environmental distance was developed. Although the system was oriented towards the surveillance of dengue fever, the methodology could also be applied to other relevant vector-borne diseases as well as other geographical regions in Latin America.Fil: Espinosa, Manuel. Fundación Mundo Sano; ArgentinaFil: Di Fino, Eliana Marina Alvarez. Fundación Mundo Sano; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Abril, Marcelo. Fundación Mundo Sano; ArgentinaFil: Lanfri, Mario. Centro Espacial Teófilo Tabanera; ArgentinaFil: Periago, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación Mundo Sano; ArgentinaFil: Scavuzzo, Carlos Marcelo. Centro Espacial Teófilo Tabanera; Argentin

Spatial patterns of high Aedes Aegypti oviposition activity in northwestern Argentina

Background: In Argentina, dengue has affected mainly the Northern provinces, including Salta. The objective of this study was to analyze the spatial patterns of high Aedes aegypti oviposition activity in San Ramo´n de la Nueva Ora´n, northwestern Argentina. The location of clusters as hot spot areas should help control programs to identify priority areas and allocate their resources more effectively. Methodology: Oviposition activity was detected in Ora´n City (Salta province) using ovitraps, weekly replaced (October 2005–2007). Spatial autocorrelation was measured with Moran’s Index and depicted through cluster maps to identify hot spots. Total egg numbers were spatially interpolated and a classified map with Ae. aegypti high oviposition activity areas was performed. Potential breeding and resting (PBR) sites were geo-referenced. A logistic regression analysis of interpolated egg numbers and PBR location was performed to generate a predictive mapping of mosquito oviposition activity. Principal Findings: Both cluster maps and predictive map were consistent, identifying in central and southern areas of the city high Ae. aegypti oviposition activity. A logistic regression model was successfully developed to predict Ae. aegypti oviposition activity based on distance to PBR sites, with tire dumps having the strongest association with mosquito oviposition activity. A predictive map reflecting probability of oviposition activity was produced. The predictive map delimitated an area of maximum probability of Ae. aegypti oviposition activity in the south of Ora´n city where tire dumps predominate. The overall fit of the model was acceptable (ROC = 0.77), obtaining 99% of sensitivity and 75.29% of specificity. Conclusions: Distance to tire dumps is inversely associated with high mosquito activity, allowing us to identify hot spots. These methodologies are useful for prevention, surveillance, and control of tropical vector borne diseases and might assist National Health Ministry to focus resources more effectively.Fil: Estallo, Elizabet Lilia. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Investigaciones Entomológicas de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas; ArgentinaFil: Más, Guillermo. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Vergara Cid, Carolina. Universidad Nacional de Cordoba. Facultad de Medicina. Instituto de Virologia "Dr. J.M. Vanella". Laboratorio de Arbovirus; ArgentinaFil: Lanfri, Mario Alberto. Comision Nacional de Actividades Espaciales. Instituto de Altos Estudios Espaciales "Mario Gulich"; ArgentinaFil: Ludueña Almeida, Francisco. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Investigaciones Entomológicas de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas; ArgentinaFil: Scavuzzo, Carlos Marcelo. Comision Nacional de Actividades Espaciales. Instituto de Altos Estudios Espaciales "Mario Gulich"; ArgentinaFil: Introini, María Virginia. Ministerio de Salud de la Nación; ArgentinaFil: Zaidenberg, Mario. Ministerio de Salud de la Nación; ArgentinaFil: Almiron, Walter Ricardo. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Investigaciones Entomológicas de Córdoba; Argentin

Geomática aplicada a un sistema de alerta temprana

En el presente trabajo se plantea una Infraestructura Informática para dar soporte a la prevención y el control estratégico del vector del dengue en Argentina por parte del Ministerio de Salud de la Nación. La misma es parte de un complejo Sistema de Alerta Temprana (SAT) y es llevado a cabo por la Comisión Nacional de Actividades Espaciales (CONAE) bajo los estándares de la European Spatial Agency (ESA). La arquitectura, diseño, metodología y codificación pretenden ser componentes re-utilizables en cualquier infraestructura informática de soporte a SATs. En su desarrollo se utiliza Open Source Software (OSS) y Patrones de Diseño (Design Patterns) garantizando una herramienta tecnológica además de re-utilizable, flexible, mantenible y robusta. En este documento se describen los requerimientos establecidos por el Ministerio de Salud de la Nación y se plantea la arquitectura y diseño del sistema a partir de los mismos. Además, se realiza un análisis de las tecnologías OSS integradas en el desarrollo y la codificación. Finalmente se describe la funcionalidad obtenida y se muestra la infraestructura con un caso en particular.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

The effect of land use change in the abundance of malaria cases in Northern Argentina

Malaria is a parasitic disease widely distributed in tropical and subtropical areas of the world. The appearance of malaria cases is determined by multiple factors including changes in land use, and climatic and environmental variables, which are key factors contributing to the prevalence and transmission of the disease. Remote sensing allows for the integrated analysis of vector-borne diseases for the purposes of disease management and control. The aim of the present research was to determine whether there is a relationship between the emergence and abundance of malaria cases and changes in land use, and, in climatic/environmental variables provided by remote sensing in San Ramón de la Nueva Orán (northwestern Salta, Argentina). Random Effect Poisson Regression was used to analyze the relationships. The emergence of malaria cases was related to decreases in piedmont rainforest of the Yungas Ecoregion, and increases both in Maximum Normalized Difference Vegetation Index (NDVI) and in mean minimum temperature and relative humidity. These results were expected since environmental change derived from agriculture-driven deforestation together with climate change are likely factors driving transmission of this disease by affecting the biology and ecology of both vectors and malaria parasites.Fil: Cuellar, Ana Carolina. Technical University of Denmark; DinamarcaFil: Manguin, Sylvie. Université Montpellier; FranciaFil: Santana, Mirta Sara. Universidad Nacional de Tucumán; ArgentinaFil: Zaidenberg, Mario. Ministerio de Salud de la Nación. Coordinación Nacional de Control de Vectores; ArgentinaFil: Lanfri, Mario. Comisión Nacional de Actividades Espaciales. Instituto de Altos Estudios Espaciales "Mario Gulich"; ArgentinaFil: Dantur Juri, Maria Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentina67th Annual Meeting American Society of Tropical Medicine and HygieneNew OrleansEstados UnidosAmerican Society of Tropical Medicine and Hygien

MODIS environmental data to assess Chikungunya, Dengue and Zika diseases through Aedes (Stegomia) aegypti oviposition activity estimation

Aedes aegypti is the main vector for Chikungunya, Dengue, and Zika viruses in Latin America and it represents a main threat for our region. Taking into account this situation, several efforts have been done to use remote sensing to support public health decision making. Moderate resolution imaging spectroradiometer (MODIS) sensor provides moderate-resolution remote sensing products; therefore, we explore the application of MODIS products to vector-borne disease problems in Argentina. We develop temporal forecasting models of Ae. aegypti oviposition, and we include its validation and its application to the 2016 Dengue outbreak. Temporal series (10/2005 to 09/2007) from MODIS products of normalized difference vegetation index and diurnal land surface temperature were built. Two linear regression models were developed: model 1 which uses environmental variables with time lag and model 2 uses environmental variables without time lags. Model 2 was the best model (AIC = 112) with high correlation (r = 0.88, p < 0.05) between observed and predicted data. We can suggest that MODIS products could be a good tool for estimating both Ae. aegypti oviposition activity and risks for Ae. aegypti-borne diseases. That statement is also supported by model results for 2016 when a dengue outbreak that started unusually earlier this season. If such activity could be forecast by a model based on remote sensing data, then a potential outbreak could be predicted.Fil: Estallo, Elizabet Lilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Investigaciones Entomológicas de Córdoba; ArgentinaFil: Benitez, Elisabet Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Investigaciones Entomológicas de Córdoba; ArgentinaFil: Lanfri, Mario Alberto. Comision Nacional de Actividades Espaciales; ArgentinaFil: Scavuzzo, Carlos Marcelo. Comision Nacional de Actividades Espaciales; ArgentinaFil: Almiron, Walter Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Investigaciones Entomológicas de Córdoba; Argentin