Correlating Remote Sensing Data with the Abundance of Pupae of the Dengue Virus Mosquito Vector, Aedes aegypti, in Central Mexico

Using a geographic transect in Central Mexico, with an elevation/climate gradient, but uniformity in socio-economic conditions among study sites, this study evaluates the applicability of three widely-used remote sensing (RS) products to link weather conditions with the local abundance of the dengue virus mosquito vector, Aedes aegypti (Ae. aegypti). Field-derived entomological measures included estimates for the percentage of premises with the presence of Ae. aegypti pupae and the abundance of Ae. aegypti pupae per premises. Data on mosquito abundance from field surveys were matched with RS data and analyzed for correlation. Daily daytime and nighttime land surface temperature (LST) values were obtained from Moderate Resolution Imaging Spectroradiometer (MODIS)/Aqua cloud-free images within the four weeks preceding the field survey. Tropical Rainfall Measuring Mission (TRMM)-estimated rainfall accumulation was calculated for the four weeks preceding the field survey. Elevation was estimated through a digital elevation model (DEM). Strong correlations were found between mosquito abundance and RS-derived night LST, elevation and rainfall along the elevation/climate gradient. These findings show that RS data can be used to predict Ae. aegypti abundance, but further studies are needed to define the climatic and socio-economic conditions under which the correlations observed herein can be assumed to apply

Niche Modeling of Dengue Fever Using Remotely Sensed Environmental Factors and Boosted Regression Trees

Dengue fever (DF), a vector-borne flavivirus, is endemic to the tropical countries of the world with nearly 400 million people becoming infected each year and roughly one-third of the world’s population living in areas of risk. The main vector for DF is the Aedes aegypti mosquito, which is also the same vector of yellow fever, chikungunya, and Zika viruses. To gain an understanding of the spatial aspects that can affect the epidemiological processes across the disease’s geographical range, and the spatial interactions involved, we created and compared Bernoulli and Poisson family Boosted Regression Tree (BRT) models to quantify the overall annual risk of DF incidence by municipality, using the Magdalena River watershed of Colombia as a study site during the time period between 2012 and 2014. A wide range of environmental conditions make this site ideal to develop models that, with minor adjustments, could be applied in many other geographical areas. Our results show that these BRT methods can be successfully used to identify areas at risk and presents great potential for implementation in surveillance programs

The burden of dengue in children by calculating spatial temperature : A methodological approach using remote sensing techniques

Funding: This research received no external funding Data Availability Statement: The authors encourage collaboration and use of the data by other re- searchers. Data are stored on the server in Mexico, and researchers interested in using the data for scientific purposes should contact the project leader Oliver Mendoza-Cano.Peer reviewedPublisher PD

Exploratory Analysis of Dengue Fever Niche Variables within the Río Magdalena Watershed

Previous research on Dengue Fever have involved laboratory tests or study areas with less diverse temperature and elevation ranges than is found in Colombia; therefore, preliminary research was needed to identify location specific attributes of Dengue Fever transmission. Environmental variables derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Tropical Rainfall Measuring Mission (TRMM) satellites were combined with population variables to be statistically compared against reported cases of Dengue Fever in the Río Magdalena watershed, Colombia. Three-factor analysis models were investigated to analyze variable patterns, including a population, population density, and empirical Bayesian estimation model. Results identified varying levels of Dengue Fever transmission risk, and environmental characteristics which support, and advance, the research literature. Multiple temperature metrics, elevation, and vegetation composition were among the more contributory variables found to identify future potential outbreak locations

Riesgo potencial por cambio climático y vectores. Factores locales de ciudad: uso de suelo y vegetación

El cambio climático está relacionado con la presencia y abundancia de vectores, en particular con Aedes aegypti (responsable de la trasmisión de dengue, chikungunya y zika) a nivel urbano; nuestra hipótesis asocia la presencia del vector con la climatología y factores socio-ambientales tales como el uso de suelo y la vegetación en espacios urbanos, mismos que inciden en favorecer un hábitat para el vector. Estudiamos una región tropical en la parte central del golfo de México desde los 0 y hasta los 2200 m.s.n.m., ya que es un reto observar el acoplamiento entre los sistemas mencionados para estimar un posible escenario de riesgo presente y futuro ante el calentamiento del sistema climático. Se usan datos de la investigación de 2011 a 2014, donde se ha estudiado la presencia de Aedes aegypti en un transecto altitudinal, con datos de factores urbanos para observar el acoplamiento entre dichas variables por medios estadísticos.The climatic change is related with the vector presence and abundance, particularly with Aedes aegypti (responsible of dengue, chikungunya and zika transmission) at urban level; our hypothesis associate vector presence with socio-environmental factors and climatology, as land use and vegetation in urban areas, these provide easily a vector habitat. We studied a tropical region on the central Gulf of México from 0 to 2200 meters above sea level, due to the challenge of coupled with the factors mentioned before, in order to estimate a possible risk scenario present or future associated at global warming. We use research data from 2011 to 2014, in which we studied the presence of Aedes on altitude transect, with urban data to observe trough statistical methods variables coupling

Riesgo potencial por cambio climático y vectores. Factores locales de ciudad: uso de suelo y vegetación

Ponencia presentada en: X Congreso de la Asociación Española de Climatología celebrado en Alicante entre el 5 y el 8 de octubre de 2016.[ES]El cambio climático está relacionado con la presencia y abundancia de vectores, en particular con Aedes aegypti (responsable de la trasmisión de dengue, chikungunya y zika) a nivel urbano; nuestra hipótesis asocia la presencia del vector con la climatología y factores socio-ambientales tales como el uso de suelo y la vegetación en espacios urbanos, mismos que inciden en favorecer un hábitat para el vector. Estudiamos una región tropical en la parte central del golfo de México desde los 0 y hasta los 2200 m.s.n.m., ya que es un reto observar el acoplamiento entre los sistemas mencionados para estimar un posible escenario de riesgo presente y futuro ante el calentamiento del sistema climático. Se usan datos de la investigación de 2011 a 2014, donde se ha estudiado la presencia de Aedes aegypti en un transecto altitudinal, con datos de factores urbanos para observar el acoplamiento entre dichas variables por medios estadísticos.[EN]The climatic change is related with the vector presence and abundance, particularly with Aedes aegypti (responsible of dengue, chikungunya and zika transmission) at urban level; our hypothesis associate vector presence with socio-environmental factors and climatology, as land use and vegetation in urban areas, these provide easily a vector habitat. We studied a tropical region on the central Gulf of México from 0 to 2200 meters above sea level, due to the challenge of coupled with the factors mentioned before, in order to estimate a possible risk scenario present or future associated at global warming. We use research data from 2011 to 2014, in which we studied the presence of Aedes on altitude transect, with urban data to observe trough statistical methods variables coupling

Strategies for dengue early warning, surveillance and control

Dengue is a neglected tropical disease of global importance today. Transmitted by the mosquito vectors Aedes aegypti and Aedes albopictus, dengue afflicts both urban and rural human populations in a cycle of endemic and epidemic transmission. As the global dengue burden continues to grow, there is an urgent need for timely and effective vector control, the only means to prevent transmission of dengue. This thesis addressed these contemporary dengue challenges by investigating three key elements of dengue outbreak alert and response. At present, entomological surveillance protocols are used to quantify vector abundance as a measure of dengue transmission risk, and although routinely undertaken in numerous endemic areas, there has been no evidence-based consideration of their reliability or accuracy. Similarly, vector control tools and approaches are numerous and widely used, especially during outbreaks, despite insufficient evidence of effectiveness and impact on dengue transmission. Finally, effective early warning systems could provide sufficient time to mobilise resources for a timely response to possibly mitigate the impact of dengue outbreaks. A systematic review of the literature explored the evidence for the value of entomological indices and dengue transmission. Of 13 studies investigating associations between vector indices (mainly the Stegomyia indices) and dengue cases, 4 reported positive correlations, 4 found no correlation and 5 reported ambiguous or inconclusive associations. Single values of the Breteau Index (BI), widely used as dengue transmission thresholds, were shown to be unreliable. Hence, there is little evidence that vector indices correlate with dengue transmission, although some methods, such as adult mosquito indices, merit further research. The effectiveness of vector control tools was examined in a systematic review and meta-analysis. Of 41 studies eligible for inclusion, 19 provided sufficient data for meta-analyses. Though evidence was weak, reduced odds of dengue incidence were observed for house screening from 3 trials (Pooled OR: 0.22 (95% CI 0.05, 0.93)). 3 community-based combination interventions significantly impacted mosquito indices: BI Rate Ratio (RR) 0.48 (95% CI 0.26, 0.89); BI RR0.65 (95% CI 0.52, 0.81); BI Mean difference (MD) -4.66 (-5.89, -3.43). Remarkably, impact on dengue cases by fogging, a method widely used during outbreaks, had never been evaluated in randomised trials; only one study demonstrated effectiveness against the vector. Effectiveness of vector control methods were also analysed in a 1-year randomised controlled trial, in particular, indoor/outdoor fogging, indoor residual spraying and handheld spray-cans. Finally, a retrospective study of data from 5 countries in Asia and Latin America was conducted to prospect for alarm signals that potentially could warn of impending dengue outbreaks. The Shewhart method and Endemic Channel identified probable dengue cases and mean temperature as predictors of outbreaks, with sensitivities and positive predictive values of 95% and 48% in Dominican Republic, 86% and 44% in Mexico, indicating that these predictors could be beneficial if utilised in early warning systems. This thesis has highlighted fundamental knowledge gaps in dengue transmission dynamics and vector control that are crucial for effective outbreak warning and response systems. These must be addressed before existing or novel vector control tools can be optimised, with or without an efficacious vaccine, to reduce endemic and epidemic dengue

Exploring for Municipality-Level Socioeconomic Variables Related to Zika Virus Incidence in Colombia

Colombia experienced an outbreak of Zika virus infection during September 2015 until July 2016. This study aimed to identify the socioeconomic factors that at the municipality level correlate with this outbreak and therefore could have influenced its incidence. An analysis of publicly available, municipality-aggregated data related to eight potential explanatory socioeconomic variables was conducted. These variables are school dropout, low energy strata, social security system, savings capacity, tax, resources, investment, and debt. The response variable of interest in this study is the number of reported cases of Zika virus infection per people (projected) per square kilometer. Binomial regression models were performed. Results show that the best predictor variables of Zika virus occurrence, assuming an expected inverse relationship with socioeconomic status, are “school”, “energy”, and “savings”. Contrary to expectations, proxies of socioeconomic status such as “investment”, “tax”, and “resources” were associated with an increase in the occurrence of Zika virus infection, while no association was detected for “social security” and “debt”. Energy stratification, school dropout rate, and the percentage of the municipality’s income that is saved conformed to the hypothesized inverse relationship between socioeconomic standing and Zika occurrence. As such, this study suggests these factors should be considered in Zika risk modeling

Life Cycle and Development of Diptera

Diptera, or true flies, are of considerable economic importance, as these flies have a valuable role as scavengers, parasitoids and predators of other insects, pollinators, food for predators, bio-indicators of water quality, and tools for scientific research. In nine chapters, this book examines various aspects of flies of the order Diptera as well as some types of mosquitos and midges. Topics covered include taxonomy, phylogeny, life cycle, feeding habits, population control strategies, and more. A unique chapter on forensic entomology is particularly interesting. Beautifully illustrated and expertly researched, this volume will appeal to entomologists, biologists, and naturalists