Browsing by Author "Rocha, Nildimar Honorio"

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    Multiscale analysis and modelling of Aedes aegypti population spatial dynamics.
    (2011) Lana, Raquel Martins; Carneiro, Tiago Garcia de Senna; Rocha, Nildimar Honorio; Codeço, Cláudia Torres
    Population dynamic models requires the evaluation of the best scale of analysis. This work analyses three spatial scales in the context of the mosquito Aedes aegypti, main vector of dengue fever. One scale is the neighborhood, the others scales are the census tract and the lot. A geographical database was developed including point maps with trap locations, number of eggs collected per trap per week, polygons of census tracts, census data, among others. For simulation purposes, a layer of regular cells (10 x 10 meters) was created to store the model’s inputs and outputs. A population dynamic model with temperature as input variable was parameterized and fitted to the neighborhood and census tract data. For the lot level, an allocation procedure was developed as the spatial resolution was higher than the data resolution. This procedure couples the population dynamic model with a kernel density map. Results indicate that at the neighborhood level, the population model captured well the overall pattern with lower mosquito density during the cold season and larger during the warm season. However, in the first warm season, two peaks did not fit well, suggesting the importance of investigating the role of other variables in the dynamics of Aedes aegypti. At the census tract level, we found no evidence of spatial clustering. At the lot level, the allocation model represented well the overall summer to winter variation in hotspot intensity. The cost of vector surveillance is high and the procedures proposed here can be used to design optimized control strategies and activities.
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    Seasonal and nonseasonal dynamics of Aedes aegypti in Rio de Janeiro, Brazil : fitting mathematical models to trap data.
    (2014) Lana, Raquel Martins; Carneiro, Tiago Garcia de Senna; Rocha, Nildimar Honorio; Codeço, Cláudia Torres
    Mathematical models suggest that seasonal transmission and temporary cross-immunity betweenserotypes can determine the characteristic multi-year dynamics of dengue fever. Seasonal transmis-sion is attributed to the effect of climate on mosquito abundance and within host virus dynamics. In thisstudy, we validate a set of temperature and density dependent entomological models that are built-incomponents of most dengue models by fitting them to time series of ovitrap data from three distinctneighborhoods in Rio de Janeiro, Brazil. The results indicate that neighborhoods differ in the strength ofthe seasonal component and that commonly used models tend to assume more seasonal structure thanfound in data. Future dengue models should investigate the impact of heterogeneous levels of seasonalityon dengue dynamics as it may affect virus maintenance from year to year, as well as the risk of diseaseoutbreaks.
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    Socioeconomic and demographic characterization of an endemic malaria region in Brazil by multiple correspondence analysis.
    (2017) Lana, Raquel Martins; Riback, Thais Irene Souza; Lima, Tiago França Melo de; Nunes, Mônica da Silva; Cruz, Oswaldo Gonçalves; Oliveira, Francisco G. S.; Moresco, Gilberto Gilmar; Rocha, Nildimar Honorio; Codeço, Cláudia Torres
    Background : In the process of geographical retraction of malaria, some important endemicity pockets remain. Here, we report results from a study developed to obtain detailed community data from an important malaria hotspot in Latin America (Alto Juruá, Acre, Brazil), to investigate the association of malaria with socioeconomic, demographic and living conditions. Methods : A household survey was conducted in 40 localities (n = 520) of Mâncio Lima and Rodrigues Alves municipalities, Acre state. Information on previous malaria, schooling, age, gender, income, occupation, household structure, habits and behaviors related to malaria exposure was collected. Multiple correspondence analysis (MCA) was applied to characterize similarities between households and identify gradients. The association of these gradients with malaria was assessed using regression. Results : The first three dimensions of MCA accounted for almost 50% of the variability between households. The first dimension defined an urban/rurality gradient, where urbanization was associated with the presence of roads, basic services as garbage collection, water treatment, power grid energy, and less contact with the forest. There is a significant association between this axis and the probability of malaria at the household level, OR = 1.92 (1.23–3.02). The second dimension described a gradient from rural settlements in agricultural areas to those in forested areas. Access via dirt road or river, access to electricity power-grid services and aquaculture were important variables. Malaria was at lower risk at the forested area, OR = 0.55 (1.23–1.12). The third axis detected intraurban differences and did not correlate with malaria. Conclusions : Living conditions in the study area are strongly geographically structured. Although malaria is found throughout all the landscapes, household traits can explain part of the variation found in the odds of having malaria. It is expected these results stimulate further discussions on modelling approaches targeting a more systemic and multi-level view of malaria dynamics.
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    The introduction of dengue follows transportation infrastructure changes in the state of Acre, Brazil : a network-based analysis.
    (2017) Lana, Raquel Martins; Gomes, Marcelo Ferreira da Costa; Lima, Tiago França Melo de; Rocha, Nildimar Honorio; Codeço, Cláudia Torres
    Human mobility, presence and passive transportation of Aedes aegypti mosquito, and environmental characteristics are a group of factors which contribute to the success of dengue spread and establishment. To understand this process, we assess data from dengue national and municipal basins regarding population and demographics, transportation network, human mobility, and Ae. aegypti monitoring for the Brazilian state of Acre since the first recorded dengue case in the year 2000 to the year 2015. During this period, several changes in Acre’s transport infrastructure and urbanization have been started. To reconstruct the process of dengue introduction in Acre, we propose an analytic framework based on concepts used in malaria literature, namely vulnerability and receptivity, to inform risk assessments in dengue-free regions as well as network theory concepts for disease invasion and propagation. We calculate the probability of dengue importation to Acre from other Brazilian states, the evolution of dengue spread between Acrean municipalities and dengue establishment in the state. Our findings suggest that the landscape changes associated with human mobility have created favorable conditions for the establishment of dengue virus transmission in Acre. The revitalization of its major roads, as well as the increased accessibility by air to and within the state, have increased dengue vulnerability. Unplanned urbanization and population growth, as observed in Acre during the period of study, contribute to ideal conditions for Ae. aegypti mosquito establishment, increase the difficulty in mosquito control and consequently its local receptivity.