Dengue and Land Cover Heterogeneity in Rio De Janeiro

Abstract

Dengue epidemics in Brazil have become more frequent and more severe and involving larger populations in the last years. In Brazil Aedes aegypti is the only known vector. During the 2007-2008 period, Rio de Janeiro state experienced the most severe dengue epidemics ever reported in terms of morbidity and mortality. During this period, 322,371 cases and 240 deaths were registered, with 100 deaths due to dengue haemorragic fever/ dengue shock syndrome and 140 due to other dengue-related complications. Dengue transmission is influenced by closely related factors, many of which directly associated to the environment. Every city has its own specificities that are mainly given by its landscape and human populations. Rio de Janeiro is a city of 6 million individuals who share a heterogeneous space of ~1,200km 2 . Human population density ranges from 5,000 inhabitants/km 2 average mainly in the lowlands, with slums (or favelas) mainly in the slopes, where densities reach ~40,000 inhabitants/km 2 . These 6 million individuals live in highly urbanized, medium-urbanized and peri-urban transition zones with pockets of rural and semi-rural areas surrounded by the expanding city, mostly in the lowlands interspersed by three mountain complexes. To analyze the heterogeneous space of the city of Rio de Janeiro in relation to dengue, neighborhoods land cover maps where juxtaposed to dengue georeferenced cases, during the epidemic period 2007-2008. This analysis resulted in the observation of spatial clusters of high incidence dengue cases (hotspots) in 7 areas, namely, Jacarepaguá, Downtown, Island, Guaratiba, Northern, Western and Pedra. The most important cluster was constituted by the Jacarepaguá lowland urban ecosystem. Do the different urban ecosystems differ epidemiologically in terms of when and how dengue is transmitted? In Rio de Janeiro, is there a dengue of highly urbanized areas, a dengue of medium urbanized areas and a dengue of medium-high vegetated areas? Or in all those different urban ecosystems there is a shared characteristic that favor dengue transmission? Even though further studies should be conducted taking other aspects into account, the present study indicates that the different urban ecosystems observed might influence dengue transmission in Rio de Janeiro. Keywords: Dengue; Rio de Janeiro; urban ecosystem. RESUMODENGUE E A HETEROGENEIDADE DA COBERTURA DA TERRA NO RIO DE JANEIRO. As epidemias de dengue no Brasil têm sido cada vez mais frequentes, de maior incidência e gravidade. No

Definition of persistent areas with increased dengue risk by detecting clusters in populations with differing mobility and immunity in Rio de Janeiro, Brazil

“…The city of Rio de Janeiro is characterized by great spatial heterogeneity and complexity. The city has a high population density, disorderly urban growth, lack of infrastructure, environmental degradation, and major socio-spatial inequality 18,19 . These territorial characteristics together with the local climate conditions contribute to establishing and maintaining the epidemics, hindering dengue control and prevention measures 20,21,22 .…”

Zika: A scourge in urban slums

“…In a study of successive dengue epidemics in Rio de Janeiro that occurred in 2007 and 2008, Rosa-Freitas et. al demonstrated that dengue incidence positively correlated with neighborhoods ( bairros ) with a larger proportion of their land area composed of urban slums [5]. In Singapore in the late 1960s, the fraction of houses that tested positive for Aedes mosquito breeding was highest in the city's slums and in those with greatest population density.…”

A Perspective on Inhabited Urban Space: Land Use and Occupation, Heat Islands, and Precarious Urbanization as Determinants of Territorial Receptivity to Dengue in the City of Rio De Janeiro

“…Located in the southeastern region of the country, it has an area of approximately 1197 km 2 and a population of 6,320,446 inhabitants in 2010 [24]. It has significant spatial heterogeneity generated by the process of urban land use and occupation, and its peculiar physiographic characteristics, making this city a mosaic of contrasting urban and environmental landscapes [25,26]. It is politically divided into 160 neighborhoods and 33 administrative regions (Figure 1).…”