Distribuição espaço-temporal e determinantes da emergência de dengue no Rio Grande do Sul – 2007 a 2023

Abstract

Neglected diseases comprise a group of diseases that still represent a persistent public health problem. Among these diseases, dengue—an arbovirus transmitted by mosquitoes of the Aedes genus—is estimated to put more than four billion people globally at risk of infection, and is considered one of the ten main threats to global public health. Since the first dengue epidemic in 1986, Brazil has been considered hyperendemic, with successive periods of epidemics generating significant social and economic impacts. In Rio Grande do Sul, the first indigenous case of the disease was recorded in 2007. Although the state was previously considered a protected area, the disease is expanding within its territory, with cases reported in 91.15% of municipalities in 2022. Therefore, the general objective of this thesis was to conduct an epidemiological analysis of data generated by routine dengue surveillance and control in Rio Grande do Sul, based on data on the distribution of the disease in the state and its determinants available in national and state information systems. Specific objectives include analyzing the temporal and geographic spread of dengue in Rio Grande do Sul from 2007 to 2023; identifying socio-environmental factors associated with dengue incidence in Rio Grande do Sul; and providing information to support more effective primary prevention strategies. To this end, a study was constructed resulting in two articles were developed using secondary epidemiological surveillance data. The first article was an ecological study of dengue cases in Rio Grande do Sul from 2007 to September 2023, aiming to assess the geographic and temporal expansion of dengue in the state during this period. For spatial description, annual maps of incidence rates by municipality were constructed; spatial autocorrelation was assessed using the Global Moran Index and Local Indicators of Spatial Association (LISA), and spatiotemporal cluster identification was performed using the discrete Poisson model and Generalized Additive Models. The analyses were performed using SatCan and R software. It was observed that during the analyzed period, Rio Grande do Sul reported 126,067 dengue cases, resulting in 142 deaths, with 80.5% of the total cases reported in the 2022-2023 biennium alone. The highest incidence and mortality rates were observed in the Northwest mesoregion, followed by the Central-Eastern mesoregion, with a sharp increase in the risk of dengue fever from 2019 onwards and a pronounced intensification from 2022 onwards – indicating an ongoing epidemic. The second article aimed to identify environmental and socioeconomic factors associated with the incidence of dengue in the state from 2013 to December 2023. To this end, the influence of the urbanization index and rural density - during the years 2010 and 2022 - and environmental quality (through the Socio-Environmental Performance Index) on the average incidence rate of dengue in the different mesoregions of the state were evaluated through geographically weighted regression (GWR) analysis using the R software. It was observed that during the analyzed period, 127,945 cases of dengue were reported in the state, with 82.74% of these reported between 2022 and 2023. The variables evaluated act heterogeneously on the expansion of the disease in the different mesoregions of the state, with emphasis on the rural density variable, which in 2022 demonstrated an expansion of influence to the Southwest mesoregion and consolidation. in the Northeast and Metropolitan mesoregions. The results observed in this thesis demonstrate the alarming epidemiological situation of dengue in Rio Grande do Sul, with expansion throughout its mesoregions and with various socio-environmental factors influencing the incidence of the disease and its spread. It is hoped, therefore, that these results can guide the adoption of effective control and prevention measures targeted at at-risk populations.