Epidemiology of Dengue: A Spatial, Temporal, and Social Analysis of Cases in the Northern Region of Brazil

Abstract

This study carried out a comprehensive epidemiological analysis of confirmed dengue cases in the Northern Region of Brazil, covering the decade between 2015 and 2025. Using secondary data obtained from the Notifiable Diseases Information System (SINAN/DATASUS), the investigation was structured along spatial, temporal, and sociodemographic dimensions to understand the factors modulating the dynamics of viral transmission in the Amazonian territory. Over the evaluated period, the region demonstrated a significant epidemiological burden, characterized by marked heterogeneity among the Federative Units. The state of Pará stood alone as the main absolute epicenter of notifications, recording over 90,000 cases, followed in magnitude by Tocantins and Acre. The temporal analysis revealed that the distribution of infections was fluctuating and asynchronous, alternating between periods of stability and severe epidemic outbreaks, with emphasis on the peaks observed in 2022 in Rondônia and Tocantins, and the recent and significant fourfold increase in records documented in Pará and Amapá in 2024. From a spatial perspective, it was identified that municipal dispersion tended to be centralized in state capitals and large integrated urban centers (such as Manaus and Macapá), coexisting with the prominence of economic and logistical hubs in the interior, such as Parauapebas in Pará and the atypical case of Cruzeiro do Sul, which numerically surpassed the Acrean capital due to its integration into the connectivity network of the BR-364 highway. The discussion of these findings indicated that interannual fluctuations are strongly influenced by global climate anomalies, such as the El Niño-Southern Oscillation (ENSO), whose phases modulate local rainfall patterns, altering the availability of breeding sites and the vector's replication speed. Furthermore, the leadership of Pará and Tocantins was associated with the presence of large research and health centers, such as the Evandro Chagas Institute and university hospital complexes, which increase surveillance sensitivity and minimize chronic underreporting. In the sociodemographic scope, a unanimous and systematic prevalence of the female gender was observed in all analyzed states, accumulating a regional total of 93,230 cases compared to 79,627 in the male gender. This asymmetry was justified by the eminently peridomestic and diurnal habits of Aedes aegypti, increasing the exposure of individuals associated with the management of the residential space. Biological studies in the literature corroborated that the blood meal on humans acts as reproductive fuel for the vector, maximizing its fecundity. Additionally, the age and educational profile revealed a priority affliction of individuals of economically active age, with a peak in the 20-to-39-year age group (66,857 cases), and with an educational level corresponding to completed high school, reflecting the impact of urban mobility on the probability of infection. In contrast, the age extremes presented the lowest frequencies, suggesting protection through cumulative immunity in the elderly and through maternal antibodies in infants. It is concluded that coping with dengue in the Legal Amazon requires recognition of its demographic and ecological particularities, demanding targeted interventions that mitigate the social determinants of health and strengthen local active surveillance networks.