Influence of Climatic Conditions on Arboviral Outbreaks in Brazil: An Ecological Approach

Climate change has been associated with the intensification of outbreaks of vector-borne diseases such as dengue, Zika, and chikungunya. In Brazil, these arboviruses are sensitive to climatic variables, including temperature and precipitation, which directly affect the proliferation of Aedes aegypti. This study analyzed the correlation between these climatic factors and the incidence of these diseases between 2020 and 2024. An ecological study was conducted using monthly data on average temperature and precipitation from different Brazilian regions between 2020 and 2024, obtained from the Instituto Nacional de Meteorologia (INMET). Data on dengue, Zika, and chikungunya cases were extracted from the Sistema de Informação de Agravos de Notificação (SINAN). Statistical analysis included Pearson correlation between climatic variables and disease cases. Multiple linear regression was performed to estimate the impact of climatic variables on arbovirus incidence, controlling for seasonal variables. A significance level of 5% was adopted (p<0.05). The average temperature in Brazil was 24.92°C in 2020, 24.23°C in 2021, 24.07°C in 2022, 25.02°C in 2023, and 25.02°C in 2024. In 2022, 1,337,413 probable dengue cases, 162,407 probable chikungunya cases, and 9,916 probable Zika cases were recorded. In 2024, Brazil reported 3,062,181 probable dengue cases, 628,081 cases of dengue, chikungunya, and Zika in the state of Minas Gerais, and 534 cases of dengue, chikungunya, and Zika in the state of Mato Grosso. The analysis revealed that an increase in average temperature was significantly associated with an increase in dengue cases, with a correlation of r = 0.92 (p<0.01). Precipitation also influenced dengue incidence, with a correlation of r = 0.65 (p<0.05). In the linear regression model, temperature had the greatest impact, with a coefficient of 14.2, indicating that a 1°C increase in temperature may result in 14.2 additional dengue cases per 100,000 inhabitants. Average temperature showed a significant association with the increase in dengue, Zika, and chikungunya cases, while precipitation had a moderate effect. These findings reinforce the importance of climate surveillance and vector control to address arboviral diseases in Brazil.