Assessing the Spatial Influence of Deforestation on Malaria Incidence in Pará State, Amazon Region, Brazil, 2008–2019

Abstract

Background: Malaria transmission is common in tropical regions and is heavily influenced by environmental factors such as deforestation, which is especially significant in the Brazilian Amazon, particularly in Pará state. Objectives: This study aimed to assess the relationship between deforestation indicators and malaria incidence across all 144 municipalities in Pará. Methods: Using municipal-level data from 2008 to 2019, the study applied Geographically Weighted Regression (GWR) to analyze spatial relationships between malaria incidence and deforestation metrics. These metrics included loss of forest cover from the previous year, pastureland, forest cover, fragmentation, urbanization, and water levels, analyzed over three distinct 4-year periods. The study also incorporated poverty levels to examine their influence on municipalities with high malaria risk. Findings: Over the study period, the total deforested area in Pará was 30,000 km², with 679,846 malaria cases reported. Malaria incidence rates varied across municipalities, with stable rates in high-risk areas, and were linked to pastureland, forest loss, fragmentation, and forest cover. The GWR models effectively captured spatial heterogeneity in these interactions. Main Conclusions: Malaria incidence was associated with areas of the Pará state experiencing significant forest loss and fragmentation, indicating that changes in forest composition and configuration influence malaria risk.