Identifying Regional Climatic and Human Influences on Dengue Fever Transmission in Puerto Rico

Abstract

Worldwide, approximately 2.5 billion people live in regions that are vulnerable to dengue fever. Dengue is primarily transmitted by Aedes aegypti mosquitoes who prefer urban habitats where they can live in close proximity to humans, their preferred source of blood meals. There is no cure for dengue fever and vaccines are still in early stages, years away from mass distribution. As a result, effective control of dengue is reliant on our ability to understand the complex relationship between humans, vectors, and the environment. The purpose of this study is to assess temporal and spatial patterns of dengue transmission in Puerto Rico, as they relate to both climatic and anthropogenic factors, using linear models and Multiple Linear Regression (MLR) analysis. Unlike previous studies, this analysis is done at an intermediate spatial scale, considering 6 regions across the island. This regional approach allows for the impact of local variations in anthropogenic and environmental factors on dengue incidence to be considered. We examined the influence of Land Use Land Cover (LULC) and environmental factors, both separately and combined, at stationary points, and over time. These analyses provide insight into the role of both anthropogenic and environmental variables as they relate to dengue incidence. The linear models between individual environmental factors and incidence showed the strongest correlations between the Central region and temperature. The MLR models showed higher incidence levels in the West region of the island and complex relationships between incidence and variables related to open space, such as shrub and herbaceous cover. The MLR model with the highest R2 value was the best fit change analysis model using both LULC and environmental factors. This best fit model (adjusted R2 = 0.343) included: average annual maximum temperature, average annual minimum temperature, crop cover, pasture, and herbaceous cover.