Understanding environmental and climatic influences on regional differences and spatio-temporalscale issues of dengue fever transmission in Puerto Rico

Abstract:

Each year, there are an estimated 50-100 million cases of dengue fever worldwide, roughly 30 times the

number of cases as 50 years ago, with some estimates even higher. Puerto Rico (PR) has experienced

epidemic dengue activity since 1963, and the disease is currently endemic. Since 1990 there have been 4

large epidemics, the most recent in 2010 where there were nearly 27,000 cases reported, amounting to

almost 1% of the island’s total population. Because no vaccine is currently available, effective control

is dependent on our ability to understand the complex relationship between environmental factors,

mosquito vector ecology, and disease epidemiology. Dengue virus is transmitted primarily by Aedes

aegypti mosquitoes, as humans are the preferred host for Ae. aegypti.

The purpose of our analysis is to assess temporal and spatial patterns of dengue transmission in PR and

relate this to both climatic and anthropogenic factors. Unlike past studies, which have used San Juan to

represent the island as a whole, our research will investigate regional dynamics in dengue transmission, as

preliminary results have shown significant differences in population density, disease incidence, and

environmental and climatic variables. Data from the Passive Dengue Surveillance System of CDC,

meteorological observations from NCDC, and remote sensing data from USGS and NASA will be used

together to identify relationships between climate, urbanization, and dengue incidence for PR at various

spatial and temporal scales. Preliminary climatic factors considered include precipitation, temperature,

humidity, and soil moisture. Finally, we will assess measures of urbanization such as land cover, land use,

population density, and infrastructure that can make regional differences in dengue incidence each year.

Results from this study could help create early warning systems for dengue surveillance in Puerto Rico,

and develop techniques that can be applied to other areas of the world.