1. Geospatial Aedes mosquito habitat mapping for arbovirus exposure reduction in Brownsville, Texas
A. Pilant1, M. Sallam3, C. Fizer2, P-Y. Whung1
1US EPA, Office of Research and Development, Research Triangle Park, NC, USA
2Student Services Contractor to EPA
3Oak Ridge Institute for Science and Education, Contact:
Executive summary and background1
Brownsville, TX one meter land cover
Brownsville, TX socioeconomic data
Vector-Borne Disease in Brownsville, Texas
In November 2016, Brownsville, Texas became the second location in the United States (US) to report locally-acquired Zika virus (ZIKV). Brownsville is a US-Mexico border city with 35% of the population below the poverty threshold, and previous dengue fever virus (DENV) outbreaks in 2005 and Aedes aegypti, the primary mosquito vector for ZIKV, DENV and chikungunya virus, is a known risk in Brownsville. Aedes aegypti is mainly a tree-hole, tall grass, tire and container species that prefers built human environment. In order to design targeted vector control programs, fine-scale spatial analyses of Aedes aegypti habitat area are needed.
Project Objectives
Portland, OR
NAIP Aerial Photo
Use EPA EnviroAtlas Meter-Scale Urban Land Cover (MULC) data, other environmental variables and socioeconomic variables to identify potential Aedes aegypti hot spots at a neighborhood scale where vector control is most effective.
Design a mosquito trap deployment scheme
Develop and provide an Aedes aegypti risk map to the City of Brownsville Department of Public Health for targeted vector control.
Brownsville, Texas median family income (left) and median age of housing structure (right) by year at the census block group level. Data were derived from the five-year American Community Survey. Lighter colors indicate potentially more vulnerable populations.
Preliminary data: Relative probability of Aedes presence by land cover class
Meter-Scale Urban Land Cover (MULC)
MULC data are used to conduct a fine-scale spatial analysis of potential Aedes aegypti habitat in Brownsville, Texas
The MULC data were developed using supervised classification of aerial imagery and LiDAR data
Study Area Selection
Brownsville, Texas meter-scale urban land cover with 50% transparency displayed over aerial imagery. The yellow box denotes the 166 km2 study area used to conduct preliminary trap site buffer analyses.
A 166 km2 study area was selected to include the most populated region of Brownsville, Texas.
Land cover composition in two Brownsville, TX neighborhoods
Project design
This figure shows the relative probability of Aedes aegypti presence by land cover class in 10 m radius buffers around each of 177 mosquito trap sites. The graph was generated by MaxEnt for environmental niche modeling. Results indicate that Aedes presence is more likely at mosquito trap sites with dominantly impervious land cover.
High socioeconomic status
Future work
Evaluate the influence of environmental and socioeconomic factors on Aedes mosquito abundance in the City of Brownsville, TX
Model spatial and temporal distribution of Aedes presence/absence in response to significant variables
Map habitat suitability for Aedes aegypti mosquitoes to highlight locations and human populations most at risk
Low socioeconomic status
Acknowledgements
NAIP: National Agriculture Imagery Program
LiDAR: Light Detection and Ranging
We thank the City of Brownsville Department of Public Health for consultation on mosquito habitat and behavior. We would also like to thank Laura Gomez (EPA and White House Strong Cities initiative) and Kenneth McPherson (EPA Region 6) for coordination of local experts and activities. Special thanks to Daniel Rosenbaum for geoprocessing. This research is funded by EPA’s Sustainable and Healthy Communities Research Program.
EnviroAtlas, a collaborative effort led by EPA, is a geospatial tool that fosters ecosystem services science and resource management. Link: epa.gov/enviroatlas
1. Pilant, A., McPherson, K., Rosenbaum D., Neale, A., and Whung, P-Y. (2016). Zika vector mitigation in the US- Mexico border city of Brownsville, TX- design for spatial analysis of environmental and socioeconomic determinants of Aedes mosquito habitat. Manuscript submitted for publication.
The circles in the images are 10, 20, 30 and 150 m radii around EPA trap sites. The pie charts on the right depict the land cover composition in each buffer zone.
Though this work was reviewed by EPA and approved for publication, it does not necessarily reflect official Agency Policy. Use of trade names does not imply endorsement by the authors or EPA.