Eco-health knowledge exchange for disease vector control in Maricopa County

As changes in climate and land use swell mosquito populations in the southwestern U.S., the threat of mosquito-borne illnesses grows with them. In Maricopa County, Arizona, outbreaks of mosquito-transmitted viruses such as West Nile have generated authorities' concern.

Understanding the relationship between risk and risk perception can inform authorities about the best ways to improve community engagement, a critical step for controlling mosquito populations and mitigating this risk.

During his fellowship, Andres Baeza-Castro quantified the differences in mosquito abundance across Maricopa County and evaluated the relationship between public awareness of mosquito-borne illness risk and the risk itself. He began by conducting Spatio-temporal analyses of mosquito surveillance data from the Maricopa County Vector Control Division. The analyses included statistical correlations between the time series of mosquito captures by epidemiological district and zip code. His team also formulated and analyzed models to understand the link between climate, land-use change, and mosquito abundance. Based on the results of the Spatio-temporal analyses, they surveyed four zip codes of Maricopa County with different combinations of mosquito population and average family income.

Baeza-Castro found a significant difference in the abundance of populations of mosquitoes between traps located in rural areas versus traps located in districts with a higher proportion of urban coverage. He found both temperature and rainfall to be important factors in the temporal dynamics of mosquito populations. Localized differences in temperature have a significant effect on the spatial distribution of risk. Traps located in areas of high heat but low vegetation tend to capture fewer mosquitoes than traps located near trees and low vegetation. Preliminary results from the survey indicated that risk awareness is higher in zones with high risk, yet other socio-economic factors could be associated with the risk itself.

In order to help community members and public health officials understand and manage mosquito-related risks, Baeza-Castro used these findings to create a decision-support tool that integrates the Vector Control mosquito surveillance system with his modeling and statistical analyses.

The risk of encountering mosquitoes is localized in urban neighborhoods, despite the socioeconomic status of its residents. Green areas and trees contribute to mosquito populations' persistence in months outside monsoon season, and, conversely, areas with few trees in industrial neighborhoods have lower mosquito populations. This study also observed that residents of high-population areas are aware of the risk posed by mosquitoes. However, even in areas without exposure to mosquitoes, communities remain aware of the risk. Campaigns to promote awareness will be most effective in areas of high exposure.