Aedes aegypti abundance in urban neighborhoods of Maricopa County, Arizona, is linked to increasing socioeconomic status and tree cover

Abstract

Background Understanding coupled human-environment factors which promote Aedes aegypti abundance is critical to preventing the spread of Zika, chikungunya, yellow fever and dengue viruses. High temperatures and aridity theoretically make arid lands inhospitable for Ae. aegypti mosquitoes, yet their populations are well established in many desert cities. Methods We investigated associations between socioeconomic and built environment factors and Ae. aegypti abundance in Maricopa County, Arizona, home to Phoenix metropolitan area. Maricopa County Environmental Services conducts weekly mosquito surveillance with CO2-baited Encephalitis Vector Survey or BG-Sentinel traps at > 850 locations throughout the county. Counts of adult female Ae. aegypti from 2014 to 2017 were joined with US Census data, precipitation and temperature data, and 2015 land cover from high-resolution (1 m) aerial images from the National Agricultural Imagery Program. Results From 139,729 trap-nights, 107,116 Ae. aegypti females were captured. Counts were significantly positively associated with higher socioeconomic status. This association was partially explained by higher densities of non-native landscaping in wealthier neighborhoods; a 1% increase in the density of tree cover around the trap was associated with a ~ 7% higher count of Ae. aegypti (95% CI: 6–9%). Conclusions Many models predict that climate change will drive aridification in some heavily populated regions, including those where Ae. aegypti are widespread. City climate change adaptation plans often include green spaces and vegetation cover to increase resilience to extreme heat, but these may unintentionally create hospitable microclimates for Ae. aegypti. This possible outcome should be addressed to reduce the potential for outbreaks of Aedes-borne diseases in desert cities. Graphical Abstract

The Mosquito Fauna of Arizona: Species Composition and Public Health Implications

“…Maricopa County, the largest county in Arizona that includes the city of Phoenix, uses EVS (Encephalitis-Virus-Surveillance) traps more than other traps [ 154 ]. Although these traps collect Aedes aegypti [ 155 , 156 , 157 ], there are other trap types that may be more efficient in trapping Aedes species, such as the BG-Sentinel trap [ 157 ]. The same applies to anopheline species, where, e.g., CDC light traps [ 158 ] and Mosquito Magnet Patriot Mosquito traps [ 159 ] may be more effective in capturing this genus.…”

“…Social scientists can play an important role in MBD prevention efforts by providing insights into the link between MBDs and socioeconomic status in order to identify locations or specific populations that are more at risk for MBDs. For example, studies have shown that lower socio-economic status is linked with higher disease incidence [ 169 , 170 ], although the opposite is observed as well [ 155 ]. The agricultural sector should also be involved if they use (or have used) insecticidal classes that are also used in public health [ 171 , 172 ].…”