Species Distribution Modelling of Aedes aegypti and Aedes albopictus in the United States with an Emphasis on Current and Predicted Distribution in Texas

Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus mosquitoes vector several pathogens of human health importance, namely chikungunya, dengue, yellow fever, and Zika virus. Though both mosquito species originally had tropical and subtropical ranges, they have been progressively reported from further poleward locations. Their augmented range increases the number of people at risk of being infected through these mosquito vectors. Local mosquito-borne transmission of Zika virus was first reported from Texas during November 2016, and is believed to be vectored only by Stegomyia spp. This study focused on two objectives, conducting surveillance for these mosquitoes throughout Texas, and to create and evaluate geospatial predictive models utilizing this data. Surveillance for gravid females of both species was conducted using ovitraps from August – November 2016 in 28 counties of the Texas Panhandle Region, and from June – October 2017 in 33 counties throughout Texas. Surveillance findings resulted in Ae. aegypti being newly identified in nine counties, while Ae. albopictus was newly identified in nine counties, and the occurrence of both species was newly identified in six counties. Maximum entropy modeling (MaxEnt) was used in R Statistical Software to estimate distributions for both species in the United States, and compared with the currently known ranges of these species in Texas specifically. Determining Ae. aegypti and Ae. albopictus species distributions in Texas and predicting their future species distributions in the United States using MaxEnt modeling could influence public health decision-making with the models used as tools to guide future practices.