The expansion of the yellow fever mosquito (Aedes aegypti) and evidence of its establishment in the Las Vegas metropolitan area, Nevada, United States of America.

Aedes aegypti (L.) is the primary vector of several arboviruses, including chikungunya, dengue, Zika, and yellow fever viruses. While models have predicted a low likelihood for establishment of Ae. aegypti in the arid climate of the Las Vegas Metropolitan (Statistical) Area, United States, surveillance indicates it is established. Since its initial detection in 2017, its distribution has spread over the Las Vegas metro area, which has low precipitation and hot summers. We mapped the spread of Ae. aegypti over 5 yr using adult catches. A total of 407 census tracts in metro Las Vegas were surveyed at least once for a total of 8,895 trap nights. In 2017, 5 of 117 (4%) surveyed census tracts were positive. By 2023, the number of positive census tracts increased to 147 of 276 (53%). Our study highlights the need for effective vector control measures and public health strategies to mitigate the growing risk of vector-borne diseases in Las Vegas and other urban areas experiencing similar introductions of Ae. aegypti.