Determinants of West Nile virus transmission in Miami-Dade County, Florida.

West Nile is a mosquito-borne disease transmitted by Culex spp. mosquitoes and is widely distributed throughout the Continental United States. The causative agent is the West Nile virus (WNV); Family Flaviviridae Genus Orthoflavivirus. However, Miami-Dade County, a subtropical region with abundant populations of Cx. quinquefasciatus and Cx. nigripalpus, has not experienced sustained WNV transmission. This integrative review examines ecological, climatic, and surveillance determinants of WNV transmission in Miami-Dade County to understand why WNV cases remain low despite abundant vector populations. A theme-based PubMed search used Boolean combinations of terms related to WNV, Cx. quinquefasciatus, Cx. nigripalpus, St. Louis encephalitis virus (SLEV), avian hosts and migration, climate, urbanization, and Florida/Miami-Dade County. Typically, reported human WNV cases in Florida are concentrated in northern and central regions, whereas Miami-Dade County experiences intermittent activity. However, limited human cases should not be interpreted as evidence that local WNV circulation is absent. Rather, available evidence of WNV activity across mosquito, avian, and human surveillance streams does exist; however, actual burden may not be fully captured. Miami-Dade County, therefore, represents an ecological setting where abundant vectors do not necessarily translate into high WNV burden. As climate change and urbanization reshape avian and vector ecology, strengthening integrated entomological, epidemiological, and avian surveillance will be essential for anticipating and mitigating future WNV risk.