Dataset describing the selection and results of mosquitoes collected across South Africa (2011-2018) screened for flaviviruses. Dataset containing information and the West Nile West virus screening rsuts on the set of animals experiencing clinical disease in South Africa (2017-2020) used in the study. Also, the information and West Nile virus screening results of the 2017 NHLS CSF collection. South African patients screened for Wst Nile virus, South Africa, 2019-2020.