Isolation of St. Louis Encephalitis Virus from Overwintering <i>Culex pipiens</i> Mosquitoes

Abstract

Two strains of St. Louis encephalitis virus were isolated from overwintering mosquitoes collected in Maryland and Pennsylvania during January and February 1977. There isolations from Culex pipiens constitute evidence that a mosquito-borne flavivirus can persist in a vector mosquito in temperate climates during the winter season.