Isolation of St. Louis Encephalitis Viruses from Mosquitoes in the Tampa Bay Area of Florida during the Epidemic of 1962

Summary St. Louis encephalitis virus was isolated on 23 occasions from mosquitoes collected between September 7 and October 25 at widely separated localities of the four-county Tampa Bay area during the St. Louis encephalitis epidemic of 1962. Twenty-two of these isolations were obtained from 485 pools of Culex nigripalpus; the 23rd was from 91 pools of Melanoconion, a subgenus of Culex. The mosquitoes were collected alive in battery-powered light traps and traps baited with ducklings or chicks. These isolations indicate that infected vectors were prevalent over a vast area exposing the human population to infection throughout the region.