St. Louis Encephalitis

Abstract

St. Louis encephalitis virus (SLEV) was isolated for the first time during a human encephalitis outbreak in St. Louis, Missouri (USA) in 1933 (Lumsden 1958). The viral isolation was carried out from a brain sample of a death patient (Webster & Fite 1933, Muckenfuss et al. 1934). The outbreak took place during an exceptionally hot and dry summer. More than 1000 cases were reported most of them localized near open storm drains, rain drainage and sewage channels, which worked as Culex mosquitoes breading sites (Reisen 2003). Further ecological studies carried out during a SLEV human encephalitis outbreak in Yakima Valley (Washington, USA) (1941-1942) incriminated peridomestics birds species as hosts and Culex mosquitoes as vectors (Hammon et al. 1941, 1942b). Understanding the ecological and epidemiological behavior of SLEV and the development of new diagnostic techniques allowed a global vision regarding the public health importance of SLEV in the USA.