Review on Infections of the Central Nervous System by St. Louis Encephalitis, Rocio and West Nile Flaviviruses in Brazil, 2004-2014

摘要

Rocio (ROCV), Saint Louis encephalitis (SLEV) and West Nile (WNV) are Flavivirus (Flaviviridae) probably carried by birds and transmitted by Culex mosquitoes. We show here a review on infections of the central nervous system by St. Louis Encephalitis, Rocio and West Nile Flaviviruses in Brazil, 2004-2014. In the last 10 years, serologic surveys in horses showed high proportions of seropositive animals which point out that SLEV and ROCV have circulated infecting horses in west-central, southeast and other regions of Brazil and that WNV has been introduced into Brazil and circulates mostly in Pantanal region. However humans infected by WNV have not been reported. In the State of Sao Paulo: SLEV was isolated from a case clinically diagnosed as dengue in 2004;in 2006, 6 SLEV patients including 3 cases of menigoencephalitis were reported in the middle of a large epidemic of dengue type 3;and in 2008, 1 patient with acute febrile illness that was IgM-positive for dengue was found infected by SLEV by detection of the virus genome. In 2010, ROCV genome was detected in the cerebrospinal fluids of 2 patients from the northern region with meningoenchephalitis and also AIDS. This was the first report of infections by ROCV in the last 34 years and curiously, it occured more than 2000 km from where the virus was firstly found. It is necessary to improve the surveillance of SLEV, ROCV and WNV in Brazil.