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

Abstract

Rocio (ROCV),\rSaint Louis encephalitis (SLEV) and West Nile (WNV) are Flavivirus\r(Flaviviridae) probably carried by birds and transmitted by Culex mosquitoes. We show here a review\ron infections of the central nervous system by St. Louis Encephalitis, Rocio\rand West Nile Flaviviruses in Brazil, 2004-2014. In the last 10 years,\rserologic surveys in horses showed high proportions of seropositive animals\rwhich point out that SLEV and ROCV have circulated infecting horses in west-central,\rsoutheast and other regions of Brazil and that WNV has been introduced into\rBrazil and circulates mostly in Pantanal region. However humans infected by WNV\rhave not been reported. In the State of Sao Paulo: SLEV was isolated from a\rcase clinically diagnosed as dengue in 2004; in 2006, 6 SLEV patients including\r3 cases of menigoencephalitis were reported in the middle of a large epidemic\rof dengue type 3; and in 2008, 1 patient with acute febrile illness that was\rIgM-positive for dengue was found infected by SLEV by detection of the virus\rgenome. In 2010, ROCV genome was detected in the cerebrospinal fluids of 2\rpatients from the northern region with meningoenchephalitis and also AIDS. This\rwas the first report of infections by ROCV in the last 34 years and curiously,\rit occured more than 2000 km from where the virus was firstly found. It is\rnecessary to improve the surveillance of SLEV, ROCV and WNV in Brazil.