8 patients, aged from 61 to 70 years, died from serous meningoencephalitis during the outburst of the West Nile fever in Volgograd in 1999-2001, were studied morphologically. Serous meningoencephalitis with necrotic vasculitis is a characteristic feature of this fever with degenerative changes and destructive foci in the brain. Proteinic and fatty inflammatory and lymphomacrophageal reactions were observed in the liver, serous productive myocarditis and cardiomyocytic necrosis dystrophy. Desquamative pneumonia, intracapillary nephritis were also seen. Immunohistochemical reaction against virus of this fever was positive in the vascular endothelium of parenchymal organs, hepatocytes, neurons of the brain.