How many locations can keep stocks of the smallpox virus ?
Other causes include infection by flaviviruses such as Japanese encephalitis virus , St. Louis encephalitis virus or West Nile virus , or by Togaviridae such as Eastern equine encephalitis virus ( EEE virus ) , Western equine encephalitis virus ( WEE virus ) or Venezuelan equine encephalitis virus ( VEE virus ) and smallpox vaccine .