A young man is experiencing fever and severe headaches, and is having difficulty staying awake. He reports having spent time in Africa on a missionary trip several months ago. Recently he spent time in a park where he went swimming in the lake and was bitten by a bat he attempted to catch. His cerebrospinal fluid is nearly clear, and contains long, slender, mobile cells. This description indicates infection with A) Neisseria meningitidisB) Trypanosoma bruceiC) AcanthamoebaD) rabies virusE) an enterovirus